|
D |
The ability of
a metal to be hammered, or rolled out is called its __________. |
elasticity |
ductility |
fusibility |
malleability |
|
D |
Reheating a hardened
component to a temperature lower than the hardening temperature and then
cooling it is known as __________. |
case hardening |
low temperature
hardening |
annealing |
tempering |
|
A |
When hardened
metal is heat-treated by a process known as tempering, what metallurgical
properties are achieved? |
decrease in brittleness |
increase in hardening |
increase in brittleness |
increase in corrosion
resistance |
|
A |
When metal is
tempered, it becomes __________. |
less brittle |
more brittle |
less tough |
harder |
|
D |
What is the purpose
of heat treating steel? |
Develop ductility |
Improve machining
qualities |
Relieve stresses |
All of the above. |
|
A |
Monel metal is
an alloy composed mainly of __________. |
nickel and copper |
zinc and copper |
bronze and tin |
copper and tin |
|
C |
When a metal is
undergoing heat treatment, what happens when the metal is heated above its
critical temperature? |
The metal changes
from the solid state to the molten state. |
The metal changes
from a molten state to a vapor state. |
The metal undergoes
a change in crystalline structure. |
The metal undergoes
thermal contraction. |
|
B |
When a metal is
undergoing heat treatment for the purposes of annealing, besides refining
the grain structure, what is the determining characteristic of the metal? |
Change in chemical
composition |
Softened condition |
High tensile strength |
Induction of toughness |
|
A |
When a low carbon
steel is undergoing heat treatment for the purposes of casehardening, what
is the process that distinguishes this procedure from other hardening methods? |
After the steel
is heated above its critical temperature, it is quenched in a carbon bath. |
After the steel
is heated above its critical temperature, it is quenched in cold water. |
After the steel
is heated above its critical temperature, it is allowed to cool slowly in
air. |
After the steel
is heated above its melting temperature, it is quenched in a carbon bath. |
|
A |
What effect does
preheating, concurrent heating, or post heating have on welding a joint? |
Decreasing the
temperature gradient in the weld area and relieving internal stresses. |
Increasing the
temperature gradient in the weld area and relieving internal stresses. |
Decreasing the
temperature gradient in the weld area and intensifying internal stresses. |
Increasing the
temperature gradient in the weld area and intensifying internal stresses. |
|
D |
What is meant
by the term tensile strength of a material? |
The ability to
resist shearing stresses. |
The ability to
resist bending stresses. |
The ability to
resist compression stresses. |
The ability to
resist stretching stresses. |
|
B |
What is meant
by the term toughness as it applies to a material? |
The ability to
resist penetration. |
The ability to
resist repeated application and release of force. |
The ability to
resist continuous tension. |
The ability to
resist continuous compression. |
|
D |
Which of the following
direct-reading pressure gauges is capable of measuring and displaying both
positive and negative pressures? |
Simplex gauge |
Differential pressure
gauge |
Duplex gauge |
Compound gauge |
|
C |
If a standard
bourdon tube type pressure gauge that is designed to measure and display
gauge pressure reads 43.8 psig, what would be the equivalent absolute pressure? |
29.1 psia |
43.8 psia |
58.5 psia |
61.2 psia |
|
B |
Which of the following
direct-reading pressure gauges is capable of measuring and displaying two
pressures simultaneously? |
Compound gauge |
Duplex gauge |
Differential pressure
gauge |
Simplex gauge |
|
C |
Which of the following
direct-reading pressure gauges is capable of measuring two pressures and
displaying the difference between the two? |
Simplex gauge |
Compound gauge |
Differential pressure
gauge |
Duplex gauge |
|
C |
Which of the following
direct-reading gauges would most likely be used in the application of a
pump suction pressure gauge? |
Differential pressure
gauge |
Vacuum gauge |
Compound gauge |
Standard pressure
gauge |
|
D |
Which of the following
system applications would require the use of a siphon tube (pigtail) to
prevent gauge damage? |
Hydraulic oil
pressure |
Heavy fuel oil |
Compressed air
pressure |
Steam pressure |
|
B |
When reading a
pressure that fluctuates severely on a direct reading pressure gauge, what
should be done? |
Attempt to determine
the midpoint between the maximum and minimum pressures and use this as an
estimate of the average pressure. |
The pulsation
dampening needle valve should be throttled down (without closing) until
the fluctuation ceases. |
The maximum and
minimum pressures should be noted and added together and divided by two
to obtain the average pressure. |
The pulsation
dampening needle valve should be opened wider until the fluctuation ceases. |
|
B |
What type of direct
reading thermometer works on the principle of thermal volumetric expansion
of a liquid as the temperature rises and features a linear scale? |
Thermocouple pyrometer |
Liquid-in-glass
thermometer |
Bourdon tube thermometer |
Bimetallic thermometer |
|
A |
If the mercury
has become separated in a liquid-in-glass thermometer, what can be done
to correct this situation? |
After removing
the thermometer, hold the thermometer by the upper end and try to recombine
the mercury by several full arm swings. |
Repeatedly tap
the side of the thermometer until the mercury recombines. |
After removing
the thermometer, hold the thermometer by the lower end and try to recombine
the mercury by several full arm swings. |
It is not possible
to correct this situation. |
|
A |
What type of direct
reading thermometer works on the principle of differential expansion of
dissimilar metals as the temperature rises and features a rotary dial scale? |
Bimetallic thermometer |
Liquid-in-glass
thermometer |
Bourdon tube thermometer |
Thermocouple pyrometer |
|
C |
What is the application
for a temperature measuring device known as a thermocouple pyrometer? |
Low to moderate
temperature applications such as refrigeration and air conditioning. |
Extremely low
temperature applications such as cryogenics. |
Extremely high
temperature applications such as boiler or engine exhaust temperatures. |
Moderate to high
temperature applications such as engine cooling and lubrication. |
|
D |
If a thermometer
reads 80°C, what is the equivalent temperature in °F? |
12oF |
76oF |
112oF |
176oF |
|
A |
If a thermometer
reads 850°F, what is the equivalent temperature in °C? |
454ºC |
490ºC |
1,472oC |
1,585oC |
|
B |
What statement
is true concerning the vent pipes and sounding tubes associated with a vented
tank?
|
Both the vent
pipe and the sounding tube attach to and end at an opening at the top of
the tank. |
The vent pipe
attaches to and ends at an opening at the top of the tank, and the sounding
tube passes through the tank top and extends almost to the tank bottom. |
Both the vent
pipe and the sounding tube pass through the tank top and extend almost to
the tank bottom. |
The sounding tube
attaches to and ends at an opening at the top of the tank, and the vent
pipe passes through the tank top and extends almost to the tank bottom. |
|
B |
What statement
best represents the characteristics of an innage tape and bob for the purposes
of taking a vented tank sounding? |
The bob has a
cupped end and sinks in the liquid when lowered by the tape. |
The bob has a
pointed end and sinks in the liquid when lowered by the tape. |
The bob has a
cupped end and floats on the surface of the liquid when lowered by the tape. |
The bob has a
pointed end and floats on the surface of the liquid when lowered by the
tape. |
|
C |
What statement
best represents the characteristics of an ullage tape and bob for the purposes
of taking a vented tank sounding? |
The bob has a
pointed end and sinks in the liquid when lowered by the tape. |
The bob has a
cupped end and sinks in the liquid when lowered by the tape. |
The bob has a
cupped end and floats on the surface of the liquid when lowered by the tape. |
The bob has a
pointed end and floats on the surface of the liquid when lowered by the
tape. |
|
D |
What statement
best represents the characteristics of innage and ullage tank soundings? |
Innage is the
distance between the surface of the liquid and the top of the tank, and
ullage is the distance between the surface of the liquid and the bottom
of the tank. |
Innage is the
distance between the oil/water interface and bottom of the tank, and ullage
is the distance between the oil/water interface and the top of the tank. |
Innage is the
distance between the oil/water interface and top of the tank, and ullage
is the distance between the oil/water interface and the bottom of the tank. |
Innage is the
distance between the surface of the liquid and the bottom of the tank, and
ullage is the distance between the surface of the liquid and the top of
the tank. |
|
D |
When determining
the level of a potable water hydro-pneumatic header tank fitted with a tubular
sight glass, what must be taken into consideration? |
The sight glass
must be drained, blown down, and re-filled before each reading is taken. |
The actual water
level in the hydro pneumatic header tank is somewhat higher than the level
shown in the sight glass. |
The actual water
level in the hydro pneumatic header tank is somewhat lower than the level
shown in the sight glass. |
The actual water
level in the hydro pneumatic header tank is identical to the level shown
in the sight glass. |
|
D |
When determining
the level of a potable water hydro-pneumatic header tank fitted with a tubular
sight glass, what must be taken into consideration? |
The sight glass
must be drained, blown down, and re-filled before each reading is taken. |
The actual water
level in the hydro-pneumatic header tank is somewhat higher than the level
shown in the sight glass |
The actual water
level in the hydro-pneumatic header tank is somewhat lower than the level
shown in the sight glass. |
The actual water
level in the hydro-pneumatic header tank is identical to the level shown
in the
sight glass. |
|
A |
In what application
would a reflex type flat gauge glass be used? |
Indicating a fresh
water level, where the water is clear. |
Indicating a lubricating oil
level, where the oil is honey colored. |
Indicating a heavy fuel oil
level, where the fuel is dark. |
ndicating a chemically
treated water level, where the water is brightly colored. |
|
C |
What is the operating
principle upon which a bubble tube system operates in indicating liquid
tank level? |
The air pressure
required to force air bubbles into the liquid near the top of the tank is
proportional to the liquid level in the tank. |
The air pressure
required to force air bubbles into the liquid near the bottom of the tank
is inversely related to the liquid level in the tank. |
The air pressure
required to force air bubbles into the liquid near the bottom of the tank
is proportional to the liquid level in the tank. |
The air pressure
required to force air bubbles into the liquid near the top of the tank is
inversely related to the liquid level in the tank. |
|
A |
Which of the following
measurements would be an example of total flow? |
cubic meters |
cubic meters per
hour |
pounds per hour |
gallons per minute |
|
C |
Which of the following
measurements would be an example of flow rate? |
barrels |
meters per second |
cubic meters per
hour |
gallons |
|
C |
Which of the following
is an example of a flow meter which has associated with it a float for flow
indication purposes? |
A turbine type
flow meter |
A differential
pressure flow meter |
A variable volume
flow meter (rotameter) |
A nutating disc
flow meter |
|
B |
What is the operating
principle of a variable area flow meter, such as a rotameter? |
The float or rotor
is less dense than the fluid being measured and is positioned so that the
gravitational force up is balanced by the downward motion of the fluid flow. |
The float or rotor
is more dense than the fluid being measured and is positioned so that the
gravitational force down is balanced by the upward motion of the fluid flow. |
The float or rotor
is less dense than the fluid being measured and is positioned so that the
gravitational force down is balanced by the upward motion of the fluid flow. |
The float or rotor
is more dense than the fluid being measured and is positioned so that the
gravitational force up is balanced by the downward motion of the fluid flow. |
|
C |
The device shown
in the illustration is commonly used to __________. Illustration GS-0120 |
pump refrigerant |
generate electricity |
compress air |
pump heavy liquids |
|
B |
The line labeled "E",
as shown in the illustration, would be identified as the __________. Illustration
GS-0175 |
oily bilge water
outlet |
oily bilge water
inlet |
processed oil
outlet |
clean water flushing
line |
|
C |
Which of the valves
listed for the device shown in the illustration will be open while the unit
is operating in the back flush mode? Illustration GS-0153 |
valve "4" |
valves "4" and "5" |
valves "4"
and "14" |
valves "4", "5",
and "14" |
|
A |
In the operation
of a lube oil clarifier, the position of the oil-water interface should
be __________. |
non-existent |
maintained by
the number of disks in the disk stack |
maintained by
the diaphragm-type, weir control valve |
maintained by
the ring dam |
|
C |
A centrifuge will
satisfactorily remove which of the listed substances from lube oil? |
Gasoline |
Diesel fuel |
Carbon particles |
Fuel oil |
|
D |
When water is
removed from lube oil passing through a centrifugal purifier, the water
removed will __________. |
force the diameter
of the oil column within the bowl to be narrowed |
be retained in
the bowl |
displace water
from the heavy phase discharge port, but of an amount less than that removed
from the oil |
displace an equal
amount of water from the bowl seal |
|
A |
Of the many impurities
commonly found in marine lubricating oil, which of the following CANNOT
be removed by a centrifugal purifier at normal operating speeds and temperatures? |
Diesel fuel oil |
Metal particles |
Water |
Carbon particles |
|
A |
What is an engine
room bilge oily-water separator designed to do? |
Remove small amounts
of oil from large amounts of water. |
Remove small amounts
of oil from small amounts of water. |
Remove small amounts
of water from large amounts of oil. |
Remove small amounts
of oil from small amounts of water. |
|
D |
What type of fuel
oil as part of an oily-water mixture is most likely to have a density approaching
that of water? |
Light distillate
oil. |
Marine diesel
oil. |
Distillate/residual
fuel oil blends. |
Heavy residual
fuel oil. |
|
C |
What statement
is true concerning the effect of elevating the temperature of the oily-water
mixture associated with an oily-water separator? |
Heating the oily-water
mixture decreases the viscosity of the oil and decreases the specific gravity
differential between the oil and water. |
Heating the oily-water
mixture increases the viscosity of the oil and decreases the specific gravity
differential between the oil and water. |
Heating the oily-water
mixture decreases the viscosity of the oil and increases the specific gravity
differential between the oil and water. |
Heating the oily-water
mixture increases the viscosity of the oil and increases the specific gravity
differential between the oil and water. |
|
D |
What statement
is true concerning the polishing coalescer filter of an oily-water separator? |
The coalescing
filter is typically a hydrophilic filter meaning that small droplets of
entrained water of the oily-water mixture coalesce on the filter and form
large globules of water that sink to the bottom of the filter housing. |
The coalescing
filter is typically an oleophilic filter meaning that small droplets of
entrained oil of the oily-water mixture coalesce on the filter and form
large globules of oil that sink to the bottom of the filter housing. |
The coalescing
filter is typically a hydrophilic filter meaning that small droplets of
entrained water of the oily-water mixture coalesce on the filter and form
large globules of water that rise to the top of the filter housing. |
The coalescing
filter is typically an oleophilic filter meaning that small droplets of
entrained oil of the oily-water mixture coalesce on the filter and form
large globules of oil that rise to the top of the filter housing. |
|
C |
Referring to the
illustration, note that the solenoid in line "C" is closed. The
check valve in line "E" is open. The separator service pump is
running. The check valve in line "G" is closed. Valve "B"
is closed. Valve "D" is open. What is the operational status of
the oily-water separator unit? Illustration GS-0175 |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content greater than 15
ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content greater than 15 ppm. |
|
D |
What is an engine
room bilge oily-water separator designed to do? |
Remove small amounts
of water from large amounts of oil. |
Remove small amounts
of water from small amounts of oil. |
Remove small amounts
of oil from small amounts of water. |
Remove small amounts
of oil from large amounts of water. |
|
A |
What statement
is true with regard to the basic operating principle of gravity associated
with an oily-water separator? |
The density of
oil is less than that of water and as a result the oil droplets in an oily-water
mixture will tend to rise. |
The density of
oil is greater than that of water and as a result the oil droplets in an
oily-water mixture will tend to sink. |
The density of
oil is greater than that of water and as a result the oil droplets in an
oily-water mixture will tend to rise. |
The density of
oil is less than that of water and as a result the oil droplets in an oily-water
mixture will tend to sink. |
|
A |
What type of fuel
oil as part of an oily-water mixture is most likely to have a density approaching
that of water? |
Heavy residual
fuel oil. |
Marine diesel
oil. |
Distillate/residual
fuel oil blends. |
Light distillate
oil. |
|
A |
What type of oil
as part of an oily-water mixture is most likely to require heating to facilitate
separation in an oily-water separator? |
Heavy residual
fuel oil. |
Diesel engine
lubricating oil. |
Marine diesel
oil. |
Steam turbine
lubricating oil. |
|
C |
In order to facilitate
separation of oil from an oily-water mixture in an oily-water separator,
what statement is true concerning the flow pattern of the oily-water? |
Ideally the flow
of the oily-water should be low in flow rate and high in turbulence. |
Ideally the flow
of the oily-water should be high in flow rate and high in turbulence. |
Ideally the flow
of the oily-water should be low in flow rate and low in turbulence. |
Ideally the flow
of the oily-water should be high in flow rate and low in turbulence. |
|
D |
What statement
is true concerning the effect of elevating the temperature of the oily-water
mixture associated with an oily-water separator? |
Heating the oily-water
mixture decreases the viscosity of the oil and decreases the specific gravity
differential between the oil and water. |
Heating the oily-water
mixture increases the viscosity of the oil and increases the specific gravity
differential between the oil and water. |
Heating the oily-water
mixture increases the viscosity of the oil and decreases the specific gravity
differential between the oil and water. |
Heating the oily-water
mixture decreases the viscosity of the oil and increases the specific gravity
differential between the oil and water. |
|
A |
If an oily-water
separator uses an inclined plate pack to facilitate separation, what statement
concerning the plate pack is true? |
The oil droplets
collect on the underside of the plates and rise when they have reached the
outer edge of the plate pack. Solid particles collect on the upper side
of the plates and sink when they have reached the inner edge of the plate
pack. |
The oil droplets
collect on the upper side of the plates and sink when they have reached
the outer edge of the plate pack. Solid particles collect on the underside
of the plates and rise when they have reached the inner edge of the plate
pack. |
The oil droplets
collect on the upper side of the plates and rise when they have reached
the outer edge of the plate pack. Solid particles collect on the underside
of the plates and sink when they have reached the inner edge of the plate
pack. |
The oil droplets
collect on the underside of the plates and sink when they have reached the
outer edge of the plate pack. Solid particles collect on the upper side
of the plates and rise when they have reached the inner edge of the plate
pack. |
|
D |
A typical oily-water
separator has three stages of separation. Which statement represents the
correct sequential order of the stages? |
First stage: polishing
filter coalescer. Second stage: inclined plate coalescer. Third stage: gravimetric. |
First stage: gravimetric.
Second stage: polishing filter coalescer. Third stage: inclined plate coalescer. |
First stage: inclined
plate coalescer. Second stage: polishing filter coalescer. Third stage:
gravimetric. |
First stage: gravimetric.
Second stage: inclined plate coalescer. Third stage: polishing filter coalescer. |
|
A |
What statement
is true concerning the polishing coalescer filter of an oily-water separator? |
The coalescing
filter is typically an oleophilic filter meaning that small droplets of
entrained oil of the oily-water mixture coalesce on the filter and form
large globules of oil that rise to the top of the filter housing. |
The coalescing
filter is typically an oleophilic filter meaning that small droplets of
entrained oil of the oily-water mixture coalesce on the filter and form
large globules of oil that sink to the bottom of the filter housing. |
The coalescing
filter is typically a hydrophilic filter meaning that small droplets of
entrained water of the oily-water mixture coalesce on the filter and form
large globules of water that sink to the bottom of the filter housing. |
The coalescing
filter is typically a hydrophilic filter meaning that small droplets of
entrained water of the oily-water mixture coalesce on the filter and form
large globules of water that rise to the top of the filter housing. |
|
B |
Suppose a steam
trap's primary purpose is to insure good heat transfer of a steam-heated
heat exchanger. What statement is true concerning the outcome of a steam
trap failure? |
Steam trap failure
in a fully open position would result in exceptionally good heat transfer,
and steam trap failure in a full closed position would result in exceptionally
poor heat transfer. |
Steam trap failure
in either a fully open or fully closed position would both result in exceptionally
poor heat transfer. |
Steam trap failure
in a fully open position would result in exceptionally poor heat transfer,
and steam trap failure in a full closed position would result in exceptionally
good heat transfer. |
Steam trap failure
in either a fully open or fully closed position would both result in exceptionally
good heat transfer. |
|
D |
The component
labeled "A", as shown in the illustration, would be identified
as the __________. Illustration GS-0175 |
oil content monitor
probe |
separator vessel
pressure relief valve |
separator vessel
vacuum breaker |
oil/water interface
level sensing probe |
|
B |
The components
indicated as "7" and "8" as shown in the illustration,
are known as the __________. Illustration GS-0153 |
first stage oil
separator and drip pan |
inlet weir and
inlet baffle |
second stage oil
separator and drip pan |
outlet weir and
outlet baffle |
|
C |
When the oily
water separator, shown in the illustration, is in operation and processing
clear bilge water, what should be the internal water level? Illustration
GS-0153 |
The water level
in the tank should be slightly above the upper coalescer bed "9".
o |
The water level
should be located in the lower section of the tank as controlled by flow
control
valve "14". |
The water level
should be located in the upper section of the tank. |
No water level
is maintained in the tank. |
|
D |
The function of
item "7" shown in the illustration is to __________. Illustration
GS-0153 |
direct the flow
of the oily-water mixture against the coalescer bed |
support the tank
access panel |
allow the oil
accumulated to exit the device, while remaining separated from the liquid |
prevent separated
oil from mixing with the incoming bilge water |
|
A |
What is the normal
direction of flow through the device shown in the illustration while operating
in the processing mode? Illustration GS-0153 |
The oily-water
mixture enters through valve "5" and exits the separator through
valve "14" as processed liquid. |
The oily-water
mixture enters through valve "4" and exits as processed liquid
through valve "14". |
The oily-water
mixture enters through valve "14" and exits with the processed
liquid through valve "4". |
The oily-water
mixture enters through the pressure control valve "2" and exits
with the processed liquid through valve "14". |
|
B |
The line labeled "C",
as shown in the illustration, would be identified as the __________. Illustration
GS-0175 |
processed water
outlet line |
clean water inlet
line |
oily bilge water
inlet line |
waste oil discharge
line |
|
D |
The line labeled "E",
as shown in the illustration, would be identified as the __________. Illustration
GS-0175 |
processed water
outlet line |
clean water inlet
line |
waste oil outlet
line |
oily bilge water
inlet line |
|
A |
The line labeled "G",
as shown in the illustration, would be identified as the __________. Illustration
GS-0175 |
waste oil outlet
line |
processed water
outlet line |
clean water inlet
line |
oily bilge water
inlet line |
|
D |
Referring to the
illustration, note that the solenoid in line "C" is closed. The
check valve in line "E" is open. The separator service pump is
running. The check valve in line "G" is closed. Valve "B"
is open. Valve "D" is closed. What is the operational status of
the oily-water separator unit? Illustration GS-0175 |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content greater than 15
ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content greater than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content less than 15 ppm. |
|
A |
Referring to the
illustration, note that the solenoid in line "C" is closed. The
check valve in line "E" is open. The separator service pump is
running. The check valve in line "G" is closed. Valve "B"
is closed. Valve "D" is open. What is the operational status of
the oily-water separator unit? Illustration GS-0175 |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content greater than 15
ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content greater than 15 ppm. |
|
A |
Referring to the
illustration, note that the solenoid in line "C" is closed. The
check valve in line "E" is open. The separator service pump is
running. The check valve in line "G" is closed. Valve "B"
is closed. Valve "D" is open. What is the operational status of
the oily-water separator unit? Illustration GS-0175 |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content greater than 15
ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content greater than 15 ppm. |
|
B |
If item "1"
in the illustrated oily water separator indicates an abnormally deep vacuum,
which of the following conditions is the most probable cause? Illustration
GS-0153 |
Process water
inlet valve, item "5", is open. |
Suction line inlet
strainer is obstructed. |
No problem exists
as a high vacuum should be maintained in the chamber whose vacuum is to
be measured. |
Coalescer beds
are severely fouled. |
|
D |
If item "1"
shown in the illustration is a compound gage indicating zero psig and the
water level in the bilges is one foot high, the unit is __________. Illustration
GS-0153 |
in the oil discharge
mode |
processing the
bilge water |
damaged and should
not be used |
not turned on |
|
D |
Referring to the
illustration, suppose after initiating the oil discharge mode, the oily-water
separator fails to come out of the oil discharge mode in a timely fashion.
Cracking open the upper sampling valve reveals the presence of water exiting
under a positive pressure. What is most likely the cause? Illustration GS-0175 |
The lower oil/water
interface detection probe fails to initiate the oil discharge mode. |
The clean water
supply solenoid fails to open, and as a result provides no discharge pressure. |
The oil discharge
check valve fails to open, and as a result no oil actually discharges. |
The upper oil/water
interface detection probe fails to end the oil discharge mode. |
|
C |
Referring to the
illustration, what would be the result if the lower oil/water interface
detection probe became faulty? Illustration GS-0175 |
The unit would
not be able to transition from ending the oil discharge mode to initiating
the separation processing mode. |
The unit would
not be able to transition from the overboard discharge mode to the recirculation
mode while in the separation processing mode. |
The unit would
not be able to transition from ending the separation processing mode to
initiating the oil discharge mode. |
The unit would
not be able to come out of the oily-water separator idle mode and begin
processing bilge water. |
|
C |
Referring to the
illustration, what would be the result if the upper oil/water interface
detection probe became faulty? Illustration GS-0175 |
The unit would
not be able to transition from ending the separation processing mode to
initiating the oil discharge mode.
|
The unit would
not be able to transition from the overboard discharge mode to the recirculation
mode while in the separation processing mode. |
The unit would
not be able to transition from ending the oil discharge mode to initiating
the separation processing mode. |
The unit would
not be able to come out of the oily-water separator idle mode and begin
processing bilge water. |
|
A |
The components
indicated as "7" and "8" as shown in the illustration,
are known as the __________. Illustration GS-0153 |
inlet weir and
inlet baffle |
first stage oil
separator and drip pan |
outlet weir and
outlet baffle |
second stage oil
separator and drip pan |
|
C |
The function of
item "7" shown in the illustration is to __________. Illustration
GS-0153 |
support the tank
access panel |
allow the oil
accumulated to exit the device, while remaining separated from the liquid |
prevent separated
oil from mixing with the incoming bilge water |
direct the flow
of the oily-water mixture against the coalescer bed |
|
B |
What is the normal
direction of flow through the device shown in the illustration while operating
in the processing mode? Illustration GS-0153 |
The oily-water
mixture enters through valve "4" and exits as processed liquid
through valve "14" |
The oily-water
mixture enters through valve "5" and exits the separator through
valve "14" as processed liquid. |
The oily-water
mixture enters through the pressure control valve "2" and exits
with the processed liquid through valve "14". |
The oily-water
mixture enters through valve "14" and exits with the processed
liquid through valve "4". |
|
D |
The component
labeled "A", as shown in the illustration, would be identified
as the __________. Illustration GS-0175 |
oil content monitor
probe |
separator vessel
pressure relief valve |
separator vessel
vacuum breaker |
oil/water interface
level sensing probe |
|
D |
The line labeled "E",
as shown in the illustration, would be identified as the __________. Illustration
GS-0175 |
clean water inlet
line |
waste oil outlet
line |
processed water
outlet line |
oily bilge water
inlet line |
|
C |
Referring to the
illustration, note that the solenoid in line "C" is closed. The
check valve in line "E" is open. The separator service pump is
running. The check valve in line "G" is closed. Valve "B"
is open. Valve "D" is closed. What is the operational status of
the oily-water separator unit? Illustration GS-0175 |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content greater than 15 ppm.
o |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content greater than 15
ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
overboard with an oil content less than 15 ppm. |
The oily-water
separator is in the bilge water separation processing mode with water discharging
back to the bilge water holding tank with an oil content less than 15 ppm. |
|
A |
Referring to the
illustration, an oil/water separator is in the recirculation mode due to
high oil content of the processed water outlet. What action may be required
before the unit is capable of discharging overboard once again? Illustration
GS-0175 |
Flushing the oil
content detector with clean water. |
Flushing the bilges
with an emulsifying agent. |
Flushing the bilges
with a detergent. |
Cleaning the bilge
suction strainer. |
|
C |
Referring to the
illustration, what would be the result if the upper oil/water interface
detection probe became faulty? Illustration GS-0175 |
The unit would
not be able to transition from ending the separation processing mode to
initiating the oil discharge mode.
|
The unit would
not be able to transition from the overboard discharge mode to the recirculation
mode while in the separation processing mode. |
The unit would
not be able to transition from ending the oil discharge mode to initiating
the separation processing mode. |
The unit would
not be able to come out of the oily-water separator idle mode and begin
processing bilge water. |
|
B |
If item "1"
in the illustrated oily water separator indicates an abnormally deep vacuum,
which of the following conditions is the most probable cause? Illustration
GS-0153 |
Coalescer beds
are severely fouled. |
Suction line inlet
strainer is obstructed. |
Process water
inlet valve, item "5", is open. |
No problem exists
as a high vacuum should be maintained in the chamber whose vacuum is to
be measured. |
|
A |
Referring to the
illustration, suppose the oily-water separator vessel compound gauge is
showing an unusually deep vacuum for operating in the separation processing
mode with the separator service pump running. The oil content is 8.3 ppm.
What is most likely the cause? Illustration GS-0175 |
The oily-water
separator bilge suction strainer is clogged. |
The oily-water
separator vessel relief valve is leaking. |
The oily-water
separator service pump is worn. |
The bilge water
holding tank level is unusually high resulting in a high level alarm. |
|
B |
Referring to the
illustration, suppose after initiating the oil discharge mode, the oily-water
separator fails to come out of the oil discharge mode in a timely fashion.
Cracking open the upper sampling valve reveals the presence of water exiting
under a positive pressure. What is most likely the cause? Illustration GS-0175 |
The oil discharge
check valve fails to open, and as a result no oil actually discharges. |
The upper oil/water
interface detection probe fails to end the oil discharge mode. |
The lower oil/water
interface detection probe fails to initiate the oil discharge mode. |
The clean water
supply solenoid fails to open, and as a result provides no discharge pressure. |
|
B |
Referring to the
illustration, suppose after initiating the oil discharge mode, the oily-water
separator fails to come out of the oil discharge mode in a timely fashion.
Cracking open the upper sampling valve reveals the presence of oil exiting
under positive pressure. What is most likely the cause? Illustration GS-0175 |
The clean water
supply solenoid fails to open, and as a result provides no discharge pressure. |
The oil discharge
check valve fails to open, and as a result no oil actually discharges. |
The lower oil/water
interface detection probe fails to initiate the oil discharge mode. |
The upper oil/water
interface detection probe fails to end the oil discharge mode. |
|
A |
Referring to the
illustration, suppose while in the oil separation processing mode, the oil
content detector display screen shows 17.9 ppm and the oily-water separator
is discharging back to the bilge water holding tank for re-circulation.
What is most likely the cause? Illustration GS-0175 |
The bilge water
holding tank contents is excessively contaminated with oil. |
The oily-water
separator bilge suction strainer is excessively clogged. |
The oily-water
separator service pump is excessively worn. |
The bilge water
holding tank level is excessively high resulting in a high level alarm. |
|
A |
The best gasket
material to use in cargo fuel oil lines is __________. |
oil-resistant
sheet packing |
cork sheet packing |
unvulcanized packing |
sheet asbestos |
|
A |
Piping cross-sections
over 12 inches in diameter are sized by the __________. |
outside diameter |
wall thickness |
threaded diameter |
inside diameter |
|
C |
The illustrated
valve is known as a __________. Illustration GS-0056 |
lift gate valve |
butterfly lift
valve |
swing check valve |
swing globe valve |
|
B |
The valve depicted
in the illustration shown is a __________. Illustration GS-0055 |
gate valve |
butterfly valve |
globe valve |
check valve |
|
D |
Taps and dies
used for threading pipe are __________. |
not hardened |
not fluted |
straight |
tapered |
|
C |
Which of the illustrations
depicts the correct procedure for applying pipe dope? Illustration GS-0046 |
D |
C |
B |
A |
|
D |
A thread die will
be easier to start if the end of the shaft to be threaded is slightly __________. |
center drilled |
peened |
reamed |
chamfered |
|
C |
A thread chaser
is a hand tool that should only be used for __________. |
enlarging existing
threads |
straightening
tapered threads |
restoring damaged
threads |
cutting original
threads |
|
B |
Copper coil tubing
is best cut with a __________. |
flare cutter |
tubing cutter |
pipe cutter |
hand hacksaw |
|
D |
After cutting
a piece of tubing to be flared, you should __________. |
crimp the tube
end in order to slip on the fitting |
flare the tube
before removing the burrs |
rough up the outside
surface of the tube end with a file |
remove inside
burrs with a reamer |
|
B |
Which of the following
descriptions should be included when identifying the length
for pipe nipples? |
Standard, extra-strong,
double extra-strong, and schedule 80 |
Close, short,
long, and tank |
Cast, wrought,
stainless, and brass |
Fully threaded,
half threaded, long, and short |
|
A |
The designation
'schedule 80 extra strong' refers to __________. |
piping wall thickness |
tubing bursting
strength |
tensile strength
of bolts |
weight of steel
plate |
|
C |
Allowances may
be made for the expansion and contraction in piping by the use of expansion
joints or __________. |
union bulkhead
fittings |
retractable flanges |
bends or loops
in the line |
unions |
|
C |
Fittings used
to close the ends of pipe are called "pipe _______". |
tees |
closures |
caps |
ells |
|
B |
A pipe coupling
is a fitting having __________. |
outside threads
on both ends |
inside threads
on both ends |
a left-hand twist |
outside threads
on one end and inside threads on one end |
|
A |
Which of the gasket
types listed is typically used on high pressure steam flange joints? |
Spiral wound flexitallic |
Wire-impregnated
sheet plastic |
High temperature
neoprene |
Wire-impregnated
rubber |
|
D |
To properly make
and fit a new gasket to a flange, you should __________. |
cut grooves into
the flange with a chisel to ensure good gasket contact |
place the gasket
over the flange and knock off the excess material with a lead mallet |
make up the flanged
joint to make an impression of the flange surfaces to insure a pattern for
proper alignment |
remove excess
gasket material by trimming with scissors or tin snips |
|
A |
When replacing
a gasket in a six-bolt flanged joint, in what order should the bolts be
tightened? |
Install and tighten
bolts in pairs which are opposite each other in the flange (1-4, 2-5, and
3-6). |
Each bolt should
be installed and tightened in consecutive order in the counterclockwise
direction. |
Each bolt should
be installed and tightened in consecutive order in the clockwise direction. |
Install and tighten
bolts 1, 3, 4, 2, 5, and 6, in that order. |
|
B |
If you were uncertain
as to what type of gasket material to install in a pipeline, you should
__________. |
make up the joint
without a gasket until you can check with the chief |
check the ship's
plans or manufacturer's instructions |
turn the old gasket
over and install it again |
leave the old
gasket in and cover it with Permatex |
|
D |
To anneal a copper
gasket, you should heat the gasket __________. |
and let cool slowly
in the air |
and quench it
in oil |
and carbonize
it |
cherry red and
quench in water |
|
D |
Which pipe listed
has the largest outside diameter? |
A 3/4" pipe
with a double extra strong wall thickness. |
A 3/4" pipe
with an extra strong wall thickness. |
A 3/4" pipe
with a standard wall thickness. |
All have the same
outside diameter. |
|
D |
Which of the listed
pipe sizes is not commonly used? |
3/4 inch |
3/8 inch |
1/2 inch |
5/8 inch |
|
D |
Tubing is sized
by __________. |
nominal inside
diameter |
allowed working
pressure |
cross-section
area |
nominal outside
diameter |
|
C |
Copper tubing
is manufactured and classified as type K, L, and M. Which type would offer
the greatest wall thickness for a given nominal size? |
Type M |
Type L and M have
identical wall thicknesses |
Type K |
Type L |
|
D |
A gate valve installed
in a piping system should be used __________. |
to throttle the
flow of liquid |
only for lube
oil service |
only with the
stem facing down |
in either fully
closed or fully opened positions |
|
D |
What type of valve
is shown in the illustration? Illustration GS-0047 |
Check valve |
Butterfly valve |
Globe valve |
Gate valve |
|
D |
Which of the following
statements is true concerning the valve shown in the illustration. Illustration
GS-0047 |
The valve only
requires one turn of the hand wheel to fully open. |
The valve seats
cannot be replaced or repaired. |
The valve is normally
used to throttle the flow of liquid. |
The valve is a
non-rising stem design. |
|
C |
The use of a needle
valve in a piping system is recommended when requiring __________. |
no back flow |
high pressure
drops |
close regulation
of flow |
no pressure drops |
|
D |
The seat of a
butterfly valve will most likely be constructed of __________. |
admiralty metal |
Monel |
stellite |
a resilient material |
|
D |
To remove a hand
held right-handed straight cut reamer after it has gone all the way through
a hole, you should __________. |
work the reamer
side to side to dislodge it |
tap the reamer
out with a soft faced hammer |
turn the tap wrench
counterclockwise, simultaneously raising the reamer |
turn the tap wrench
clockwise, simultaneously raising the reamer |
|
D |
The tool used
for cutting external pipe threads is called a pipe __________. |
cutter |
ratchet cutter |
threader |
stock and die |
|
B |
Before making
up a flanged joint, you should __________. |
cut grooves in
the flange face with a chisel |
be certain that
the flanges line up squarely |
heat the pipeline
to expand the bolt holes |
have a second
spare gasket on hand |
|
D |
Before disconnecting
a joint in a pipeline, you should __________. |
have a first aid
kit on hand |
determine the
size of the gasket |
hang a bucket
under the joint |
be sure no pressure
exists in the line |
|
B |
When cutting external
threads on a steel pipe with a die, you should __________.
|
tap the die with
a hammer to break up the chips |
continue turning
until the end of the pipe has gone through the die and is flush with the
die face |
never use a lubricant |
start the die
at a slight angle with the work to create tapered threads |
|
A |
The tool used
to prepare copper tubing for the installation of fittings is called a __________. |
flaring tool |
spreader |
stretcher |
swaging tool |
|
A |
Enlarging one
tube end so the end of another tube of the same size will fit inside is
termed __________. |
swaging |
flaring |
stretching |
belling |
|
A |
What statement
representing the primary purpose of a steam trap is true? |
By draining the
low point of a horizontal run of steam piping, a steam trap is used primarily
to keep the steam line dry and eliminate water hammer. |
By draining the
high point of a horizontal run of steam piping, a steam trap is used primarily
to keep the steam line dry and eliminate water hammer. |
By draining the
high point of a vertical run of steam piping, a steam trap is used primarily
to keep the steam line dry and eliminate water hammer. |
By draining the
low point of a horizontal run of steam piping, a steam trap is used primarily
to insure good heat transfer efficiency. |
|
D |
In order for a
steam trap to be effective in accomplishing its intended purpose, what statement
is true regarding its installation? |
The steam trap
should never be painted, but should be covered with insulation. |
The steam trap
should be painted to reduce corrosion and should be covered with insulation. |
The steam trap
should be painted to reduce corrosion but should never be covered with
insulation. |
The steam trap
should never be painted and should never be covered with insulation. |
|
D |
Referring to the
illustrated impulse steam trap, what would be the effect of threading the
control cylinder "E" downward further into the trap body? Illustration
GS-0002 |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will decrease, and as a result, the pressure drop across
the periphery of the valve disk will decrease. |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will decrease, and as a result, the pressure drop across
the periphery of the valve disk will increase. |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will increase, and as a result, the pressure drop across
the periphery of the valve disk will increase. |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will increase, and as a result, the pressure drop across
the periphery of the valve disk will decrease. |
|
A |
Referring to the
illustrated impulse steam trap, what would be the effect of threading the
control cylinder "E" upward out of the trap body? Illustration
GS-0002 |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will decrease, and as a result, the pressure drop across
the periphery of the valve disk will increase. |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will decrease, and as a result, the pressure drop across
the periphery of the valve disk will decrease. |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will increase, and as a result, the pressure drop across
the periphery of the valve disk will decrease. |
The clearance
between the reverse taper of the control cylinder's inner wall and the periphery
of the valve disk will increase, and as a result, the pressure drop across
the periphery of the valve disk will increase. |
|
A |
Referring to the
illustrated bellows-type thermostatic steam trap, what statement is true
concerning its operation? Illustration GS-0005 |
When the bellows
comes into contact with relatively cool condensate, the vapor within the
bellows condenses resulting in bellows contraction and valve opening. |
When the bellows
comes into contact with relatively hot steam, the vapor within the bellows
condenses resulting in bellows contraction and valve opening. |
When the bellows
comes into contact with relatively cool condensate, the liquid within the
bellows vaporizes resulting in bellows expansion and valve closing. |
When the bellows
comes into contact with relatively hot steam, the liquid within the bellows
vaporizes resulting in bellows contraction and valve opening. |
|
D |
What type of steam
trap is most susceptible to damage if allowed to come into contact with
superheated steam? |
Mechanical traps
relying on the principle of buoyancy. |
Thermodynamic
traps relying on the principle of condensate undergoing a pressure drop
and flashing. |
Thermostatic traps
relying on the principle of differing expansion rates for dissimilar metals. |
Thermostatic traps
relying on the principle of expansion/contraction of a volatile fluid. |
|
B |
In the illustrated
self-contained, internal-pilot, piston-operated temperature control valve,
what statement is true concerning the pilot and main valves? Illustration
GS-0045 |
The pilot valve
is downward seating and the main valve is upward seating. |
The pilot valve
is upward seating and the main valve is upward seating. |
The pilot valve
is downward seating and the main valve is downward seating. |
The pilot valve
is upward seating and the main valve is downward seating. |
|
B |
Suppose the illustrated
self-contained, internal-pilot, piston-operated temperature control valve
is part of the temperature control system for a steam-heated heavy fuel
oil service heater for a steam boiler. If there was an increase in demand
for fuel by the boiler, what statement correctly represents how the valve
would initially respond? Illustration GS-0045 |
The fuel oil heater
fuel outlet temperature would increase, causing the remote bulb pressure
to increase and the control diaphragm to flex downward and through lever
action, further close the pilot valve. |
The fuel oil heater
fuel outlet temperature would decrease, causing the remote bulb pressure
to decrease and the control diaphragm to flex upward and through lever action,
further open the pilot valve. |
The fuel oil heater
fuel outlet temperature would decrease, causing the remote bulb pressure
to decrease and the control diaphragm to flex downward and through lever
action, further close the pilot valve. |
The fuel oil heater
fuel outlet temperature would increase, causing the remote bulb pressure
to increase and the control diaphragm to flex upward and through lever action,
further open the pilot valve. |
|
B |
How would the
illustrated valve respond to a complete loss of charge from the remote bulb-to-control
diaphragm power element if the valve is used as a temperature control valve
for a steam-heated heavy fuel oil service heater? Illustration GS-0045 |
The valve would
fail in the fully-closed position, resulting in a low fuel oil temperature
alarm. |
The valve would
fail in the fully-open position, resulting in a high fuel oil temperature
alarm. |
It is not possible
to predict how the valve will respond to a complete loss of charge from
the power element. |
The valve would
fail in the exact position it was in before the power element lost its complete
charge, resulting in a fluctuation in fuel oil temperature as demand changes. |
|
A |
In the illustrated
self-contained, internal-pilot, piston-operated steam pressure-reducing
valve, what statement is true concerning the opening and closing forces
acting upon the control diaphragm? Illustration GS-0044 |
The spring (F)
force acting on the control diaphragm is a pilot valve opening force, and
the downstream pressure (J) acting on the control diaphragm is a pilot valve
closing force. |
The spring (F)
force acting on the control diaphragm is a pilot valve opening force, and
the upstream pressure (C) acting on the control diaphragm is a pilot valve
closing force. |
The spring (F)
force acting on the control diaphragm is a pilot valve closing force, and
the upstream pressure (C) acting on the control diaphragm is a pilot valve
opening force. |
The spring (F)
force acting on the control diaphragm is a pilot valve closing force, and
the downstream pressure (J) acting on the control diaphragm is a pilot valve
opening force. |
|
B |
How would the
pressure setting of the illustrated self-contained, internal-pilot, piston-operated
steam pressure-reducer be reduced to a lower set point? Illustration GS-0044 |
The adjusting
spring would need to have its compression load reduced by rotating the adjusting
screw clockwise further into the adjusting spring chamber. |
The adjusting
spring would need to have its compression load reduced by rotating the adjusting
screw counter-clockwise further out of the adjusting spring chamber. |
The adjusting
spring would need to have its compression load increased by rotating the
adjusting screw counter-clockwise further out of the adjusting spring chamber. |
The adjusting
spring would need to have its compression load increased by rotating the
adjusting screw clockwise further into the adjusting spring chamber. |
|
D |
Suppose the illustrated
self-contained, internal-pilot, piston-operated temperature control valve
is part of the temperature control system for a steam-heated heavy fuel
oil service heater for a steam boiler. If there was a decrease in demand
for fuel by the boiler, what statement correctly represents how the valve
would initially respond? Illustration GS-0045 |
The fuel oil heater
fuel outlet temperature would decrease, causing the remote bulb pressure
to decrease and the control diaphragm to flex upward and through lever action,
further open the pilot valve. |
The fuel oil heater
fuel outlet temperature would increase, causing the remote bulb pressure
to increase and the control diaphragm to flex upward and through lever action,
further open the pilot valve. |
The fuel oil heater
fuel outlet temperature would decrease, causing the remote bulb pressure
to decrease and the control diaphragm to flex downward and through lever
action, further close the pilot valve. |
The fuel oil heater
fuel outlet temperature would increase, causing the remote bulb pressure
to increase and the control diaphragm to flex downward and through lever
action, further close the pilot valve. |
|
A |
Concerning pressure-relief
valves, what statement is true? |
No stop isolation
valve may be installed between the relief valve and its source of pressure,
and no stop isolation valve may be installed in the relief valve discharge
piping. |
It is permissible
to install a stop isolation valve between the relief valve and its source
of pressure, but no stop isolation valve may be installed in the relief
valve discharge piping. |
It is permissible
for a stop isolation valve to be installed between the relief valve and
its source of pressure, and it is permissible for a stop isolation valve
to be installed in the relief valve discharge piping. |
No stop isolation
valve may be installed between the relief valve and its source of pressure,
but it is permissible for a stop isolation valve to be installed in the
relief valve discharge piping. |
|
C |
Referring to the
illustrated huddling-chamber safety valve, what statement concerning the
blowdown adjusting ring (B) is true? Illustration SG-0018 |
Lowering the blow
down adjusting ring further increases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will decrease. |
Lowering the blow
down adjusting ring further decreases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will increase. |
Lowering the blow
down adjusting ring further decreases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will decrease. |
Lowering the blow
down adjusting ring further increases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will increase. |
|
C |
Concerning sentinel
valves, what statement is true? |
The set point
of the sentinel valve is usually above the maximum allowable working pressure
of the system. |
The capacity of
a sentinel valve must exceed the capacity of the pressure source. |
The sentinel valve's
sole purpose is to warn personnel of excessive system pressure. |
The set point
of a sentinel valve is normally set below the normal working pressure of
the system. |
|
A |
Concerning safety
valves, what statement is true? |
Safety valves
are designed to open wide when lifted by excessive pressure and only reseat
when the pressure has dropped significantly. |
Safety valves
are always set to relieve at a pressure exceeding the maximum allowable
working pressure of the system. |
Safety valves
are designed to throttle and adjust the flow rate to just keep up with the
capacity
of the pressure source. |
Safety valves
are designed to open wide when lifted by excessive pressure and immediately
reseat when the pressure has dropped by a very small amount. |
|
A |
In the illustrated
huddling-chamber safety valve, what statement is true concerning the opening
and closing forces acting upon the disc? Illustration SG-0018 |
The spring force
acting upward on the disc is a valve opening force, and the sensed pressure
acting downward on the disc is a valve closing force. |
The spring force
acting upward on the disc is a valve closing force, and the sensed pressure
acting downward on the disc is a valve opening force. |
The spring force
acting downward on the disc is a valve opening force, and the sensed pressure
acting upward on the disc is a valve closing force. |
The spring force
acting downward on the disc is a valve closing force, and the sensed pressure
acting upward on the disc is a valve opening force. |
|
C |
Which of the following
listed valves would require "blow down" to insure proper operation
and prevent damage due to repeated and rapid opening and closing? |
Pressure-reducing
valve |
Pressure-relief
valve |
Safety valve |
Pressure-regulating
relief valve |
|
B |
Referring to the
illustrated huddling-chamber safety valve, what statement is true concerning
the adjustment of blow down? Illustration SG-0018 |
Blow down is adjusted
by rotating the release nut (A). |
Blow down is adjusted
by rotating the adjusting ring (B). |
Blow down is adjusted
by rotating the compression screw after first loosening the compression
screw locking nut (C). |
Blow down is adjusted
by rotating the seat bushing (G). |
|
C |
Referring to the
illustrated huddling-chamber safety valve, what statement is true concerning
the adjustment of the popping pressure? Illustration SG-0018 |
Popping pressure
is adjusted by rotating the adjusting ring (B). |
Popping pressure
is adjusted by rotating the release nut (A). |
Popping pressure
is adjusted by rotating the compression screw after first loosening the
compression screw locking nut (C). |
Popping pressure
is adjusted by rotating the seat bushing (G). |
|
C |
As it pertains
to safety valves, what is the definition of blow down? |
Blow down is the
feature of a valve that allows drainage of condensate away from the disc
to prevent sticking. |
Blow down is the
difference between the maximum allowable working pressure and the valve
popping pressure. |
Blow down is the
difference between the valve popping pressure and the valve reseating pressure. |
Blow down is the
difference between the maximum allowable working pressure and the valve
reseating pressure. |
|
D |
Referring to the
illustrated huddling-chamber safety valve, what statement concerning the
blowdown adjusting ring (B) is true? Illustration SG-0018 |
Raising the blow
down adjusting ring further decreases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will decrease. |
Raising the blow
down adjusting ring further increases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will decrease. |
Raising the blow
down adjusting ring further decreases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will increase. |
Raising the blow
down adjusting ring further increases the area of exposure to pressure after
the valve pops and as a result, the valve blow down will increase. |
|
A |
Referring to the
illustrated pneumatically operated diaphragm actuated control valve, what
statement is true? Illustration GS-0051 |
The control valve
is direct-acting and normally open (NO). |
The control valve
is indirect-acting and normally open (NO). |
The control valve
is direct-acting and normally closed (NC). |
The control valve
is indirect-acting and normally closed (NC). |
|
C |
Suppose the illustrated
pneumatically operated diaphragm actuated control valve is used to control
the fuel oil outlet temperature of a steam-heated heavy fuel oil heater
by controlling the steam flow. What would be the result if the stem packing
was over-tightened and the stem was unable to vertically move in either
direction? Illustration GS-0051 |
The valve would
fail in the fully-closed position, most likely resulting in a low fuel oil
temperature alarm condition.
o |
It is not possible
to predict how the valve would respond to over-tightened valve stem packing. |
The valve will
lose control of the fuel oil temperature with the result that the fuel temperature
will fluctuate with changes in fuel demand. |
The valve would
fail in the fully-open position, most likely resulting in a high fuel oil
temperature alarm condition. |
|
D |
Referring to the
illustrated pneumatically-operated diaphragm-actuated control valve, what
statement is true? Illustration GS-0051 |
The control valve
has a single disc which is upward seating. |
The control valve
has a single disc which is downward seating. |
The control valve
has two discs which are both upward seating. |
The control valve
has two discs which are both downward seating. |
|
B |
Assuming that
the flow is from left to right on the illustrated pneumatically-operated
diaphragm-actuated control valve, what statement is true? Illustration GS-0051 |
Inlet pressure
acts on the upper surface of the top disc and the lower surface of the bottom
disc for the purpose of achieving hydraulic balance so that inlet pressure
does not influence the valve position. |
Inlet pressure
acts on the lower surface of the top disc and the upper surface of the bottom
disc for the purpose of achieving hydraulic balance so that inlet pressure
does not influence the valve position. |
Inlet pressure
acts on the upper surface of the top disc and the upper surface of the bottom
disc for the purpose of achieving a hydraulic assist to aid in valve closing. |
Inlet pressure
acts on the lower surface of the top disc and the lower surface of the bottom
disc for the purpose of achieving a hydraulic assist to aid in valve opening. |
|
C |
In the illustrated
pneumatically-operated diaphragm-actuated control valve, what statement
is true concerning the opening and closing forces acting upon the control
diaphragm? Illustration GS-0051 |
The spring force
acting on the control diaphragm is a valve opening force, and the pilot
pressure acting on the bottom of the control diaphragm is a valve closing
force.
o |
The spring force
acting on the control diaphragm is a valve closing force, and the pilot
pressure acting on the top of the control diaphragm is a valve opening force. |
The spring force
acting on the control diaphragm is a valve opening force, and the pilot
pressure acting on the top of the control diaphragm is a valve closing force. |
The spring force
acting on the control diaphragm is a valve closing force, and the pilot
pressure acting on the bottom of the control diaphragm is a valve opening
force. |
|
C |
Suppose the pilot
pressure range is from 3 to 15 psig for the illustrated pneumatically operated
diaphragm-actuated control valve. Assuming the control valve is trimmed
for a linear response and the travel position indicator is calibrated in
percentage, what would the approximate valve position with a 9 psig pilot
pressure? Illustration GS-0051 |
25% open |
33% open |
50% open |
75% open |
|
B |
Suppose the pilot
pressure is from 3 to 15 psig for the illustrated pneumatically operated,
diaphragm actuated control valve. Assuming the control valve is trimmed
for a linear response and the travel position indicator is calibrated in
percentage, what would be the approximate pilot pressure if the position
indicator showed the valve to be 75% open? Illustration GS-0051 |
4.5 psig |
6.0 psig |
7.5 psig |
9.0 psig |
|
A |
Suppose the pilot
controller for the illustrated pneumatically operated diaphragm actuated
control valve is supplied with 20 psig control air and is designed to operate
the valve with a pilot pressure ranging from 3 to 15 psig. What would be
the indication of a properly adjusted spring (6) by means of the adjusting
nut (12)? Illustration GS-0051 |
The valve should
indicate fully open at 3 psig and should indicate fully closed at 15 psig. |
The valve should
indicate fully closed at 3 psig and should indicate fully open at 15 psig |
The valve should
indicate fully open at 0 psig and should indicate fully closed at 20 psig. |
The valve should
indicate fully closed at 0 psig and should indicate fully open at 20 psig. |
|
C |
Suppose the illustrated
pneumatically operated diaphragm actuated control valve is used to control
the fuel oil outlet temperature of a steam-heated heavy fuel oil heater
by controlling the steam flow. What would be the result if there was a complete
loss of pilot air being delivered to the valve actuator? Illustration GS-0051 |
The valve would
fail in the fully closed position, most likely resulting in a low fuel oil
temperature alarm condition. |
The valve would
fail in the exact position just before the loss of pilot air. The fuel temperature
will fluctuate with changes in fuel demand. |
The valve would
fail in the fully open position, most likely resulting in a high fuel oil
temperature alarm condition. |
It is not possible
to predict how the valve would respond to a loss of pilot air. |
|
B |
As shown in the
illustration, if figure "21" indicates the "TOP VIEW"
of an orthographic projection, and figure "11" indicates the "FRONT
VIEW", which figure would best represent the correct "RIGHT SIDE
VIEW"? Illustration GS-0165 |
Figure "2" |
Figure "10" |
Figure "8" |
Figure "15" |
|
A |
Which of the figures
shown in the illustrations depicts an orthographic projection? Illustration
GS-0142 |
A |
B |
C |
D |
|
A |
Which of the projections
represents the left side view of the object "X" in the illustration?
Illustration GS-0022 |
A |
B |
C |
D |
|
B |
The exploded drawing
shown in the illustration is intended to show the __________. Illustration
GS-0025 |
total number of
parts in the assembled component |
parts aligned
for the correct order of reassembly |
disassembled component
in a one point perspective view |
parts without
using hidden lines |
|
D |
Of the views labeled "1", "2", "3",
and "4", select the one that correctly represents the right side
view of the unnumbered object in the illustration. Illustration GS-0003 |
1 |
2 |
3 |
4 |
|
A |
In the illustration
shown, what is the proper description of the hole represented by "C"?
Illustration GS-0015 |
Counter bored |
Countersunk |
Counter drilled |
Spot faced |
|
B |
In the illustration,
line "J" is used to depict a __________. Illustration GS-0006 |
hidden line |
cutting plane
line |
outline |
centerline |
|
A |
In the illustration,
line "C" is a __________. Illustration GS-0006 |
dimension line |
leader line |
cutting plane
line |
phantom line |
|
A |
How many hidden
lines are shown in the right side (end) view of the drawing illustrated?
Illustration GS-0021 |
None |
Two |
Four |
Six |
|
A |
Which of the conditions
listed does the blueprint symbol shown in the illustration represent? Illustration
GS-0028 |
All surfaces are
to be machine finished. |
A groove must
be machined at the points designated. |
The thread form
to be machined on the bolt. |
The surface should
be finished with a welded overlay. |
|
A |
In the illustration,
line "C" is a __________. Illustration GS-0006 |
dimension line |
leader line |
cutting plane
line |
phantom line |
|
A |
In the illustration,
line "D" is a/an __________. Illustration GS-0006 |
hidden line |
sectioning line |
outline |
phantom line |
|
A |
In the figure
shown in the illustration, the standard blueprint symbols above the letters "A", "B",
and "C" indicate __________. Illustration GS-0036 |
the use of internal
threads |
hole tolerance |
finished diameter |
interference fit |
|
B |
A 'centerline'
depicted in a drawing or blueprint is represented by which of the figures
shown in the illustration? Illustration GS-0031 |
A |
E |
D |
C |
|
B |
A 'centerline'
depicted in a drawing or blueprint is represented by which of the figures
shown in the illustration? Illustration GS-0031 |
A |
E |
C |
D |
|
C |
In the illustration
shown, an efficient seal is maintained between the suction cover and the
volute by __________. Illustration GS-0012 |
good metal-to-metal
contact |
sealant between
the two parts |
an asbestos gasket |
compressing the
packing rings |
|
C |
Which of the speeds
listed represents the synchronous speed rating of the lube oil pump motor
shown in the illustration? Illustration GS-0011 |
1,000 RPM |
1,150 RPM |
1,200 RPM |
1,250 RPM |
|
D |
What is the length
of the stud used to secure the packing gland shown in the illustration?
Illustration GS-0012 |
1 inch |
1 1/4 inches |
1 1/2 inches |
2 1/2 inches |
|
D |
What is the distance
between the center of the discharge outlet and the top of the motor illustrated?
Illustration GS-0011 |
34 5/8 inches |
35 inches |
35 5/8 inches |
36 inches |
|
D |
In the pump shown
in the illustration, what is the distance from the bottom of the inlet to
the bottom end of the motor shaft? Illustration GS-0011 |
45 1/4 inches |
45 5/16 inches |
53 5/8 inches |
57 5/8 inches |
|
C |
The working depth
of the gear illustrated is represented by __________. Illustration GS-0111 |
C |
I |
A |
B |
|
D |
The term, whole
depth of the gear, shown in the illustration, is equal to __________. Illustration
GS-0111 |
A + D |
B + D |
C + A |
C + D |
|
A |
Which letter represents
the gear tooth working depth of the gear set illustrated? Illustration GS-0111 |
A |
B |
C |
D |
|
A |
The dimension
of the sensing gap in the left hand limit sensor assembly shown in the illustration
is __________. Illustration GS-0010 |
1/8 inch |
1/4 inch |
3/8 inch |
1/2 inch |
|
B |
The shaft shown
in the illustration has an overall length of 42 inches in addition to the
following dimensions of "A" = 8", "B" = 8", "C"
= 10", and "D"=8 3/16" The tapered length "X"
is __________. Illustration GS-0133 |
6.375 inches |
7.812 inches |
8.185 inches |
8.312 inches |
|
A |
The physical feature
indicated for each of the smallest diameter ends of the device illustrated
is that they are __________. Illustration GS-0008 |
threaded |
smooth surfaced
with opposing machined flats |
smoothed surfaced
only |
threaded with
opposing machined flats |
|
A |
Which of the following
statements is correct regarding the device shown in the illustration? Illustration
GS-0008 |
The areas dimensioned
0.64 in length are flats on the shaft. |
The areas dimensioned
0.64 in length are steps in the shaft diameter. |
If the piece is
symmetrical about the 3/16 hole, the threaded ends have longitudinal tolerance
dimensions of 0.789 inch to 0.825 inch. |
All the 0.03 under
cuts must be taken into account when adjusting lengths to meet the specified
tolerances. |
|
A |
Figure "B",
shown in the illustration, is dimensioned to indicate a/an __________. Illustration
GS-0019 |
interference fit |
clearance of .005
inch |
running fit |
tolerance of .005
inch |
|
A |
The illustration
shown represents a blueprint of a metal __________. Illustration GS-0028 |
rod with a conventional
break |
tube with a broken
out section |
pipe with a missing
center section |
bar with a sawn
out section |
|
A |
The letters 'NPT'
used in the notation 1/8-27 NPT as shown in the illustration, indicates
the __________. Illustration GS-0010 |
thread series |
thread profile |
class of finish |
class of fit |
|
B |
In the illustration
shown, what is the distance indicated by dimension "I"? Illustration
GS-0001 |
1 1/2 inches |
1 3/4 inches |
1 7/8 inches |
2 inches |
|
B |
The illustration
is drawn to a scale of 3/8 inch = 1 inch. What is the full size dimension
of "X", if the scale lengths for "E" = 5/8", "F"
= 1 3/8", "G" = 2 1/8", and "H" = 5 3/4"?
Illustration GS-0007 |
1.625 inches |
4.333 inches |
6.094 inches |
15.333 inches |
|
B |
Using the information
in the illustration shown, the tail of the welding symbol will __________.
Illustration GS-0030
|
designate the
type of weldment |
designate the
welding specifications |
specify the size
of weldment |
specify the direction
of welding |
|
A |
Which of the following
propulsor types represents the proper terminology for a Kort nozzle? |
Ducted propeller |
Vane wheel |
Cycloidal propeller |
Tandem propellers |
|
A |
Which of the following
propulsor types does not require the use of a separate rudder for steerage? |
Cycloidal propellers. |
Contra-rotating
propellers. |
Tandem propellers. |
Conventional fixed-pitch
propeller. |
|
D |
Which of the following
propulsor types represents the proper terminology for a Voith Schneider
drive? |
Ducted propeller |
Tandem propellers |
Vane wheel |
Cycloidal propeller |
|
A |
Which of the following
propulsor types represents the proper terminology for a screw propeller
of the conventional design? |
Fixed pitch propeller |
Cycloidal propeller |
Detachable-blade
(built-up) propeller |
Controllable-pitch
propeller |
|
C |
When an electricity
generating plant features shaft-driven generators, what type of propulsor
is generally used for main propulsion? |
Tandem propellers |
Detachable-blade
(built-up) propeller |
Controllable-pitch
propeller |
Fixed-pitch propeller |
|
B |
Which of the following
propulsor types would be used with unidirectional propulsion shafting rotation? |
Fixed-pitch propeller |
Controllable-pitch
propeller |
Tandem propellers |
Detachable-blade
(built-up) propeller |
|
D |
What type of propeller
consists of a flat disc set flush with the under surface of the vessel's
hull with a number of vertical, rudder like blades projecting from it? |
Contra-rotating
propeller |
Tandem propeller |
Helicoidal propeller |
Cycloidal propeller |
|
A |
Which of the following
propulsor types represents the proper terminology for a Z-drive? |
Azimuthing propulsor |
Jet drive |
Cycloidal propeller |
Azipod propulsor |
|
C |
Which of the following
propulsor types represents the proper terminology for electric propulsion
where the drive motors are outside the ship's hull? |
Jet drive |
Azimuthing propulsor |
Azipod propulsor |
Cycloidal propeller |
|
D |
Concerning the
operating mechanism of a controllable-pitch propeller, what statement is
true? |
If the hydraulic
actuator is outboard, a mechanical pull-push rod is located within the propeller
shaft. If the hydraulic actuator is inboard, hydraulic oil pipes are located
within the propeller shaft. |
If the hydraulic
actuator is inboard or outboard, the blade rotating mechanism is actuated
by a mechanical pull-push rod located within the propeller shaft. |
If the hydraulic
actuator is inboard or outboard, hydraulic oil pipes are located within
the propeller shaft in either case. |
If the hydraulic
actuator is inboard, a mechanical pull-push rod is located within the propeller
shaft. If the hydraulic actuator is outboard, hydraulic oil pipes are located
within the propeller shaft. |
|
B |
If a main propulsion
shafting arrangement is such that no strut or strut bearing is required,
what is an alternative name given to the propeller shaft, which is the section
of shafting that the propeller is attached to? |
Line shaft |
Tail shaft |
Thrust shaft |
Head shaft |
|
D |
What type of bearing
is most generally used as an independent main thrust block on merchant ships? |
Split-half journal
type bearing. |
Plain thrust bearing. |
Single piece bushing. |
Pivoted-shoe thrust
bearing. |
|
D |
What statement
is true concerning the lubrication of line shaft bearings? |
Line shaft bearings
are generally lubricated by wick lubrication. |
Line shaft bearing
are generally lubricated by force-feed lubrication. |
Line shaft bearings
are generally lubricated by gravity feed lubrication. |
Line shaft bearings
are generally lubricated by oiling rings or discs |
|
A |
What statement
is true concerning the arrangement of line shaft bearing housings? |
Line shaft bearing
housings are typically split half pedestal type bearing housings. |
Line shaft bearing
housings are typically split half flange type bearing housings. |
Line shaft bearing
housings are typically single-piece flange type bearing housings. |
Line shaft bearing
housings are typically single-piece pedestal type bearing housings. |
|
A |
What statement
is true concerning the ability of a line shaft bearing to adapt to shaft
misalignment as the ship's hull flexes? |
Some line shaft
bearings may have only a bottom half bearing shell, which allows for deflection
upwards only. Other line shaft bearings may be spherically-seated self-aligning
bearings or conventional non-aligning type bearings. |
All line shaft
bearings have only a top half bearing shell, which allows for deflection
downwards only. As such no provision is made for allowing for deflection
in other directions. |
All line shaft
bearings have only a bottom half bearing shell, which allows for deflection
upwards only. As such no provision is made for allowing for deflection in
other directions. |
Some line shaft
bearings may have only a top half bearing shell, which allows for deflection
downwards only. Other line shaft bearings may be spherically-seated self-aligning
bearings or conventional non-aligning type bearings. |
|
A |
What statement
is true concerning the purpose of an independent main thrust bearing where
used? |
The main purpose
of the main thrust bearing is to absorb axial thrust and to transmit the
axial thrust developed by the propeller to the ship's hull. |
The main purpose
of the main thrust bearing is to absorb axial thrust and maintain the shaft
in proper axial alignment. |
The main purpose
of the main thrust bearing is to absorb radial thrust and maintain the shaft
in proper radial alignment. |
The main purpose
of the main thrust bearing is to absorb radial thrust and to transmit the
radial thrust developed by the propeller to the ship's hull. |
|
D |
Which line shaft
bearing is most likely to have both upper and lower half bearing shells
on merchant ships? |
The intermediate
line shaft bearing. |
The forward most
line shaft bearing. |
All line shaft
bearings have only a lower bearing shell. |
The aftermost
line shaft bearing. |
|
C |
Concerning the
arrangements of a disk-oiled line shaft bearing, what statement is true? |
The disk is clamped
to the shaft with the lowermost part immersed in oil, and the distribution
of the oil to the bearing is by the action of an oil wick.
o |
The disk fits
loosely on the shaft with the lowermost part immersed in oil, and the distribution
of the oil to the bearing is by wick action |
The disk is clamped
to the shaft with the lowermost part immersed in oil, and the distribution
of the oil to the bearing is by the action of an oil scraper. |
The disk fits
loosely on the shaft with the lowermost part immersed in oil, and the distribution
of the oil to the bearing is similar to the action of oiling rings. |
|
D |
What statement
is true with respect to the back of a propeller blade? |
The back of the
propeller blade is the side of the blade which faces upstream during ahead
motion and is the side of the blade known as the pressure side. |
The back of the
propeller blade is the side of the blade which faces downstream during ahead
motion and is the side of the blade known as the pressure side. |
The back of the
propeller blade is the side of the blade which faces downstream during ahead
motion and is the side of the blade known as the suction side. |
The back of the
propeller blade is the side of the blade which faces upstream during ahead
motion and is the side of the blade known as the suction side. |
|
D |
What is meant
by the term "left-handed" propeller? |
A "left-handed"
propeller is a propeller located on the starboard side and which can rotate
in either direction. |
A "left-handed"
propeller is a propeller located on the port side and which can rotate in
either direction. |
A "left-handed"
propeller is a propeller which rotates in the counter-clockwise direction
when viewed from ahead. |
A "left-handed"
propeller is a propeller which rotates in the counter-clockwise direction
when viewed from astern. |
|
B |
What is meant
by the term "right-handed" propeller? |
A "right-handed"
propeller is a propeller located on the port side and which can rotate in
either direction. |
A "right-handed"
propeller is a propeller which rotates in the clockwise direction when viewed
from astern. |
A "right-handed"
propeller is a propeller located on the starboard side and which can rotate
in either direction. |
A "right-handed"
propeller is a propeller which rotates in the clockwise direction when viewed
from ahead. |
|
D |
What statement
is true with respect to the pressure side of a propeller blade? |
The pressure side
of the propeller blade is the side of the blade which faces downstream during
ahead motion and is also known as the back of the blade. |
The pressure side
of the propeller blade is the side of the blade which faces upstream during
ahead motion and is also known as the back of the blade. |
The pressure side
of the propeller blade is the side of the blade which faces upstream during
ahead motion and is also known as the face of the blade. |
The pressure side
of the propeller blade is the side of the blade which faces downstream during
ahead motion and is also known as the face of the blade. |
|
C |
Concerning transverse
fixed tunnel thrusters, what statement is true? |
Transverse fixed
tunnel thrusters are oriented fore-to-aft, usually located at the stern
of a vessel, and used for docking, undocking, and low-speed maneuvering.
|
Transverse fixed
tunnel thrusters are oriented athwartships, usually located at the bow of
a vessel, and used to supplement main propulsion for higher sustained speeds. |
Transverse fixed
tunnel thrusters are oriented athwartships, usually located at the bow of
a vessel, and used for docking, undocking, and low-speed maneuvering. |
Transverse fixed
tunnel thrusters are oriented fore-to-aft, usually located at the stern
of a vessel, and used to supplement main propulsion for higher sustained
speeds. |
|
C |
Which set of operating
conditions would be most problematic in terms of the deterioration of the
insulation resistance of the drive motor of an electric motor driven transverse
tunnel bow thruster? |
Frequently used
thrusters where the bow thruster machinery compartment is particularly cold.
|
Frequently used
thrusters where the bow thruster machinery compartment is particularly warm. |
Infrequently used
thrusters where the bow thruster machinery compartment is particularly cold. |
Infrequently used
thrusters where the bow thruster machinery compartment is particularly warm. |
|
D |
Concerning steerable
internal duct thrusters, what statement is true? |
The thrust direction
of the steerable internal duct thruster is determined by the direction of
rotation of the pump. |
The thrust direction
of the steerable internal duct thruster is determined by reversing the pitch
angle of the pump impeller. |
The thrust direction
of the steerable internal duct thruster is determined by the orientation
of the pump inlet guide vanes. |
The thrust direction
of the steerable internal duct thruster is determined by the orientation
of the water discharge vectoring ring. |
|
B |
With respect to
the vectoring ring of a steerable internal duct thruster, what statement
represents the operating principle of the vectoring ring? |
The vectoring
ring is used to control the orientation of the inlet guide vanes to the
pump inlet. |
The vectoring
ring is used to control the orientation of the deflector vanes of the pump
discharge. |
The vectoring
ring is used to control the speed and direction of rotation of the pump. |
The vectoring
ring is used to control the orientation of the vanes on the pump impeller. |
|
A |
What statement
represents the fundamental difference between an azimuthing thruster and
a podded propulsor? |
With an azimuthing
thruster the prime mover is located inside the hull, and with a podded propulsor
the prime mover is located outside the hull. |
With an azimuthing
thruster the prime mover is located outside the hull, and with a podded
propulsor the prime mover is located inside the hull. |
With an azimuthing
thruster the thruster is not steerable, and with a podded propulsor the
propulsor is steerable. |
With an azimuthing
thruster the thruster is steerable, and with a podded propulsor the propulsor
is not steerable. |
|
D |
With respect to
a "pusher" type azimuthing thruster, what statement is true? |
With an azimuthing
angle of 0°, the azimuthing thruster's propeller is directly abaft of the
gear unit, but the gear unit is in the wake of the azimuthing thruster's
propeller. |
With an azimuthing
angle of 0°, the gear unit is directly abaft of and in the wake of the azimuthing
thruster's propeller. |
With an azimuthing
angle of 0°, the gear unit is directly abaft of the azimuthing thruster's
propeller, but the azimuthing thruster's propeller is in the wake of the
gear unit. |
With an azimuthing
angle of 0°, the azimuthing thruster's propeller is directly abaft of and
in the wake of the gear unit. |
|
A |
With respect to
a "tractor" type azimuthing thruster, what statement is true? |
With an azimuthing
angle of 0°, the gear unit is directly abaft of and in the wake of the azimuthing
thruster's propeller. |
With an azimuthing
angle of 0°, the azimuthing thruster's propeller is directly abaft of and
in the wake of the gear unit. |
With an azimuthing
angle of 0°, the gear unit is directly abaft of the azimuthing thruster's
propeller, but the azimuthing thruster's propeller is in the wake of the
gear unit. |
With an azimuthing
angle of 0°, the azimuthing thruster's propeller is directly abaft of the
gear unit, but the gear unit is in the wake of the azimuthing thruster's
propeller. |
|
C |
By what means
is electric current conveyed to the electric drive motor of a podded propulsor? |
Current is conveyed
from the source to a set of stationary brushes, then through a single rotating
slip ring and then on to the motor windings.
|
Current is conveyed
from the source to a set of stationary slip rings, then through a set of
rotating brushes and then on to the motor windings. |
Current is conveyed
from the source to a set of stationary brushes, then through a set of rotating
slip rings and then on to the motor windings. |
Current is conveyed
from the source to the stator of a synchronous transmitter, and by synchro
action to the rotor of a synchronous receiver. |
|
D |
What type of propulsor
is typically used in electric motor driven, transverse, tunnel bow thrusters
to limit the starting current of the single speed drive motor? |
Fixed-pitch propeller |
Detachable-blade
(built-up) propeller |
Cycloidal propeller |
Controllable-pitch
propeller |
|
B |
What is the primary
advantage of transverse bow and stern tunnel thrusters when installed on
ships? |
They provide increased
overall propulsive reverse thrust. |
They provide increased
maneuverability at low ship speeds. |
They provide increased
overall propulsive forward thrust. |
They provide increased
maneuverability at high ship speeds. |
|
C |
The gears used
for virtually all marine propulsion reduction gear sets are of what type? |
Single spur gears |
Single helical
gears |
Double helical
gears |
Double bevel gears |
|
D |
Of the following
propulsion modes, which one would operate with a geared-drive featuring
a double reduction? |
Slow speed diesel |
Medium speed diesel |
High speed diesel |
Gas turbine |
|
A |
An 8" diameter
wheel is driving a 20" diameter wheel via a pair of belts. The power
input is supplied by a 5 HP motor rotating the driving wheel at 300 RPM.
If the efficiency of the transmission is 80%, what RPM and torque is delivered
to the driven wheel? |
120 RPM at 4 HP |
160 RPM at 4 HP |
220 RPM at 4.5
HP |
220 RPM at 4.8
HP |
|
B |
Of the following
propulsion modes, which one would operate with a geared-drive featuring
a single reduction? |
Slow speed diesel |
Medium speed diesel |
Steam turbine |
Gas turbine |
|
A |
What is an example
of an epicyclic gear? |
Planetary gear |
Articulated gear |
Nested gear |
Locked train gear |
|
A |
For a parallel
axis single reduction gear, what statement is true? |
The drive pinion
is the smaller of the two gears and rotates at a relatively high speed.
The driven gear is the larger of the two gears and rotates at a relatively
low speed. |
The drive pinion
is the smaller of the two gears and rotates at a relatively low speed. The
driven gear is the larger of the two gears and rotates at a relatively high
speed. |
The drive pinion
is the larger of the two gears and rotates at a relatively high speed. The
driven gear is the smaller of the two gears and rotates at a relatively
low speed. |
The drive pinion
is the larger of the two gears and rotates at a relatively low speed. The
driven gear is the smaller of the two gears and rotates at a relatively
high speed. |
|
D |
Which of the listed
reduction gear sets has the input and output shafts in-line with one another? |
Parallel axis
gearing |
Bevel gearing |
Worm gearing |
Epicyclic gearing |
|
B |
Which of the following
couplings or clutches would be able to prevent the transmission of torsional
vibrations from an engine to a reduction gear? |
Inflatable tire-type
pneumatic clutch |
Hydraulic fluid-type
clutch |
Multiple disk
friction clutch |
Solid coupling |
|
D |
Which of the following
couplings or clutches allows, within limits, a certain degree of slip? |
Inflatable tire
type clutch |
Flexible coupling |
Multiple disk
friction clutch |
Electro-magnetic
clutch |
|
A |
Concerning main
propulsion reduction gears, what statement is true? |
The reduction
gear allows the prime mover to rotate efficiently at relatively high speed
and low torque and allows the propeller to rotate efficiently at relatively
low speed and high torque. |
The reduction
gear allows the prime mover to rotate efficiently at relatively high speed
and high torque and allows the propeller to rotate efficiently at relatively
low speed and low torque. |
The reduction
gear allows the prime mover to rotate efficiently at relatively low speed
and low torque and allows the propeller to rotate efficiently at relatively
high speed and high torque. |
The reduction
gear allows the prime mover to rotate efficiently at relatively low speed
and high torque and allows the propeller to rotate efficiently at relatively
high speed and low torque. |
|
C |
What is a shipboard
application for a worm gear drive? |
Main propulsion
reduction gear. |
Turbo-generator
reduction gear. |
Main engine turning
gear. |
Auxiliary power
take-off gear. |
|
C |
Which of the following
propulsor types represents the proper terminology for a Voith Schneider
drive? |
Tandem propellers |
Ducted propeller |
Cycloidal propeller |
Vane wheel |
|
A |
When an electricity
generating plant features shaft-driven generators, what type of propulsor
is generally used for main propulsion? |
Controllable-pitch
propeller |
Tandem propellers |
Fixed-pitch propeller |
Detachable-blade
(built-up) propeller |
|
B |
What type of propeller
consists of a flat disc set flush with the under surface of the vessel's
hull with a number of vertical, rudder-like blades projecting from it? |
Helicoidal propeller |
Cycloidal propeller |
Contra-rotating
propeller |
Tandem propeller |
|
B |
Which of the following
propulsor types represents the proper terminology for electric propulsion
where the drive motors are outside the ship's hull? |
Jet drive |
Azipod propulsor |
Cycloidal propeller |
Azimuthing propulsor |
|
B |
Which of the following
propulsor types does not require the use of a separate rudder for steerage? |
Contra-rotating
propellers. |
Cycloidal propellers. |
Conventional fixed-pitch
propeller. |
Tandem propellers. |
|
C |
Concerning steerable
internal duct thrusters, what statement is true? |
The thrust direction
of the steerable internal duct thruster is determined by the orientation
of the pump inlet guide vanes.
|
The thrust direction
of the steerable internal duct thruster is determined by reversing the pitch
angle of the pump impeller. |
The thrust direction
of the steerable internal duct thruster is determined by the orientation
of the water discharge vectoring ring. |
The thrust direction
of the steerable internal duct thruster is determined by the direction of
rotation of the pump. |
|
D |
What statement
represents the fundamental difference between an azimuthing thruster and
a podded propulsor? |
With an azimuthing
thruster the thruster is not steerable, and with a podded propulsor the
propulsor is steerable. |
With an azimuthing
thruster the thruster is steerable, and with a podded propulsor the propulsor
is not steerable. |
With an azimuthing
thruster the prime mover is located outside the hull, and with a podded
propulsor the prime mover is located inside the hull. |
With an azimuthing
thruster the prime mover is located inside the hull, and with a podded propulsor
the prime mover is located outside the hull. |
|
B |
With respect to
a "tractor" type azimuthing thruster, what statement is true? |
With an azimuthing
angle of 0°, the gear unit is directly abaft of the azimuthing thruster's
propeller, but the azimuthing thruster's propeller is in the wake of the
gear unit. |
With an azimuthing
angle of 0°, the gear unit is directly abaft of and in the wake of the azimuthing
thruster's propeller. |
With an azimuthing
angle of 0°, the azimuthing thruster's propeller is directly abaft of the
gear unit, but the gear unit is in the wake of the azimuthing thruster's
propeller. |
With an azimuthing
angle of 0°, the azimuthing thruster's propeller is directly abaft of and
in the wake of the gear unit. |
|
C |
What type of propulsor
is typically used in electric motor driven, transverse, tunnel bow thrusters
to limit the starting current of the single speed drive motor? |
Cycloidal propeller |
Detachable-blade
(built-up) propeller |
Controllable-pitch
propeller |
Fixed-pitch propeller |
|
D |
Which set of operating
conditions would be most problematic in terms of the deterioration of the
insulation resistance of the drive motor of an electric motor driven transverse
tunnel bow thruster? |
Frequently used
thrusters where the bow thruster machinery compartment is particularly warm. |
Frequently used
thrusters where the bow thruster machinery compartment is particularly cold. |
Infrequently used
thrusters where the bow thruster machinery compartment is particularly warm. |
Infrequently used
thrusters where the bow thruster machinery compartment is particularly cold. |
|
B |
Of the following
propulsion modes, which one would operate with a geared-drive featuring
a single reduction? |
Slow speed diesel |
Medium speed diesel |
Steam turbine |
Gas turbine |
|
A |
For a parallel
axis single reduction gear, what statement is true? |
The drive pinion
is the smaller of the two gears and rotates at a relatively high speed.
The driven gear is the larger of the two gears and rotates at a relatively
low speed. |
The drive pinion
is the smaller of the two gears and rotates at a relatively low speed. The
driven gear is the larger of the two gears and rotates at a relatively high
speed. |
The drive pinion
is the larger of the two gears and rotates at a relatively high speed. The
driven gear is the smaller of the two gears and rotates at a relatively
low speed. |
The drive pinion
is the larger of the two gears and rotates at a relatively low speed. The
driven gear is the smaller of the two gears and rotates at a relatively
high speed. |
|
B |
Which of the following
couplings or clutches would be able to prevent the transmission of torsional
vibrations from an engine to a reduction gear? |
Inflatable tire-type
pneumatic clutch |
Hydraulic fluid-type
clutch |
Multiple disk
friction clutch |
Solid coupling |
|
A |
Concerning main
propulsion reduction gears, what statement is true? |
The reduction
gear allows the prime mover to rotate efficiently at relatively high speed
and low torque and allows the propeller to rotate efficiently at relatively
low speed and high torque. |
The reduction
gear allows the prime mover to rotate efficiently at relatively high speed
and high torque and allows the propeller to rotate efficiently at relatively
low speed and low torque. |
The reduction
gear allows the prime mover to rotate efficiently at relatively low speed
and low torque and allows the propeller to rotate efficiently at relatively
high speed and high torque. |
The reduction
gear allows the prime mover to rotate efficiently at relatively low speed
and high torque and allows the propeller to rotate efficiently at relatively
high speed and low torque. |
|
D |
Of the following
propulsion modes, which one would operate with a geared-drive featuring
a double reduction? |
Slow speed diesel |
Medium speed diesel |
High speed diesel |
Gas turbine |
|
D |
If a main propulsion
shafting arrangement is such that a strut and strut bearing is required,
what is the name of the section of shafting that passes through the hull
penetration to the closest water-tight bulkhead? |
Tail or propeller
shaft |
Line shaft |
Thrust shaft |
Stern tube shaft |
|
A |
What statement
is true concerning the arrangement of line shaft bearing housings? |
Line shaft bearing
housings are typically split half pedestal type bearing housings. |
Line shaft bearing
housings are typically single-piece pedestal type bearing housings. |
Line shaft bearing
housings are typically single-piece flange type bearing housings. |
Line shaft bearing
housings are typically split half flange type bearing housings. |
|
A |
What statement
is true concerning the purpose of an independent main thrust bearing where
used? |
The main purpose
of the main thrust bearing is to absorb axial thrust and to transmit the
axial thrust developed by the propeller to the ship's hull. |
The main purpose
of the main thrust bearing is to absorb axial thrust and maintain the shaft
in proper axial alignment. |
The main purpose
of the main thrust bearing is to absorb radial thrust and maintain the shaft
in proper radial alignment. |
The main purpose
of the main thrust bearing is to absorb radial thrust and to transmit the
radial thrust developed by the propeller to the ship's hull. |
|
C |
Concerning the
proper lubrication of a ring-oiled line shaft bearing, what statement is
true? |
The oil level
should be maintained high enough so that some oil is seen exiting the bearing
along the shaft.
|
The oil level
should be high enough so that the oiling rings dip into the oil, but the
rings must not be allowed to freely rotate with the shaft. |
The oil level
should be high enough so that the oiling rings dip into the oil, and the
rings must freely rotate with the shaft. |
The oil level
should be maintained high enough so that the entire bearing is continuously
flooded. |
|
D |
What type of bearing
is most generally used as an independent main thrust block on merchant ships? |
Split-half journal
type bearing. |
Plain thrust bearing. |
Single piece bushing. |
Pivoted-shoe thrust
bearing. |
|
C |
The property of
a fuel oil which is a measurement of its available energy, is known as its
__________. |
cetane index |
cetane number |
heating value |
viscosity index |
|
D |
Which of the listed
characteristics of fuel oil establishes the danger point as far as transferring,
pumping, and firing procedures are concerned? |
Viscosity |
Fire point |
Specific gravity |
Flash point |
|
B |
Which characteristic
of fuel oil is the most significant when determining the temperature to
which the fuel oil must be heated for proper atomization? |
Flash point |
Viscosity |
Pour point |
Specific gravity |
|
B |
The BTU value
of fuel oil is determined by a/an __________. |
viscosimeter |
calorimeter |
open cup test |
hydrometer |
|
A |
Which combustible
element in fuel oil is considered a significant and major source of air
pollution? |
Sulfur |
Vanadium |
Nitrogen |
Hydrogen |
|
D |
When heated, fuel
oil will __________. |
have a higher
specific heat |
increase in specific gravity |
increase in viscosity |
expand in volume |
|
B |
The main reason
for having a low suction line on the fuel oil service or settling tanks
is to __________. |
prevent loss of
suction during rough weather |
facilitate water
removal |
decrease suction
head on the pump |
increase the amount
of fuel available for use |
|
A |
Which of the following
terms is used to identify the pressure of a liquid entering a centrifugal
pump? |
Suction head |
Pump head |
Discharge head |
Total head |
|
A |
The shaft sleeve
for the pump illustrated is identified by the item numbered as
__________. Illustration GS-0143 |
14 |
17 |
27 |
68 |
|
D |
A centrifugal
bilge pump requires priming __________. |
o initially unload
the pump by having its head pressure equal to discharge pressure |
in order to overcome
the potential energy of water in the discharge line |
primarily to lubricate
the shaft seals |
due to the inability
of this type of pump to lift water to cover the suction (eye) of the impeller |
|
D |
The simplest method
to use for determining if a centrifugal pump is operating as designed, is
to __________. |
closely observe
the pump discharge temperature |
momentarily close
off the suction valve, and watch for a rise in pressure |
use a clamp on
ammeter and compare the readings to past records |
close off the
discharge valve, and watch for a rise in pressure |
|
A |
The pressure of
a liquid leaving the pump can be referred to as the __________. |
discharge head |
total head |
suction head |
net positive suction
head |
|
C |
Which of the following
statements is true concerning centrifugal pumps? |
They are particularly
suited for pumping high viscosity fluids. |
They are always
mounted in a horizontal position. |
The flow of liquid
is developed by imparting energy due to the rotation of an impeller. |
They are started
with the discharge valve opened. |
|
D |
A pump is defined
as a device that __________. |
produces pressure |
creates a vacuum
to move a liquid in all installations |
is to develop
a pressure differential |
imparts energy
to a fluid to move it from point "A" to point "B" |
|
B |
The basic function
of the centrifugal pump impeller is to __________. |
separate air from
the liquid being pumped |
directly increase
the velocity of the liquid being pumped |
directly increase
the pressure of the liquid being pumped |
convert the potential
energy of the liquid to kinetic energy |
|
B |
The function of
seal cages, or lantern rings installed in the centrifugal pump stuffing
boxes, is to __________. |
lubricate the
packing |
distribute the
sealing liquid within the stuffing box |
seal air from
entering along the shaft |
cool the shaft |
|
C |
Air leakage between
the shaft and stuffing box packing in a centrifugal pump is prevented by
__________. |
lantern rings
between the packing rings |
a compressed packing
gland |
a liquid seal |
the stuffing box
gland |
|
C |
Permanent centrifugal
pump shaft damage due to erosion, corrosion, and wear at the stuffing box
is usually prevented by __________. |
wearing rings |
internally flooded
lantern rings |
renewable sleeves |
a hardened sprayed
metal coating |
|
D |
What should be
done if localized scoring is discovered on a pump shaft sleeve during routine
maintenance inspection? |
Reassemble the
pump and provide more water leak off for lubrication. |
Reassemble the
pump and set the governor to obtain a slower speed. |
Check for parallel
alignment of the sleeve radial face to the sleeve bore. |
Correct the cause
of scoring and install a new shaft sleeve. |
|
D |
To prevent overheating
and scoring of the shaft after repacking the stuffing box, which of the
following procedures should be carried out? |
Operating the
pump slowly and applying oil freely to the shaft until the packing is properly
seated. |
Tightening the
gland in all the way and then backing it off slightly. |
Lubricate the
lantern ring with cylinder oil before installing new turns of packing. |
Tighten the packing
in small increments while the pump is operating. |
|
B |
A centrifugal
pump gradually develops insufficient discharge pressure. What corrective
action is required? |
Throttle in on
the discharge valve. |
Replace the wearing
rings. |
Replace the lantern
rings. |
Throttle in on
the suction valve. |
|
B |
When repacking
a stuffing box fitted with a lantern ring, which of the following precautions
should be observed? |
Be certain that
all packing is fitted loosely to the shaft. |
Replace all of
the packing rings. |
For good lubrication,
apply a fine grade lapping compound between the shaft and packing. |
Block off the
sealing water connection. |
|
A |
When renewing
spiral packing in a centrifugal pump stuffing box, after the packing is
firmly seated, the packing gland nuts should be __________. |
loosened, and
then retightened with the pump running under normal conditions |
loosened until
the gland clears the stuffing box |
left in that position |
tightened an additional
10% to compress the packing |
|
C |
A pump shaft that
is bent or distorted should normally be __________. |
reconditioned
by metalizing and machining |
straightened by
applying heat and torsion |
replaced with
a satisfactory spare |
repaired by a
suitable welding process |
|
A |
Why should the
use of metallic or semi-metallic packing hooks or pullers be avoided on
bronze or brass shafts, rods, plungers, or sleeves? |
Scoring may result. |
Bonnet corrosion
may result. |
Heat transfer
is restricted. |
Valve seat will
be damaged. |
|
D |
You suspect a
problem with the centrifugal fire pump on your ship, and begin to slowly
close the discharge valve. Your suspicion is confirmed when the __________. |
suction valve
is closed off, and the discharge pressure begins to decrease |
suction valve
is closed off, yet the relief valve does not lift |
discharge valve
is 80% closed and the relief valve lifts |
discharge valve
is closed off and there is no change in the discharge pressure |
|
B |
A centrifugal
pump may fail to deliver water when first started if the __________. |
seal ring is improperly
located |
pump is not primed |
water seal pipe
is plugged |
impeller is flooded |
|
A |
Reduced capacity,
accompanied by vibration and noise at the suction of a centrifugal pump,
results from cavitation in the fluid being pumped. Cavitation describes
the formation of __________. |
vapor pockets |
steam knock |
fluid friction |
water hammer action |
|
A |
Pitting in the
suction areas of a centrifugal pump bronze impeller is usually caused by
__________. |
cavitation |
corrosion |
electrolysis |
abrasion |
|
B |
Charring or glazing
of the inner circumference of the packing rings in a centrifugal pump is
caused by __________. |
under tightening
the packing |
insufficient lubrication
of the packing |
failure to seat
the packing rings |
packing ring rotation |
|
A |
Excessive air
leakage into the suction side of a centrifugal pump would be indicated by
which of the following operational problems? |
The pump delivers
full capacity when started, but gradually slackens off to an abnormally
low flow. |
The motor over
current protective device continually shuts the pump down. |
The pump packing
gland overheats after short operating periods. |
Pounding noises
can be heard at the pump suction chest. |
|
B |
Which of the following
methods applies to how a vacuum is created by a jet pump or an eductor? |
A reciprocating
plunger directly applying force to a fluid. |
A rapidly moving
stream of fluid passing through a nozzle. |
A propeller drawing
a fluid through a Venturi nozzle. |
Centrifugal force
converted into potential energy. |
|
D |
The three basic
parts of any eductor are the nozzle, the suction chamber, and the __________. |
compressor |
injector |
siphon |
diffuser |
|
C |
A distinguishing
feature of an eductor, when compared to other pumps, is the __________. |
small size of
impeller |
ease at which
the wearing rings may be changed |
lack of moving
parts |
discharge end
being smaller than the suction end |
|
A |
Which of the following
statements represents the main difference between a stuffing box gland and
a mechanical seal for sealing the shaft of a centrifugal pump? |
If packing fails,
the pump can be kept running temporarily by tightening the gland, but if
a mechanical seal fails it must be totally renewed to stop the leakage. |
Packed stuffing
box glands are subject to wear, but mechanical seals are not. |
The sealing surface
of a mechanical seal is parallel to the shaft, but the sealing surface of
a packed gland is perpendicular to the shaft. |
Packed stuffing
box glands must be cooled by the liquid being pumped, but mechanical seals
do not require cooling. |
|
C |
Which of the materials
listed is used as the dynamic seal material on mechanical seals installed
on most centrifugal pumps used in water service? |
Copper and carbon. |
Copper. |
Carbon. |
Bronze. |
|
D |
Which of the following
statements is true regarding mechanical seals? |
They may be used
in lieu of conventional packing glands for any service other than saltwater. |
Once placed into
service, leakage between the dynamic seal surfaces may be reduced by monthly
adjustment of the spring compression. |
They are not suitable
for use on fuel oil transfer pumps. |
They are normally
lubricated and cooled by the fluid being pumped. |
|
B |
Which of the listed
types of seals is used effectively for pumps handling toxic or highly flammable
liquids that cannot be permitted to escape into the atmosphere? |
Conventional stuffing
box |
Double mechanical
seal |
Rubber bellows
mechanical seal |
External mechanical
seal |
|
B |
Mechanical shaft
seals used on water service pumps require lubrication of the seal faces
to minimize deposits of foreign matter on those surfaces. Which of the following
pressures and lubricants are required? |
Water under negative
pressure. |
Water under positive
pressure. |
Oil under positive
pressure. |
Oil under negative
pressure. |
|
C |
Which of the devices
listed is used to maintain a snug interface between the rotating and stationary
seal members shown in the illustration? Illustration GS-0071 |
notch and keyway |
bellows |
spring |
seal retaining
ring |
|
D |
Spring reinforced
oil seals are generally installed with the tail or lip of the seal facing
__________. Illustration GS-0152 |
away from the
oil pressure being sealed |
away from the
bearing housing recess |
toward the bearing
preload washer |
toward the oil
pressure being sealed |
|
A |
One disadvantage
of using a mechanical shaft seal instead of mechanical packing is that __________. |
seal failure usually
requires the immediate removal of the pump from service |
it requires periodic
disassembly and adjustment |
it is unsuitable
for high pressure applications |
it is unsuitable
for high temperature applications |
|
D |
When installing
a mechanical shaft seal on a pump, it is important to __________. |
run the pump "dry"
for initial break-in of the shaft seal |
polish the seating
faces with emery cloth prior to assembly |
make the final
spring collar adjustments with the pump running |
ensure that correct
spring pressure is applied to the seating faces |
|
B |
One of the main
differences between a propeller pump and a centrifugal pump is the absence
of a __________. |
reciprocating
piston in the centrifugal type pump |
volute in the
propeller type pump |
velocity nozzle
in the centrifugal type pump |
volute in the
centrifugal type pump |
|
D |
Which type of
pump would normally be used to transfer fairly large quantities of fluids
at relatively low pressures? |
gear type |
reciprocating
type |
screw type |
propeller type |
|
D |
Which of the pumping
systems listed for use aboard ship will most likely use a propeller type
pump? |
Fuel oil service
booster system |
Fluid power transmission
system |
Steering gear
system |
Main circulating
system |
|
C |
Which of the following
is NOT an identifiable characteristic of a steam reciprocating pump? |
Direct-acting |
Vertical |
Diffuser |
High-pressure |
|
B |
Which of the following
valve arrangements permits the reciprocating pump liquid piston to take
suction from the suction chamber, and simultaneously discharge through the
discharge chamber during the up and down strokes? |
Two relief valves,
one on each of the liquid cylinder. |
Two sets of valves,
one set each for suction and discharge located in the water chest. |
One set of valves
in the water chest and another set in the liquid cylinder. |
Two sets of suction
and discharge valves in the liquid cylinder. |
|
C |
The suction-force
principle of operation is a typical characteristic of __________. |
centrifugal pumps |
jet pumps |
reciprocating
pumps |
propeller pumps |
|
B |
Which of the listed
devices is used to control the admission of steam to the steam cylinder
of a reciprocating pump? |
Valve operating
differential |
Pilot valve and
operating rod |
Pump rod |
Crosshead arm |
|
B |
Which of the listed
reciprocating pump parts control the position of the pilot slide valve? |
Moving tappets |
Movement of the
main piston through the steam cylinder |
Adjusting of the
tappet collars |
Stay rods |
|
D |
The total length
of stroke in a reciprocating steam pump can be adjusted by __________. |
twisting the stay
rod in a clockwise direction |
variations in
the throttle adjustment |
increasing or
decreasing the number of packing rings around the piston rod |
changing the setting
of the tappet collars on the pilot valve operating rod |
|
A |
When a reciprocating
pump is operating at maximum speed, the cushioning valves should be __________. |
almost completely
closed |
wide opened |
half opened |
3/4 opened |
|
B |
When securing
a steam reciprocating pump, which of the valves listed should remain open? |
Water cylinder
drain valve |
Steam cylinder
drain valve |
Steam supply valve |
Steam exhaust
valve |
|
B |
When the danger
of freezing exists, all steam driven reciprocating pumps and deck equipment
should be __________. |
watched carefully
while idled |
cycled at least
once a day |
cycled once every
week |
cycled once every
4 days |
|
B |
Which of the lubricants
listed is the best to use on a reciprocating pump rod? |
Vegetable oil. |
Graphite and oil. |
Engine oil. |
Oil mixed with
kerosene. |
|
C |
Which of the listed
types of steam end piston rod packing should be used in a steam reciprocating
pump? |
Reinforced rubber
packing |
Wire impregnated
high temperature packing |
High pressure
graphite packing |
Low pressure braided
asbestos packing |
|
B |
The first step
when resetting the slide valves on a duplex reciprocating pump is to __________. |
position the steam
pistons on 3/4 stroke |
place the steam
pistons in the mid stroke position |
ensure the balance
piston is on the down stroke |
measure the present
port openings to ensure reassembly will be the same |
|
C |
When repacking
a reciprocating pump with more than four rings of packing, the packing is
cut square, installed with the ends abutted, and each succeeding ring staggered
with the butted ends __________. |
120° apart |
180° apart |
90° apart |
45° apart |
|
D |
To safely remove
the piston rod packing from the steam end of a reciprocating pump, you should
__________. |
open the throttle
valve and 'blow' the old packing out |
do nothing, as
this type of pump utilizes O-rings in lieu of packing |
open the steam
chest and pry the packing loose with a scraper |
use a packing
hook |
|
A |
An inadequate
reciprocating bilge pump discharge is most often caused by __________. |
clogged suction
strainers |
clogged drain
valves |
scarred cylinder
walls |
defective intake
valves |
|
A |
Which of the following
conditions would prevent a steam reciprocating pump from delivering its
rated capacity? |
Excessive suction
lift |
Air trapped in
the discharge expansion chamber |
A leaking snifter
valve allowing air to enter the suction side of the pump |
All of the above. |
|
A |
When piston rod
packing persists in leaking on a reciprocating steam pump, the cause may
be __________. |
misalignment of
the crosshead guide |
a loose tappet
collar |
an open snifter
valve |
clogged suction
strainers |
|
B |
A pounding noise
occurring in one cylinder of a steam reciprocating general service pump
could be caused by __________. |
lower than normal
supply steam pressure |
improper adjustment
of steam cushion valves |
loss of air charge
in the pump discharge plenum chamber |
lower than normal
supply steam temperature |
|
A |
Excessive lost
motion in the valve mechanism of a duplex reciprocating pump will cause
the __________. |
pump to operate
sluggishly |
pump to short
stroke continuously at both ends of the stroke for both cylinders |
cushioning valves
to wear |
pistons to stop
in mid-stroke |
|
C |
The output volume
of a positive fixed displacement pump can be changed only by __________. |
changing the angle
of the tilting plate |
moving the shaft
trunnion block |
changing the speed
of the pump |
moving the slide
block and rotor |
|
D |
What type of pump
is shown in the illustration? Illustration GS-0144 |
Double screw rotary
pump |
Deep well centrifugal
pump |
Simplex reciprocating
pump |
Triple screw rotary
pump |
|
D |
The function of
the section labeled "C" in the device illustrated is to provide
a/an __________. Illustration GS-0075 |
area for pump
packing |
passage for sealing
liquid to enter the pump |
bearing surface
for the rotor shaft |
passage for gas
to be discharged |
|
D |
Which of the listed
parts is used in a lobe-type rotary pump to allow for wear on the lobe edges? |
Spur gear adjusters |
Replaceable liner
plates |
Casing gear thrust
bearings |
Replaceable gib
inserts |
|
B |
Liquid is kept
from leaking out at the shaft ends of a helical gear pump by __________. |
the use of shaft
end caps |
a stuffing box |
overlapping spaces
between gear teeth |
a roller bearing |
|
C |
Positive displacement,
helical gear pumps are well suited for pumping oil because __________. |
these pumps are
designed with extreme tooth angles |
it is not necessary
to closely maintain design clearances with this pump |
they are essentially
self-priming and capable of a high suction lift |
stuffing boxes
eliminate the leakage problems usually associated with other gear pumps |
|
D |
The capacity of
a gear type rotary pump, when operated at a constant speed, will decrease
with an increase in the pump __________. |
suction pressure |
discharge volume |
torque rating |
rotor clearances |
|
A |
A spur gear pump
should be operated with the discharge valves __________. |
fully opened |
halfway opened |
throttled |
slightly opened |
|
C |
How does the viscosity
of a fluid being pumped affect the operation of a spur gear pump? |
The pump can only
be used for fluids of high viscosity. |
The pump can only
be used for light oils. |
The viscosity
of the fluid is relatively unimportant in the pump operation. |
The pump cannot
handle fluids more viscous than lubricating oil. |
|
A |
Why is the discharge
pressure of a herringbone gear pump steadier than the discharge pressure
of a simple spur gear pump? |
One discharge
phase begins before the previous discharge phase has been completed. |
The herringbone
gear pump has four spur gears instead of two. |
Clearance between
the gear teeth and casing is smaller. |
The gear teeth
are smaller than those of the simple spur gear pump. |
|
B |
One of the main
differences between the various types of screw pumps is in the __________. |
stuffing box diameter |
pitch of the screws |
direction of rotation
of the screws |
type of driving
gears |
|
A |
An increase in
rotor clearances in a rotary pump will __________. |
decrease pump
capacity |
decrease pump
cavitation |
increase discharge
pressure |
decrease reaction
ring clearance |
|
C |
The pressure of
a liquid leaving the pump can be referred to as the __________. |
suction head |
net positive suction
head |
discharge head |
total head |
|
A |
If the existing
vapor pressure is subtracted from the indicated pressure at the pump suction,
the remainder is the __________. |
apparent net positive
suction head |
pump head |
discharge head |
total suction
head |
|
B |
Which of the following
terms is used to identify the pressure of a liquid entering a centrifugal
pump? |
Discharge head |
Suction head |
Pump head |
Total head |
|
A |
A pump is defined
as a device that __________. |
imparts energy
to a fluid to move it from point "A" to point "B" |
creates a vacuum
to move a liquid in all installations |
produces pressure |
is to develop
a pressure differential |
|
C |
If the existing
vapor pressure is subtracted from the indicated pressure at the pump suction,
the remainder is the __________. |
total suction
head |
pump head |
apparent net positive
suction head |
discharge head |
|
D |
Which of the following
terms is used to identify the pressure of a liquid entering a centrifugal
pump? |
Total head |
Discharge head |
Pump head |
Suction head |
|
D |
Item "B"
in the pump illustration is the __________. Illustration GS-0129 |
wearing ring |
stuffing box |
shaft sleeve |
packing gland |
|
B |
Which of the materials
listed is used as the dynamic seal material on mechanical seals installed
on most centrifugal pumps used in water service? |
Bronze. |
Carbon. |
Copper and carbon. |
Copper. |
|
D |
Which of the following
statements is true regarding mechanical seals? |
They may be used
in lieu of conventional packing glands for any service other than saltwater. |
Once placed into
service, leakage between the dynamic seal surfaces may be reduced by monthly
adjustment of the spring compression. |
They are not suitable
for use on fuel oil transfer pumps. |
They are normally
lubricated and cooled by the fluid being pumped. |
|
C |
Air leakage between
the shaft and stuffing box packing in a centrifugal pump is prevented by
__________. |
lantern rings
between the packing rings |
a compressed packing
gland |
a liquid seal |
the stuffing box
gland |
|
C |
The shaft sleeve
for the pump illustrated is identified by the item numbered as
__________. Illustration GS-0143 |
68 |
27 |
14 |
17 |
|
C |
Water leaking
from a pump packing gland is kept away from the bearing housing by the use
of __________. |
shaft sleeves |
water seals |
water flingers |
lantern rings |
|
B |
Why are removable
sleeves installed on centrifugal pump shafts? |
They can be removed
when it is necessary to lighten the weight of the pump. |
They can be economically
replaced as they wear out. |
They increase
the strength of the shaft. |
They make it easier
to replace the pump shaft packing. |
|
C |
The function of
seal cages, or lantern rings installed in the centrifugal pump stuffing
boxes, is to __________. |
cool the shaft |
lubricate the
packing |
distribute the
sealing liquid within the stuffing box |
seal air from
entering along the shaft |
|
C |
Permanent centrifugal
pump shaft damage due to erosion, corrosion, and wear at the stuffing box
is usually prevented by __________. |
a hardened sprayed
metal coating |
internally flooded
lantern rings |
renewable sleeves |
wearing rings |
|
C |
A recirculating,
or bleed off line is installed on a centrifugal pump in order to __________. |
equalize pressure
on both sides of the suction valve disc |
establish a back
pressure at the labyrinth seal to eliminate leakage |
prevent the pump
from overheating when operating at shutoff head |
decrease the net
positive suction head |
|
C |
Which of the following
statements represents the main difference between a stuffing box gland and
a mechanical seal for sealing the shaft of a centrifugal pump? |
Packed stuffing
box glands are subject to wear, but mechanical seals are not.
|
Packed stuffing
box glands must be cooled by the liquid being pumped, but mechanical seals
do not require cooling. |
If packing fails,
the pump can be kept running temporarily by tightening the gland, but if
a mechanical seal fails it must be totally renewed to stop the leakage. |
The sealing surface
of a mechanical seal is parallel to the shaft, but the sealing surface of
a packed gland is perpendicular to the shaft. |
|
B |
The simplest method
to use for determining if a centrifugal pump is operating as designed, is
to __________. |
use a clamp on
ammeter and compare the readings to past records |
close off the
discharge valve, and watch for a rise in pressure |
closely observe
the pump discharge temperature |
momentarily close
off the suction valve, and watch for a rise in pressure |
|
B |
A centrifugal
bilge pump requires priming __________. |
primarily to lubricate
the shaft seals |
due to the inability
of this type of pump to lift water to cover the suction (eye) of the impeller |
in order to overcome
the potential energy of water in the discharge line |
to initially unload
the pump by having its head pressure equal to discharge pressure |
|
B |
A centrifugal
bilge pump requires priming __________. |
primarily to lubricate
the shaft seals |
due to the inability
of this type of pump to lift water to cover the suction (eye) of the impeller |
in order to overcome
the potential energy of water in the discharge line |
to initially unload
the pump by having its head pressure equal to discharge pressure |
|
B |
If a centrifugal
pump were continually operated with the discharge valve closed, the __________. |
motor controller
overload would open |
pump would eventually
overheat |
relief valve would
continuously cycle open |
motor would overheat |
|
C |
Excessive air
leakage into the suction side of a centrifugal pump would be indicated by
which of the following operational problems? |
The motor over
current protective device continually shuts the pump down.
o |
The pump packing
gland overheats after short operating periods. |
The pump delivers
full capacity when started, but gradually slackens off to an abnormally
low flow. |
Pounding noises
can be heard at the pump suction chest. |
|
A |
Pitting in the
suction areas of a centrifugal pump bronze impeller is usually caused by
__________. |
cavitation |
abrasion |
corrosion |
electrolysis |
|
B |
Reduced capacity,
accompanied by vibration and noise at the suction of a centrifugal pump,
results from cavitation in the fluid being pumped. Cavitation describes
the formation of __________. |
steam knock |
vapor pockets |
fluid friction |
water hammer action |
|
D |
You suspect a
problem with the centrifugal fire pump on your ship, and begin to slowly
close the discharge valve. Your suspicion is confirmed when the __________. |
suction valve
is closed off, and the discharge pressure begins to decrease |
discharge valve
is 80% closed and the relief valve lifts |
suction valve
is closed off, yet the relief valve does not lift |
discharge valve
is closed off and there is no change in the discharge pressure |
|
D |
A centrifugal
pump may fail to deliver water when first started if the __________. |
seal ring is improperly
located |
water seal pipe
is plugged |
impeller is flooded |
pump is not primed |
|
D |
Charring or glazing
of the inner circumference of the packing rings in a centrifugal pump is
caused by __________. |
failure to seat
the packing rings |
packing ring rotation |
under tightening
the packing |
insufficient lubrication
of the packing |
|
B |
When repacking
a stuffing box fitted with a lantern ring, which of the following precautions
should be observed? |
For good lubrication,
apply a fine grade lapping compound between the shaft and packing. |
Replace all of
the packing rings. |
Block off the
sealing water connection. |
Be certain that
all packing is fitted loosely to the shaft. |
|
C |
A centrifugal
pump gradually develops insufficient discharge pressure. What corrective
action is required? |
Throttle in on
the suction valve. |
Replace the lantern
rings. |
Replace the wearing
rings. |
Throttle in on
the discharge valve. |
|
A |
When renewing
spiral packing in a centrifugal pump stuffing box, after the packing is
firmly seated, the packing gland nuts should be __________. |
loosened, and
then retightened with the pump running under normal conditions |
loosened until
the gland clears the stuffing box |
left in that position |
tightened an additional
10% to compress the packing |
|
D |
What should be
done if localized scoring is discovered on a pump shaft sleeve during routine
maintenance inspection? |
Reassemble the
pump and set the governor to obtain a slower speed. |
Reassemble the
pump and provide more water leak off for lubrication. |
Check for parallel
alignment of the sleeve radial face to the sleeve bore. |
Correct the cause
of scoring and install a new shaft sleeve. |
|
A |
Why should the
use of metallic or semi-metallic packing hooks or pullers be avoided on
bronze or brass shafts, rods, plungers, or sleeves? |
Scoring may result. |
Valve seat will
be damaged. |
Heat transfer
is restricted. |
Bonnet corrosion
may result. |
|
A |
A pump shaft that
is bent or distorted should normally be __________. |
replaced with
a satisfactory spare |
straightened by
applying heat and torsion |
repaired by a
suitable welding process |
reconditioned
by metalizing and machining |
|
A |
When installing
a mechanical shaft seal on a pump, it is important to __________. |
ensure that correct
spring pressure is applied to the seating faces |
polish the seating
faces with emery cloth prior to assembly |
run the pump "dry"
for initial break-in of the shaft seal |
make the final
spring collar adjustments with the pump running |
|
A |
Which of the following
statements is true concerning centrifugal pumps? |
A flow is developed
by imparting kinetic energy to the fluid by the rotation of an impeller. |
They operate best
under negative suction pressure conditions. |
They are particularly
well suited for pumping high viscosity fluids. |
They operate more
efficiently when mounted in a horizontal position. |
|
D |
The primary function
of a centrifugal pump volute is to __________. |
develop a high
velocity liquid |
limit hydraulic
end thrust |
initiate flow |
convert velocity
to pressure |
|
C |
The basic function
of the centrifugal pump impeller is to __________. |
separate air from
the liquid being pumped |
convert the potential
energy of the liquid to kinetic energy |
directly increase
the velocity of the liquid being pumped |
directly increase
the pressure of the liquid being pumped |
|
C |
Which of the following
statements is true concerning centrifugal pumps? |
They are always
mounted in a horizontal position. |
They are started
with the discharge valve opened. |
The flow of liquid
is developed by imparting energy due to the rotation of an impeller. |
They are particularly
suited for pumping high viscosity fluids. |
|
D |
The function of
the section labeled "C" in the device illustrated is to provide
a/an __________. Illustration GS-0075 |
passage for sealing
liquid to enter the pump |
bearing surface
for the rotor shaft |
area for pump
packing |
passage for gas
to be discharged |
|
A |
Which of the devices
listed is used to maintain a snug interface between the rotating and stationary
seal members shown in the illustration? Illustration GS-0071 |
spring |
notch and keyway |
seal retaining
ring |
bellows |
|
A |
Which of the listed
parts is used in a lobe-type rotary pump to allow for wear on the lobe edges? |
Replaceable gib
inserts |
Casing gear thrust
bearings |
Spur gear adjusters |
Replaceable liner
plates |
|
C |
What type of pump
is shown in the illustration? Illustration GS-0144 |
Deep well centrifugal
pump |
Simplex reciprocating
pump |
Triple screw rotary
pump |
Double screw rotary
pump |
|
D |
The output volume
of a positive fixed displacement pump can be changed only by __________. |
moving the slide
block and rotor |
changing the angle
of the tilting plate |
moving the shaft
trunnion block |
changing the speed
of the pump |
|
B |
One of the main
differences between the various types of screw pumps is in the __________. |
stuffing box diameter |
pitch of the screws |
direction of rotation
of the screws |
type of driving
gears |
|
D |
Spring reinforced
oil seals are generally installed with the tail or lip of the seal facing
__________. Illustration GS-0152 |
away from the
bearing housing recess |
toward the bearing
preload washer |
away from the
oil pressure being sealed |
toward the oil
pressure being sealed |
|
B |
Which of the listed
types of seals is used effectively for pumps handling toxic or highly flammable
liquids that cannot be permitted to escape into the atmosphere? |
Rubber bellows
mechanical seal |
Double mechanical
seal |
External mechanical
seal |
Conventional stuffing
box |
|
A |
One disadvantage
of using a mechanical shaft seal instead of mechanical packing is that __________. |
seal failure usually
requires the immediate removal of the pump from service |
it is unsuitable
for high pressure applications |
it requires periodic
disassembly and adjustment |
it is unsuitable
for high temperature applications |
|
D |
A spur gear pump
should be operated with the discharge valves __________. |
slightly opened |
halfway opened |
throttled |
fully opened |
|
A |
An increase in
rotor clearances in a rotary pump will __________. |
decrease pump
capacity |
decrease pump
cavitation |
increase discharge
pressure |
decrease reaction
ring clearance |
|
D |
Positive displacement,
helical gear pumps are well suited for pumping oil because __________. |
it is not necessary
to closely maintain design clearances with this pump |
these pumps are
designed with extreme tooth angles |
stuffing boxes
eliminate the leakage problems usually associated with other gear pumps |
they are essentially
self-priming and capable of a high suction lift |
|
D |
The capacity of
a gear type rotary pump, when operated at a constant speed, will decrease
with an increase in the pump __________. |
discharge volume |
suction pressure |
torque rating |
rotor clearances |
|
B |
How does the viscosity
of a fluid being pumped affect the operation of a spur gear pump? |
The pump can only
be used for light oils. |
The viscosity
of the fluid is relatively unimportant in the pump operation. |
The pump cannot
handle fluids more viscous than lubricating oil. |
The pump can only
be used for fluids of high viscosity. |
|
A |
Why is the discharge
pressure of a herringbone gear pump steadier than the discharge pressure
of a simple spur gear pump? |
One discharge
phase begins before the previous discharge phase has been completed. |
The gear teeth
are smaller than those of the simple spur gear pump. |
The herringbone
gear pump has four spur gears instead of two. |
Clearance between
the gear teeth and casing is smaller. |
|
D |
Which of the following
is NOT an identifiable characteristic of a steam reciprocating pump? |
Vertical |
Direct-acting |
High-pressure |
Diffuser |
|
D |
Which of the following
valve arrangements permits the reciprocating pump liquid piston to take
suction from the suction chamber, and simultaneously discharge through the
discharge chamber during the up and down strokes? |
Two sets of suction
and discharge valves in the liquid cylinder. |
One set of valves
in the water chest and another set in the liquid cylinder. |
Two relief valves,
one on each of the liquid cylinder. |
Two sets of valves,
one set each for suction and discharge located in the water chest. |
|
D |
Which of the listed
devices is used to control the admission of steam to the steam cylinder
of a reciprocating pump? |
Pump rod |
Valve operating
differential |
Crosshead arm |
Pilot valve and
operating rod |
|
B |
Which of the listed
reciprocating pump parts control the position of the pilot slide valve? |
Adjusting of the
tappet collars |
Movement of the
main piston through the steam cylinder |
Moving tappets |
Stay rods |
|
A |
The total length
of stroke in a reciprocating steam pump can be adjusted by __________. |
changing the setting
of the tappet collars on the pilot valve operating rod |
variations in
the throttle adjustment |
twisting the stay
rod in a clockwise direction |
increasing or
decreasing the number of packing rings around the piston rod |
|
B |
When securing
a steam reciprocating pump, which of the valves listed should remain open? |
Water cylinder
drain valve |
Steam cylinder
drain valve |
Steam exhaust
valve |
Steam supply valve |
|
B |
When the danger
of freezing exists, all steam driven reciprocating pumps and deck equipment
should be __________. |
watched carefully
while idled |
cycled at least
once a day |
cycled once every
4 days |
cycled once every
week |
|
B |
Excessive lost
motion in the valve mechanism of a duplex reciprocating pump will cause
the __________. |
cushioning valves
to wear |
pump to operate
sluggishly |
pump to short
stroke continuously at both ends of the stroke for both cylinders |
pistons to stop
in mid-stroke |
|
B |
An inadequate
reciprocating bilge pump discharge is most often caused by __________. |
scarred cylinder
walls |
clogged suction
strainers |
clogged drain
valves |
defective intake
valves |
|
C |
A pounding noise
occurring in one cylinder of a steam reciprocating general service pump
could be caused by __________. |
lower than normal
supply steam temperature |
loss of air charge
in the pump discharge plenum chamber |
improper adjustment
of steam cushion valves |
lower than normal
supply steam pressure |
|
D |
When piston rod
packing persists in leaking on a reciprocating steam pump, the cause may
be __________. |
a loose tappet
collar |
an open snifter
valve |
clogged suction
strainers |
misalignment of
the crosshead guide |
|
C |
Which of the following
conditions would prevent a steam reciprocating pump from delivering its
rated capacity? |
Air trapped in
the discharge expansion chamber |
A leaking snifter
valve allowing air to enter the suction side of the pump |
Excessive suction
lift |
All of the above. |
|
B |
When repacking
a reciprocating pump with more than four rings of packing, the packing is
cut square, installed with the ends abutted, and each succeeding ring staggered
with the butted ends __________. |
45° apart |
90° apart |
120° apart |
180° apart |
|
A |
To safely remove
the piston rod packing from the steam end of a reciprocating pump, you should
__________. |
use a packing
hook |
do nothing, as
this type of pump utilizes O-rings in lieu of packing |
open the throttle
valve and 'blow' the old packing out |
open the steam
chest and pry the packing loose with a scraper |
|
A |
Which of the listed
types of steam end piston rod packing should be used in a steam reciprocating
pump? |
High pressure
graphite packing |
Wire impregnated
high temperature packing |
Low pressure braided
asbestos packing |
Reinforced rubber
packing |
|
B |
Which of the lubricants
listed is the best to use on a reciprocating pump rod? |
Oil mixed with
kerosene. |
Graphite and oil. |
Engine oil. |
Vegetable oil. |
|
D |
The first step
when resetting the slide valves on a duplex reciprocating pump is to __________. |
position the steam
pistons on 3/4 stroke |
measure the present
port openings to ensure reassembly will be the same |
ensure the balance
piston is on the down stroke |
place the steam
pistons in the mid stroke position |
|
B |
If you have a
duplex, single acting, reciprocating pump making 140 strokes/minute with
a 3" diameter cylinder, and a 12" stroke with a 94% volumetric
efficiency, what is the capacity of this pump? |
58 gpm |
48 gpm |
38 gpm |
28 gpm |
|
C |
If you have a
duplex, single acting, reciprocating pump making 140 strokes/minute with
a 3" diameter cylinder, and a 12" stroke with a 94% volumetric
efficiency, what is the capacity of this pump? |
28 gpm |
38 gpm |
48 gpm |
58 gpm |
|
A |
The suction-force
principle of operation is a typical characteristic of __________. |
reciprocating
pumps |
jet pumps |
centrifugal pumps |
propeller pumps |
|
B |
Which of the pumping
systems listed for use aboard ship will most likely use a propeller type
pump? |
Steering gear
system |
Main circulating
system |
Fuel oil service
booster system |
Fluid power transmission
system |
|
C |
One of the main
differences between a propeller pump and a centrifugal pump is the absence
of a __________. |
velocity nozzle
in the centrifugal type pump |
volute in the
centrifugal type pump |
volute in the
propeller type pump |
reciprocating
piston in the centrifugal type pump |
|
D |
Which type of
pump would normally be used to transfer fairly large quantities of fluids
at relatively low pressures? |
reciprocating
type |
screw type |
gear type |
propeller type |
|
B |
The three basic
parts of any eductor are the nozzle, the suction chamber, and the __________. |
injector |
diffuser |
compressor |
siphon |
|
D |
A distinguishing
feature of an eductor, when compared to other pumps, is the __________. |
discharge end
being smaller than the suction end |
ease at which
the wearing rings may be changed |
small size of
impeller |
lack of moving
parts |
|
C |
Which of the following
methods applies to how a vacuum is created by a jet pump or an eductor? |
A propeller drawing
a fluid through a Venturi nozzle. |
A reciprocating
plunger directly applying force to a fluid. |
A rapidly moving
stream of fluid passing through a nozzle. |
Centrifugal force
converted into potential energy. |
|
C |
The simplest method
to use for determining if a centrifugal pump is operating as designed, is
to __________. |
use a clamp on
ammeter and compare the readings to past records |
closely observe
the pump discharge temperature |
close off the
discharge valve, and watch for a rise in pressure |
momentarily close
off the suction valve, and watch for a rise in pressure |
|
A |
Both existing
centrifugal cooling water pumps will be replaced by two of a higher GPM.
Only one pump is used in normal operation and there will be no modifications
to their discharge piping. This is an operational concern since increased
velocity will increase pipe erosion. What is the fluid velocity in feet/minute
in the discharge piping with new pumps, given the following data?
{{{
Existing Pump:
Capacity = 200 GPM
Internal discharge pipe Diameter = 7 1/2 inches
Present discharge piping velocity = 87.088 feet/minute
New Pump:
Capacity = 230 GPM
New velocity 'V' = ?}}}
|
100.149 ft./min. |
112.151 ft./min. |
78.719 ft./min. |
126.151 ft./min. |
|
A |
On disassembling
a centrifugal pump for overhaul, the third engineer reports holes drilled
axially in the back side of a single suction closed impeller. The reason
for the these holes is which of the following? |
To reduce the
axial thrust forces on the impeller |
To allow for water
to recirculate for impeller cooling |
To reduce the
power required for the pump |
To fit a puller
for removing the impeller |
|
B |
The assistant
engineer reports an installed centrifugal pump has a history of running
higher than normal amperage since new construction. Capacity and discharge
head for the pump are more than adequate. All other system parameters are
normal. The best way to reduce the pump load is to do which of the following? |
By replace the
pump with a new pump. |
By reducing the
impeller diameter. |
By install a bypass
line between the pump discharge and suction. |
By place another
equal size pump in parallel. |
|
B |
Which of the following
statements is true concerning centrifugal pumps? |
They operate more
efficiently when mounted in a horizontal position. |
A flow is developed
by imparting kinetic energy to the fluid by the rotation of an impeller. |
They operate best
under negative suction pressure conditions. |
They are particularly
well suited for pumping high viscosity fluids. |
|
D |
Pitting in the
suction areas of a centrifugal pump bronze impeller is usually caused by
__________. |
corrosion |
abrasion |
electrolysis |
cavitation |
|
C |
When ordering
a new centrifugal pump for installation, what is the advantage of a pump
with a double suction impeller over a single suction impeller? |
Pump capacity
will be doubled. |
The pump can be
used with a reversible drive. |
The pump will
experience less axial thrust. |
The pump will
experience less water turbulence. |
|
B |
A pumping system
utilizing a centrifugal pump is designed for a specific discharge head in
feet. What happens to the pump's discharge pressure when the Specific Gravity
(SG) of the fluid pumped changes? |
SG will change
the system's head. |
Lower SG fluids
will cause the discharge pressure to decline. |
Higher SG fluids
will cause the discharge pressure to decline. |
Pump discharge
pressure will remain the same. |
|
A |
After a disassembly
of a single stage centrifugal pump, one finds the outer circumference of
the impeller badly pitted and worn. Not having a spare impeller on board,
it is decided to turn down the impeller to eliminate the wear/pitting. What
will be the pump capacity, in GPM, after the reduction of impeller diameter
by 0.5 inches? GIVEN: Original pump capacity = 30 GPM Original impeller
diameter = 8 in. |
28.12 GPM |
24.78 GPM |
Capacity would
not change. |
26.37 GPM |
|
A |
One is informed
by the owner that two of the vessel's electrically driven centrifugal cooling
water pumps will be replaced with two of higher capacity pumps. No modification
of existing piping will be involved. What should be your concerns from an
operational perspective? |
Upgrading of circuit
breakers and controllers and possible increased erosion of discharge piping
due to increased system velocities. |
Piping should
be of no concern since it is designed with a safety factor. Electrical power
should be of concern. |
Electrical power
should be of no concern due to safety margins designed into power systems.
Increased erosion may be a long term consideration. |
One should not
be concerned operationally since all systems are designed with future modifications/upgrades
in mind. |
|
D |
When repacking
a stuffing box fitted with a lantern ring, which of the following precautions
should be observed? |
For good lubrication,
apply a fine grade lapping compound between the shaft and packing. |
Block off the
sealing water connection. |
Be certain that
all packing is fitted loosely to the shaft. |
Replace all of
the packing rings. |
|
A |
When renewing
spiral packing in a centrifugal pump stuffing box, after the packing is
firmly seated, the packing gland nuts should be __________. |
loosened, and
then retightened with the pump running under normal conditions |
left in that position |
tightened an additional
10% to compress the packing |
loosened until
the gland clears the stuffing box |
|
C |
Why should the
use of metallic or semi-metallic packing hooks or pullers be avoided on
bronze or brass shafts, rods, plungers, or sleeves? |
Bonnet corrosion
may result. |
Valve seat will
be damaged. |
Scoring may result. |
Heat transfer
is restricted. |
|
B |
A pump shaft that
is bent or distorted should normally be __________. |
reconditioned
by metalizing and machining |
replaced with
a satisfactory spare |
repaired by a
suitable welding process |
straightened by
applying heat and torsion |
|
B |
When installing
a mechanical shaft seal on a pump, it is important to __________. |
make the final
spring collar adjustments with the pump running |
ensure that correct
spring pressure is applied to the seating faces |
run the pump "dry"
for initial break-in of the shaft seal |
polish the seating
faces with emery cloth prior to assembly |
|
C |
Your centrifugal
ballast pump is producing a pressure less than the designed discharge pressure.
What could be the cause? |
Excessive high
suction head. |
Excessive pump
speed. |
Worn wearing rings. |
Pump misalignment. |
|
A |
The shipyard has
just reassembled an overhauled centrifugal pump. On testing, water is coming
from the mechanical seal area. Which of the following are likely reasons
for the leakage? |
The shaft o-ring
was not installed. |
The pump was started
with the discharge valve closed. |
The pump was started
with the suction valve closed. |
The pump was air
bound. |
|
A |
While pumping
ballast the Chief Mate reports there is a decrease in vacuum on the pump
suction when drawing from a partially full saddle tank. Which of the following
could be a possible cause? |
An air leak in
the suction piping from the tank. |
The suction valve
from the pump is partially closed. |
The tank suction
valve is partially closed. |
The pump suction
strainer is clogged. |
|
A |
While making a
round in the lower engine room you discover a leak in the suction pipe to
the main salt water pump. How would proceed to correct this problem? |
Use a type of
banded patch (from a simple gasket with hose clamps to forge clamp style)
on the pipe to seal the hole in the pipe until a permanent repair can be
made. |
Wrap the leaky
section of pipe with duct tape to slow the leak down. |
Let the pipe leak
until a permanent repair can be made at your next port call. |
Monitor the leak
to see if it worsens. |
|
C |
When reviewing
log books, the main salt water cooling pump discharge pressure has decreased
in the three years since overhaul. Which of the following would most likely
be the cause of the problem. |
Bus frequency
lower than normal. |
Worn pump shaft
bearings. |
Increased impeller
and wear ring clearance. |
Fouled suction
strainer. |
|
A |
When opening a
ballast pump for inspection, the wear ring clearance is found to be approaching
maximum. Which of the following would be expected? |
Pump capacity
would be decreased. |
Pump vibration
would be decreased. |
Pump discharge
pressure would be increased. |
Pump lift would
be increased. |
|
B |
Referring to illustrated
diagram, what type of HVAC system is shown? Illustration GS-RA-42 |
A dual duct system |
A terminal reheat
system |
A variable air
volume system |
A single zone
system |
|
D |
A spur gear pump
should be operated with the discharge valves __________. |
halfway opened |
throttled |
slightly opened |
fully opened |
|
A |
Traditionally,
which of the listed refrigerants has been more suitable than the others
for use in a centrifugal refrigeration compressor? |
R-11 |
Carbon dioxide |
Ammonia |
R-12 |
|
D |
Which of the fluids
listed is suitable for use as a secondary refrigerant? |
Carbon dioxide |
Cuprous chloride |
Methyl alcohol |
Brine |
|
A |
R-134a is often
the replacement for which older type of refrigerant? |
R-12 |
R-123 |
R-11 |
R-22 |
|
B |
Which of the following
substances is normally classified as a low pressure refrigerant? |
R-22 |
R-123 |
R-134A |
R-12 |
|
B |
Which of the following
refrigerants is chlorine free and safe regarding atmospheric ozone depletion? |
R-11 |
R-134a |
R-12 |
R-22 |
|
A |
What is the most
important consideration in selecting a lubricating oil for use in a refrigeration
compressor? |
have a low pour
point |
have a high wax
content |
have a high freezing
point |
have a low viscosity
index |
|
A |
Properties of
a good refrigeration compressor lubricating oil include which of the following? |
low wax content |
high pour point |
high viscosity |
All of the above. |
|
A |
The lubrication
oil in the crankcase of a refrigeration compressor that is shut down is
heated. For what purpose is this done? |
reduce absorption
of refrigerant by the oil |
prevent refrigerant
vaporization |
remove wax and
gum |
remove entrained
water |
|
B |
If you mistakenly
change from a lower pour point lubricant to a higher pour point lubricant
in a refrigeration system, what will be the result? |
compressor lubrication
will be improved |
oil may congeal
in the evaporator |
compressor valves
will be damaged |
oil will not leave
the crankcase |
|
C |
What is the color
coding for a storage container of R-134a refrigerant? |
green |
grey |
light blue |
purple |
|
D |
The term 'oil
foaming' in refrigeration practice, is used to describe what event? |
release of dissolved
lubricant from the refrigerant in the crankcase |
sudden evaporation
of entrapped moisture from the crankcase lubricant |
sudden evaporation
of entrapped air from the refrigerant liquid |
release of miscible
refrigerant from the lubricant in the crankcase |
|
D |
The gas that exists
in the stratosphere forming a protective shield that helps to protect the
environment from the harmful effects ultraviolet radiation is called what? |
nitrogen |
oxygen |
radon |
ozone |
|
B |
The "tare
weight" of a refrigerant storage cylinder refers to what weight? |
the total weight
of a fully charged cylinder |
the weight of
an empty cylinder |
the weight of
a cylinder AND its current contents |
the maximum weight
of the refrigerant allowed |
|
B |
At ambient temperature
and atmospheric pressure, what is the status of R-134a? |
sub cooled gas |
odorless gas |
corrosive liquid |
superheated liquid |
|
D |
Regarding heat
transfer principles, which of the following is true? |
Heat transfer
always flows from cold regions to hot regions. |
A gas can transfer
heat more efficiently than a liquid. |
Steel pipe can
transfer heat more efficiently than copper pipe. |
Heat transfer
always flows from hot regions to cold regions. |
|
A |
Refrigerant entering
the compressor of a refrigeration system should be in which of the following
conditions? |
Low pressure vapor |
High pressure
liquid |
High pressure
vapor |
Low pressure liquid |
|
C |
What is the physical
state and pressure condition of refrigerant as it enters the condenser of
a typical refrigeration system. |
low pressure vapor |
low pressure liquid |
high pressure
vapor |
high pressure
liquid |
|
D |
What is the physical
state and pressure condition of refrigerant as it leaves a receiver in a
typical refrigeration system? |
low pressure vapor |
high pressure
vapor |
low pressure liquid |
high pressure
liquid |
|
D |
What is the pressure
and condition of the refrigerant entering the receiver of a refrigeration
system? |
superheated low
pressure vapor |
sub cooled low
pressure liquid |
superheated high
pressure vapor |
sub cooled high
pressure liquid |
|
C |
When repairing
a refrigeration system, a swaging tool set would be used to carry out which
of the following operations? |
Swaging tools
are no longer used with repairing refrigeration systems due to progressive
changes in the tool industry. |
Swaging tools
are used to remove any sweated edges formed on the tubing while soldering. |
Swaging tools
can be used to expand an end of one tube to fit onto a tube of the same
original outside diameter. |
Swaging tools
are used during the breaking-in of refrigeration compressors and drive motors. |
|
A |
In a refrigeration
system, once the gage manifold hoses are attached to the compressor service
valve connections and properly purged, what should be the status of the
manifold valves and the service valves when the purpose for attachment is
to read system pressures? |
both manifold
hand valves should be closed and the compressor Service Valves should be
cracked-off their back seats |
both manifold
hand valves should be open and the compressor Service Valves should be cracked-off
their back seats |
both manifold
hand valves should be open and the compressor Service Valves should both
be back-seated |
both manifold
hand valves should be open and the compressor Service Valves should both
be front-seated |
|
B |
Which pair of
the illustrated service gauge manifold sets would require switching hoses
when transitioning from a dehydration evacuation to refrigerant charging?
Illustration GS-RA-30 |
A and B |
B and D |
C and D |
D and A |
|
B |
With a service
gauge manifold set connected to a refrigerant compressor as shown in the
illustration, which arrangement of the gauge manifold set valves and compressor
Service Valves would allow for simultaneous reading of the compressor suction
and discharge pressures? Illustration GS-RA-03 |
Valves "2"
and "5" both open, along with valves "1" and "6"
both open in the mid-position. |
Valves "2"
and "5" both closed, along with valves "1" and "6"
both cracked open off their backseats. |
Valves "2"
and "5" both open, along with valves "1" and "6"
both front-seated. |
Valves "2"
and "5" both closed, along with valves "1" and "6"
both back-seated. |
|
B |
When purging a
refrigeration gage manifold using system pressure as the source of refrigerant
for purging, which of the fittings listed is normally tightened LAST? |
the high pressure
hose fitting at the gage manifold high pressure connection |
the low pressure
hose fitting at the suction service valve service port |
the low pressure
hose fitting at the gage manifold low pressure connection |
the high pressure
hose fitting at the discharge service valve service port |
|
C |
Which of the following
statements is true concerning the illustrated gauge manifold set? Illustration
GS-RA-01 |
Closing the valve
labeled "G" isolates the hose labeled "H" from the gauge
labeled "A". |
The valves labeled "G"
and "C" must both be open to read system pressures on the respective
gages labeled "A" and "B". |
Closing the valve
labeled "G" isolates the hose labeled "H" from the hose
labeled "J". |
Opening fully
and back seating the valve labeled "G" isolates the gauge labeled "A"
from the hose labeled "H". |
|
A |
In a refrigeration
system, from what location would air and non-condensable gases be removed? |
the top of the
condenser purge connection |
expansion valve
equalizer connection |
compressor oil
fill connection |
the bottom of
the receiver drain connection |
|
D |
Loss of refrigerant
during the process of purging of air and non-condensable gases can be kept
to a minimum by what action? |
purging through
the discharge service valve rather than the top of the condenser |
purging through
the top of the receiver rather than the top of the condenser |
purging through
a dehydrator |
cracking the purge
valve briefly and allowing the refrigerant to re-settle between purges |
|
C |
Before charging
a refrigeration unit, unless quick disconnect fittings are used, the refrigerant
charging hoses should be prepared in what way? |
they should be
flushed with clean refrigerant oil |
they should be
cleaned with carbon tetrachloride |
they should be
purged with refrigerant |
they should be
warmed in an oven |
|
C |
Concerning the
charging of refrigerant into a vapor compression refrigerating system, which
of the following is true? |
when charging
as a liquid it should be to the low side only |
when charging
as a liquid it may be to the low or high side |
when charging
as a liquid it should be to the high side only |
when charging
as a vapor it should be directly to the receiver only |
|
D |
The amount of
HCFC-123 in a storage cylinder is measured by what means? |
volume |
saturation pressure |
saturation temperature |
weight |
|
C |
Which of the illustrated
valves is used to gain access to a hermetic system and features a Schrader
core valve which is unseated by the core depressor of hose fitting when
attached? Illustration GS-RA-69 |
B |
A |
D |
C |
|
A |
How should small
appliances with less than three pounds of refrigerant be charged with refrigerant? |
vapor charged |
either vapor or
liquid charged |
liquid charged |
initially liquid
charged and then topped with a vapor charge |
|
C |
If passive recovery
is used on a small appliance fitted with a capillary tube as a metering
device with a non-operating compressor, the recovery should be made through
what means? |
recovery from
the low side only |
by venting to
atmosphere, cannot be recovered |
recovery from
both the high and low sides |
recovery from
the high side only |
|
B |
In a low pressure
refrigeration system, excessive running of the purge recovery unit generally
indicates which probable condition? |
faulty purge system
vent valve |
system leaks on
the low side |
system leaks on
the high side |
overcharged system |
|
A |
In a low-pressure
centrifugal chiller, what is meant by the term 'high efficiency purge unit? |
Those purge units
which discharge very little refrigerant with the air being removed. |
Those purge units
which draw very little electrical power. |
Those purge units
which need the least amount of on-going Maintenance. |
Those purge units
which discharge the highest percentage of refrigerant with the air being
removed. |
|
B |
During normal
operation, traditionally, how has most of the refrigerant released to the
atmosphere from low pressure systems? |
through a leaking
rupture disk |
through the purge
unit vent |
through the compressor
shaft seal |
through water-side
system leaks |
|
C |
Charging liquid
HCFC-123 into a system under a deep vacuum could cause what to happen unless
necessary precautions are taken? |
air and moisture
to enter the receiver |
the purge unit
to operate |
system secondary
refrigerant to freeze |
rupture disk to
rupture |
|
A |
After the refrigerant
has been recovered, leaks repaired if necessary, the system ideally should
undergo a dehydration evacuation prior to recharging with refrigerant. As
shown in the illustration, besides the vacuum pump suction manifold isolation
valve being opened, what would be the proper valve positions to accomplish
and prove the evacuation? Illustration GS-RA-51 |
Valves 1, 2, and
3 should be in the mid-position and the low-side gauge manifold hand valve
should be closed, and the high-side gauge manifold hand valve should be
open. |
Valves 1, 2, and
3 should be in the mid-position and the low-side gauge manifold hand valve
should be open, and the high-side gauge manifold hand valve should be closed. |
Valves 1, 2, and
3 should be front-seated and both gauge manifold hand valves should be closed. |
Valves 1, 2, and
3 should be back-seated and both gauge manifold hand valves should be open. |
|
B |
When a refrigeration
system is being topped off with a small amount of refrigerant through the
low side with the compressor running, what should be done? |
the refrigerant
charging cylinder should be turned upside down |
the refrigerant
should be charged into the system as a vapor |
the suction service
valve must be back seated |
the discharge
service valve must be front seated |
|
C |
Which of the valves
listed is normally closed when charging the refrigeration system through
the high side? |
Thermal expansion
valve |
Suction line valve |
Liquid line king
valve |
Dehydrator inlet
valve |
|
A |
Using the device
shown in the illustration, which of the following statements is true when
adding refrigerant as a vapor to the low side of the refrigeration system
__________. Illustration GS-RA-01 |
The hose labeled "H"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "G" should be open. |
The hose labeled "K"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "C" should be closed. |
The hose labeled "H"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "G" should be closed. |
The hose labeled "K"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "C" should be closed. |
|
D |
What must be done,
at a minimum, before a system can legally be opened up for repairs while
adhering to the prohibition against the venting of halogenated fluoro-carbon
refrigerants to the atmosphere? |
reclamation of
the refrigerant |
destruction of
the refrigerant |
recycling of the
refrigerant |
recovery of the
refrigerant |
|
A |
The process of
removing refrigerant from a system and storing it without testing or processing
it in any way is known as what under the EPA Clean Air Act rule definitions? |
recovering |
recouping |
reclaiming |
recycling |
|
C |
What is the correct
color coding of refrigerant recovery cylinders regardless of the refrigerant
contained within? |
gray top and light
blue lower body |
gray top and yellow
lower body |
yellow top and
gray body |
light blue top
and yellow lower body |
|
C |
In reclaiming
recovered refrigerant, which type of contamination will the reclamation
process be unable to separate? |
moisture |
acid |
mixed refrigerants |
air |
|
D |
In a refrigeration
system, the push-pull technique can be used for the recovery of the refrigerant
in what state? |
should never be
used with low pressure systems |
liquid only |
vapor only |
both liquid and
vapor |
|
B |
Which recovery
procedure should be used to minimize the loss of oil from the system during
the recovery of refrigerant from small appliances such as a water cooler? |
vapor-liquid recovery |
vapor recovery |
liquid recovery |
initial recovery |
|
A |
What is true concerning
highly contaminated refrigerant recovered from burned out small appliances? |
The recovered
refrigerant should be sent to a designated reclamation facility for processing. |
The recovered
refrigerant may be blended with new refrigerant for eventual re-use. |
The recovered
refrigerant may be used to clean out systems that have suffered from a burnout. |
The recovered
refrigerant must be destroyed by the refrigeration technician. |
|
C |
Technicians servicing
small refrigeration appliances can employ what type of recovery equipment? |
passive only |
do not need to
recover the refrigerant |
either active
or passive |
active only |
|
B |
Minor repairs
may be performed on low pressure refrigerant systems without recovering
the refrigerant charge if the pressure in the system is raised to atmospheric.
How may this be accomplished? |
open the system
vent to the atmosphere and allow the pressure to equalize |
heat the refrigerant |
pressurize the
system with nitrogen |
charge the system
until it is completely filled with liquid refrigerant |
|
A |
Why is a purge
recovery unit typically fitted on low pressure centrifugal chillers? |
such a chiller
can operate at a pressure below atmospheric pressure on the low side thus
drawing in air through any low-side leaks |
low pressure chillers
are routinely opened for Maintenance thus introducing air at each opening |
low pressure chillers
use extremely low boiling point refrigerants |
evacuation of
the air from a low pressure chiller prior to charging with refrigerant is
not possible |
|
D |
The most cost-effective
method of recovering refrigerant from a low pressure chiller with more than
500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant
using what protocol? |
vapor recovery
using a vacuum pump based recovery unit followed by liquid recovery using
a liquid pump |
recovery using
a vacuum pump based vapor recovery machine only |
recovering using
a liquid pump only |
liquid recovery
using a liquid pump, followed by vapor recovery using a vacuum pump based
recovery unit |
|
B |
As shown in the
illustrated flow diagram for a self-contained recovery unit designed for
the recovery of refrigerants from high pressure appliances as defined by
the EPA Clean Air Act rules, what is the functional purpose of the item
labeled "FS2"? Illustration GS-RA-32 |
It automatically
shuts down the recovery unit compressor when the recovery cylinder becomes
80% full. |
It automatically
transitions the recovery unit from the direct liquid recovery mode to the
direct vapor recovery mode. |
It automatically
shuts down the recovery unit compressor when the discharge pressure becomes
excessive. |
It automatically
shuts down the recovery unit compressor when the refrigeration system has
reached a depth of 15" Hg. |
|
B |
Some 'hot gas'
defrost systems reheat the refrigerant just prior to its returning to the
compressor for what purpose? |
to increase the
circulation of liquid refrigerant |
to prevent the
damaging effects of liquid slugging |
to improve the
efficiency of the expansion valve |
to prevent chill
shocking the compressor suction valves |
|
A |
What is true concerning
frost build-up on the evaporator coils of a multi-box direct expansion refrigeration
system? |
the frost can
be removed by passing hot gas through the coils or energizing defrost heaters
with the evaporator fan shut down |
the frost can
be removed by passing hot gas through the coils or energizing defrost heaters
with the evaporator fan still running |
the frost can
be quickly removed by simply shutting down the compressor |
the frost will
increase the refrigeration effect |
|
D |
Concerning frost
appearing on one set of evaporator coils of a multi-box, direct expansion
type refrigeration system, what is true? |
the frost can
be quickly removed by simply shutting off fluid flow to the coils |
the frost will
assist in increasing the refrigeration effect |
the frost will
increase the value of superheat to the fluid leaving the coils |
the frost can
be removed by passing hot vapors through the coils |
|
C |
The pressure in
the part of a high pressure refrigeration system about to be opened for
a non-major repair should be brought to what value? |
11 to 12 psig |
4 to 7 psig |
0 psig |
1 to 2 psig |
|
D |
What is the maximum
volume to which refillable refrigeration cylinders should be filled? |
90% full |
60% full |
70% full |
80% full |
|
C |
If the combination
moisture indicator and sight glass indicates an accumulation of moisture
within the system, which of the listed procedures would be the most practical
to follow? |
Secure the system,
disassemble and de-ice the thermostatic expansion valve. |
Using a vacuum
pump, draw the entire system down to 1,270 microns for a period of three
hours. |
Close the king
valve, pump down the system, isolate the drier, remove the desiccant core
and replace with new drier cartridge. |
Purge the entire
system to the atmosphere, replace the drier cartridge, and recharge the
system with refrigerant. |
|
D |
If the discharge
reed valves used in a refrigeration compressor are leaking badly, what statement
is true? |
the reed valves
should be reground and relapped |
the low side pressure
will indicate below normal |
the high pressure
cut-out setting should be lowered |
the reed valves
should be replaced |
|
C |
In addition to
the drive belt itself, a V-belt that is tensioned too tight will cause excessive
wear to what other drive component? |
the compressor
drive pulley |
the prime mover
drive pulley |
motor shaft and
compressor main bearings |
the shaft of the
prime mover |
|
C |
When one belt
of a multiple V-belt drive requires replacing, what will be required? |
ensure the seasoned
belts are reinstalled in their proper sequence |
season the new
belt prior to installation |
replace the entire
belt set |
ensure the proper
belt dressing is applied |
|
D |
When installing
a mechanical shaft seal on a refrigeration compressor, extreme care must
be taken to prevent what from happening? |
any lubricant
from contacting the carbon surface that would cause the expulsion of the
saturated Teflon film |
any lubricant
from contacting the stationary seal face that would cause etching of the
face surface |
the spring from
being damaged by the corrosive effects of excessive handling |
dirt and foreign
particles from coming in contact with the highly polished sealing surfaces |
|
B |
Excessively tight
drive belts installed between a motor and a refrigeration compressor pulley
may cause what condition? |
normal wear of
the pulley end motor shaft bearing, but premature wear of the pulley end
compressor crankshaft main bearing |
premature wear
of both the pulley end motor shaft bearing and the pulley end compressor
crankshaft main bearing due to overloading |
premature wear
of the pulley end motor shaft bearing, but normal wear of the pulley end
compressor crankshaft main bearing |
premature wear
of both motor shaft bearings and both compressor crankshaft main bearings
due to belt slippage |
|
C |
The primary purpose
of the liquid line strainer used in a refrigeration system is to prevent
dirt and scale from entering what system component(s)? |
condenser and
receiver |
evaporator coil
piping |
thermal expansion
valves |
compressor and
oil separator |
|
B |
Of the various
possible methods shown in the illustration, which is the correct method
of attaching a TXV feeler bulb to a small large line (7/8" and larger)
with a horizontal run? Illustration GS-RA-50 |
A |
C |
D |
B |
|
D |
A thermostatic
expansion valve is properly controlling evaporator superheat. Adjusting
this valve to lower the evaporator superheat setting will result in which
of the following? |
the expansion
valve will further close |
the expansion
valve diaphragm will rupture |
the evaporator
pressure will decrease |
the evaporator
feed will increase |
|
A |
When replacing
a thermostatic expansion valve power element, what is true concerning the
thermal bulb? |
with steel wool
or an abrasive cloth remove oxidation on the bulb and suction line |
carefully coat
the device with silicone sealant to reduce the effects of convective cooling |
apply a heavy
coating of grease to function as a heat sink |
apply a light
film of oil to increase heat transfer |
|
A |
If the evaporator
coil horizontal return line of a container refrigeration system is less
than 0.875" (2.21 cm) in diameter (considered small); the thermostatic
expansion valve sensing bulb should be attached where on the return line? |
on the upper surface
of the line |
directly below
the point of maximum heat transfer |
as close as possible
to the expansion valve |
on the bottom
of the line to enable the bulb to absorb the maximum amount of heat |
|
A |
An evaporator
coil of a single evaporator, air cooled refrigerator is accumulating excessive
frost due to a failure of the defrost mechanism. If the refrigerator features
a thermostatically controlled box solenoid and a low pressure cutout controlled
compressor, as well as a high pressure cutout, in terms of the compressor,
what would be the most likely operating symptom? |
short cycle on
low pressure cutout |
fail to start |
short cycle on
high pressure cutout |
run continuously |
|
A |
If an abnormally
large difference is maintained between the evaporator refrigerant temperature
and the box air temperature within the refrigerated compartment, what will
be the result? |
the evaporator
coil will tend to excessively frost |
the box temperature
will be pulled down too low |
the compressor
will tend to trip out on high head pressure |
the compressor
will tend to overheat due to high suction temperature |
|
C |
Concerning the
operation of refrigeration systems, frosting or sweating of a liquid line
is usually indicative of what condition? |
high relative
humidity surrounding the liquid line |
the refrigerant
contaminated with moisture |
a liquid line
restriction |
proper cooling
taking place |
|
C |
What is a quick
method used to test a water cooled condenser for the presence of a refrigerant
leak without actually pinpointing the actual location? |
test the cooling
water for proper pH |
test the receiver
for water content |
check the drains
on the condenser heads with a halide torch |
test the condenser
tubes hydrostatically |
|
C |
What must be done
to use standard leak detection methods on a low pressure refrigeration system
charged with refrigerant? |
lower the pressure
in the system below atmospheric |
add nitrogen to
the system |
raise the pressure
in the system above atmospheric |
cool the refrigerant |
|
C |
What is the color
of the flame produced by a halide torch when there is no halogenated refrigerant
present at the location of the exploring tube? |
purple |
green |
blue |
orange |
|
D |
Which of the following
statements is correct concerning the testing of an R-22 refrigeration system
for leaks in an enclosed compartment with a halide torch? |
Halide torches
are not suitable for detecting R-22 leaks. |
The flame of a
halide torch will turn blue in the presence of R-22. |
To gain sensitivity,
the largest possible flame should be used with the halide torch. |
Halide torches
are useful in locating very small R-22 leaks. |
|
B |
To test for a
suspected large refrigerant leak from an R-22 refrigeration system in an
enclosed area, how should this be done? |
perform a hydrostatic
test with water |
apply a soap solution
to fittings seen to have oil residue |
perform a standing
vacuum test |
use an electronic
leak detector to check all fittings for leaks |
|
C |
Excessive moisture
being collected in the purge unit of a low pressure refrigeration system
could indicate which probable condition? |
low efficiency
purge unit |
dryer core needs
replacement |
leaking condenser
or chiller tubes |
improper charging
of refrigerant |
|
B |
Moisture entering
a typical refrigeration system will most likely produce what effect? |
cause sweating
and frost on the evaporator coils |
freeze in the
expansion valve |
boil in the condenser |
be removed by
the liquid line strainers |
|
D |
Moisture in a
refrigeration system can cause which of the following conditions? |
freezing the expansion
valve closed |
corrosion of system
piping |
hermetic motor
burnout |
All of the above. |
|
D |
High suction pressure
accompanied by low suction temperature to a refrigeration system compressor
is caused by which of the following? |
the king valve
is insufficiently open |
the expansion
valve is insufficiently opened |
a clogged liquid-line
strainer |
the expansion
valve being open too wide |
|
B |
If a refrigeration
system were short of refrigerant, besides an elevated box temperature, what
would be an observable symptom? |
high suction pressure |
continuous running
of the compressor |
short cycling
of the compressor on the water failure switch |
high discharge
pressure |
|
A |
Which of the conditions
listed could cause excessively low refrigerant pressure at the compressor
suction of a TXV controlled refrigeration system? |
The system is
low on refrigerant. |
The box solenoid
valve 'stuck' in the open position. |
The high pressure
cutout switch is inoperative. |
Insufficient flow
of condenser cooling water. |
|
C |
When a refrigeration
compressor has developed a high head pressure as a result of a refrigerant
overcharge, what should be done to compensate for or to correct this situation? |
increase the amount
of cooling water to the condenser |
decrease the amount
of cooling water to the condenser |
remove some refrigerant
from the system |
raise the high
pressure cut-out opening pressure |
|
C |
Low compressor
head pressure in a refrigeration system can be caused by which of the following? |
insufficient condenser
cooling water flow |
air in the refrigeration
system |
excessive condenser
cooling water flow |
excessive refrigerant
in the system |
|
D |
Which of the following
conditions will occur if the power element of the thermostatic expansion
valve shown in the illustration loses its charge? Illustration GS-RA-07 |
The valve will
begin to close, but the external equalizing line will assist in keeping
the valve unseated. |
The valve will
fail open and the cooling capacity will be increased. |
The valve will
fail open as designed to provide continuous cooling. |
The valve will
fail closed, providing no cooling capacity. |
|
D |
Which of the following
statements describes the accepted method for testing a thermostatic expansion
valve? |
Chill the bulb
in ice water while observing the compressor for an increase in suction pressure. |
Remove the power
head from the unit, heat the bulb with a torch while using a scale to measure
the distance the diaphragm has moved. |
Heat the bulb
by using a halide torch or similar device and observe the valve stem movement. |
Place the sensing
bulb in ice water and then warm by hand. Observe flood-through and temperature
change at the suction line. |
|
B |
If the superheat
setting of a thermostatic expansion valve is set too low, what would be
the result, assuming that the system has a single evaporator? |
the suction line
will be abnormally warm due to a reduced amount of refrigerant returning
back to the compressor |
the suction line
will be abnormally cold and liquid may flood back to the compressor |
the receiver level
will be abnormally high due to a reduced amount of refrigerant returning
back to the compressor |
the box temperature
will be pulled way down below the normal temperature range |
|
A |
If the superheat
value of the thermostatic expansion valve is adjusted too high, what would
be the result? |
the suction line
of the compressor will be abnormally warm |
the heat removal
capacity of the evaporator will increase |
the evaporator
will be overfed with liquid refrigerant |
the suction line
of the compressor will be abnormally cold |
|
A |
A small obstruction
at the thermostatic expansion valve inlet will result in which of the following
conditions? |
Lower than normal
suction pressure. |
Ice is the sole
cause of this and will soon melt due to superheat; no adverse condition
will occur. |
Higher than normal
discharge pressure. |
Expansion valves
are designed to pass small foreign particles so no adverse condition will
occur. |
|
C |
You are checking
the supply chilled water temperature thermistor probe on a high-pressure
hermetic centrifugal chiller. Using the illustrated chart, what statement
is true if the supply water temperature is verified 45 ° F with a digital
thermometer? Illustration GS-RA-48 |
When checked with
control power on and the thermistor probe isolated, the thermistor probe
voltage drop should be 3.805 volts. |
When checked with
control power on and the thermistor probe connected into the circuit, the
thermistor probe voltage drop should be 11.416 volts. |
When checked with
control power on and the thermistor probe connected into the circuit, the
thermistor probe voltage drop should be 3.805 volts. |
When checked with
control power off and the thermistor probe isolated, the thermistor probe
voltage drop should be 3.805 volts. |
|
B |
Some refrigeration
systems have chemical moisture indicators installed in conjunction with
the sight glass in the liquid line. If excess moisture is present in the
system, how will a typical moisture indicator respond? |
add a predetermined
amount of liquid drying agent |
change color |
automatically
cut in the driers |
secure the compressor |
|
D |
If the compressor
is heard to knock while pumping down the low side for repairs, but otherwise
the compressor sounds normal; this is a possible indication of what condition? |
worn piston rings |
faulty bearings |
air being introduced
to the system |
foaming of the
crankcase oil |
|
D |
Excessive, prolonged
oil foaming in the crankcase of a refrigeration compressor can result in
what condition? |
wax crystals forming
in the thermal expansion valve |
excessively high
lube oil viscosity |
carbon deposits
on the compressor piston rings |
overheated compressor
bearings |
|
A |
Which of the following
conditions would indicate that the liquid line strainer in a refrigeration
system has become excessively restricted and requires cleaning or replacement? |
Noticeable temperature
drop between the strainer inlet and the outlet tubing. |
Frosting at the
outlet of the receiver. |
Frosting at the
inlet of the compressor. |
Excessively high
suction pressure. |
|
D |
Why are dehydrators
usually located in the liquid line of refrigeration systems? |
prevent liquid
slugging in the suction line |
reduce compressor
discharge line sweating |
remove oil from
the refrigerant |
prevent icing
of the expansion valve |
|
A |
Which of the devices
listed will indicate whether or not a refrigeration system's dehydrator
continues to be capable of removing moisture from the circulating refrigerant? |
Liquid line moisture
indicating sight glass |
McLeod gage |
Dryer sensing
bulb |
Particulate test |
|
C |
In a refrigeration
system, silica gel is found in what component? |
condenser/receiver |
compressor suction
scale trap |
dehydrator or
combination filter/drier |
moisture indicating
liquid line sight glass |
|
A |
If a liquid drying
agent is used in a refrigeration system already equipped with a solid drying
agent, the liquid drying agent will cause what type of reaction? |
it will release
the moisture already trapped in the solid drying agent |
it will cause
toxic gases to form in the refrigerated space |
it will react
violently with the solid drying agent |
it will solidify
the refrigerant oil in the compressor crankcase |
|
C |
Standard filter/driers
used in many commercial type refrigeration units may contain what type of
substance? |
activated charcoal |
alcohol based
liquid drying agents |
activated alumina
or silica gel desiccant beads |
All of the above. |
|
D |
Capacity control
of a centrifugal refrigeration compressor can be accomplished by what means? |
varying the speed
of the compressor |
varying the position
of the suction inlet damper vanes |
varying the position
of the hot gas bypass valve |
All of the above. |
|
D |
The fluid used
as a source of actuating power against the underside of the unloader power
element piston of the refrigeration compressor capacity control mechanism
illustrated is obtained from where? Illustration GS-RA-13 |
discharge of a
secondary hydraulic pump specifically installed for this operation |
high side liquid
receiver |
gas discharge
from the compressor |
discharge of the
compressor lube oil pump |
|
C |
During operating
periods of a multi-box refrigeration system using a capacity controlled
compressor, when all of the evaporators of a four box plant are actively
being fed with liquid refrigerant, the control oil pressure acting on the
hydraulic relay piston will be at what value? Illustration GS-RA-13 |
the lowest |
at its mid-range |
the highest |
of no consequence
as the lube oil is not used in the operation of the unloader |
|
B |
A refrigeration
compressor used in a multi-box refrigeration system is designed with six
of its eight cylinders able to be controlled for variable load conditions.
If all of the reefer boxes are currently feeding, what percentage of the
total number of compressor cylinders will be loaded after start up? |
50 (%) |
100 (%) |
25 (%) |
0 (%) |
|
A |
On a modern refrigerated
container unit employing suction modulation for the purposes of capacity
control and capacity limitation, what happens when the applied voltage and
current draw associated with the normally open (NO) suction modulation valve
located in the suction line both increase? |
the valve will
further close, raising evaporator pressure and lowering suction pressure |
the valve will
further close, lowering evaporator pressure and raising suction pressure |
the valve will
further open, lowering evaporator pressure and raising suction pressure |
the valve will
further open, raising evaporator pressure and lowering suction pressure |
|
C |
To prevent motor
overload during start-up of a hermetically sealed centrifugal refrigeration
system, what is true concerning the compressor suction gas variable inlet
guide vanes? |
opened until the
motor is connected across the line at full voltage and current drawn is
up to full load current |
opened until the
motor is connected across the line at full voltage and current drawn is
below full load current |
closed until the
motor is connected across the line at full voltage and current drawn is
below full load current |
closed until the
motor is connected across the line at full voltage and current drawn is
up to full load current |
|
C |
A box solenoid
valve used in a refrigeration system should be installed in what manner? |
upright, controlled
by a thermostat sensing the temperature of the box, and downstream of the
thermal expansion valve |
with the axis
of the solenoid horizontal, controlled by a thermostat sensing the temperature
of the box, and upstream of the thermal expansion valve |
upright, controlled
by a thermostat sensing the temperature of the box, and upstream of the
thermal expansion valve |
upright, controlled
by a thermostat sensing evaporator superheat, and upstream of the thermal
expansion valve |
|
D |
In a multi-evaporator
refrigeration system, a solenoid valve is installed in the liquid line prior
to what device? |
the condenser |
the oil separator |
the receiver |
each expansion
valve |
|
B |
A liquid line
solenoid valve controls refrigerant flow to the evaporator by what means? |
sensing the superheat
in the tail coil |
fully opening
or closing |
sensing the temperature
in the liquid line |
throttling the
refrigerant |
|
D |
A box solenoid
valve used in a multi-box refrigeration system is operated by electromagnetic
action by what control device? |
evaporator outlet
temperature actuated thermostat |
discharge pressure
actuated pressure switch |
suction pressure
actuated pressure switch |
box temperature
actuated thermostat |
|
D |
How does a refrigeration
solenoid valve differ from a modulating valve? |
Both valves operate
in exactly the same manner, only the manufacturer's terminology is the differentiating
factor. |
A solenoid valve
can only be installed in liquid lines. |
Solenoid Valves
are only used in low voltage refrigeration control systems, while modulation
valves are used in high voltage applications. |
A liquid line
solenoid valve is either completely opened or closed, whereas a modulation
valve is infinitely positioned according to the strength of the applied
electrical signal. |
|
C |
If it is necessary
to increase the operating head pressure of the refrigeration system using
the device shown in the illustration, what should be done? Illustration
GS-RA-14 |
"4"
should be rotated to compress the enclosed bellows |
"2"
should be turned to relax the compression of the spring |
"2"
should be turned to further compress the spring |
"4"
should be rotated to relax the enclosed bellows |
|
C |
In a refrigeration
system that is not protected by a water failure switch, if the cooling water
to the condenser fails, what will be the result for protective purposes? |
the king valve
will open |
the box temperature
solenoid valve will close initiating a pump down |
the compressor
will shut down by the action of the high pressure cutout switch |
the expansion
valve will close due to high superheat |
|
A |
In a refrigeration
system, the valve shown in the illustration is used for what purpose? Illustration
GS-RA-14 |
head pressure
regulating valve |
suction pressure
regulating valve |
evaporator pressure
regulating valve |
thermostatic expansion
valve |
|
D |
The set point
adjustment of the device shown in the illustration is made by rotating what
component? Illustration GS-RA-14 |
"4" |
"3" |
"1" |
"2" |
|
B |
As shown in the
illustrated refrigeration system piping schematic diagram with the various
accessories and controls and equipped with an air-cooled condenser with
high side pressure controls, what statement is true concerning the fan cycling
control pressure switch? Illustration GS-RA-39 |
With a condenser
fitted with a single fan driven by a single-speed electric motor, the fan
would cycle off under high ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a multi-speed electric motor, the fan
speed would decrease under low ambient temperature conditions. |
With a condenser
fitted with multiple electric-motor driven fans, the number of fans in use
would increase under low ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a multi-speed electric motor, the fan
speed would decrease under high ambient temperature conditions. |
|
B |
An arrow stamped
on the valve body of a water regulating valve indicates which of the following? |
closed position |
direction of the
flow |
open position |
direction of the
plunger slide |
|
B |
Through which
of the components shown in the illustration is flash gas formation a normal
occurrence? Illustration GS-RA-25 |
receiver tank |
thermostatic expansion
valve |
evaporator coil |
condenser coil |
|
C |
In the multi-evaporator
refrigeration system shown in the illustration, what is the proper name
for the valve labeled "29"? Illustration GS-RA-12 |
freeze box thermostatic
expansion valve |
chill box evaporator
pressure regulating valve |
chill box thermostatic
expansion valve |
chill box solenoid
valve |
|
B |
Rather than design
an infinite variety of thermostatic expansion valve sizes to accommodate
different capacities for heat removal, some manufacturers use a few standard
valve body sizes in conjunction with what other feature? |
an externally
adjustable superheat to accommodate different heat removal capacities |
internal needle
valve orifices of various sizes to accommodate different heat removal capacities |
a flexible diaphragm
to accommodate different heat removal capacities |
internal equalizers
to accommodate different heat removal capacities |
|
A |
Constant superheat
is maintained at the evaporator coil outlet of a refrigeration system or
unit by the action of what device? |
thermal expansion
valve |
low pressure cutout
switch |
king valve |
solenoid valve |
|
A |
Besides the evaporator
pressure, the thermal expansion valve reacts directly to changes in what
parameter? |
temperature of
the evaporator coil outlet |
liquid refrigerant
pressure at the solenoid valve |
pressure drop
across the evaporator coils |
temperature of
the space being cooled |
|
A |
Refrigeration
system isolation valves are specially designed with a back-seat, as well
as a front-seat. For what purpose are these valves designed in this way? |
permit repacking
the valve stem under pressure without shutting down |
allow for operation
as a suction or discharge valve |
allow for operation
as a liquid or vapor valve |
allow for removal
and replacement of the valve without shutting down |
|
D |
Which lettered
component, shown in the illustration, indicates the location of the receiver?
Illustration GS-RA-12 |
A |
B |
F |
C |
|
B |
In a refrigeration
plant, what is one vital purpose of the receiver? |
superheat the
refrigerant liquid |
store the refrigerant
charge |
condense the refrigerant |
cool the refrigerant
gas |
|
A |
In addition to
the indicated gauge pressure, what other information is presented on the
compound gauge for the hypothetical refrigerant illustrated? Illustration
GS-RA-16 |
the saturation
temperature of the refrigerant that corresponds to the gauge pressure at
the point of measurement |
the metric pressure
equivalent of the refrigerant at the point of measurement |
the absolute pressure
of the refrigerant at the point of measurement |
the actual temperature
of the refrigerant at the point of measurement |
|
B |
The receiver used
in a refrigeration system performs what essential function? |
allows the refrigerant
to be superheated |
holds the entire
refrigerant charge after system pump down |
prevents liquid
refrigerant from flooding back to the compressor |
collects air and
non-condensable gases |
|
A |
During the initial
cooling down of a box temperature in a refrigeration system, which of the
devices listed is used to prevent excessive gas pressure at the compressor
suction for the purpose of prevention of overloading of the compressor driver? |
Crankcase pressure
regulator |
High pressure
cutout |
Solenoid valve |
Low pressure cutout |
|
B |
Which of the lettered
components shown in the illustration indicates the high-pressure cut-out?
Illustration GS-RA-12 |
Y |
X |
Z |
W |
|
B |
The rupture disc
on a low pressure centrifugal refrigeration unit is used as an over pressure
protection device and is set to relieve at 15 psig and is most likely to
lift when the compressor is idle? Where is the rupture disc located? |
at the top of
the upper chamber of the economizer |
on top of chiller
evaporator shell |
at the discharge
of the compressor |
on top of the
condenser shell |
|
B |
When the relief
valve opens on a refrigeration compressor discharge line, it discharges
high pressure refrigerant vapor to what location? |
liquid strainer |
suction side of
the compressor |
inlet side of
the evaporator |
refrigerant inlet
of the condenser |
|
D |
The safety heads
of most large reciprocating compressors used in refrigeration systems are
held in place by what means? |
large Teflon gaskets |
tack welding on
the sides |
discharge pressure
in the relief valve return line |
heavy coil springs |
|
D |
In the illustrated
refrigeration system, what is the proper name for the component labeled "A"?
Illustration GS-RA-12 |
condenser |
accumulator |
filter drier |
compressor |
|
A |
What is the purpose
of running a refrigeration compressor in short intermittent spurts or throttling
the suction isolation valve when starting the system after a prolonged shutdown? |
prevent liquid
slugging or overloading the compressor |
determine actual
compressor oil level |
let the refrigerated
compartment cool gradually |
allow refrigerant
vapor cycling time |
|
A |
A device used
to hold open the refrigeration compressor suction valve during starting
to reduce the compression load is called what? |
cylinder unloader |
discharge line
bypass |
suction line bypass |
relief valve |
|
B |
In a refrigeration
system, what component is installed directly downstream of the thermal expansion
valve? |
box solenoid valve |
evaporator coil |
receiver |
compressor |
|
D |
Refrigeration
systems using forced air circulation evaporators have a tendency to cause
rapid dehydration of produce in chill boxes. Which of the following will
minimize this dehydration? |
the air is circulated
rapidly over a small evaporator with a minimum temperature differential |
the air is circulated
rapidly over a small evaporator with a maximum temperature differential |
the air is circulated
slowly over a large evaporator with a maximum temperature differential |
the air is circulated
slowly over a large evaporator with a minimum temperature differential |
|
B |
In a dry-type
direct expansion refrigeration evaporator, what is true concerning the evaporator
coils? |
the coils are
surrounded on the outside by refrigerant |
the coils are
surrounded on the outside by air |
the coils are
covered on the outside with insulation |
the coils are
coated on the inside with insulation |
|
B |
If a condenser
coil of an air-cooled container refrigeration system becomes dirty and requires
cleaning, what would be an acceptable method of cleaning? |
Binks' gun with
weak acid solvent |
high pressure
water wash |
copper wire rotary
brush |
All of the above. |
|
B |
Zinc plates commonly
found in refrigeration systems and used as sacrificial anodes are located
where? |
cooling water
suction strainer |
saltwater side
of the condenser |
refrigerant side
of the condenser |
evaporator coils |
|
B |
Seawater or low
temperature central fresh water is typically provided to a ship's stores
refrigeration plant for what purpose? |
prevent motor
overheating |
condense the refrigerant
gas |
cool the expansion
valve |
prevent refrigerant
superheating |
|
A |
Heat is removed
from the refrigerant circulating through the refrigeration system, shown
in the illustration, by which component? Illustration GS-RA-12 |
B |
A |
K |
J |
|
C |
When checking
zinc plates, or pencil Zincs in the refrigerating system condenser, what
should you do? |
paint and insulate
the plates to prevent corrosion |
file the plates
to change the negative value |
replace the Zincs
if deteriorated by 50% |
renew the plates
at each inspection |
|
A |
For safe storage,
the maximum allowable temperature to which refrigerant bottles should be
exposed is what temperature? |
125°F |
100°F |
150°F |
175°F |
|
C |
Which of the precautions
listed should be taken before opening any part of a refrigeration system
for the purpose of accomplishing non-major repairs? |
Bring the part
of the system to be opened to a pressure corresponding to the ambient temperature. |
Use the hot gas
defrost line to remove any frost on the evaporator coils. |
Bring the part
of the system to be opened to 0 psig. |
Set the high pressure
cutout on manual to prevent automatic starting. |
|
A |
Overfilling a
refrigerant container is extremely dangerous because of the high pressures
generated. The generation of pressure is the result of what? |
hydrostatic pressure
of the expanding liquid |
vapor pressure
of the refrigerant at saturation temperature |
discharge pressure
from the recovery cylinder |
discharge pressure
of the recovery compressor |
|
D |
The FIRST thing
to do to ensure that a refrigeration unit will not start while undergoing
repairs is to do what? |
inform all persons
in the area not to start the unit |
place a crow bar
in the flywheel of the unit |
make a log book
entry |
secure and tag
the electrical circuit |
|
B |
Personnel servicing
refrigeration systems and subject to the exposure to commonly used refrigerants
should wear what type of personal protective equipment? |
an all purpose
gas mask |
goggles and gloves |
rubber soled shoes |
a respirator |
|
D |
Inhalation of
high concentrations of chlorofluorocarbon refrigerants (CFCs) may have which
of the following effects? |
drowsiness |
loss of concentration |
cardiac arrhythmia's |
All of the above. |
|
D |
In the presence
of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants
decompose and form what chemical substance? |
water vapor |
petroleum crystals |
carbon monoxide |
phosgene gas |
|
C |
If there is a "large"
release of R-134a refrigerant gas in a confined area, which of the following
statements would be true? |
safety goggles
and lined butyl gloves would be required before entering the space |
an explosive atmosphere
would be created |
a self-contained
breathing apparatus (SCBA) would be required before entering the space |
dust or particle
masks would be required before entering the space |
|
A |
Why can CFC or
HCFC refrigerants leaking into a confined space or in limited surroundings
cause suffocation? |
Refrigerants are
heavier than air and displace oxygen. |
Refrigerants lighter
than air will rise. |
Refrigerants obnoxious
odor prevents breathing. |
Refrigerants contain
an acidic substance. |
|
C |
When recovering
R-12 from a small appliance with a working compressor, using a recovery
device manufactured after November 15, 1993, what percentage of the remaining
charge must be removed from the system? |
75 (%) |
99 (%) |
90 (%) |
80 (%) |
|
A |
As shown in figure "B"
of the illustrated self-contained recovery unit connection diagrams, what
is the recovery method supported by the connection scheme? Illustration
GS-RA-33 |
direct vapor recovery |
direct liquid
recovery |
liquid recovery/push-pull |
vapor recovery/push-pull |
|
B |
What must be done,
at a minimum, before a system can legally be opened up for repairs while
adhering to the prohibition against the venting of halogenated fluoro-carbon
refrigerants to the atmosphere? |
destruction of
the refrigerant |
recovery of the
refrigerant |
reclamation of
the refrigerant |
recycling of the
refrigerant |
|
B |
What is the correct
color coding of refrigerant recovery cylinders regardless of the refrigerant
contained within? |
light blue top
and yellow lower body |
yellow top and
gray body |
gray top and light
blue lower body |
gray top and yellow
lower body |
|
B |
In a refrigeration
system, the push-pull technique can be used for the recovery of the refrigerant
in what state? |
vapor only |
both liquid and
vapor |
should never be
used with low pressure systems |
liquid only |
|
C |
Which recovery
procedure should be used to minimize the loss of oil from the system during
the recovery of refrigerant from small appliances such as a water cooler? |
liquid recovery |
vapor-liquid recovery |
vapor recovery |
initial recovery |
|
B |
What is true concerning
highly contaminated refrigerant recovered from burned out small appliances? |
The recovered
refrigerant may be used to clean out systems that have suffered from a burn
out. |
The recovered
refrigerant should be sent to a designated reclamation facility for processing. |
The recovered
refrigerant may be blended with new refrigerant for eventual re-use. |
The recovered
refrigerant must be destroyed by the refrigeration technician. |
|
C |
Technicians servicing
small refrigeration appliances can employ what type of recovery equipment? |
do not need to
recover the refrigerant |
active only |
either active
or passive |
passive only |
|
A |
If passive recovery
is used on a small appliance fitted with a capillary tube as a metering
device with a non-operating compressor, the recovery should be made through
what means? |
recovery from
both the high and low sides |
by venting to
atmosphere, cannot be recovered |
recovery from
the high side only |
recovery from
the low side only |
|
B |
Minor repairs
may be performed on low pressure refrigerant systems without recovering
the refrigerant charge if the pressure in the system is raised to atmospheric.
How may this be accomplished? |
pressurize the
system with nitrogen |
heat the refrigerant |
open the system
vent to the atmosphere and allow the pressure to equalize |
charge the system
until it is completely filled with liquid refrigerant |
|
C |
Why is a purge
recovery unit typically fitted on low pressure centrifugal chillers? |
evacuation of
the air from a low pressure chiller prior to charging with refrigerant is
not
possible |
low pressure chillers
use extremely low boiling point refrigerants |
such a chiller
can operate at a pressure below atmospheric pressure on the low side thus
drawing in air through any low-side leaks |
low pressure chillers
are routinely opened for maintenance thus introducing air at each opening |
|
B |
The most cost-effective
method of recovering refrigerant from a low pressure chiller with more than
500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant
using what protocol? |
recovery using
a vacuum pump based vapor recovery machine only |
liquid recovery
using a liquid pump, followed by vapor recovery using a vacuum pump based
recovery unit |
vapor recovery
using a vacuum pump based recovery unit followed by liquid recovery using
a liquid pump |
recovering using
a liquid pump only |
|
D |
As shown in the
illustrated flow diagram for a self-contained recovery unit designed for
the recovery of refrigerants from high pressure appliances as defined by
the EPA Clean Air Act rules, what is the functional purpose of the item
labeled "FS2"? Illustration GS-RA-32 |
It automatically
shuts down the recovery unit compressor when the recovery cylinder becomes
80% full. |
It automatically
shuts down the recovery unit compressor when the discharge pressure becomes
excessive. |
It automatically
shuts down the recovery unit compressor when the refrigeration system has
reached a depth of 15" Hg. |
It automatically
transitions the recovery unit from the direct liquid recovery mode to the
direct vapor recovery mode. |
|
D |
Traditionally,
which of the listed refrigerants has been more suitable than the others
for use in a centrifugal refrigeration compressor? |
R-12 |
Carbon dioxide |
Ammonia |
R-11 |
|
C |
Which of the illustrated
devices would be the LEAST accurate for the purposes of weighing-in a refrigerant
charge? Illustration GS-RA-45 |
A |
B |
C |
D |
|
B |
Before charging
a refrigeration unit, unless quick disconnect fittings are used, the refrigerant
charging hoses should be prepared in what way? |
they should be
cleaned with carbon tetrachloride |
they should be
purged with refrigerant |
they should be
flushed with clean refrigerant oil |
they should be
warmed in an oven |
|
A |
Concerning the
charging of refrigerant into a vapor compression refrigerating system, which
of the following is true? |
when charging
as a liquid it should be to the high side only |
when charging
as a liquid it should be to the low side only |
when charging
as a vapor it should be directly to the receiver only |
when charging
as a liquid it may be to the low or high side |
|
D |
The amount of
HCFC-123 in a storage cylinder is measured by what means? |
volume |
saturation pressure |
saturation temperature |
weight |
|
A |
Which of the illustrated
valves is used to gain access to a hermetic system and features a Schrader
core valve which is unseated by the core depressor of hose fitting when
attached? Illustration GS-RA-69 |
D |
A |
B |
C |
|
B |
How should small
appliances with less than three pounds of refrigerant be charged with refrigerant? |
initially liquid
charged and then topped with a vapor charge |
vapor charged |
either vapor or
liquid charged |
liquid charged |
|
C |
Charging liquid
HCFC-123 into a system under a deep vacuum could cause what to happen unless
necessary precautions are taken? |
the purge unit
to operate |
air and moisture
to enter the receiver |
system secondary
refrigerant to freeze |
rupture disk to
rupture |
|
A |
When a refrigeration
system is being topped off with a small amount of refrigerant through the
low side with the compressor running, what should be done? |
the refrigerant
should be charged into the system as a vapor |
the refrigerant
charging cylinder should be turned upside down |
the discharge
service valve must be front seated |
the suction service
valve must be back seated |
|
A |
Which of the valves
listed is normally closed when charging the refrigeration system through
the high side? |
Liquid line king
valve |
Dehydrator inlet
valve |
Suction line valve |
Thermal expansion
valve |
|
D |
Using the device
shown in the illustration, which of the following statements is true when
adding refrigerant as a vapor to the low side of the refrigeration system
__________. Illustration GS-RA-01 |
The hose labeled "K"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "C" should be closed. |
The hose labeled "K"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "C" should be open. |
The hose labeled "H"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "G" should be closed. |
The hose labeled "H"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "G" should be open. |
|
C |
Which of the fluids
listed is suitable for use as a secondary refrigerant? |
Carbon dioxide |
Methyl alcohol |
Brine |
Cuprous chloride |
|
A |
According to 46
CFR, Part 58, for protection purposes, what is required of all refrigeration
systems? |
pressure relief
device |
refrigerant receiver |
low pressure cut-out |
high pressure
cut-out |
|
C |
With regards to
shipboard refrigeration systems, after July 1, 1992, what action became
illegal? |
working on a refrigeration
system without permission of the Officer in Charge Marine
Inspection |
mixing R-12 and
R-22 |
intentionally
venting class I or II refrigerants to the atmosphere |
producing a class
I refrigerant |
|
B |
Refillable tanks
used to ship CFC and HCFC refrigerants or used to recover these refrigerants
must meet the standards of what entity? |
the United States
Coast Guard |
the United States
Department of Transportation |
the Underwriters
Laboratories |
the Environmental
Protection Agency |
|
B |
Coast Guard Regulations
(46 CFR Part 58) require a method for the relieving pressure of an over
pressurized refrigeration system. Which of the following statements complies
with these Regulations? |
The rupture disk
shall burst at a pressure not higher than 10% above the relief valve setting. |
A rupture disk
may be fitted in series with the relief valve. |
The relief valve
settings shall be 1 1/4 times the maximum allowable working pressure. |
The relief valve
from the receiver must relieve to the condenser first. |
|
D |
Coast Guard Regulations
(46 CFR Part 113) require refrigerated spaces that can be locked from the
outside and that cannot be opened from the inside to have an audible alarm.
Where is the audible alarm required to be? |
the wheelhouse |
the galley |
the chief steward's
berthing quarters |
a manned location |
|
A |
What would be
an example of a small appliance as defined in the EPA Clean Air Act rules? |
a hermetically
sealed water cooler with a 2 lb. refrigerant charge |
a 200 ton low
pressure centrifugal chiller for cargo hold air conditioning |
a 25 ton air conditioning
system set up as a split plant with the condensing unit on deck |
a self-contained
walk-in freezer with a 60 lbs. refrigerant charge |
|
B |
Within the territorial
limits of the United States, violations of the Clean Air Act of 1990, that
includes the intentional release of R-11, R-12, R-22 and other related class
I or class II substances may result in fines for each violation per day
of what amount? |
$50,000 |
$25,000 |
$5,000 |
$10,000 |
|
C |
All shipboard
personnel responsible for the maintenance and repair of air conditioning
systems using refrigerants covered under the EPA Clean Air Act venting prohibition,
must be certified through an approved Environmental Protection Agency (EPA)
program to do which of the following? |
before they can
pump down the system in preparation for shifting over to the standby
condensing unit |
before they can
set the operating controls of the system |
before performing
Maintenance, service or repair that could reasonably be expected to release
Class 1 or Class 2 refrigerants into the atmosphere |
before performing
any Maintenance or repair regardless of the actual procedure |
|
A |
EPA Clean Air
Act rules permit refrigerant to be released to the atmosphere under which
of the following conditions? |
when release is
considered 'de minimis' |
during replacement
of a compressor |
when adding oil
to a compressor |
when testing a
system for leaks using R-12 and nitrogen |
|
C |
Persons recovering
refrigerant from small appliances must be certified as what type of technician
under the EPA Clean Air Act rules? |
Type II technician |
Type III technician |
Type I or Universal
technician |
All of the above. |
|
C |
According to the
EPA Clean Air Act rules, what is true concerning refrigerant leaks in a
small hermetically sealed shipboard water cooler with a 20 ounce charge
weight? |
The leaks must
be repaired if the annual leak rate exceeds 15% of the total charge |
The leaks must
be repaired if the annual leak rate exceeds 35% of the total charge. |
Legally, the leaks
are not required to be repaired, but morally it is advisable to repair the
leaks. |
The leaks must
be repaired within 30 days. |
|
C |
If you find the
pressure of a refrigeration system containing a Class I or Class II refrigerant
to be opened for the accomplishment of repairs is 0 psig, what must be done? |
recover liquid
and vapor refrigerant and have it reclaimed |
only recover the
liquid refrigerant in the system |
do not attempt
to recover the refrigerant and repair the leak before pulling a vacuum on
the system |
only recover the
vapor refrigerant |
|
A |
Which best defines
a "Type I" small refrigeration appliance according to the EPA
Regulations Section 608? |
systems manufactured
and hermetically sealed having a capacity of five pounds (2.27 kg) or less
of refrigerant |
any appliance
charged with less than ten pounds (4.54 kg) of refrigerant |
refrigerators,
freezers, room air conditioners and central air conditioners |
any appliance
charged with less than two pounds (0.91 kg) of refrigerant |
|
C |
Alkylbenzene ISO
32 cSt synthetic refrigerant oil is miscible and suitable to use with which
of the following refrigerants? |
R-32 |
R-143a |
R-22 |
R-134a |
|
B |
For safe storage,
the maximum allowable temperature to which refrigerant bottles should be
exposed is what temperature? |
150°F |
125°F |
100°F |
175°F |
|
A |
Overfilling a
refrigerant container is extremely dangerous because of the high pressures
generated. The generation of pressure is the result of what? |
hydrostatic pressure
of the expanding liquid |
discharge pressure
from the recovery cylinder |
discharge pressure
of the recovery compressor |
vapor pressure
of the refrigerant at saturation temperature |
|
D |
Personnel servicing
refrigeration systems and subject to the exposure to commonly used refrigerants
should wear what type of personal protective equipment? |
rubber soled shoes |
a respirator |
an all purpose
gas mask |
goggles and gloves |
|
A |
In the presence
of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants
decompose and form what chemical substance? |
phosgene gas |
carbon monoxide |
water vapor |
petroleum crystals |
|
A |
Why can CFC or
HCFC refrigerants leaking into a confined space or in limited surroundings
cause suffocation? |
Refrigerants are
heavier than air and displace oxygen. |
Refrigerants lighter
than air will rise. |
Refrigerants obnoxious
odor prevents breathing. |
Refrigerants contain
an acidic substance. |
|
C |
The amount of
HCFC-123 in a storage cylinder is measured by what means? |
saturation pressure |
volume |
weight |
saturation temperature |
|
A |
Which of the following
statements is true concerning the gauge labeled "A" of the illustrated
gauge manifold set? Illustration GS-RA-01 |
The gauge labeled "A"
is a compound gauge and is usually color-coded blue. |
The gauge labeled "A"
is a compound gauge and is usually color-coded red. |
The gauge labeled "A"
is a standard pressure gauge and is usually color-coded blue. |
The gauge labeled "A"
is a standard pressure gauge and is usually color-coded red. |
|
D |
Which of the following
statements is true concerning the illustrated gauge manifold set? Illustration
GS-RA-01 |
The valves labeled "G"
and "C" must both be open to read system pressures on the
respective gages labeled "A" and "B". |
Closing the valve
labeled "G" isolates the hose labeled "H" from the gauge
labeled "A". |
Opening fully
and back seating the valve labeled "G" isolates the gauge labeled "A"
from the
hose labeled "H". |
Closing the valve
labeled "G" isolates the hose labeled "H" from the hose
labeled "J". |
|
A |
When repairing
a refrigeration system, a swaging tool set would be used to carry out which
of the following operations? |
Swaging tools
can be used to expand an end of one tube to fit onto a tube of the same
original outside diameter. |
Swaging tools
are used to remove any sweated edges formed on the tubing while soldering. |
Swaging tools
are used during the breaking-in of refrigeration compressors and drive motors. |
Swaging tools
are no longer used with repairing refrigeration systems due to progressive
changes in the tool industry. |
|
B |
Which of the illustrated
gauges is capable of measuring vacuums at the micron level for the purpose
of proving system dehydration during system evacuation with a vacuum pump,
but displays the achieved vacuums at incremental threshold intervals rather
than continuously. Illustration GS-RA-37 |
A |
B |
C |
D |
|
A |
Which of the following
substances is normally classified as a low pressure refrigerant? |
R-123 |
R-22 |
R-12 |
R-134A |
|
A |
What is the purpose
of running a refrigeration compressor in short intermittent spurts or throttling
the suction isolation valve when starting the system after a prolonged shutdown? |
prevent liquid
slugging or overloading the compressor |
allow refrigerant
vapor cycling time |
let the refrigerated
compartment cool gradually |
determine actual
compressor oil level |
|
B |
When starting
a reciprocating refrigeration compressor that has been shut down for a period
of time, you should manually throttle which valve? |
king valve |
suction valve |
expansion valve |
sea water valve |
|
A |
When opening or
closing compressor service and line isolation valves on a typical refrigeration
system that is fitted with packed valves, what must you do? |
you must first
remove the stem seal cap |
you should replace
the gasket each time the valve position is changed |
you should never
loosen or tighten the packing gland |
you should turn
valves slowly to avoid thermal stresses due to low temperatures |
|
C |
What is the color
coding for a storage container of R-134a refrigerant? |
green |
purple |
light blue |
grey |
|
B |
The gas that exists
in the stratosphere forming a protective shield that helps to protect the
environment from the harmful effects ultraviolet radiation is called what? |
radon |
ozone |
oxygen |
nitrogen |
|
A |
In an air conditioning
system, what is the name of the chamber where the duct-work originates? |
plenum chamber |
exhaust chamber |
vapor chamber |
intake chamber |
|
B |
In a two stage
centrifugal air conditioning system, the liquid refrigerant passes through
the condenser directly to what component? |
expansion valve |
economizer |
chiller |
evaporator |
|
A |
A reheater in
an air conditioning system performs what function? |
restores the conditioned
air temperature to a comfortable level |
controls the inlet
air volume |
controls the inlet
air temperature |
maintains the
relative humidity at 15% |
|
D |
What is one benefit
of Maintenance of proper air circulation in an air conditioned cargo space? |
more temperature
differential |
increased moisture
content |
increased density
of the air |
reduced slime
and mold |
|
A |
What is the wet
bulb temperature of air if the dry bulb temperature of the air is 90 degrees
and the relative humidity is 65%? Illustration GS-RA-22 |
80 degrees F |
63 degrees F |
77 degrees F |
62 degrees F |
|
B |
In general, the
thermal bulb for a thermal expansion valve used in a reciprocating air conditioning
system is usually charged with what substance? |
bees wax |
the same refrigerant
as the system |
mercuric sulfate |
distilled water |
|
D |
To prevent the
unnecessary loading of an air conditioning system while maintaining the
designed dry bulb temperature and relative humidity in an air conditioning
system, what should be done? |
operate the purge
recovery unit continuously |
reduce the air
reheating system load |
lower the compressor
head pressure |
admit only enough
fresh outside air to provide proper ventilation |
|
D |
Which of the following
is true concerning the class "D" air conditioning system shown
in the following illustration? Illustration GS-RA-42 |
The heat load
will increase by increasing the amount of recirculated air. |
The room thermostat
controls the wet bulb temperature of the air conditioned space. |
System cooling
is the direct result of the Freon circuit of a direct type air conditioning
unit. |
The duct thermostat
determines the amount of water flow circulating through the cooling coil. |
|
A |
Concerning the
arrangement of equipment and associated hoses shown in the illustration,
what statement is true? Illustration GS-RA-59 |
When recovering
refrigerant from the centrifugal chiller using this method, it is possible
to achieve the recovery levels required by law without any further recovery. |
When recovering
refrigerant from the centrifugal chiller using this method, the refrigerant
is being recovered as a liquid. |
When recovering
refrigerant from the centrifugal chiller using this method, the containment
tank should be vented back to the chiller evaporator shell. |
When recovering
refrigerant from the centrifugal chiller using this method, the entire charge
may be removed in one procedure. |
|
B |
Which of the following
methods is normally used to control the circulated air temperature of an
air conditioning system using chilled water circulation? |
A fan speed controller
regulates the amount of air flowing across the coils. |
A regulating valve
controls the quantity of chilled water flowing in the cooling coils. |
A regulating valve
changes the inlet temperature of the water in the cooling coils. |
Control dampers
varying the number of passes the air makes across the cooling coils. |
|
D |
For the proper
control of the air temperature in an air conditioning system using chilled
water circulation, which of the listed conditions should remain constant
regardless of load changes? |
Compressor discharge
temperature. |
Chilled water
system return temperature. |
Compressor suction
pressure. |
Chilled water
system supply temperature. |
|
C |
Which of the processes
listed would be the most satisfactory method to use to lower the humidity
of the air being circulated by an air conditioning system? |
Cooling the air
to a temperature just above dew point. |
Heating the air
and then cooling it to a point below dew point. |
Cooling the air
to a point below dew point, then reheating it. |
Heating the air
to a point at which moisture will boil off, then recooling it. |
|
C |
A room humidistat
initiates the lowering of the humidity of the conditioned supply air to
a space, while the actual process is accomplished by what means? |
raising the cooling
coil temperature and lowering the reheater temperature |
raising both the
cooling coil temperature and the reheater temperature |
lowering the cooling
coil temperature and raising the reheater temperature |
lowering both
the cooling coil temperature and the reheater temperature |
|
D |
In an air conditioning
system, moisture is removed from the air by what means? |
separators |
ducted traps |
filters |
cooling coils |
|
A |
The introduction
of outside air to the air conditioning system is 90°F with a relative humidity
of 60%. The air has been conditioned to 70°F with a relative humidity of
80%. Using the psychrometric chart, shown in the illustration, determine
the quantity of moisture removed from one pound of the conditioned air __________.
Illustration GS-RA-22 |
40 grains |
50 grains |
30 grains |
20 grains |
|
B |
If outside air
at 80 degrees F and 70 percent relative humidity is conditioned, what will
be the resulting dew point temperature of the air just before it comes into
contact with the cooling coil? Illustration GS-RA-22 |
64 degrees F |
70 degrees F |
73 degrees F |
67 degrees F |
|
C |
Which of the following
is true concerning the class "A" air conditioning system shown
in the illustration as used to condition the air of large public spaces?
Illustration GS-RA-09 |
The reheater is
not used when in the cooling mode. |
The preheater
steam flow is controlled by the space thermostat. |
The dry bulb room
temperature is controlled by a steam heated reheater and its associated
pneumatic control valve. Illustration GS-RA-09 |
It is not possible
for both the cooling coil and the steam heated reheater to be used
simultaneously. |
|
A |
To add small amounts
of refrigerant to the low side of an air conditioning system, the refrigerant
should be introduced through a particular valve and in a particular state.
What valve and state combination is correct? |
suction service
valve as a vapor |
discharge service
valve as a liquid |
discharge service
valve as a vapor |
suction service
valve as a liquid |
|
D |
To add refrigerant
to the high side of an air conditioning system, you should close the king
valve and introduce the refrigerant through what valve in what state? |
condenser purge
valve as a vapor |
suction service
valve as a liquid |
discharge service
valve as a vapor |
charging valve
as a liquid |
|
C |
When pumping down
an air conditioning system to test the low-pressure cut-out switch, assuming
that the compressor is running, what should be done to initiate the test? |
secure the condenser |
stop the compressor |
close the 'king'
valve |
stop the circulating
pump |
|
C |
When recovering
the remaining R-134a refrigerant from the centrifugal chiller shown in the
illustration as a vapor using the recovery unit's compressor, in addition
to opening valves "1a", "1b", and the compressor suction
and discharge isolation valves, which of the following would be the correct
valve lineup? Illustration GS-RA-28 |
valves "3", "5",
and "6" open; valves "2", "4", "7", "8",
and "10" closed |
valves "3", "4", "7", "6"
and "10" open; valves "2", "5", and "8"
closed |
valves "3", "4",
and "6" open; valves "2", "5", "7", "8",
and "10" closed |
valves "2", "5", "7", "8",
and "10" open; valves "3", "4", and "6"
closed |
|
B |
The compressor
used in a water-cooled air conditioning system is short cycling. A service
check determines that the suction pressure remains above the normal cut-in
point during cycling and that the discharge pressure rapidly builds up to
the cut-out point while running and gradually falls to the cut-in point
during the off cycle. What is likely the cause? |
back seated discharge
service valve |
reduction in condenser
water flow (scaled condenser) |
loosely fitted
compressor drive belt |
front seated liquid
line service valve |
|
D |
Using the illustrated
chart giving the boiling point of moisture at various depths of vacuum,
with an ambient temperature of 72 °F, what depth of vacuum would be associated
with the BEST chance of achieving a dehydration evacuation with a deep vacuum
pump? Illustration GS-RA-56 |
29" Hg gauge
or 25,400 microns of Hg absolute |
28.75" Hg
gauge or 31,750 microns of Hg absolute |
29.20" Hg
or 20,320 microns of Hg absolute |
29.99" Hg
or 254 microns of Hg absolute |
|
B |
Concerning the
arrangement of equipment and associated hoses shown in the illustration,
what statement is true? Illustration GS-RA-58 |
When recovering
refrigerant from the centrifugal chiller using this method, it is permissible
to exceed 90% of the weight capacity of the refrigerant drum. |
When recovering
refrigerant from the centrifugal chiller using this method, it minimizes
the risk of chiller tube freeze-up |
When recovering
refrigerant from the centrifugal chiller using this method, it is possible
to achieve the recovery levels required by law without any further recovery. |
When recovering
refrigerant from the centrifugal chiller using this method, the vent hose
connection should be closed. |
|
A |
The surging that
occurs in a centrifugal air conditioning compressor is a result of what
conditions? |
low pressure in
the evaporator at low load |
low pressure in
the condenser at low load |
low pressure in
the condenser at high load |
low pressure in
the evaporator at high load |
|
C |
In an air conditioning
system, low discharge head pressure associated with a reciprocating compressor
can be the result of what condition? |
insufficient cooling
water to the condenser |
air in the evaporator
coils |
leaky suction
valves |
air in the condenser |
|
A |
The air temperature
associated with a direct reciprocating air conditioning plant is found to
be too warm, and the compressor is not operating. A service check determines
the compressor suction pressure to be above the normal cut-in point, with
a normal head pressure, and high evaporator superheat. Which of the following
could be the cause of this problem? |
The low pressure
control contacts are stuck open. |
A liquid line
solenoid valve has failed closed. |
Cooling water
flow to the condenser is excessive. |
A liquid line
solenoid valve is stuck open. |
|
A |
Sludge may form
in the crankcase of an air conditioning compressor as a result of what condition? |
overheating and
carbonization of the oil in the crankcase |
reducing the cloud
or floc point of the oil |
lowered compressor
operating temperatures |
excessive foaming
of the oil in the crankcase |
|
A |
As shown in the
illustrated LP centrifugal chiller high efficiency purge recovery unit piping
schematic, what statement is true concerning the vacuum pump? Illustration
GS-RA-55 |
The vacuum pump
is designed to remove refrigerant vapor from the carbon filter tank and
transfer these vapors to the evaporator to minimize the loss of refrigerant
to the atmosphere. |
The vacuum pump
is designed to remove refrigerant vapor from the carbon filter tank and
transfer these vapors to the purge chamber to blow the float valve clear.
Illustration GS-RA-55 |
The vacuum pump
is designed to remove air and non-condensable gases from the evaporator
and transfer these gases to the carbon filter tank for eventual venting
to the atmosphere. |
The vacuum pump
is designed to perform a dehydration evacuation on the system prior to charging
with refrigerant. |
|
B |
The "tare
weight" of a refrigerant storage cylinder refers to what weight? |
the total weight
of a fully charged cylinder |
the weight of
an empty cylinder |
the weight of
a cylinder AND its current contents |
the maximum weight
of the refrigerant allowed |
|
A |
The term 'oil
foaming' in refrigeration practice, is used to describe what event? |
release of miscible
refrigerant from the lubricant in the crankcase |
release of dissolved
lubricant from the refrigerant in the crankcase |
sudden evaporation
of entrapped moisture from the crankcase lubricant |
sudden evaporation
of entrapped air from the refrigerant liquid |
|
C |
What is the physical
state and pressure condition of refrigerant as it enters the condenser of
a typical refrigeration system? |
low pressure vapor |
low pressure liquid |
high pressure
vapor |
high pressure
liquid |
|
B |
What is the physical
state and pressure condition of refrigerant as it leaves a receiver in a
typical refrigeration system? |
high pressure
vapor |
high pressure
liquid |
low pressure vapor |
low pressure liquid |
|
D |
What is the pressure
and condition of the refrigerant entering the receiver of a refrigeration
system? |
superheated low
pressure vapor |
superheated high
pressure vapor |
sub cooled low
pressure liquid |
sub cooled high
pressure liquid |
|
B |
The safety heads
of most large reciprocating compressors used in refrigeration systems are
held in place by what means? |
tack welding on
the sides |
heavy coil springs |
discharge pressure
in the relief valve return line |
large Teflon gaskets |
|
B |
In the illustrated
refrigeration system, what is the proper name for the component labeled "A"?
Illustration GS-RA-12 |
accumulator |
compressor |
condenser |
filter drier |
|
A |
A device used
to hold open the refrigeration compressor suction valve during starting
to reduce the compression load is called what? |
cylinder unloader |
relief valve |
suction line bypass |
discharge line
bypass |
|
C |
The carbon seal
ring of a refrigeration compressor crankshaft mechanical seal is held in
position against the stationary ring face by using what device? |
snap ring |
woodruff key |
spring |
thrust washer |
|
A |
What is the drive
arrangement of refrigeration compressor shown in figure "B" of
the illustration? Illustration GS-RA-41 |
welded, fully
hermetic |
external-drive |
open |
serviceable, bolted,
accessible semi-hermetic |
|
B |
If the discharge
reed valves used in a refrigeration compressor are leaking badly, what statement
is true? |
the reed valves
should be reground and relapped |
the reed valves
should be replaced |
the low side pressure
will indicate below normal |
the high pressure
cut-out setting should be lowered |
|
B |
In addition to
the drive belt itself, a V-belt that is tensioned too tight will cause excessive
wear to what other drive component? |
the compressor
drive pulley |
motor shaft and
compressor main bearings |
the shaft of the
prime mover |
the prime mover
drive pulley |
|
B |
When one belt
of a multiple V-belt drive requires replacing, what will be required? |
ensure the proper
belt dressing is applied |
replace the entire
belt set |
season the new
belt prior to installation |
ensure the seasoned
belts are reinstalled in their proper sequence |
|
A |
When installing
a mechanical shaft seal on a refrigeration compressor, extreme care must
be taken to prevent what from happening? |
dirt and foreign
particles from coming in contact with the highly polished sealing surfaces |
any lubricant
from contacting the carbon surface that would cause the expulsion of the
saturated Teflon film |
any lubricant
from contacting the stationary seal face that would cause etching of the
face surface |
the spring from
being damaged by the corrosive effects of excessive handling |
|
C |
Excessively tight
drive belts installed between a motor and a refrigeration compressor pulley
may cause what condition? |
premature wear
of the pulley end motor shaft bearing, but normal wear of the pulley end
compressor crankshaft main bearing |
premature wear
of both motor shaft bearings and both compressor crankshaft main bearings
due to belt slippage |
premature wear
of both the pulley end motor shaft bearing and the pulley end compressor
crankshaft main bearing due to overloading |
normal wear of
the pulley end motor shaft bearing, but premature wear of the pulley end
compressor crankshaft main bearing |
|
B |
Which of the listed
statements describes the reason why oil foaming occurs when starting a refrigeration
compressor? |
This phenomenon
is inherent only in hermetically sealed units and is always provisional. |
This condition
is the result of the sudden low pressure created in the crankcase at start
up causing the release of refrigerant absorbed within the oil. |
If the oil level
is not initially high, this condition is the result of agitation created
by the movement of the mechanical components. |
This will occur
only if crankcase heaters are used. |
|
C |
A reciprocating
refrigeration compressor may be tested for leaking discharge valves by stopping
the compressor, turning the discharge service valve all the way in, and
then turning the compressor over by hand. If the discharge valves are leaking,
the compound gage will show pressures which react in which way? |
decreasing to
a vacuum |
increasing with
each stroke |
rising and falling
with each stroke |
decreasing with
each stroke |
|
D |
Unusual noise
coming from a refrigeration compressor can be caused by which of the following
conditions? |
worn bearings
and piston pins |
slugging due to
flooding back |
too much oil in
circulation |
All of the above. |
|
B |
Leaking suction
valves in a refrigeration compressor are indicated by which of the following? |
noticeable increase
in compressor noise |
higher than normal
suction pressure |
lower than normal
suction pressure |
lower than normal
evaporator temperature |
|
B |
For most multi-box
refrigeration systems, the refrigerant sight glass would be located where
in the system? |
after the condenser
in the drain line to the receiver |
after the receiver
in the liquid line |
before the compressor
in the suction line |
after the compressor
in the discharge line |
|
C |
Which of the following
dehydrators or combination filter/driers features a core that can be replaced
when the desiccant becomes saturated with moisture? Illustration GS-RA-10 |
B |
D |
A |
C |
|
B |
A liquid indicator
sight glass is useful in determining whether or not a refrigeration system
is sufficiently charged. Where is it generally located in the system? |
low pressure liquid
line |
high pressure
liquid line |
low pressure vapor
line |
high pressure
vapor line |
|
B |
Why are dehydrators
usually located in the liquid line of refrigeration systems? |
reduce compressor
discharge line sweating |
prevent icing
of the expansion valve |
prevent liquid
slugging in the suction line |
remove oil from
the refrigerant |
|
D |
Which of the devices
listed will indicate whether or not a refrigeration system's dehydrator
continues to be capable of removing moisture from the circulating refrigerant? |
Particulate test |
McLeod gage |
Dryer sensing
bulb |
Liquid line moisture
indicating sight glass |
|
A |
In a refrigeration
system, silica gel is found in what component? |
dehydrator or
combination filter/drier |
condenser/receiver |
moisture indicating
liquid line sight glass |
compressor suction
scale trap |
|
A |
The device shown
in the illustration which is used for removing moisture from the liquid
refrigerant in the system is labeled with what letter? Illustration GS-RA-12 |
E |
C |
B |
D |
|
C |
If a liquid drying
agent is used in a refrigeration system already equipped with a solid drying
agent, the liquid drying agent will cause what type of reaction? |
it will solidify
the refrigerant oil in the compressor crankcase |
it will cause
toxic gases to form in the refrigerated space |
it will release
the moisture already trapped in the solid drying agent |
it will react
violently with the solid drying agent |
|
A |
Moisture is removed
from a refrigeration system by what action? |
cutting in the
dehydrator |
condensing the
water in the heat exchanger |
draining refrigerant
from the bottom of the condenser |
opening a drain
petcock on the oil separator |
|
C |
Standard filter/driers
used in many commercial type refrigeration units may contain what type of
substance? |
activated charcoal |
alcohol based
liquid drying agents |
activated alumina
or silica gel desiccant beads |
All of the above. |
|
B |
The primary purpose
of the liquid line strainer used in a refrigeration system is to prevent
dirt and scale from entering what system component(s)? |
evaporator coil
piping |
thermal expansion
valves |
compressor and
oil separator |
condenser and
receiver |
|
B |
On a modern refrigerated
container unit employing suction modulation for the purposes of capacity
control and capacity limitation, what happens when the applied voltage and
current draw associated with the normally open (NO) suction modulation valve
located in the suction line both increase? |
the valve will
further close, lowering evaporator pressure and raising suction pressure |
the valve will
further close, raising evaporator pressure and lowering suction pressure |
the valve will
further open, lowering evaporator pressure and raising suction pressure |
the valve will
further open, raising evaporator pressure and lowering suction pressure |
|
D |
To prevent motor
overload during start-up of a hermetically sealed centrifugal refrigeration
system, what is true concerning the compressor suction gas variable inlet
guide vanes? |
opened until the
motor is connected across the line at full voltage and current drawn is
up to full load current |
opened until the
motor is connected across the line at full voltage and current drawn is
below full load current |
closed until the
motor is connected across the line at full voltage and current drawn is
up to full load current |
closed until the
motor is connected across the line at full voltage and current drawn is
below full load current |
|
D |
Capacity control
of a centrifugal refrigeration compressor can be accomplished by what means? |
varying the speed
of the compressor |
varying the position
of the suction inlet damper vanes |
varying the position
of the hot gas bypass valve |
All of the above. |
|
A |
The fluid used
as a source of actuating power against the underside of the unloader power
element piston of the refrigeration compressor capacity control mechanism
illustrated is obtained from where? Illustration GS-RA-13 |
discharge of the
compressor lube oil pump |
gas discharge
from the compressor |
high side liquid
receiver |
discharge of a
secondary hydraulic pump specifically installed for this operation |
|
C |
During operating
periods of a multi-box refrigeration system using a capacity controlled
compressor, when all of the evaporators of a four box plant are actively
being fed with liquid refrigerant, the control oil pressure acting on the
hydraulic relay piston will be at what value? |
the lowest |
at its mid-range |
the highest |
of no consequence
as the lube oil is not used in the operation of the unloader |
|
B |
A refrigeration
compressor used in a multi-box refrigeration system is designed with six
of its eight cylinders able to be controlled for variable load conditions.
If all of the reefer boxes are currently feeding, what percentage of the
total number of compressor cylinders will be loaded after start up? |
0 (%) |
100 (%) |
25 (%) |
50 (%) |
|
A |
What is the purpose
of the low pressure cut-out switch as used as a primary controller for a
refrigeration system or unit? |
start and stop
the compressor as needed |
control the capacity
of the compressor |
maintain a preset
suction pressure to the compressor |
maintain a preset
low-side pressure for the system |
|
A |
A box solenoid
valve used in a multi-box refrigeration system is operated by electromagnetic
action by what control device? |
box temperature
actuated thermostat |
discharge pressure
actuated pressure switch |
suction pressure
actuated pressure switch |
evaporator outlet
temperature actuated thermostat |
|
B |
How does a refrigeration
solenoid valve differ from a modulating valve? |
Both valves operate
in exactly the same manner, only the manufacturer's terminology is the differentiating
factor. |
A liquid line
solenoid valve is either completely opened or closed, whereas a modulation
valve is infinitely positioned according to the strength of the applied
electrical signal. |
Solenoid Valves
are only used in low voltage refrigeration control systems, while modulation
valves are used in high voltage applications. |
A solenoid valve
can only be installed in liquid lines. |
|
D |
A container unit's
microprocessor-controlled temperature controller is set at -28.9 ° C, appropriate
for a frozen cargo of ice cream. In this mode of operation, according to
the illustrated temperature controller functional diagrams, what should
be the operational status of the unit if the actual box temperature is -18.0
° C? Illustration GS-RA-35 |
heating mode |
modulating cooling
mode |
air circulation
mode |
cooling mode |
|
A |
Which of the following
electrically operated refrigeration system valves would be most appropriate
for use as a 2 position diverting hot gas bypass solenoid valve? Illustration
GS-RA-19 |
B |
D |
C |
A |
|
B |
In a multi-evaporator
refrigeration system, a solenoid valve is installed in the liquid line prior
to what device? |
the receiver |
each expansion
valve |
the oil separator |
the condenser |
|
A |
A liquid line
solenoid valve controls refrigerant flow to the evaporator by what means? |
fully opening
or closing |
sensing the temperature
in the liquid line |
throttling the
refrigerant |
sensing the superheat
in the tail coil |
|
A |
The thermostat
controlling the operation of the solenoid valve to a refrigerated box evaporator
senses what temperature? |
the refrigerated
box temperature |
compressor discharge
temperature |
evaporator coil
outlet temperature |
evaporator coil
inlet temperature |
|
D |
In a refrigeration
system featuring low-side pump down prior to the automatic shut down of
the compressor, the temperature of the refrigerated space is controlled
by the action of a thermostat wired to what device? |
suction line solenoid |
thermostatic expansion
valve |
low pressure cutout
switch |
liquid line box
solenoid |
|
A |
Which of the following
statements is true? Illustration GS-RA-12 |
Valve "14"
is the king solenoid, valve "28" is the chill box solenoid, and
valve "36" is the freeze box solenoid. |
Valve "14"
is the king solenoid, valves "28" and "36" are both
freeze box solenoids. |
Valve "14"
is the king solenoid, valve "36" is the chill box solenoid, and
valve "28" is the freeze box solenoid. |
Valve "14"
is the king solenoid, valves "28" and "36" are both
chill box solenoids. |
|
C |
If it is necessary
to increase the operating head pressure of the refrigeration system using
the device shown in the illustration, what should be done? Illustration
GS-RA-14 |
"4"
should be rotated to relax the enclosed bellows |
"4"
should be rotated to compress the enclosed bellows |
"2"
should be turned to further compress the spring |
"2"
should be turned to relax the compression of the spring |
|
C |
As shown in the
illustrated refrigeration system piping schematic diagram with the various
accessories and controls and equipped with an air-cooled condenser with
high side pressure controls, what statement is true concerning the fan cycling
control pressure switch? Illustration GS-RA-39 |
With a condenser
fitted with multiple electric-motor driven fans, the number of fans in use
would increase under low ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a multi-speed electric motor, the fan
speed would decrease under high ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a multi-speed electric motor, the fan
speed would decrease under low ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a single-speed electric motor, the fan
would cycle off under high ambient temperature conditions. |
|
C |
In a refrigeration
system, the valve shown in the illustration is used for what purpose? Illustration
GS-RA-14 |
suction pressure
regulating valve |
thermostatic expansion
valve |
head pressure
regulating valve |
evaporator pressure
regulating valve |
|
D |
The set point
adjustment of the device shown in the illustration is made by rotating what
component? Illustration GS-RA-14 |
"3" |
"1" |
"4" |
"2" |
|
B |
An arrow stamped
on the valve body of a water regulating valve indicates which of the following? |
closed position |
direction of the
flow |
open position |
direction of the
plunger slide |
|
C |
Which of the following
illustrated expansion valves is designed to maintain a constant evaporator
pressure rather than a constant evaporator superheat? Illustration GS-RA-24 |
D |
B |
C |
A |
|
C |
Refrigeration
system isolation valves are specially designed with a back-seat, as well
as a front-seat. For what purpose are these valves designed in this way? |
allow for operation
as a suction or discharge valve |
allow for removal
and replacement of the valve without shutting down |
permit repacking
the valve stem under pressure without shutting down |
allow for operation
as a liquid or vapor valve |
|
D |
In addition to
pressure, most compound and standard pressure gauges used for refrigeration
service are also provided with a scale indicating what parameter? |
superheated refrigerant
temperature |
sub cooled refrigerant
temperature |
absolute pressure |
saturated refrigerant
temperature |
|
A |
What is the purpose
of the pressure transducer as shown in the illustration? Illustration GS-RA-17 |
it senses compressor
suction pressure and controls the quench valve |
it senses compressor
suction pressure and controls the suction modulation valves |
it senses compressor
discharge pressure and controls the suction modulation valves |
it senses compressor
discharge pressure and controls the quench valve |
|
B |
Which lettered
component, shown in the illustration, indicates the location of the receiver?
Illustration GS-RA-12 |
B |
C |
F |
A |
|
C |
In a refrigeration
plant, what is one vital purpose of the receiver? |
condense the refrigerant |
cool the refrigerant
gas |
store the refrigerant
charge |
superheat the
refrigerant liquid |
|
B |
In addition to
the indicated gauge pressure, what other information is presented on the
compound gauge for the hypothetical refrigerant illustrated? Illustration
GS-RA-16 |
the actual temperature
of the refrigerant at the point of measurement |
the saturation
temperature of the refrigerant that corresponds to the gauge pressure at
the point of measurement |
the absolute pressure
of the refrigerant at the point of measurement |
the metric pressure
equivalent of the refrigerant at the point of measurement |
|
C |
The receiver used
in a refrigeration system performs what essential function? |
prevents liquid
refrigerant from flooding back to the compressor |
allows the refrigerant
to be superheated |
holds the entire
refrigerant charge after system pump down |
collects air and
non-condensable gases |
|
B |
Hard drawn copper
tubing is commonly used in larger refrigeration systems. What statement
concerning its use is true? |
Hard drawn copper
tubing is easily bent, so elbow fittings are rarely used in changing direction. |
Hard drawn copper
tubing is not easily flared, bent, or swaged, so brazed fittings are commonly
used. |
Hard drawn copper
tubing is easily flared, so flare fittings are commonly used. |
Hard drawn copper
tubing is easily swaged, so reducing fittings are rarely used in changing
line size. |
|
B |
In a large refrigeration
system having more than one evaporator, a king solenoid valve should be
installed in what location? |
before the condenser |
just after the
receiver |
before the back
pressure regulating valve |
between the condenser
and receiver |
|
C |
If the valve labeled "D"
in the illustration is a suction service valve, what will the port labeled "7"
be connected to? Illustration RA-0008 |
to the outlet
of the compressor |
to the inlet of
the compressor |
to the line connected
to the evaporator outlet |
to the line connected
to the evaporator inlet |
|
C |
As shown in the
illustrated LP centrifugal chiller pressure maintenance system, what is
its functional purpose? Illustration GS-RA-40 |
prevent the entrance
of air into the chiller under low heat load conditions |
prevent surging |
prevent the entrance
of air into the chiller when the chiller is idle |
maintain a relatively
low compression ratio under low heat load conditions |
|
C |
During the initial
cooling down of a box temperature in a refrigeration system, which of the
devices listed is used to prevent excessive gas pressure at the compressor
suction for the purpose of prevention of overloading of the compressor driver? |
Low pressure cutout |
Solenoid valve |
Crankcase pressure
regulator |
High pressure
cutout |
|
D |
Which of the lettered
components shown in the illustration indicates the high-pressure cut-out?
Illustration GS-RA-12 |
Y |
Z |
W |
X |
|
C |
In a refrigeration
system that is not protected by a water failure switch, if the cooling water
to the condenser fails, what will be the result for protective purposes? |
the king valve
will open |
the expansion
valve will close due to high superheat |
the compressor
will shut down by the action of the high pressure cutout switch |
the box temperature
solenoid valve will close initiating a pump down |
|
A |
When the relief
valve opens on a refrigeration compressor discharge line, it discharges
high pressure refrigerant vapor to what location? |
suction side of
the compressor |
inlet side of
the evaporator |
refrigerant inlet
of the condenser |
liquid strainer |
|
D |
The rupture disc
on a low pressure centrifugal refrigeration unit is used as an over pressure
protection device and is set to relieve at 15 psig and is most likely to
lift when the compressor is idle? Where is the rupture disc located? |
on top of the
condenser shell |
at the discharge
of the compressor |
at the top of
the upper chamber of the economizer |
on top of chiller
evaporator shell |
|
A |
In a refrigeration
system, what component is installed directly downstream of the thermal expansion
valve? |
evaporator coil |
receiver |
compressor |
box solenoid valve |
|
B |
Refrigeration
systems using forced air circulation evaporators have a tendency to cause
rapid dehydration of produce in chill boxes. Which of the following will
minimize this dehydration? |
the air is circulated
slowly over a large evaporator with a maximum temperature differential |
the air is circulated
slowly over a large evaporator with a minimum temperature differential |
the air is circulated
rapidly over a small evaporator with a maximum temperature differential |
the air is circulated
rapidly over a small evaporator with a minimum temperature differential |
|
B |
In a dry-type
direct expansion refrigeration evaporator, what is true concerning the evaporator
coils? |
the coils are
surrounded on the outside by refrigerant |
the coils are
surrounded on the outside by air |
the coils are
coated on the inside with insulation |
the coils are
covered on the outside with insulation |
|
B |
Seawater or low
temperature central fresh water is typically provided to a ship's stores
refrigeration plant for what purpose? |
prevent motor
overheating |
condense the refrigerant
gas |
prevent refrigerant
superheating |
cool the expansion
valve |
|
B |
Heat is removed
from the refrigerant circulating through the refrigeration system, shown
in the illustration, by which component? Illustration GS-RA-12 |
K |
B |
J |
A |
|
B |
If a condenser
coil of an air-cooled container refrigeration system becomes dirty and requires
cleaning, what would be an acceptable method of cleaning? |
Binks' gun with
weak acid solvent |
high pressure
water wash |
copper wire rotary
brush |
All of the above. |
|
C |
When checking
zinc plates, or pencil Zincs in the refrigerating system condenser, what
should you do? |
renew the plates
at each inspection |
file the plates
to change the negative value |
replace the Zincs
if deteriorated by 50% |
paint and insulate
the plates to prevent corrosion |
|
C |
What is true concerning
the accumulation of air and other non-condensable gases in a refrigeration
system? |
cause a loss of
the liquid seal |
cause foaming
of the oil in the crankcase |
collect in the
condenser |
create a vapor
lock in the liquid receiver |
|
D |
Zinc plates commonly
found in refrigeration systems and used as sacrificial anodes are located
where? |
cooling water
suction strainer |
refrigerant side
of the condenser |
evaporator coils |
saltwater side
of the condenser |
|
D |
Through which
of the components shown in the illustration is flash gas formation a normal
occurrence? Illustration GS-RA-25 |
evaporator coil |
condenser coil |
receiver tank |
thermostatic expansion
valve |
|
C |
In a refrigeration
system, the pressure within the power element of a thermostatic expansion
valve depends directly upon what factor? |
compressor suction
pressure |
temperature in
the box |
temperature of
the evaporator coil outlet |
heat transferred
from the saturated liquid in the evaporator |
|
B |
In the multi-evaporator
refrigeration system shown in the illustration, what is the proper name
for the valve labeled "29"? Illustration GS-RA-12 |
chill box solenoid
valve |
chill box thermostatic
expansion valve |
freeze box thermostatic
expansion valve |
chill box evaporator
pressure regulating valve |
|
A |
Rather than design
an infinite variety of thermostatic expansion valve sizes to accommodate
different capacities for heat removal, some manufacturers use a few standard
valve body sizes in conjunction with what other feature? |
internal needle
valve orifices of various sizes to accommodate different heat removal capacities |
an externally
adjustable superheat to accommodate different heat removal capacities |
internal equalizers
to accommodate different heat removal capacities |
a flexible diaphragm
to accommodate different heat removal capacities |
|
A |
Constant superheat
is maintained at the evaporator coil outlet of a refrigeration system or
unit by the action of what device? |
thermal expansion
valve |
king valve |
low pressure cutout
switch |
solenoid valve |
|
C |
Besides the evaporator
pressure, the thermal expansion valve reacts directly to changes in what
parameter? |
pressure drop
across the evaporator coils |
liquid refrigerant
pressure at the solenoid valve |
temperature of
the evaporator coil outlet |
temperature of
the space being cooled |
|
B |
Which of the following
illustrated expansion valves is designed to maintain a constant evaporator
pressure rather than a constant evaporator superheat? Illustration GS-RA-24 |
D |
C |
A |
B |
|
B |
Which of the following
illustrated thermal expansion valves would be appropriate to use on an evaporator
coil with a 2 psi pressure drop, where externally adjustable superheat and
a replaceable power element are both desired? Illustration GS-RA-06 |
C |
B |
A |
D |
|
D |
What is one function
of the thermal expansion valve used in a refrigeration system? |
act as a pilot
controlling the box solenoid valve |
turn the compressor
off and on |
regulate the water
flow to the water-cooled condenser |
regulate the amount
of refrigerant flow to the evaporator coil |
|
A |
When a refrigeration
compressor is in the 'off' cycle, the thermal expansion valve will react
in what way? |
it will continue
to function as a result of the net balance of forces acting on the diaphragm |
it will always
remain in the same position just prior to the cycling off of the compressor |
it will always
completely close regardless of whether or not the system employs a pump
down cycle |
it will always
open wide regardless of whether or not the system employs a pump down cycle |
|
A |
Of the various
possible methods shown in the illustration, which is the correct method
of attaching a TXV feeler bulb to a small large line (7/8" and larger)
with a horizontal run? Illustration GS-RA-50 |
C |
D |
A |
B |
|
C |
When a thermostatic
expansion valve is installed in a refrigerated container unit, the sensing
bulb almost always requires insulation. Why is this so? |
the insulation
prevents the bulb from vibrating loose |
the insulation
prevents oil entrained in the suction gas from influencing the bulb temperature |
the insulation
prevents air stream temperatures from influencing the bulb temperature |
the insulation
protects the clamp and screws from corrosion |
|
C |
A thermostatic
expansion valve is properly controlling evaporator superheat. Adjusting
this valve to lower the evaporator superheat setting will result in which
of the following? |
the evaporator
pressure will decrease |
the expansion
valve will further close |
the evaporator
feed will increase |
the expansion
valve diaphragm will rupture |
|
D |
When replacing
a thermostatic expansion valve power element, what is true concerning the
thermal bulb? |
apply a heavy
coating of grease to function as a heat sink |
apply a light
film of oil to increase heat transfer |
carefully coat
the device with silicone sealant to reduce the effects of convective cooling |
with steel wool
or an abrasive cloth remove oxidation on the bulb and suction line |
|
D |
Expansion valve
maintenance should include which of the following procedures? |
Cleaning of in-line
strainers as necessary. |
Ensuring that
the thermal bulb is in good contact with the suction line and insulated. |
Checking that
the thermal bulb is in the proper location. |
All of the above. |
|
D |
Which statement
about calibrating a newly installed thermostatic expansion valve is correct? |
This procedure
is done at the factory with tools not available to a mariner. |
The procedure
requires a refrigeration wrench and a digital thermometer to measure box
temperature. |
No special tools
are required as long as the solid state circuit control panels are functioning
properly. |
An accurate thermometer
and suction pressure gage are essential to this process. |
|
C |
Which of the installation
steps listed is necessary for the proper operation of the thermostatic expansion
valve? |
Attach the thermal
bulb to the suction line using plastic ties. |
Heat shrink insulating
material around the device once the bulb has been properly secured. |
Clean off oxidation
from the surface of the suction line and sensing bulb with fine abrasive
cloth or steel wool. |
Remove excess
lengths of the sensing bulb capillary tube from the device to increase sensitivity. |
|
B |
Which of the listed
statements describes the method used to determine the amount of superheat
present in the suction gas leaving the evaporator coil? Illustration GS-RA-16 |
Note the low side
pressure, determine the corresponding saturation temperature, and add it
to the temperature measured with a thermometer at the thermostatic expansion
valve sensing bulb. |
Note the low side
pressure, determine the corresponding saturation temperature, and subtract
it from the temperature measured with a thermometer at the thermostatic
expansion valve sensing bulb. |
Note the low side
pressure, determine the corresponding saturation temperature, and subtract
it from the temperature measured with a thermometer at the compressor suction
inlet. |
Subtract the temperature
measured at the thermostatic expansion valve sensing bulb from the saturation
temperature corresponding to the low side pressure. |
|
B |
What maintenance
may be carried out on a thermostatic expansion valve? |
The rate action
may be increased. |
The inlet screen
may be cleaned. |
The thermal bulb
may be recharged. |
The proportional
action may be varied. |
|
C |
Moisture entering
a typical refrigeration system will most likely produce what effect? |
cause sweating
and frost on the evaporator coils |
boil in the condenser |
freeze in the
expansion valve |
be removed by
the liquid line strainers |
|
D |
Which of the following
conditions will occur if the power element of the thermostatic expansion
valve shown in the illustration loses its charge? Illustration GS-RA-07 |
The valve will
fail open and the cooling capacity will be increased. |
The valve will
begin to close, but the external equalizing line will assist in keeping
the valve unseated. |
The valve will
fail open as designed to provide continuous cooling. |
The valve will
fail closed, providing no cooling capacity. |
|
C |
If the superheat
setting of a thermostatic expansion valve is set too low, what would be
the result, assuming that the system has a single evaporator? |
the receiver level
will be abnormally high due to a reduced amount of refrigerant returning
back to the compressor |
the box temperature
will be pulled way down below the normal temperature range |
the suction line
will be abnormally cold and liquid may flood back to the compressor |
the suction line
will be abnormally warm due to a reduced amount of refrigerant returning
back to the compressor |
|
A |
If the superheat
value of the thermostatic expansion valve is adjusted too high, what would
be the result? |
the suction line
of the compressor will be abnormally warm |
the heat removal
capacity of the evaporator will increase |
the suction line
of the compressor will be abnormally cold |
the evaporator
will be overfed with liquid refrigerant |
|
D |
A small obstruction
at the thermostatic expansion valve inlet will result in which of the following
conditions? |
Higher than normal
discharge pressure. |
Expansion valves
are designed to pass small foreign particles so no adverse condition will
occur. |
Ice is the sole
cause of this and will soon melt due to superheat; no adverse condition
will occur. |
Lower than normal
suction pressure. |
|
A |
An obstructed
expansion valve may be indicated by an incompletely cooled evaporator and
what other symptom? |
frosting at the
evaporator inlet |
a higher than
normal discharge pressure |
a decrease in
the amount of frosting across the drier |
frosting at the
suction side of the compressor |
|
D |
If the needle
and seat assembly is excessively eroded, the valve cage assembly can be
replaced. In replacing the original valve cage assembly rated at 1/2 tons,
what would be the result if the replacement valve cage was oversized at
5 tons? Illustration GS-RA-07 |
The evaporator
would be overfed producing consistently insufficient superheat. |
The expansion
valve would function normally, with the presentation of no problems. |
The evaporator
would be starved producing consistently excessive superheat. |
The expansion
valve would hunt excessively, alternately starving and overfeeding the evaporator
coil. |
|
C |
Vapor bubbles
present in the liquid upon arrival to the thermal expansion valve in a refrigeration
system may cause erosion of the expansion valve's needle and seat. This,
in turn, could cause what condition? |
TXV freezing shut |
TXV freezing open |
TXV hunting |
TXV overheating |
|
C |
Some 'hot gas'
defrost systems reheat the refrigerant just prior to its returning to the
compressor for what purpose? |
to prevent chill
shocking the compressor suction valves |
to improve the
efficiency of the expansion valve |
to prevent the
damaging effects of liquid slugging |
to increase the
circulation of liquid refrigerant |
|
A |
What is true concerning
frost build-up on the evaporator coils of a multi-box direct expansion refrigeration
system? |
the frost can
be removed by passing hot gas through the coils or energizing defrost heaters
with the evaporator fan shut down |
the frost can
be removed by passing hot gas through the coils or energizing defrost heaters
with the evaporator fan still running |
the frost will
increase the refrigeration effect |
the frost can
be quickly removed by simply shutting down the compressor |
|
B |
Concerning frost
appearing on one set of evaporator coils of a multi-box, direct expansion
type refrigeration system, what is true? |
the frost will
increase the value of superheat to the fluid leaving the coils |
the frost can
be removed by passing hot vapors through the coils |
the frost can
be quickly removed by simply shutting off fluid flow to the coils |
the frost will
assist in increasing the refrigeration effect |
|
B |
A box solenoid
valve used in a refrigeration system should be installed in what manner? |
upright, controlled
by a thermostat sensing evaporator superheat, and upstream of the thermal
expansion valve |
upright, controlled
by a thermostat sensing the temperature of the box, and upstream of the
thermal expansion valve |
with the axis
of the solenoid horizontal, controlled by a thermostat sensing the temperature
of the box, and upstream of the thermal expansion valve |
upright, controlled
by a thermostat sensing the temperature of the box, and downstream of the
thermal expansion valve |
|
D |
You are checking
the supply chilled water temperature thermistor probe on a high-pressure
hermetic centrifugal chiller. Using the illustrated chart, what statement
is true if the supply water temperature is verified 45 ° F with a digital
thermometer __________. Illustration GS-RA-48 |
When checked with
control power off and the thermistor probe isolated, the thermistor probe
voltage drop should be 3.805 volts. |
When checked with
control power on and the thermistor probe isolated, the thermistor probe
voltage drop should be 3.805 volts. |
When checked with
control power on and the thermistor probe connected into the circuit, the
thermistor probe voltage drop should be 11.416 volts. |
When checked with
control power on and the thermistor probe connected into the circuit, the
thermistor probe voltage drop should be 3.805 volts. |
|
D |
Which of the precautions
listed should be taken before opening any part of a refrigeration system
for the purpose of accomplishing non-major repairs? |
Bring the part
of the system to be opened to a pressure corresponding to the ambient temperature. |
Use the hot gas
defrost line to remove any frost on the evaporator coils. |
Set the high pressure
cutout on manual to prevent automatic starting. |
Bring the part
of the system to be opened to 0 psig. |
|
D |
The pressure in
the part of a high pressure refrigeration system about to be opened for
a non-major repair should be brought to what value? |
11 to 12 psig |
4 to 7 psig |
1 to 2 psig |
0 psig |
|
D |
Overfilling a
refrigerant container is extremely dangerous because of the high pressures
generated. The generation of pressure is the result of what? |
discharge pressure
from the recovery cylinder |
vapor pressure
of the refrigerant at saturation temperature |
discharge pressure
of the recovery compressor |
hydrostatic pressure
of the expanding liquid |
|
B |
The FIRST thing
to do to ensure that a refrigeration unit will not start while undergoing
repairs is to do what? |
make a log book
entry |
secure and tag
the electrical circuit |
inform all persons
in the area not to start the unit |
place a crow bar
in the flywheel of the unit |
|
A |
What is the maximum
volume to which refillable refrigeration cylinders should be filled? |
80% full |
70% full |
90% full |
60% full |
|
D |
When a refrigeration
compressor has developed a high head pressure as a result of a refrigerant
overcharge, what should be done to compensate for or to correct this situation? |
raise the high
pressure cut-out opening pressure |
increase the amount
of cooling water to the condenser |
decrease the amount
of cooling water to the condenser |
remove some refrigerant
from the system |
|
B |
A high-pressure
centrifugal chiller currently charged with R-134a is being evaluated for
the need for leak testing. Using the leak-test procedures decision tree
illustrated and the R-134a pressure-temperature chart illustrated, with
the machine idle and the pressures equalized at 10 psig with an ambient
temperature of 60 ° F, what statement is true? Illustration GS-RA-47 |
The machine has
a suspected leak, therefore nitrogen should be added to bring the pressure
to 70 psig prior to checking for leaks. |
The machine has
a suspected leak, therefore the refrigerant pressure should be raised to
35 psig by adding refrigerant prior to checking for leaks. |
The machine definitely
does not have a leak, therefore no attempt at leak detection is necessary. |
The machine may
or may not have a leak, therefore the machine should be checked for leaks
without any adjustments in pressure. |
|
B |
When using nitrogen
to pressure leak test a system, the nitrogen cylinder should always be equipped
with what device or feature? |
temperature indicator |
pressure regulator |
blue top |
level indicator |
|
C |
Which of the following
statements is correct concerning the testing of an R-22 refrigeration system
for leaks in an enclosed compartment with a halide torch? |
The flame of a
halide torch will turn blue in the presence of R-22. |
Halide torches
are not suitable for detecting R-22 leaks. |
Halide torches
are useful in locating very small R-22 leaks. |
To gain sensitivity,
the largest possible flame should be used with the halide torch. |
|
A |
In a refrigeration
system, from what location would air and non-condensable gases be removed? |
the top of the
condenser purge connection |
expansion valve
equalizer connection |
the bottom of
the receiver drain connection |
compressor oil
fill connection |
|
C |
Loss of refrigerant
during the process of purging of air and non-condensable gases can be kept
to a minimum by what action? |
purging through
a dehydrator |
purging through
the top of the receiver rather than the top of the condenser |
cracking the purge
valve briefly and allowing the refrigerant to re-settle between purges |
purging through
the discharge service valve rather than the top of the condenser |
|
D |
In a low-pressure
centrifugal chiller, what is meant by the term 'high efficiency purge unit? |
Those purge units
which need the least amount of on-going Maintenance. |
Those purge units
which draw very little electrical power. |
Those purge units
which discharge the highest percentage of refrigerant with the air being
removed. |
Those purge units
which discharge very little refrigerant with the air being removed. |
|
B |
During normal
operation, traditionally, how has most of the refrigerant released to the
atmosphere from low pressure systems? |
through water-side
system leaks |
through the purge
unit vent |
through the compressor
shaft seal |
through a leaking
rupture disk |
|
D |
If you find a
refrigerant leak while using a halide torch, what will happen to the flame
as the exploring tube approaches the leak? |
it will change
from green to blue |
it will change
from blue to orange |
it will stay blue |
it will change
from blue to green |
|
D |
After the refrigerant
has been recovered, leaks repaired if necessary, the system ideally should
undergo a dehydration evacuation prior to recharging with refrigerant. As
shown in the illustration, besides the vacuum pump suction manifold isolation
valve being opened, what would be the proper valve positions to accomplish
and prove the evacuation? Illustration GS-RA-51 |
Valves 1, 2, and
3 should be back-seated and both gauge manifold hand valves should be open. |
Valves 1, 2, and
3 should be front-seated and both gauge manifold hand valves should be closed. |
Valves 1, 2, and
3 should be in the mid-position and the low-side gauge manifold hand valve
should be open, and the high-side gauge manifold hand valve should be closed. |
Valves 1, 2, and
3 should be in the mid-position and the low-side gauge manifold hand valve
should be closed, and the high-side gauge manifold hand valve should be
open. |
|
B |
Concerning the
operation of refrigeration systems, frosting or sweating of a liquid line
is usually indicative of what condition? |
high relative
humidity surrounding the liquid line |
a liquid line
restriction |
the refrigerant
contaminated with moisture |
proper cooling
taking place |
|
D |
An air-cooled
refrigerated container unit using R-134a as a refrigerant has a box temperature
set point of -15 °F, but it is currently operating with a stable return
air temperature of 0 °F. The fresh air makeup vent is closed, the unit is
operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating
valve 100% open). Using the illustrated troubleshooting guide, what would
be the normal range of expected discharge pressures if the ambient air temperature
is 90 °F? GS-RA-52 |
190-230 psig |
200-220 psig |
160-180 psig |
150-190 psig |
|
D |
High suction pressure
accompanied by low suction temperature to a refrigeration system compressor
is caused by which of the following? |
the expansion
valve is insufficiently opened |
the king valve
is insufficiently open |
a clogged liquid-line
strainer |
the expansion
valve being open too wide |
|
C |
Which of the conditions
listed could cause excessively low refrigerant pressure at the compressor
suction of a TXV controlled refrigeration system? |
The high pressure
cutout switch is inoperative. |
Insufficient flow
of condenser cooling water. |
The system is
low on refrigerant. |
The box solenoid
valve 'stuck' in the open position. |
|
A |
Low compressor
head pressure in a refrigeration system can be caused by which of the following? |
excessive condenser
cooling water flow |
insufficient condenser
cooling water flow |
excessive refrigerant
in the system |
air in the refrigeration
system |
|
D |
In an operating,
water-cooled, multi-box refrigeration system, both low discharge and high
suction pressures are being simultaneously experienced. The probable cause
for this condition is which of the following? |
improper superheat
adjustment on the low side |
fouled shell-and-tube
condenser |
overcharge of
refrigerant in the system |
discharge relief
valve leaking back to the suction side |
|
C |
If the running
suction pressure at the refrigeration compressor of a TXV controlled air-cooled
refrigeration system is below normal, which of the following can be a cause? |
a dirty condenser |
overfeeding by
the expansion valve |
a restricted liquid-line
strainer |
refrigerant overcharge |
|
B |
If increasing
the cooling water flow to a refrigeration condenser fails to lower the condenser
pressure, the probable cause may be due to what condition? |
a low level of
Freon in the receiver |
excessive amount
of non-condensable gases trapped in the condenser |
an evaporator
coil in need of defrosting |
partially blocked
thermal expansion valve |
|
B |
A refrigeration
unit will tend to short cycle when operating under what conditions? |
during starting
conditions |
lack of refrigerant |
during hot gas
defrost |
under heavy loads |
|
B |
If the refrigeration
compressor crankcase is sweating or frosting and is operating with an unusual
noise, what is most likely the cause? |
the compressor
running continuously |
liquid refrigerant
returning to the compressor |
a shortage of
refrigerant |
the compressor
short cycling on the high pressure cutout |
|
D |
If a refrigeration
system, equipped with a reciprocating compressor, has a liquid-line solenoid
valve that is leaking during the 'off' cycle, what would this cause? |
refrigerant slugs
in the receiver |
high superheat
in the outlet coil |
low suction pressure |
noisy compressor
operation upon starting |
|
C |
If a refrigeration
compressor had developed a slightly high suction pressure accompanied with
an abnormally low suction temperature, the problem could be a result of
which of the following? |
a clogged sub
cooler |
a leaking king
valve |
liquid refrigerant
flooding back from the cooling coil |
a minor accumulation
of air or non-condensable gases in the system |
|
B |
An excessive charge
of refrigerant in a thermostatically controlled, air-cooled, refrigeration
system using a TXV as an expansion device can cause which of the following? |
the compressor
to run continuously |
higher than normal
discharge pressure |
lower than normal
box temperature |
oil foaming in
the compressor |
|
C |
If a refrigeration
compressor using a thermostat as a primary controller is running continuously
without significantly lowering the temperature in the refrigerated space,
which of the following is most likely the trouble? |
a shortage of
compressor oil |
warm food in the
refrigerator |
a shortage of
refrigerant |
excessive condenser
cooling water |
|
B |
During tests to
discover why a refrigeration compressor is running continuously, it is determined
that the refrigerated space temperature is slightly above normal without
ever reaching the desired minimum temperature. Suction and discharge pressures
are normal for the corresponding box temperature. In this situation, what
should you suspect? |
air in the system |
leaking door gaskets |
a shortage of
refrigerant |
high cooling water
temperature |
|
A |
If a refrigeration
system were short of refrigerant, besides an elevated box temperature, what
would be an observable symptom? |
continuous running
of the compressor |
short cycling
of the compressor on the water failure switch |
high suction pressure |
high discharge
pressure |
|
A |
If a refrigeration
compressor were short cycling on the low pressure cutout switch, what is
the most probable cause? |
the expansion
valve strainers were fouled |
the suction valves
were leaking slightly |
the high pressure
switch was improperly adjusted |
the system was
overcharged with refrigerant |
|
A |
When a refrigeration
compressor motor fails to start, the FIRST thing that should be checked
for is what? |
blown fuse or
tripped circuit breaker in the motor circuit |
faulty suction
pressure regulator |
loose expansion
valve control bulb |
low differential
setting on the H.P. cutout |
|
C |
If the evaporator
coil horizontal return line of a container refrigeration system is less
than 0.875" (2.21 cm) in diameter (considered small), the thermostatic
expansion valve sensing bulb should be attached where on the return line? |
as close as possible
to the expansion valve |
directly below
the point of maximum heat transfer |
on the upper surface
of the line |
on the bottom
of the line to enable the bulb to absorb the maximum amount of heat |
|
B |
For safe storage,
the maximum allowable temperature to which refrigerant bottles should be
exposed is what temperature? |
150°F |
125°F |
175°F |
100°F |
|
C |
Overfilling a
refrigerant container is extremely dangerous because of the high pressures
generated. The generation of pressure is the result of what? |
discharge pressure
from the recovery cylinder |
vapor pressure
of the refrigerant at saturation temperature |
hydrostatic pressure
of the expanding liquid |
discharge pressure
of the recovery compressor |
|
C |
Personnel servicing
refrigeration systems and subject to the exposure to commonly used refrigerants
should wear what type of personal protective equipment? |
an all purpose
gas mask |
rubber soled shoes |
goggles and gloves |
a respirator |
|
D |
In the presence
of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants
decompose and form what chemical substance? |
petroleum crystals |
water vapor |
carbon monoxide |
phosgene gas |
|
A |
Why can CFC or
HCFC refrigerants leaking into a confined space or in limited surroundings
cause suffocation? |
Refrigerants are
heavier than air and displace oxygen. |
Refrigerants contain
an acidic substance. |
Refrigerants obnoxious
odor prevents breathing. |
Refrigerants lighter
than air will rise. |
|
A |
Traditionally,
which of the listed refrigerants has been more suitable than the others
for use in a centrifugal refrigeration compressor? |
R-11 |
Carbon dioxide |
R-12 |
Ammonia |
|
B |
Which of the fluids
listed is suitable for use as a secondary refrigerant? |
Cuprous chloride |
Brine |
Methyl alcohol |
Carbon dioxide |
|
B |
What is the purpose
of running a refrigeration compressor in short intermittent spurts or throttling
the suction isolation valve when starting the system after a prolonged shutdown? |
let the refrigerated
compartment cool gradually |
prevent liquid
slugging or overloading the compressor |
allow refrigerant
vapor cycling time |
determine actual
compressor oil level |
|
A |
When starting
a reciprocating refrigeration compressor that has been shut down for a period
of time, you should manually throttle which valve? |
suction valve |
sea water valve |
king valve |
expansion valve |
|
C |
When opening or
closing compressor service and line isolation valves on a typical refrigeration
system that is fitted with packed valves, what must you do? |
you should replace
the gasket each time the valve position is changed |
you should never
loosen or tighten the packing gland |
you must first
remove the stem seal cap |
you should turn
valves slowly to avoid thermal stresses due to low temperatures |
|
C |
Alkylbenzene ISO
32 cSt synthetic refrigerant oil is miscible and suitable to use with which
of the following refrigerants? |
R-134a |
R-143a |
R-22 |
R-32 |
|
C |
Coast Guard Regulations
(46 CFR Part 58) require a method for the relieving pressure of an over
pressurized refrigeration system. Which of the following statements complies
with these Regulations? |
The relief valve
from the receiver must relieve to the condenser first. |
The relief valve
settings shall be 1 1/4 times the maximum allowable working pressure. |
A rupture disk
may be fitted in series with the relief valve. |
The rupture disk
shall burst at a pressure not higher than 10% above the relief valve setting. |
|
A |
In an air conditioning
system, what is the name of the chamber where the duct-work originates? |
plenum chamber |
vapor chamber |
exhaust chamber |
intake chamber |
|
B |
Coast Guard Regulations
(46 CFR Part 113) require refrigerated spaces that can be locked from the
outside and that cannot be opened from the inside to have an audible alarm.
Where is the audible alarm required to be? |
the galley |
a manned location |
the wheelhouse |
the chief steward's
berthing quarters |
|
C |
In a two stage
centrifugal air conditioning system, the liquid refrigerant passes through
the condenser directly to what component? |
chiller |
evaporator |
economizer |
expansion valve |
|
A |
A reheater in
an air conditioning system performs what function? |
restores the conditioned
air temperature to a comfortable level |
controls the inlet
air volume |
maintains the
relative humidity at 15% |
controls the inlet
air temperature |
|
C |
With regards to
shipboard refrigeration systems, after July 1, 1992, what action became
illegal? |
working on a refrigeration
system without permission of the Officer in Charge Marine
Inspection |
producing a class
I refrigerant |
intentionally
venting class I or II refrigerants to the atmosphere |
mixing R-12 and
R-22 |
|
A |
Refillable tanks
used to ship CFC and HCFC refrigerants or used to recover these refrigerants
must meet the standards of what entity? |
the United States
Department of Transportation |
the Environmental
Protection Agency |
the United States
Coast Guard |
the Underwriters
Laboratories |
|
B |
What is one benefit
of Maintenance of proper air circulation in an air conditioned cargo space? |
more temperature
differential |
reduced slime
and mold |
increased moisture
content |
increased density
of the air |
|
D |
According to 46
CFR, Part 58, for protection purposes, what is required of all refrigeration
systems? |
refrigerant receiver |
high pressure
cut-out |
low pressure cut-out |
pressure relief
device |
|
C |
What is the wet
bulb temperature of air if the dry bulb temperature of the air is 90 degrees
and the relative humidity is 65%? Illustration GS-RA-22 |
62 degrees F |
63 degrees F |
80 degrees F |
77 degrees F |
|
D |
In general, the
thermal bulb for a thermal expansion valve used in a reciprocating air conditioning
system is usually charged with what substance? |
mercuric sulfate |
bees wax |
distilled water |
the same refrigerant
as the system |
|
D |
To prevent the
unnecessary loading of an air conditioning system while maintaining the
designed dry bulb temperature and relative humidity in an air conditioning
system, what should be done? |
reduce the air
reheating system load |
lower the compressor
head pressure |
operate the purge
recovery unit continuously |
admit only enough
fresh outside air to provide proper ventilation |
|
C |
What would be
an example of a small appliance as defined in the EPA Clean Air Act rules? |
a 25 ton air conditioning
system set up as a split plant with the condensing unit on deck |
a 200 ton low
pressure centrifugal chiller for cargo hold air conditioning |
a hermetically
sealed water cooler with a 2 lb. refrigerant charge |
a self-contained
walk-in freezer with a 60 lbs. refrigerant charge |
|
A |
Which of the following
is true concerning the class "D" air conditioning system shown
in the following illustration? Illustration GS-RA-42 |
The duct thermostat
determines the amount of water flow circulating through the cooling coil. |
System cooling
is the direct result of the Freon circuit of a direct type air conditioning
unit. |
The heat load
will increase by increasing the amount of recirculated air. |
The room thermostat
controls the wet bulb temperature of the air conditioned space. |
|
B |
Concerning the
arrangement of equipment and associated hoses shown in the illustration,
which statement is true? Illustration GS-RA-59 |
When recovering
refrigerant from the centrifugal chiller using this method, the entire charge
may be removed in one procedure. |
When recovering
refrigerant from the centrifugal chiller using this method, it is possible
to achieve the recovery levels required by law without any further recovery. |
When recovering
refrigerant from the centrifugal chiller using this method, the containment
tank should be vented back to the chiller evaporator shell. |
When recovering
refrigerant from the centrifugal chiller using this method, the refrigerant
is being recovered as a liquid. |
|
B |
Which best defines
a "Type I" small refrigeration appliance according to the EPA
Regulations Section 608? |
refrigerators,
freezers, room air conditioners and central air conditioners |
systems manufactured
and hermetically sealed having a capacity of five pounds (2.27 kg) or less
of refrigerant |
any appliance
charged with less than two pounds (0.91 kg) of refrigerant |
any appliance
charged with less than ten pounds (4.54 kg) of refrigerant |
|
C |
Which of the following
methods is normally used to control the circulated air temperature of an
air conditioning system using chilled water circulation? |
A regulating valve
changes the inlet temperature of the water in the cooling coils. |
A fan speed controller
regulates the amount of air flowing across the coils. |
A regulating valve
controls the quantity of chilled water flowing in the cooling coils. |
Control dampers
varying the number of passes the air makes across the cooling coils. |
|
A |
For the proper
control of the air temperature in an air conditioning system using chilled
water circulation, which of the listed conditions should remain constant
regardless of load changes? |
Chilled water
system supply temperature. |
Chilled water
system return temperature. |
Compressor discharge
temperature. |
Compressor suction
pressure. |
|
D |
If you find the
pressure of a refrigeration system containing a Class I or Class II refrigerant
to be opened for the accomplishment of repairs is 0 psig, what must be done? |
only recover the
vapor refrigerant |
only recover the
liquid refrigerant in the system |
recover liquid
and vapor refrigerant and have it reclaimed |
do not attempt
to recover the refrigerant and repair the leak before pulling a vacuum on
the system |
|
B |
EPA Clean Air
Act rules permit refrigerant to be released to the atmosphere under which
of the following conditions? |
when testing a
system for leaks using R-12 and nitrogen |
when release is
considered 'de minimis' |
when adding oil
to a compressor |
during replacement
of a compressor |
|
B |
Which of the processes
listed would be the most satisfactory method to use to lower the humidity
of the air being circulated by an air conditioning system? |
Heating the air
and then cooling it to a point below dew point. |
Cooling the air
to a point below dew point, then reheating it. |
Cooling the air
to a temperature just above dew point. |
Heating the air
to a point at which moisture will boil off, then recooling it. |
|
A |
A room humidistat
initiates the lowering of the humidity of the conditioned supply air to
a space, while the actual process is accomplished by what means? |
lowering the cooling
coil temperature and raising the reheater temperature |
raising both the
cooling coil temperature and the reheater temperature |
lowering both
the cooling coil temperature and the reheater temperature |
raising the cooling
coil temperature and lowering the reheater temperature |
|
C |
All shipboard
personnel responsible for the maintenance and repair of air conditioning
systems using refrigerants covered under the EPA Clean Air Act venting prohibition,
must be certified through an approved Environmental Protection Agency (EPA)
program to do which of the following? |
before performing
any maintenance or repair regardless of the actual procedure |
before they can
set the operating controls of the system |
before performing
maintenance, service or repair that could reasonably be expected to release
Class 1 or Class 2 refrigerants into the atmosphere |
before they can
pump down the system in preparation for shifting over to the standby
condensing unit |
|
B |
In an air conditioning
system, moisture is removed from the air by what means? |
separators |
cooling coils |
ducted traps |
filters |
|
D |
When recovering
R-12 from a small appliance with a working compressor, using a recovery
device manufactured after November 15, 1993, what percentage of the remaining
charge must be removed from the system? |
99 (%) |
80 (%) |
75 (%) |
90 (%) |
|
C |
Persons recovering
refrigerant from small appliances must be certified as what type of technician
under the EPA Clean Air Act rules? |
Type II technician |
Type III technician |
Type I or Universal
technician |
All of the above. |
|
C |
The introduction
of outside air to the air conditioning system is 90°F with a relative humidity
of 60%. The air has been conditioned to 70°F with a relative humidity of
80%. Using the psychrometric chart, shown in the illustration, determine
the quantity of moisture removed from one pound of the conditioned air __________.
Illustration GS-RA-22 |
50 grains |
20 grains |
40 grains |
30 grains |
|
A |
According to the
EPA Clean Air Act rules, what is true concerning refrigerant leaks in a
small hermetically sealed shipboard water cooler with a 20 ounce charge
weight? |
Legally, the leaks
are not required to be repaired, but morally it is advisable to repair the
leaks. |
The leaks must
be repaired if the annual leak rate exceeds 15% of the total charge |
The leaks must
be repaired within 30 days. |
The leaks must
be repaired if the annual leak rate exceeds 35% of the total charge. |
|
D |
If outside air
at 80 degrees F and 70 percent relative humidity is conditioned, what will
be the resulting dew point temperature of the air just before it comes into
contact with the cooling coil? Illustration GS-RA-22 |
67 degrees F |
73 degrees F |
64 degrees F |
70 degrees F |
|
C |
Which of the following
is true concerning the class "A" air conditioning system shown
in the illustration as used to condition the air of large public spaces?
Illustration GS-RA-09 |
The preheater
steam flow is controlled by the space thermostat. |
It is not possible
for both the cooling coil and the steam heated reheater to be used
simultaneously. |
The dry bulb room
temperature is controlled by a steam heated reheater and its associated
pneumatic control valve. Illustration GS-RA-09 |
The reheater is
not used when in the cooling mode. |
|
A |
Within the territorial
limits of the United States, violations of the Clean Air Act of 1990, that
includes the intentional release of R-11, R-12, R-22 and other related class
I or class II substances may result in fines for each violation per day
of what amount? |
25000 |
10000 |
50000 |
5000 |
|
B |
To add small amounts
of refrigerant to the low side of an air conditioning system, the refrigerant
should be introduced through a particular valve and in a particular state.
What valve and state combination is correct? |
discharge service
valve as a vapor |
suction service
valve as a vapor |
discharge service
valve as a liquid |
suction service
valve as a liquid |
|
B |
To add refrigerant
to the high side of an air conditioning system, you should close the king
valve and introduce the refrigerant through what valve in what state? |
discharge service
valve as a vapor |
charging valve
as a liquid |
suction service
valve as a liquid |
condenser purge
valve as a vapor |
|
C |
When pumping down
an air conditioning system to test the low-pressure cut-out switch, assuming
that the compressor is running, what should be done to initiate the test? |
stop the compressor |
secure the condenser |
close the "king"
valve |
stop the circulating
pump |
|
A |
When recovering
the remaining R-134a refrigerant from the centrifugal chiller shown in the
illustration as a vapor using the recovery unit's compressor, in addition
to opening valves "1a", "1b", and the compressor suction
and discharge isolation valves, which of the following would be the correct
valve lineup? Illustration GS-RA-28 |
valves "3", "4",
and "6" open; valves "2", "5", "7", "8",
and "10" closed |
valves "2", "5", "7", "8",
and "10" open; valves "3", "4", and "6"
closed |
valves "3", "5",
and "6" open; valves "2", "4", "7", "8",
and "10" closed |
valves "3", "4", "7", "6"
and "10" open; valves "2", "5", and "8"
closed |
|
D |
The compressor
used in a water-cooled air conditioning system is short cycling. A service
check determines that the suction pressure remains above the normal cut-in
point during cycling and that the discharge pressure rapidly builds up to
the cut-out point while running and gradually falls to the cut-in point
during the off cycle. What is likely the cause? |
front seated liquid
line service valve |
back seated discharge
service valve |
loosely fitted
compressor drive belt |
reduction in condenser
water flow (scaled condenser) |
|
D |
Using the illustrated
chart giving the boiling point of moisture at various depths of vacuum,
with an ambient temperature of 72 °F, what depth of vacuum would be associated
with the BEST chance of achieving a dehydration evacuation with a deep vacuum
pump? Illustration GS-RA-56 |
29.20" Hg
or 20,320 microns of Hg absolute |
28.75" Hg
gauge or 31,750 microns of Hg absolute |
29" Hg gauge
or 25,400 microns of Hg absolute |
29.99" Hg
or 254 microns of Hg absolute |
|
B |
Concerning the
arrangement of equipment and associated hoses shown in the illustration,
which statement is true? Illustration GS-RA-58 |
When recovering
refrigerant from the centrifugal chiller using this method, it is possible
to achieve the recovery levels required by law without any further recovery. |
When recovering
refrigerant from the centrifugal chiller using this method, it minimizes
the risk of chiller tube freeze-up. |
When recovering
refrigerant from the centrifugal chiller using this method, the vent hose
connection should be closed. |
When recovering
refrigerant from the centrifugal chiller using this method, it is permissible
to exceed 90% of the weight capacity of the refrigerant drum. |
|
B |
The surging that
occurs in a centrifugal air conditioning compressor is a result of what
conditions? |
low pressure in
the evaporator at high load |
low pressure in
the evaporator at low load |
low pressure in
the condenser at high load |
low pressure in
the condenser at low load |
|
A |
In an air conditioning
system, low discharge head pressure associated with a reciprocating compressor
can be the result of what condition? |
leaky suction
valves |
insufficient cooling
water to the condenser |
air in the condenser |
air in the evaporator
coils |
|
C |
The amount of
HCFC-123 in a storage cylinder is measured by what means? |
saturation pressure |
saturation temperature |
weight |
volume |
|
C |
Which of the following
substances is normally classified as a low pressure refrigerant? |
R-22 |
R-12 |
R-123 |
R-134A
|
|
D |
What is the color
coding for a storage container of R-134a refrigerant? |
green |
purple |
grey |
light blue |
|
B |
The gas that exists
in the stratosphere forming a protective shield that helps to protect the
environment from the harmful effects ultraviolet radiation is called what? |
nitrogen |
ozone |
oxygen |
radon |
|
A |
The "tare
weight" of a refrigerant storage cylinder refers to what weight? |
the weight of
an empty cylinder |
the total weight
of a fully charged cylinder |
the weight of
a cylinder AND its current contents |
the maximum weight
of the refrigerant allowed |
|
A |
The safety heads
of most large reciprocating compressors used in refrigeration systems are
held in place by what means? |
heavy coil springs |
large Teflon gaskets |
tack welding on
the sides |
discharge pressure
in the relief valve return line |
|
A |
In the illustrated
refrigeration system, what is the proper name for the component labeled "A"?
Illustration GS-RA-12 |
compressor |
condenser |
accumulator |
filter drier |
|
C |
A device used
to hold open the refrigeration compressor suction valve during starting
to reduce the compression load is called what? |
relief valve |
discharge line
bypass |
cylinder unloader |
suction line bypass |
|
C |
The carbon seal
ring of a refrigeration compressor crankshaft mechanical seal is held in
position against the stationary ring face by using what device? |
snap ring |
woodruff key |
spring |
thrust washer |
|
B |
What is the drive
arrangement of refrigeration compressor shown in figure "B" of
the illustration? Illustration GS-RA-41 |
external-drive |
welded, fully
hermetic |
open |
serviceable, bolted,
accessible semi-hermetic |
|
D |
If the discharge
reed valves used in a refrigeration compressor are leaking badly, what statement
is true? |
the reed valves
should be reground and relapped |
the low side pressure
will indicate below normal |
the high pressure
cut-out setting should be lowered |
the reed valves
should be replaced |
|
D |
In addition to
the drive belt itself, a V-belt that is tensioned too tight will cause excessive
wear to what other drive component? |
the prime mover
drive pulley |
the shaft of the
prime mover |
the compressor
drive pulley |
motor shaft and
compressor main bearings |
|
C |
When one belt
of a multiple V-belt drive requires replacing, what will be required? |
season the new
belt prior to installation |
ensure the proper
belt dressing is applied |
replace the entire
belt set |
ensure the seasoned
belts are reinstalled in their proper sequence |
|
A |
Excessively tight
drive belts installed between a motor and a refrigeration compressor pulley
may cause what condition? |
premature wear
of both the pulley end motor shaft bearing and the pulley end compressor
crankshaft main bearing due to overloading |
premature wear
of both motor shaft bearings and both compressor crankshaft main bearings
due to belt slippage |
premature wear
of the pulley end motor shaft bearing, but normal wear of the pulley end
compressor crankshaft main bearing |
normal wear of
the pulley end motor shaft bearing, but premature wear of the pulley end
compressor crankshaft main bearing |
|
A |
When installing
a mechanical shaft seal on a refrigeration compressor, extreme care must
be taken to prevent what from happening? |
dirt and foreign
particles from coming in contact with the highly polished sealing surfaces |
any lubricant
from contacting the carbon surface that would cause the expulsion of the
saturated Teflon film |
any lubricant
from contacting the stationary seal face that would cause etching of the
face surface |
the spring from
being damaged by the corrosive effects of excessive handling |
|
C |
If a refrigeration
system were short of refrigerant, besides an elevated box temperature, what
would be an observable symptom? |
short cycling
of the compressor on the water failure switch |
high suction pressure |
continuous running
of the compressor |
high discharge
pressure |
|
A |
A reciprocating
refrigeration compressor may be tested for leaking discharge valves by stopping
the compressor, turning the discharge service valve all the way in, and
then turning the compressor over by hand. If the discharge valves are leaking,
the compound gage will show pressures which react in which way? |
rising and falling
with each stroke |
decreasing to
a vacuum |
increasing with
each stroke |
decreasing with
each stroke |
|
B |
Which of the conditions
listed could cause excessively low refrigerant pressure at the compressor
suction of a TXV controlled refrigeration system? |
The high pressure
cutout switch is inoperative. |
The system is
low on refrigerant. |
The box solenoid
valve 'stuck' in the open position. |
Insufficient flow
of condenser cooling water. |
|
B |
Low compressor
head pressure in a refrigeration system can be caused by which of the following? |
air in the refrigeration
system |
excessive condenser
cooling water flow |
excessive refrigerant
in the system |
insufficient condenser
cooling water flow |
|
A |
An excessive charge
of refrigerant in a thermostatically controlled, air-cooled, refrigeration
system using a TXV as an expansion device can cause which of the following? |
higher than normal
discharge pressure |
the compressor
to run continuously |
lower than normal
box temperature |
oil foaming in
the compressor |
|
C |
In an operating,
water-cooled, multi-box refrigeration system, both low discharge and high
suction pressures are being simultaneously experienced. The probable cause
for this condition is which of the following? |
overcharge of
refrigerant in the system |
fouled shell-and-tube
condenser |
discharge relief
valve leaking back to the suction side |
improper superheat
adjustment on the low side |
|
D |
If a refrigeration
system, equipped with a reciprocating compressor, has a liquid-line solenoid
valve that is leaking during the 'off' cycle, what would this cause? |
high superheat
in the outlet coil |
refrigerant slugs
in the receiver |
low suction pressure |
noisy compressor
operation upon starting |
|
D |
Unusual noise
coming from a refrigeration compressor can be caused by which of the following
conditions? |
worn bearings
and piston pins |
too much oil in
circulation |
slugging due to
flooding back |
All of the above. |
|
C |
Which of the listed
statements describes the reason why oil foaming occurs when starting a refrigeration
compressor? |
This phenomenon
is inherent only in hermetically sealed units and is always provisional. |
This will occur
only if crankcase heaters are used. |
This condition
is the result of the sudden low pressure created in the crankcase at start
up causing the release of refrigerant absorbed within the oil. |
If the oil level
is not initially high, this condition is the result of agitation created
by the
movement of the mechanical components. |
|
C |
A refrigeration
unit will tend to short cycle when operating under what conditions? |
under heavy loads |
during starting
conditions |
lack of refrigerant |
during hot gas
defrost |
|
C |
If a refrigeration
compressor were short cycling on the low pressure cutout switch, what is
the most probable cause? |
the high pressure
switch was improperly adjusted |
the system was
overcharged with refrigerant |
the expansion
valve strainers were fouled |
the suction valves
were leaking slightly |
|
B |
A box solenoid
valve used in a multi-box refrigeration system is operated by electromagnetic
action by what control device? |
evaporator outlet
temperature actuated thermostat |
box temperature
actuated thermostat |
discharge pressure
actuated pressure switch |
suction pressure
actuated pressure switch |
|
C |
What is the purpose
of the low pressure cut-out switch as used as a primary controller for a
refrigeration system or unit? |
maintain a preset
low-side pressure for the system |
control the capacity
of the compressor |
start and stop
the compressor as needed |
maintain a preset
suction pressure to the compressor |
|
D |
The sensing line
for the low pressure cutout switch for a refrigeration system is typically
connected at what location? |
at the outlet
side of the receiver |
at the discharge
side of the compressor |
at the inlet side
of the receiver |
at the suction
side of the compressor |
|
C |
Which of the listed
operations will cause an automatically controlled refrigeration compressor
to restart if the system features a pump-down cycle? |
Decreasing the
suction pressure |
Closing of the
expansion valve |
An increase in
the suction pressure |
Closing of the
solenoid valve |
|
A |
The low pressure
cutout switch settings vary with the refrigerant used and the temperature
application. If the low pressure cutout switch for a particular application
is set with a cut-in pressure of 5 psig, what would be the cut-out pressure
if the differential is 7.5 psig? |
5" Hg |
0 psig |
2.5 psig |
12.5 psig |
|
D |
In a multi-evaporator
refrigeration system, a solenoid valve is installed in the liquid line prior
to what device? |
the condenser |
the receiver |
the oil separator |
each expansion
valve |
|
B |
A liquid line
solenoid valve controls refrigerant flow to the evaporator by what means? |
sensing the temperature
in the liquid line |
fully opening
or closing |
throttling the
refrigerant |
sensing the superheat
in the tail coil |
|
A |
How does a refrigeration
solenoid valve differ from a modulating valve? |
A liquid line
solenoid valve is either completely opened or closed, whereas a modulation
valve is infinitely positioned according to the strength of the applied
electrical signal. |
Both valves operate
in exactly the same manner, only the manufacturer's terminology is the differentiating
factor. |
A solenoid valve
can only be installed in liquid lines. |
Solenoid Valves
are only used in low voltage refrigeration control systems, while modulation
valves are used in high voltage applications. |
|
A |
Which of the following
electrically operated refrigeration system valves would be most appropriate
for use as a 2 position diverting hot gas bypass solenoid valve? Illustration
GS-RA-19 |
B |
D |
A |
C |
|
B |
In a refrigeration
system featuring low-side pump down prior to the automatic shut down of
the compressor, the temperature of the refrigerated space is controlled
by the action of a thermostat wired to what device? |
suction line solenoid |
liquid line box
solenoid |
low pressure cutout
switch |
thermostatic expansion
valve |
|
D |
The thermostat
controlling the operation of the solenoid valve to a refrigerated box evaporator
senses what temperature? |
evaporator coil
outlet temperature |
compressor discharge
temperature |
evaporator coil
inlet temperature |
the refrigerated
box temperature |
|
B |
Which of the following
statements is true? Illustration GS-RA-12 |
Valve "14"
is the king solenoid, valve "36" is the chill box solenoid, and
valve "28" is the freeze box solenoid. |
Valve "14"
is the king solenoid, valve "28" is the chill box solenoid, and
valve "36" is the freeze box solenoid. |
Valve "14"
is the king solenoid, valves "28" and "36" are both
freeze box solenoids. |
Valve "14"
is the king solenoid, valves "28" and "36" are both
chill box solenoids. |
|
A |
A container unit's
microprocessor-controlled temperature controller is set at -28.9 ° C, appropriate
for a frozen cargo of ice cream. In this mode of operation, according to
the illustrated temperature controller functional diagrams, what should
be the operational status of the unit if the actual box temperature is -18.0
° C? Illustration GS-RA-35 |
cooling mode |
modulating cooling
mode |
air circulation
mode |
heating mode |
|
D |
Capacity control
of a centrifugal refrigeration compressor can be accomplished by what means? |
varying the speed
of the compressor |
varying the position
of the suction inlet damper vanes |
varying the position
of the hot gas bypass valve |
All of the above. |
|
B |
The fluid used
as a source of actuating power against the underside of the unloader power
element piston of the refrigeration compressor capacity control mechanism
illustrated is obtained from where? Illustration GS-RA-13 |
gas discharge
from the compressor |
discharge of the
compressor lube oil pump |
high side liquid
receiver |
discharge of a
secondary hydraulic pump specifically installed for this operation |
|
C |
During operating
periods of a multi-box refrigeration system using a capacity controlled
compressor, when all of the evaporators of a four box plant are actively
being fed with liquid refrigerant, the control oil pressure acting on the
hydraulic relay piston will be at what value? GS-RA-13 |
the lowest |
at its mid-range |
the highest |
of no consequence
as the lube oil is not used in the operation of the unloader |
|
B |
A refrigeration
compressor used in a multi-box refrigeration system, is designed with six
of its eight cylinders able to be controlled for variable load conditions.
If all of the reefer boxes are currently feeding, what percentage of the
total number of compressor cylinders will be loaded after start up? |
25 (%) |
100 (%) |
50 (%) |
0 (%) |
|
C |
On a modern refrigerated
container unit employing suction modulation for the purposes of capacity
control and capacity limitation, what happens when the applied voltage and
current draw associated with the normally open (NO) suction modulation valve
located in the suction line both increase? |
the valve will
further open, lowering evaporator pressure and raising suction pressure |
the valve will
further open, raising evaporator pressure and lowering suction pressure |
the valve will
further close, raising evaporator pressure and lowering suction pressure |
the valve will
further close, lowering evaporator pressure and raising suction pressure |
|
A |
To prevent motor
overload during start-up of a hermetically sealed centrifugal refrigeration
system, what is true concerning the compressor suction gas variable inlet
guide vanes? |
closed until the
motor is connected across the line at full voltage and current drawn is
below full load current |
opened until the
motor is connected across the line at full voltage and current drawn is
up to full load current |
closed until the
motor is connected across the line at full voltage and current drawn is
up to full load current |
opened until the
motor is connected across the line at full voltage and current drawn is
below full load current |
|
B |
As shown in the
illustrated refrigeration system piping schematic diagram with the various
accessories and controls and equipped with an air-cooled condenser with
high side pressure controls, what statement is true concerning the fan cycling
control pressure switch? Illustration GS-RA-39 |
With a condenser
fitted with a single fan driven by a multi-speed electric motor, the fan
speed would decrease under high ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a multi-speed electric motor, the fan
speed would decrease under low ambient temperature conditions. |
With a condenser
fitted with multiple electric-motor driven fans, the number of fans in use
would increase under low ambient temperature conditions. |
With a condenser
fitted with a single fan driven by a single-speed electric motor, the fan
would cycle off under high ambient temperature conditions. |
|
C |
If it is necessary
to increase the operating head pressure of the refrigeration system using
the device shown in the illustration, what should be done? Illustration
GS-RA-14 |
"2"
should be turned to relax the compression of the spring |
"4"
should be rotated to compress the enclosed bellows |
"2"
should be turned to further compress the spring |
"4"
should be rotated to relax the enclosed bellows |
|
D |
In a refrigeration
system, the valve shown in the illustration is used for what purpose? Illustration
GS-RA-14 |
thermostatic expansion
valve |
suction pressure
regulating valve |
evaporator pressure
regulating valve |
head pressure
regulating valve |
|
A |
The set point
adjustment of the device shown in the illustration is made by rotating what
component? Illustration GS-RA-14 |
"2" |
"3" |
"4" |
"1" |
|
C |
An arrow stamped
on the valve body of a water regulating valve indicates which of the following? |
closed position |
direction of the
plunger slide |
direction of the
flow |
open position |
|
B |
During the initial
cooling down of a box temperature in a refrigeration system, which of the
devices listed is used to prevent excessive gas pressure at the compressor
suction for the purpose of prevention of overloading of the compressor driver? |
High pressure
cutout |
Crankcase pressure
regulator |
Low pressure cutout |
Solenoid valve |
|
D |
The rupture disc
on a low pressure centrifugal refrigeration unit is used as an over pressure
protection device and is set to relieve at 15 psig and is most likely to
lift when the compressor is idle? Where is the rupture disc located? |
on top of the
condenser shell |
at the top of
the upper chamber of the economizer |
at the discharge
of the compressor |
on top of chiller
evaporator shell |
|
D |
Which of the lettered
components shown in the illustration indicates the high-pressure cut-out?
Illustration GS-RA-12 |
Z |
W |
Y |
X |
|
D |
When the relief
valve opens on a refrigeration compressor discharge line, it discharges
high pressure refrigerant vapor to what location? |
refrigerant inlet
of the condenser |
liquid strainer |
inlet side of
the evaporator |
suction side of
the compressor |
|
C |
In a refrigeration
system that is not protected by a water failure switch, if the cooling water
to the condenser fails, what will be the result for protective purposes? |
the king valve
will open |
the box temperature
solenoid valve will close initiating a pump down |
the compressor
will shut down by the action of the high pressure cutout switch |
the expansion
valve will close due to high superheat |
|
A |
The receiver used
in a refrigeration system performs what essential function? |
holds the entire
refrigerant charge after system pump down |
collects air and
non-condensable gases |
prevents liquid
refrigerant from flooding back to the compressor |
allows the refrigerant
to be superheated |
|
D |
In a large refrigeration
system having more than one evaporator, a king solenoid valve should be
installed in what location? |
before the condenser |
between the condenser
and receiver |
before the back
pressure regulating valve |
just after the
receiver |
|
B |
If the valve labeled "D"
in the illustration is a suction service valve, what will the port labeled "7"
be connected to? Illustration RA-0008 |
to the inlet of
the compressor |
to the line connected
to the evaporator outlet |
to the line connected
to the evaporator inlet |
to the outlet
of the compressor |
|
C |
Refrigeration
system isolation valves are specially designed with a back-seat, as well
as a front-seat. For what purpose are these valves designed in this way? |
allow for operation
as a suction or discharge valve |
allow for removal
and replacement of the valve without shutting down |
permit repacking
the valve stem under pressure without shutting down |
allow for operation
as a liquid or vapor valve |
|
D |
In addition to
the indicated gauge pressure, what other information is presented on the
compound gauge for the hypothetical refrigerant illustrated? Illustration
GS-RA-16 |
the absolute pressure
of the refrigerant at the point of measurement |
the actual temperature
of the refrigerant at the point of measurement |
the metric pressure
equivalent of the refrigerant at the point of measurement |
the saturation
temperature of the refrigerant that corresponds to the gauge pressure at
the point of measurement |
|
B |
Which lettered
component, shown in the illustration, indicates the location of the receiver?
Illustration GS-RA-12 |
A |
C |
F |
B |
|
A |
In a refrigeration
plant, what is one vital purpose of the receiver? |
store the refrigerant
charge |
superheat the
refrigerant liquid |
cool the refrigerant
gas |
condense the refrigerant |
|
D |
As shown in the
illustrated LP centrifugal chiller pressure maintenance system, what is
its functional purpose? Illustration GS-RA-40 |
prevent surging |
maintain a relatively
low compression ratio under low heat load conditions |
prevent the entrance
of air into the chiller under low heat load conditions |
prevent the entrance
of air into the chiller when the chiller is idle |
|
A |
What is the purpose
of the pressure transducer as shown in the illustration? Illustration GS-RA-17 |
it senses compressor
suction pressure and controls the quench valve |
it senses compressor
discharge pressure and controls the suction modulation valves |
it senses compressor
suction pressure and controls the suction modulation valves |
it senses compressor
discharge pressure and controls the quench valve |
|
D |
In addition to
pressure, most compound and standard pressure gauges used for refrigeration
service are also provided with a scale indicating what parameter? |
absolute pressure |
sub cooled refrigerant
temperature |
superheated refrigerant
temperature |
saturated refrigerant
temperature |
|
A |
Hard drawn copper
tubing is commonly used in larger refrigeration systems. What statement
concerning its use is true? |
Hard drawn copper
tubing is not easily flared, bent, or swaged, so brazed fittings are
commonly used. |
Hard drawn copper
tubing is easily swaged, so reducing fittings are rarely used in changing
line size. |
Hard drawn copper
tubing is easily bent, so elbow fittings are rarely used in changing
direction. |
Hard drawn copper
tubing is easily flared, so flare fittings are commonly used. |
|
C |
In a refrigeration
system, what component is installed directly downstream of the thermal expansion
valve? |
box solenoid valve |
receiver |
evaporator coil |
compressor |
|
C |
Refrigeration
systems using forced air circulation evaporators have a tendency to cause
rapid dehydration of produce in chill boxes. Which of the following will
minimize this dehydration? |
the air is circulated
rapidly over a small evaporator with a maximum temperature differential
o |
the air is circulated
rapidly over a small evaporator with a minimum temperature differential |
the air is circulated
slowly over a large evaporator with a minimum temperature differential |
the air is circulated
slowly over a large evaporator with a maximum temperature differential |
|
D |
In a dry-type
direct expansion refrigeration evaporator, what is true concerning the evaporator
coils? |
the coils are
covered on the outside with insulation |
the coils are
coated on the inside with insulation |
the coils are
surrounded on the outside by refrigerant |
the coils are
surrounded on the outside by air |
|
C |
Zinc plates commonly
found in refrigeration systems and used as sacrificial anodes are located
where? |
refrigerant side
of the condenser |
cooling water
suction strainer |
saltwater side
of the condenser |
evaporator coils |
|
B |
Seawater or low
temperature central fresh water is typically provided to a ship's stores
refrigeration plant for what purpose? |
prevent motor
overheating |
condense the refrigerant
gas |
cool the expansion
valve |
prevent refrigerant
superheating |
|
B |
Heat is removed
from the refrigerant circulating through the refrigeration system, shown
in the illustration, by which component? Illustration GS-RA-12 |
A |
B |
J |
K |
|
B |
If a condenser
coil of an air-cooled container refrigeration system becomes dirty and requires
cleaning, what would be an acceptable method of cleaning? |
Binks' gun with
weak acid solvent |
high pressure
water wash |
copper wire rotary
brush |
All of the above. |
|
A |
When checking
zinc plates, or pencil Zincs in the refrigerating system condenser, what
should you do? |
replace the Zincs
if deteriorated by 50% |
renew the plates
at each inspection |
file the plates
to change the negative value |
paint and insulate
the plates to prevent corrosion |
|
A |
What is true concerning
the accumulation of air and other non-condensable gases in a refrigeration
system? |
collect in the
condenser |
create a vapor
lock in the liquid receiver |
cause a loss of
the liquid seal |
cause foaming
of the oil in the crankcase |
|
B |
Through which
of the components shown in the illustration is flash gas formation a normal
occurrence? Illustration GS-RA-25 |
evaporator coil |
thermostatic expansion
valve |
receiver tank |
condenser coil |
|
C |
In a refrigeration
system, the pressure within the power element of a thermostatic expansion
valve depends directly upon what factor? |
compressor suction
pressure |
temperature in
the box |
temperature of
the evaporator coil outlet |
heat transferred
from the saturated liquid in the evaporator |
|
A |
In a refrigeration
system, the bulb for the thermal expansion valve is always located where? |
at the evaporator
coil outlet |
in the middle
of the evaporator coils |
at the evaporator
coil inlet |
at the beginning
of the bottom row of the evaporator coils |
|
A |
Concerning the
proper installation of the sensing bulb of a thermal expansion valve that
is attached to the evaporator tail coil on a horizontal run, what statement
is true? |
the bulb should
be attached so that the pinched off tubing should be oriented down and the
capillary tube running to the valve diaphragm should be oriented up |
the bulb should
be attached with no regard to the orientation of the pinched off tubing
or the capillary tube running to the valve diaphragm |
the bulb should
be attached so that the pinched off tubing should be oriented up and the
capillary tube running to the valve diaphragm should be oriented down |
the bulb should
be attached so that the pinched off tubing should be oriented to one side
and the capillary tube running to the valve diaphragm should be oriented
to the opposite side |
|
D |
Which of the statements
listed is applicable to the thermostatic expansion valve shown in the illustration?
Illustration GS-RA-07 |
It regulates the
temperature of the refrigerated space. |
It regulates the
amount of superheat at the solenoid valve. |
The external equalizing
pipe is connected to the liquid receiver. |
The control bulb
is located on the evaporator coil outlet. |
|
A |
When the sensing
bulb of a thermostatic expansion valve is charged with a fluid different
from the charge used in the system, what name of the charge is associated
with the power element? |
cross charged |
blended charged |
straight charged |
mixed charged |
|
D |
A typical shipboard
domestic multi-box refrigeration system operates with one compressor and
condenser. What is the purpose of the sensing line connected to the thermal
bulb at the evaporator coil outlet? |
To direct evaporator
outlet pressure to the lower part of the solenoid bellows. |
To open or close
the solenoid valve when the box temperature increases or decreases. |
To open the back-pressure
regulating valve when evaporator coil pressure increases. |
To transmit the
bulb pressure (proportional to the coil temperature) to the thermal expansion
valve diaphragm. |
|
B |
Refrigerant flow
through a thermostatic expansion valve is greatest under what conditions? |
when the low side
and high side pressures are equal |
when the evaporator
has just begun feeding at relatively high box temperature |
when the low side
pressure and the bulb pressure are equal |
just before the
evaporator stops feeding at relatively low box temperature |
|
C |
In a vapor compression
type refrigeration cycle, the refrigerant temperature decreases the most
when passing through which system component? |
evaporator |
compressor |
expansion valve |
condenser receiver |
|
A |
The thermostatic
expansion valve in a refrigeration system further opens when the diaphragm
flexes downward. With all other conditions being the same, what single condition
causes this? |
an increase in
sensing bulb temperature |
an increase in
the evaporator pressure |
a decrease in
sensing bulb temperature |
increasing the
superheat setting of the valve |
|
D |
In refrigeration
systems with multiple evaporators, the metering of refrigerant to each refrigerated
space evaporator is accomplished by what device? |
the individual
back pressure regulating valves |
the King valve |
the individual
box Solenoid Valves |
the individual
thermal expansion valves |
|
C |
In the multi-evaporator
refrigeration system shown in the illustration, what is the proper name
for the valve labeled "29"? Illustration GS-RA-12 |
chill box evaporator
pressure regulating valve |
freeze box thermostatic
expansion valve |
chill box thermostatic
expansion valve |
chill box solenoid
valve |
|
D |
Rather than design
an infinite variety of thermostatic expansion valve sizes to accommodate
different capacities for heat removal, some manufacturers use a few standard
valve body sizes in conjunction with what other feature? |
a flexible diaphragm
to accommodate different heat removal capacities |
an externally
adjustable superheat to accommodate different heat removal capacities |
internal equalizers
to accommodate different heat removal capacities |
internal needle
valve orifices of various sizes to accommodate different heat removal
capacities |
|
C |
Constant superheat
is maintained at the evaporator coil outlet of a refrigeration system or
unit by the action of what device? |
king valve |
low pressure cutout
switch |
thermal expansion
valve |
solenoid valve |
|
A |
Besides the evaporator
pressure, the thermal expansion valve reacts directly to changes in what
parameter? |
temperature of
the evaporator coil outlet |
temperature of
the space being cooled |
liquid refrigerant
pressure at the solenoid valve |
pressure drop
across the evaporator coils |
|
C |
Which of the following
illustrated expansion valves is designed to maintain a constant evaporator
pressure rather than a constant evaporator superheat? Illustration GS-RA-24 |
A |
D |
C |
B |
|
C |
Which of the following
illustrated thermal expansion valves would be appropriate to use on an evaporator
coil with a 2 psi pressure drop, where externally adjustable superheat and
a replaceable power element are both desired? Illustration GS-RA-06 |
D |
C |
B |
A |
|
B |
What is one function
of the thermal expansion valve used in a refrigeration system? |
turn the compressor
off and on |
regulate the amount
of refrigerant flow to the evaporator coil |
act as a pilot
controlling the box solenoid valve |
regulate the water
flow to the water-cooled condenser |
|
D |
When a refrigeration
compressor is in the 'off' cycle, the thermal expansion valve will react
in what way? |
it will always
completely close regardless of whether or not the system employs a pump
down cycle |
it will always
open wide regardless of whether or not the system employs a pump down cycle |
it will always
remain in the same position just prior to the cycling off of the compressor |
it will continue
to function as a result of the net balance of forces acting on the diaphragm |
|
C |
Of the various
possible methods shown in the illustration, which is the correct method
of attaching a TXV feeler bulb to a large line (7/8" and larger) with
a horizontal run? Illustration GS-RA-50 |
A |
B |
C |
D |
|
A |
When a thermostatic
expansion valve is installed in a refrigerated container unit, the sensing
bulb almost always requires insulation. Why is this so? |
the insulation
prevents air stream temperatures from influencing the bulb temperature |
the insulation
protects the clamp and screws from corrosion |
the insulation
prevents the bulb from vibrating loose |
the insulation
prevents oil entrained in the suction gas from influencing the bulb temperature |
|
D |
Which of the following
statements describes the accepted method for testing a thermostatic expansion
valve? |
Chill the bulb
in ice water while observing the compressor for an increase in suction pressure. |
Remove the power
head from the unit, heat the bulb with a torch while using a scale to measure
the distance the diaphragm has moved. |
Heat the bulb
by using a halide torch or similar device and observe the valve stem movement. |
Place the sensing
bulb in ice water and then warm by hand. Observe flood-through and temperature
change at the suction line. |
|
C |
The coil temperature
measured at the expansion valve sensing bulb of an operating system is 10°F.
The low side pressure with the compressor running as shown on the gauge
illustrated indicates 15 psig. What adjustments or changes, if any, should
be made to the system? Illustration GS-RA-16 |
The evaporator
coils need to be steam cleaned or high pressure washed. |
The liquid line
strainer is obviously fouled and needs to be cleaned. |
The expansion
valve should not be adjusted, as the degree of superheat is within the
accepted range. |
The filter drier
needs to be changed to increase the suction pressure. |
|
A |
Concerning the
proper installation of the sensing bulb of a thermal expansion valve that
is attached to the evaporator tail coil on a horizontal run, which statement
is true? |
the bulb should
be attached so that the pinched off tubing should be oriented down and the
capillary tube running to the valve diaphragm should be oriented up |
the bulb should
be attached so that the pinched off tubing should be oriented to one side
and the capillary tube running to the valve diaphragm should be oriented
to the opposite side |
the bulb should
be attached with no regard to the orientation of the pinched off tubing
or the capillary tube running to the valve diaphragm |
the bulb should
be attached so that the pinched off tubing should be oriented up and the
capillary tube running to the valve diaphragm should be oriented down |
|
D |
A thermostatic
expansion valve is properly controlling evaporator superheat. Adjusting
this valve to lower the evaporator superheat setting will result in which
of the following? |
the expansion
valve will further close |
the expansion
valve diaphragm will rupture |
the evaporator
pressure will decrease |
the evaporator
feed will increase |
|
B |
When replacing
a thermostatic expansion valve power element, what is true concerning the
thermal bulb? |
apply a heavy
coating of grease to function as a heat sink |
with steel wool
or an abrasive cloth remove oxidation on the bulb and suction line |
apply a light
film of oil to increase heat transfer |
carefully coat
the device with silicone sealant to reduce the effects of convective cooling |
|
B |
If the evaporator
coil horizontal return line of a container refrigeration system is less
than 0.875" (2.21 cm) in diameter (considered small), the thermostatic
expansion valve sensing bulb should be attached where on the return line? |
as close as possible
to the expansion valve |
on the upper surface
of the line |
on the bottom
of the line to enable the bulb to absorb the maximum amount of heat |
directly below
the point of maximum heat transfer |
|
D |
Expansion valve
maintenance should include which of the following procedures? |
Cleaning of in-line
strainers as necessary. |
Ensuring that
the thermal bulb is in good contact with the suction line and insulated. |
Checking that
the thermal bulb is in the proper location. |
All of the above. |
|
D |
Which statement
about calibrating a newly installed thermostatic expansion valve is correct? |
This procedure
is done at the factory with tools not available to a mariner. |
No special tools
are required as long as the solid state circuit control panels are functioning
properly. |
The procedure
requires a refrigeration wrench and a digital thermometer to measure box
temperature. |
An accurate thermometer
and suction pressure gage are essential to this process. |
|
C |
Which of the installation
steps listed is necessary for the proper operation of the thermostatic expansion
valve? |
Remove excess
lengths of the sensing bulb capillary tube from the device to increase
sensitivity. |
Attach the thermal
bulb to the suction line using plastic ties. |
Clean off oxidation
from the surface of the suction line and sensing bulb with fine abrasive
cloth or steel wool. |
Heat shrink insulating
material around the device once the bulb has been properly secured. |
|
D |
Which of the listed
statements describes the method used to determine the amount of superheat
present in the suction gas leaving the evaporator coil? Illustration GS-RA-16 |
Note the low side
pressure, determine the corresponding saturation temperature, and subtract
it from the temperature measured with a thermometer at the compressor suction
inlet. |
Subtract the temperature
measured at the thermostatic expansion valve sensing bulb from the saturation
temperature corresponding to the low side pressure. |
Note the low side
pressure, determine the corresponding saturation temperature, and add it
to the temperature measured with a thermometer at the thermostatic expansion
valve sensing bulb. |
Note the low side
pressure, determine the corresponding saturation temperature, and subtract
it from the temperature measured with a thermometer at the thermostatic
expansion valve sensing bulb. |
|
C |
What maintenance
may be carried out on a thermostatic expansion valve? |
The thermal bulb
may be recharged. |
The proportional
action may be varied. |
The inlet screen
may be cleaned. |
The rate action
may be increased. |
|
B |
Which of the following
conditions will occur if the power element of the thermostatic expansion
valve shown in the illustration loses its charge? Illustration GS-RA-07 |
The valve will
begin to close, but the external equalizing line will assist in keeping
the valve
unseated. |
The valve will
fail closed, providing no cooling capacity. |
The valve will
fail open and the cooling capacity will be increased. |
The valve will
fail open as designed to provide continuous cooling. |
|
D |
If the superheat
setting of a thermostatic expansion valve is set too low, what would be
the result, assuming that the system has a single evaporator? |
the box temperature
will be pulled way down below the normal temperature range |
the receiver level
will be abnormally high due to a reduced amount of refrigerant returning
back to the compressor |
the suction line
will be abnormally warm due to a reduced amount of refrigerant returning
back
to the compressor |
the suction line
will be abnormally cold and liquid may flood back to the compressor |
|
B |
If the superheat
value of the thermostatic expansion valve is adjusted too high, what would
be the result? |
the heat removal
capacity of the evaporator will increase |
the suction line
of the compressor will be abnormally warm |
the evaporator
will be overfed with liquid refrigerant |
the suction line
of the compressor will be abnormally cold |
|
C |
A small obstruction
at the thermostatic expansion valve inlet will result in which of the following
conditions? |
Higher than normal
discharge pressure. |
Expansion valves
are designed to pass small foreign particles so no adverse condition will
occur. |
Lower than normal
suction pressure. |
Ice is the sole
cause of this and will soon melt due to superheat; no adverse condition
will occur. |
|
A |
An obstructed
expansion valve may be indicated by an incompletely cooled evaporator and
what other symptom? |
frosting at the
evaporator inlet |
frosting at the
suction side of the compressor |
a higher than
normal discharge pressure |
a decrease in
the amount of frosting across the drier |
|
A |
If the needle
and seat assembly is excessively eroded, the valve cage assembly can be
replaced. In replacing the original valve cage assembly rated at 1/2 tons,
what would be the result if the replacement valve cage was oversized at
5 tons? Illustration GS-RA-07 |
The expansion
valve would hunt excessively, alternately starving and overfeeding the
evaporator coil. |
The expansion
valve would function normally, with the presentation of no problems. |
The evaporator
would be overfed producing consistently insufficient superheat. |
The evaporator
would be starved producing consistently excessive superheat. |
|
D |
Vapor bubbles
present in the liquid upon arrival to the thermal expansion valve in a refrigeration
system may cause erosion of the expansion valve's needle and seat. This,
in turn, could cause what condition? |
TXV freezing open |
TXV overheating |
TXV freezing shut |
TXV hunting |
|
B |
Moisture entering
a typical refrigeration system will most likely produce what effect? |
boil in the condenser |
freeze in the
expansion valve |
be removed by
the liquid line strainers |
cause sweating
and frost on the evaporator coils |
|
D |
Concerning the
operation of refrigeration systems, frosting or sweating of a liquid line
is usually indicative of what condition? |
proper cooling
taking place |
high relative
humidity surrounding the liquid line |
the refrigerant
contaminated with moisture |
a liquid line
restriction |
|
D |
An air-cooled
refrigerated container unit using R-134a as a refrigerant has a box temperature
set point of -15 °F, but it is currently operating with a stable return
air temperature of 0 °F. The fresh air makeup vent is closed, the unit is
operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating
valve 100% open). Using the illustrated troubleshooting guide, what would
be the normal range of expected discharge pressures if the ambient air temperature
is 90 °F? Illustration GS-RA-52 |
190-230 psig |
200-220 psig |
160-180 psig |
150-190 psig |
|
B |
If increasing
the cooling water flow to a refrigeration condenser fails to lower the condenser
pressure, the probable cause may be due to what condition? |
partially blocked
thermal expansion valve |
excessive amount
of non-condensable gases trapped in the condenser |
an evaporator
coil in need of defrosting |
a low level of
Freon in the receiver |
|
D |
Which of the conditions
listed could cause excessively low refrigerant pressure at the compressor
suction of a TXV controlled refrigeration system? |
The box solenoid
valve 'stuck' in the open position. |
Insufficient flow
of condenser cooling water. |
The high pressure
cutout switch is inoperative. |
The system is
low on refrigerant. |
|
C |
In an operating,
water-cooled, multi-box refrigeration system, both low discharge and high
suction pressures are being simultaneously experienced. The probable cause
for this condition is which of the following? |
fouled shell-and-tube
condenser |
improper superheat
adjustment on the low side |
discharge relief
valve leaking back to the suction side |
overcharge of
refrigerant in the system |
|
C |
High suction pressure
accompanied by low suction temperature to a refrigeration system compressor
is caused by which of the following? |
a clogged liquid-line
strainer |
the expansion
valve is insufficiently opened |
the expansion
valve being open too wide |
the king valve
is insufficiently open |
|
D |
Low compressor
head pressure in a refrigeration system can be caused by which of the following? |
excessive refrigerant
in the system |
insufficient condenser
cooling water flow |
air in the refrigeration
system |
excessive condenser
cooling water flow |
|
D |
If the running
suction pressure at the refrigeration compressor of a TXV controlled air-cooled
refrigeration system is below normal, which of the following can be a cause? |
overfeeding by
the expansion valve |
a dirty condenser |
refrigerant overcharge |
a restricted liquid-line
strainer |
|
C |
During tests to
discover why a refrigeration compressor is running continuously, it is determined
that the refrigerated space temperature is slightly above normal without
ever reaching the desired minimum temperature. Suction and discharge pressures
are normal for the corresponding box temperature. In this situation, what
should you suspect? |
high cooling water
temperature |
a shortage of
refrigerant |
leaking door gaskets |
air in the system |
|
D |
If a refrigeration
compressor using a thermostat as a primary controller is running continuously
without significantly lowering the temperature in the refrigerated space,
which of the following is most likely the trouble? |
excessive condenser
cooling water |
warm food in the
refrigerator |
a shortage of
compressor oil |
a shortage of
refrigerant |
|
D |
Moisture in a
refrigeration system can cause which of the following conditions? |
freezing the expansion
valve closed |
corrosion of system
piping |
hermetic motor
burnout |
All of the above. |
|
B |
Excessive moisture
being collected in the purge unit of a low pressure refrigeration system
could indicate which probable condition? |
improper charging
of refrigerant |
leaking condenser
or chiller tubes |
low efficiency
purge unit |
dryer core needs
replacement |
|
C |
An evaporator
coil of a single evaporator, air cooled refrigerator is accumulating excessive
frost due to a failure of the defrost mechanism. If the refrigerator features
a thermostatically controlled box solenoid and a low pressure cutout controlled
compressor, as well as a high pressure cutout, in terms of the compressor,
what would be the most likely operating symptom? |
run continuously |
fail to start |
short cycle on
low pressure cutout |
short cycle on
high pressure cutout |
|
B |
In a low pressure
refrigeration system, excessive running of the purge recovery unit generally
indicates which probable condition? |
overcharged system |
system leaks on
the low side |
faulty purge system
vent valve |
system leaks on
the high side |
|
C |
The compressor
on the ships service refrigeration system starts up but stops after a brief
period of running. Subsequent attempts to start it produce no result. What
control component would you suspect? |
The water regulating
valve. |
The high pressure
cut out. |
The lube oil differential
pressure switch. |
The back pressure
regulator. |
|
D |
While troubleshooting
intermittent failures of the ship service refrigeration system you suspect
the problem is with the lube oil pressure differential switch. The recommended
course of action would be: |
Decrease the time
delay setting and see if problem persists. |
Increase the switch
setting and see if problem persists. |
Lower the switch
setting and see if problem persists. |
Replace the switch
as there is generally no adjustments available on the switch. |
|
A |
When a refrigeration
compressor motor fails to start, the FIRST thing that should be checked
for is what? |
blown fuse or
tripped circuit breaker in the motor circuit |
loose expansion
valve control bulb |
faulty suction
pressure regulator |
low differential
setting on the H.P. cutout |
|
D |
If the refrigeration
compressor crankcase is sweating or frosting and is operating with an unusual
noise, what is most likely the cause? |
the compressor
short cycling on the high pressure cutout |
the compressor
running continuously |
a shortage of
refrigerant |
liquid refrigerant
returning to the compressor |
|
C |
If a refrigeration
system were short of refrigerant, besides an elevated box temperature, what
would be an observable symptom? |
short cycling
of the compressor on the water failure switch |
high suction pressure |
continuous running
of the compressor |
high discharge
pressure |
|
A |
If a refrigeration
compressor were short cycling on the low pressure cutout switch, what is
the most probable cause? |
the expansion
valve strainers were fouled |
the high pressure
switch was improperly adjusted |
the system was
overcharged with refrigerant |
the suction valves
were leaking slightly |
|
C |
If a refrigeration
system, equipped with a reciprocating compressor, has a liquid-line solenoid
valve that is leaking during the 'off' cycle, what would this cause? |
high superheat
in the outlet coil |
refrigerant slugs
in the receiver |
noisy compressor
operation upon starting |
low suction pressure |
|
A |
A refrigeration
unit will tend to short cycle when operating under what conditions? |
lack of refrigerant |
during starting
conditions |
under heavy loads |
during hot gas
defrost |
|
B |
If a refrigeration
compressor had developed a slightly high suction pressure accompanied with
an abnormally low suction temperature, the problem could be a result of
which of the following? |
a clogged sub
cooler |
liquid refrigerant
flooding back from the cooling coil |
a minor accumulation
of air or non-condensable gases in the system |
a leaking king
valve |
|
C |
An excessive charge
of refrigerant in a thermostatically controlled, air-cooled, refrigeration
system using a TXV as an expansion device can cause which of the following? |
the compressor
to run continuously |
oil foaming in
the compressor |
higher than normal
discharge pressure |
lower than normal
box temperature |
|
B |
Which recovery
procedure should be used to minimize the loss of oil from the system during
the recovery of refrigerant from small appliances such as a water cooler? |
initial recovery |
vapor recovery |
liquid recovery |
vapor-liquid recovery |
|
D |
What is true concerning
highly contaminated refrigerant recovered from burned out small appliances? |
The recovered
refrigerant may be blended with new refrigerant for eventual re-use. |
The recovered
refrigerant must be destroyed by the refrigeration technician. |
The recovered
refrigerant may be used to clean out systems that have suffered from a burn
out. |
The recovered
refrigerant should be sent to a designated reclamation facility for processing. |
|
B |
Technicians servicing
small refrigeration appliances can employ what type of recovery equipment? |
do not need to
recover the refrigerant |
either active
or passive |
passive only |
active only |
|
B |
If passive recovery
is used on a small appliance fitted with a capillary tube as a metering
device with a non-operating compressor, the recovery should be made through
what means? |
by venting to
atmosphere, cannot be recovered |
recovery from
both the high and low sides |
recovery from
the high side only |
recovery from
the low side only |
|
D |
Minor repairs
may be performed on low pressure refrigerant systems without recovering
the refrigerant charge if the pressure in the system is raised to atmospheric.
How may this be accomplished? |
pressurize the
system with nitrogen |
open the system
vent to the atmosphere and allow the pressure to equalize |
charge the system
until it is completely filled with liquid refrigerant |
heat the refrigerant |
|
D |
The most cost-effective
method of recovering refrigerant from a low pressure chiller with more than
500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant
using what protocol? |
recovery using
a vacuum pump based vapor recovery machine only |
vapor recovery
using a vacuum pump based recovery unit followed by liquid recovery using
a liquid pump |
recovering using
a liquid pump only |
liquid recovery
using a liquid pump, followed by vapor recovery using a vacuum pump based
recovery unit |
|
B |
Why is a purge
recovery unit typically fitted on low pressure centrifugal chillers? |
low pressure chillers
are routinely opened for maintenance thus introducing air at each opening |
such a chiller
can operate at a pressure below atmospheric pressure on the low side thus
drawing in air through any low-side leaks |
low pressure chillers
use extremely low boiling point refrigerants |
evacuation of
the air from a low pressure chiller prior to charging with refrigerant is
not
possible |
|
D |
As shown in the
illustrated flow diagram for a self-contained recovery unit designed for
the recovery of refrigerants from high pressure appliances as defined by
the EPA Clean Air Act rules, what is the functional purpose of the item
labeled "FS2"? Illustration GS-RA-32 |
It automatically
shuts down the recovery unit compressor when the recovery cylinder becomes
80% full. |
It automatically
shuts down the recovery unit compressor when the discharge pressure becomes
excessive. |
It automatically
shuts down the recovery unit compressor when the refrigeration system has
reached a depth of 15" Hg. |
It automatically
transitions the recovery unit from the direct liquid recovery mode to the
direct vapor recovery mode. |
|
C |
How should small
appliances with less than three pounds of refrigerant be charged with refrigerant? |
liquid charged |
initially liquid
charged and then topped with a vapor charge |
vapor charged |
either vapor or
liquid charged |
|
C |
Charging liquid
HCFC-123 into a system under a deep vacuum could cause what to happen unless
necessary precautions are taken? |
rupture disk to
rupture |
air and moisture
to enter the receiver |
system secondary
refrigerant to freeze |
the purge unit
to operate |
|
C |
When a refrigeration
system is being topped off with a small amount of refrigerant through the
low side with the compressor running, what should be done? |
the discharge
service valve must be front seated |
the refrigerant
charging cylinder should be turned upside down |
the refrigerant
should be charged into the system as a vapor |
the suction service
valve must be back seated |
|
C |
Which of the valves
listed is normally closed when charging the refrigeration system through
the high side? |
Dehydrator inlet
valve |
Thermal expansion
valve |
Liquid line king
valve |
Suction line valve |
|
A |
Using the device
shown in the illustration, which of the following statements is true when
adding refrigerant as a vapor to the low side of the refrigeration system
__________. Illustration GS-RA-01 |
The hose labeled "H"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "G" should be open. |
The hose labeled "H"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "G" should be closed. |
The hose labeled "K"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "C" should be closed. |
The hose labeled "K"
should be connected to the suction service valve service port, the hose
labeled "J" should be connected to the vapor valve on the refrigerant
cylinder and the valve labeled "C" should be closed. |
|
D |
What is the primary
purpose of a reach rod as used as a valve remote operator? |
It changes the
type of motion normally required to operate the valve. |
It decreases the
turning effort required to operate the valve. |
It reverses the
direction of rotation normally required to operate the valve. |
It allows for
the operation of valves that would otherwise be out of reach. |
|
A |
Where is the location
of a chain-operated valve when a chain wheel is attached to the stem and
is associated with an endless chain for operation? |
The valve is located
too far directly above the deck where it is operated from. |
The valve is located
too far directly across from the location where it is operated. |
The valve is located
too far directly below the deck where it is operated from. |
A chain-operated
valve can be used in any of the applications listed above. |
|
D |
In what application
is a remote valve operator most likely to be located outside the machinery
space when the valve itself is located within the machinery space? |
A valve located
in a compressed air line. |
A valve located
in potable-water transfer line. |
A valve located
in a sea-water cooling line. |
A valve located
in a fuel oil transfer line. |
|
B |
Suppose a remote
valve operator is fitted with a gearbox. What is the purpose of the gearbox? |
The gearbox may
be used to change the orientation of the hand wheel to the valve stem, or
it may be used to reduce the turning effort, but NEVER both. |
The gearbox may
be used to change the orientation of the hand wheel to the valve stem, or
it may be used to reduce the turning effort, OR both. |
The gearbox is
strictly used to change the orientation of the hand wheel to the valve stem.
The gearbox is never used to reduce the turning effort. |
The gearbox is
strictly used to reduce the turning effort. The gearbox is never used to
change the orientation of the hand wheel to the valve stem. |
|
A |
In what application
is an emergency shutdown most likely to be located outside the machinery
space when the pump itself is located within the machinery space? |
Fuel oil transfer
pump |
Steering pump |
Lube oil circulating
pump |
Fire pump |
|
B |
What application
often requires a valve to be remotely operated from a control station, where
the valve itself is operated by an electric, pneumatic, or hydraulic motor? |
A small valve
that is routinely operated during plant operations. |
A large valve
that is routinely operated during plant operations. |
A large valve
that is rarely operated during plant operations. |
A small valve
that is rarely operated during plant operations. |
|
D |
What type of valve
would be fitted with a quarter-turn power actuator, such as a rack-and-pinion? |
Non-rising stem
gate valve |
Rising stem gate
valve |
Globe valve |
Butterfly valve |
|
D |
What is the purpose
of the torque limit switch as fitted on an electric motor operated rising
stem gate valve? |
The torque limit
switch protects the valve from being damaged if a foreign object prevents
the valve from fully opening. |
The torque limit
switch protects the motor from being damaged if a foreign object prevents
the valve from fully opening. |
The torque limit
switch protects the motor from being damaged if a foreign object prevents
the valve from fully closing. |
The torque limit
switch protects the valve from being damaged if a foreign object prevents
the valve from fully closing. |
|
A |
Remote valve operators
are frequently fitted with a handwheel for local operation if the motor
fails. If this is so, what is the procedure for local manual control? |
First move the
lever to disengage the motor clutch, and then rotate the hand wheel. |
Just rotate the
hand wheel in the appropriate direction for valve operation. |
First move the
lever to engage the motor clutch, and then rotate the hand wheel. |
Motor operated
valves are generally not fitted with local hand wheels. |
|
D |
A vessel is in
compliance with federal regulations regarding the discharge of sewage by
__________. |
holding all sewage
onboard |
treating sewage
in an approved system |
pumping the sewage
ashore to an approved container |
All of the above. |
|
C |
Which type of
Marine Sanitation Device (MSD) is used solely for the storage of sewage
and flush water at ambient air pressure and temperature? |
Type I |
Type II |
Type III |
Type IV |
|
C |
Which of the following
statements correctly describes the construction of the close coupled sanitary
pump shown in the illustration? Illustration GS-0070 |
The pump housing
and motor frame provide for radial adjustment of the shaft coupling. |
The pump impeller
is classified as double suction. |
The pump and motor
have a common shaft. |
The pump suction
and discharge connections are made with screwed pipe fittings. |
|
C |
Which type of
Marine Sanitation Device (MSD) is used solely for the storage of sewage
and flush water at ambient air pressure and temperature? |
Type I |
Type II |
Type III |
Type IV |
|
C |
A constant pressure
range is maintained in the potable water system of many vessels by using
__________. |
constant speed
supply pumps |
variable speed
supply pumps |
an air cushion
in the hydro-pneumatic tank |
a pressure regulator
in the pressure tank discharge piping |
|
A |
According to the
illustration, which of the following conditions would most likely cause
pump "A" to short cycle? Illustration GS-0173 |
The hydro-pneumatic
expansion tank is operating with an insufficient air charge. |
The hydro-pneumatic
tank is operating with a low water level. |
A low water level
exists in the potable water storage tank. |
Pump "A"
wearing rings have excessive clearance. |
|
B |
The flame screens
installed on sewage system tank vents prevent explosions by __________. |
allowing the escape
of flammable vapors |
dissipating the
heat of a flame |
absorbing any
flammable vapors in the vicinity |
preventing flammable
vapors from entering the tank |
|
D |
If water continues
to trickle into the toilet bowl after the device shown in the illustration
has apparently closed, the problem is likely due to __________. Illustration
GS-0155 |
"E"
being stuck or held in a position other horizontal |
a problem with "H"
that allows continuous low flow across the device |
"A"
being cocked into a fully open position |
"C"
having developed a warp or ripple at the seating surface |
|
C |
If water continues
to flow excessively from the device shown in the illustration, the problem
is most likely due to __________. Illustration GS-0155 |
"E"
being stuck or held in a position other than indicated in the illustration |
a hole being formed
in the outboard edge of "C" |
item "H"
being fouled or plugged |
a hole developing
in "B" |
|
D |
A vessel is in
compliance with federal regulations regarding the discharge of sewage by
__________. |
holding all sewage
onboard |
treating sewage
in an approved system |
pumping the sewage
ashore to an approved container |
All of the above. |
|
A |
Marine sanitation
devices installed on vessels must be certified by the __________. |
U.S. Coast Guard |
American Bureau
of Shipping |
Society of Naval
Architects and Marine Engineers |
Environmental
Protection Agency |
|
A |
Coast Guard regulations
concerning marine sanitation devices may be found in __________. |
33 CFR Section
159 |
33 CFR Section
153 |
33 CFR Section
155 |
33 CFR Section
156 |
|
B |
The process of
grinding, shredding, or reducing the size of sewage particles is known as
__________. |
detention |
maceration |
bulking |
chlorinating |
|
C |
Which type of
Marine Sanitation Device (MSD) is used solely for the storage of sewage
and flush water at ambient air pressure and temperature? |
Type I |
Type II |
Type III |
Type IV |
|
A |
According to the
illustration, which of the following conditions would most likely cause
Pump "A" to short cycle? Illustration GS-0173 |
The hydro-pneumatic
expansion tank is operating with an insufficient air charge. |
The hydro-pneumatic
tank is operating with a low water level. |
A low water level
exists in the potable water storage tank. |
Pump "A"
wearing rings have excessive clearance. |
|
A |
A pneumatic pressure
tank is installed in a sanitary system to __________. |
reduce excessive
cycling of the sanitary pump |
prevent the sanitary
pump from losing suction |
provide a higher
pressure in the system than the pump can deliver |
increase water
flow through the system |
|
D |
What type of bottom
construction is used on most commercial deep-draft vessels with the exception
of tankers? |
Triple bottom
construction |
Single bottom
construction |
Double hull construction |
Double bottom
construction |
|
A |
What is the name
of an internal passage of watertight construction fitted along the centerline
between the double-bottoms of some ships, usually from the forepeak to the
forward machinery space bulkhead, used to carry pipe work along the length
of the ship to the various holds or tanks? |
Duct keel |
Vertical keel |
Bar keel |
Pipe keel |
|
D |
What statement
is true concerning the keel arrangements of a double-bottomed ship? |
A ship with an "duct
keel" has a single continuous transverse girder positioned along the
centerline and perpendicular to the flat plate keel, and a ship with a "I-section
keel" has two continuous transverse girders spaced apart and positioned
on either side of the centerline and perpendicular to the flat plate keel. |
A ship with an "I-section
keel" has a single continuous transverse girder positioned along the
centerline and perpendicular to the flat plate keel, and a ship with a "duct
keel" has two continuous transverse girders spaced apart and positioned
on either side of the centerline and perpendicular to the flat plate keel. |
A ship with an "duct
keel" has a single continuous longitudinal girder positioned along
the centerline and perpendicular to the flat plate keel, and a ship with
a "I-section keel" has two continuous longitudinal girders spaced
apart and positioned on either side of the centerline and perpendicular
to the flat plate keel. |
A ship with an "I-section
keel" has a single continuous longitudinal girder positioned along
the centerline and perpendicular to the flat plate keel, and a ship with
a "duct keel" has two continuous longitudinal girders spaced apart
and positioned on either side of the centerline and perpendicular to the
flat plate keel. |
|
D |
For a transverse-framed
ship of double-bottom construction, what structural members supports the
inner bottom shell (or tank-tops)? |
Longitudinally
arranged continuous vertical floors. |
Transversely arranged
continuous vertical girders. |
Longitudinally
arranged continuous vertical girders. |
Transversely arranged
continuous vertical floors. |
|
C |
What is usually
contained within the double-bottom tanks associated with the machinery spaces? |
Machinery space
double-bottom tanks generally contain liquid cargo. |
Machinery space
double-bottom tanks generally are kept dry and function as void spaces. |
Machinery space
double-bottom tanks generally contain fuel oil, lubricating oil, or fresh
water. |
Machinery space
double-bottom tanks generally contain seawater ballast. |
|
B |
How is access
to the double-bottom tanks usually provided for inspection, cleaning, maintenance,
and repairs of tank interiors? |
Gasketed and bolted
manholes associated with vertical tank boundaries |
Gasketed and bolted
manholes associated with the inner plating (tank tops). |
Hinged hatches
associated with the inner plating (tank tops). |
Gasketed and bolted
manholes associated with the outer plating. |
|
D |
While in dry-dock,
what means are provided for completely draining the double bottom tanks
in preparation for inspection? |
Sounding tubes. |
Gasketed and bolted
manholes. |
Stripping eductor
connections. |
Docking plugs. |
|
D |
As it applies
to a transverse-framed ship with double bottom construction, what does the
term "floor" represent? |
Floors are vertical
longitudinal members supporting the inner-bottoms. |
Floors are the
actual inner-bottom tank tops. |
Floors are the
actual outer-bottom shell plating. |
Floors are vertical
transverse members supporting the inner-bottoms. |
|
A |
What is the name
of the opening in a bilge margin bracket that reduces the weight of the
bracket without materially reducing its strength? |
Lightening holes |
Manholes |
Air holes |
Drain holes |
|
A |
What statement
concerning the orientation and welds of adjoining shell plates is true? |
The shell plates
(or strakes) run horizontally in a fore and aft direction and any horizontal
welds are called "seams" and any vertical welds are called "butts". |
The shell plates
(or strakes) run vertically in a gunwales to keel direction and any horizontal
welds are called "butts" and any vertical welds are called "seams". |
The shell plates
(or strakes) run horizontally in a fore and aft direction and any horizontal
welds are called "butts" and any vertical welds are called "seams". |
The shell plates
(or strakes) run vertically in a gunwales to keel direction and any horizontal
welds are called "seams" and any vertical welds are called "butts". |
|
C |
Even though bilge
keels do provide some improvement in longitudinal strength at the bilge
radius, what is the primary purpose of the bilge keels? |
Dampen the tendency
the ship has to heave. |
Dampen the tendency
the ship has to yaw. |
Dampen the tendency
the ship has to roll. |
Dampen the tendency
the ship has to pitch. |
|
D |
In terms of ship
construction framing methods, which statement is true concerning the transverse
framing system? |
With transverse
framing, transverse frames are horizontal and intercostal between vertical
girders which are continuous. |
With transverse
framing, transverse frames are horizontal and continuous and vertical stiffeners
are intercostal between frames. |
With transverse
framing, transverse frames are vertical and intercostal between longitudinal
girders which are horizontal and continuous. |
With transverse
framing, transverse frames are vertical and continuous and longitudinal
stiffeners are horizontal and intercostal between frames. |
|
A |
In terms of ship
construction framing methods, what statement is true concerning the longitudinal
framing system? |
With longitudinal
framing, longitudinal frames are horizontal and continuous and vertical
stiffeners are intercostal between frames. |
With longitudinal
framing, longitudinal frames are horizontal and intercostal between vertical
girders which are continuous. |
With longitudinal
framing, longitudinal frames are vertical and continuous and horizontal
stiffeners are intercostal between frames. |
With longitudinal
framing, longitudinal frames are vertical and intercostal between horizontal
girders which are continuous. |
|
B |
What statement
is true concerning the plating meeting at the gunwales of a ship? |
The strakes of
deck plating nearest to the sides are termed "sheerstrakes" and
the side plating nearest to the deck are termed "stringer plates".
The sheerstrakes and stringer plates meet at the gunwales. |
The strakes of
side plating nearest to the deck are termed "sheerstrakes" and
the deck plating nearest to the side are termed "stringer plates".
The sheerstrakes and stringer plates meet at the gunwales. |
The strakes of
side plating nearest to the deck and the deck plating nearest to the side
are both termed "sheerstrakes". These sheerstrakes meet at the
gunwales. |
The strakes of
side plating nearest to the deck and the deck plating nearest to the side
are both termed "stringer plates". These stringer plates meet
at the gunwales. |
|
A |
With a ship built
with a transverse framing system, by what means are double-bottom floors
and the transverse frames joined? |
By way of bilge
margin brackets. |
By way of bilge
margin girders. |
By way of bilge
margin gussets. |
By way of bilge
margin stiffeners. |
|
B |
For a typical
transverse-framed deep-draft commercial vessel, what is the normal arrangement
for the support of decks?
|
Deck beams are
transversely arranged and deck girders are longitudinally arranged and the
deck beams are continuous with the exception of hatches and other openings.
The deck girders are intercostal. |
Deck beams are
transversely arranged and deck girders are longitudinally arranged and both
are continuous with the exception of hatches and other openings. |
Deck beams are
transversely arranged and deck girders are longitudinally arranged and the
deck girders are continuous with the exception of hatches and other openings.
The deck beams are intercostal. |
Deck beams are
longitudinally arranged and deck girders are transversely arranged and both
are continuous with the exception of hatches and other openings. |
|
A |
What is another
name for the "collision" bulkhead? |
Fore peak bulkhead |
Forward engine
room bulkhead |
After engine room
bulkhead |
After peak bulkhead |
|
B |
What term is used
to represent the bulkhead type used for tank boundary bulkheads? |
Watertight bulkheads |
Oil tight bulkheads |
Airtight bulkheads |
Non-watertight
bulkheads |
|
B |
Which of the following
listed bulkhead types has the most rigorous standard for testing purposes? |
Watertight bulkheads |
Oil tight bulkheads |
Non-watertight
bulkheads |
Wash bulkheads |
|
A |
What statement
is true concerning the construction of watertight bulkheads? |
The strakes of
the bulkhead are horizontal and the stiffeners are vertical and the bulkhead
must have increasingly greater strength towards the base. |
The strakes of
the bulkhead are horizontal and the stiffeners are vertical and the bulkhead
must have increasingly greater strength towards the top. |
The strakes of
the bulkhead are vertical and the stiffeners are horizontal and the bulkhead
must have increasingly greater strength towards the top. |
The strakes of
the bulkhead are vertical and the stiffeners are horizontal and the bulkhead
must have increasingly greater strength towards the base. |
|
C |
What is the name
of the structural member that is designed to transfer load from one deck
to another? |
Girders |
Stiffeners |
Pillars |
Beams |
|
B |
What statement
is true concerning watertight doors fitted below the waterline of a vessel? |
Watertight doors
below the waterline may be of the vertical or horizontal sliding type or
the
swinging hinged type. |
Watertight doors
below the waterline may be either of the vertical or horizontal sliding
type. |
Watertight doors
below the waterline may be either of the vertical sliding type or the swinging
hinged type. |
Watertight doors
below the waterline may be either of the horizontal sliding type or the
swinging hinged type. |
|
A |
What means of
emergency escape from a shaft tunnel are provided? |
Two means of escape
are provided, one which is a sliding watertight door at the forward end
of the tunnel and the other a ladder and watertight trunk at the aft end
of the tunnel. |
Only one means
of escape is provided which is a sliding watertight door at the aft end
of the tunnel. |
Only one means
of escape is provided which is a sliding watertight door at the forward
end of the tunnel. |
Two means of escape
are provided, one which is a sliding watertight door at the aft end of the
tunnel and the other a ladder and watertight trunk at the forward end of
the tunnel. |
|
D |
What statement
is true concerning the forward and after bulkheads of a shaft tunnel? |
The shaft tunnel
aft bulkhead is the aft peak bulkhead which is watertight, and the shaft
tunnel forward bulkhead is the machinery space aft bulkhead which is non-watertight. |
The shaft tunnel
aft bulkhead is the aft peak bulkhead, the shaft tunnel forward bulkhead
is the machinery space aft bulkhead, and both bulkheads are non-watertight. |
The shaft tunnel
aft bulkhead is the aft peak bulkhead which is non-watertight, and the shaft
tunnel forward bulkhead is the machinery space aft bulkhead which is watertight. |
The shaft tunnel
aft bulkhead is the aft peak bulkhead, the shaft tunnel forward bulkhead
is the machinery space aft bulkhead, and both bulkheads are watertight. |
|
C |
What is the arrangement
of a shaft tunnel as fitted on a single-screw vessel? |
The shaft tunnel
is situated on the centerline of the vessel with walkways positioned on
either side of the shaft and any piping runs carried underneath the two
walkways.
o |
The shaft tunnel
is offset from centerline of the vessel with a walkway positioned on one
side of the shaft any piping runs carried overhead above the shaft. |
The shaft tunnel
is offset from centerline of the vessel with a walkway positioned on one
side of the shaft any piping runs carried underneath the walkway. |
The shaft tunnel
is situated on the centerline of the vessel with walkways positioned on
either side of the shaft and any piping runs carried overhead above the
shaft. |
|
C |
What is the general
arrangement for bilge wells in the machinery spaces? |
Generally a single
bilge well is provided on the centerline forward since a vessel is typically
trimmed by the bow.
o |
Generally a single
bilge well is provided on the centerline aft since a vessel is typically
trimmed by the stern. |
Generally a bilge
wells are provided in the port and starboard aft corners since a vessel
is typically trimmed by the stern and to facilitate pump when the ship has
a list. |
Generally a bilge
wells are provided in the port and starboard forward corners since a vessel
is typically trimmed by the bow and to facilitate pump when the ship has
a list. |
|
D |
What provisions
are generally made to reduce the noise and vibration emanating from the
propulsion machinery installation, especially on passenger ships? |
The propulsion
machinery is resiliently mounted to machinery beds integral to the double-bottom
structure, and power is transmitted without use of flexible couplings. |
The propulsion
machinery is rigidly bolted to machinery beds integral to the double-bottom
structure, and power is transmitted with use of flexible couplings. |
The propulsion
machinery is rigidly bolted to machinery beds integral to the double-bottom
structure, and power is transmitted without use of flexible couplings. |
The propulsion
machinery is resiliently mounted to machinery beds integral to the double-bottom
structure, and power is transmitted with use of flexible couplings. |
|
A |
What is the name
associated with the dividing bulkheads separating the accommodation spaces
from the engine room of a ship? |
Engine casing |
Accommodation
casing |
Engine flat |
Engine trunk |
|
A |
What is the name
associated with a minor section of interior deck within a machinery space
serving as a seat or bed for a particular piece or set of machinery? |
Flat or platform |
Floor |
Tween deck |
Bulwark |
|
C |
What is the name
associated with the surround and support for the various uptakes to ensure
the dispersion of exhaust gases to the atmosphere and away from the ship? |
Uptakes |
Flue |
Funnel |
Stack |
|
C |
When making welding
repairs to a ship's structural member, why is it important to avoid weld
faults? |
The poor quality
weld can lead to points of stress relief, which in addition to a weak joint,
may form the starting points for cracks.
|
The poor quality
weld can lead to points of stress concentration, which in addition to a
weak joint, may cause plate distortion. |
The poor quality
weld can lead to points of stress concentration, which in addition to a
weak joint, may form the starting points for cracks. |
The poor quality
weld can lead to points of stress relief, which in addition to a weak joint,
may cause plate distortion. |
|
C |
If a welding fabrication
becomes unacceptably distorted, what means of distortion correction should
be avoided? |
Complete splitting
of the joint followed by rewelding. |
Gouging or grooving
of the joint followed by rewelding. |
Employing mechanical
straightening techniques. |
Strategic application
of spot heating with an acetylene torch. |
|
C |
When accomplishing
welding repairs with an electric arc welding process, what is generally
the cause of slag inclusion when welding a single-V butt joint? |
The weld was performed
with too high a current setting. |
The weld was performed
with an improper rod angle. |
The weld was performed
with inadequate cleaning between passes. |
The weld was performed
with too low a current setting. |
|
C |
When accomplishing
welding repairs using the electric arc welding process, what statement is
true concerning the characteristics of a good quality weld when welding
a single-V butt joint? |
There should be
no overlap, but there should be undercut at the toe of the weld. |
There should be
both overlap and undercut at the toe of the weld. |
There should be
no overlap and no undercut at the toe of the weld. |
There should be
overlap, but there should be no undercut at the toe of the weld. |
|
D |
When accomplishing
welding repairs using the electric arc welding process, what statement is
true concerning the characteristics of a good quality weld when welding
a single-V butt joint? |
There should be
no reinforcement or build-up of material on the top surface, but there should
be root penetration along the bottom surface. |
There should be
a slight reinforcement or build-up of material on the top surface, but there
should be no root penetration along the bottom surface. |
There should be
a no reinforcement or build-up of material on the top surface, and there
should be no root penetration along the bottom surface. |
There should be
a slight reinforcement or build-up of material on the top surface, and there
should be root penetration along the bottom surface. |
|
C |
When accomplishing
welding repairs using the electric arc welding process, what statement is
true concerning the characteristics of a good quality weld when welding
a single-V butt joint? |
There should be
no penetration at the sides of the weld, and there should be no penetration
between passes.
o |
There should be
no penetration at the sides of the weld, but there should be penetration
between passes. |
There should be
penetration at the sides of the weld, and there should be penetration between
passes. |
There should be
penetration at the sides of the weld, but there should be no penetration
between passes. |
|
B |
Before welding
repairs are performed to repair a crack, what is the correct procedure for
performing an emergency crack stopper?
|
A 3/8-inch hole
should be drilled at one end of the crack only, making sure that none of
the crack extends beyond the hole. |
A 3/8-inch hole
should be drilled at each end of the crack, making sure that none of the
crack extends beyond the two holes. |
A 3/8-inch hole
should be drilled at one end of the crack only, making sure that approximately
1/2-inch of the crack extends beyond the hole. |
A 3/8-inch hole
should be drilled at each end of the crack, making sure that 1/2-inch of
the crack extends beyond the two holes. |
|
A |
Before welding
repairs are performed to repair a crack, after drilling a 3/8-inch hole
at each end of the crack, what is the correct procedure for welding overlays
as an emergency crack stopper? |
A welded overlay
of trapezoidal shape shall be deposited perpendicularly at each end of the
crack no closer than 1/2-inch from each drilled hole. |
A welded overlay
of trapezoidal shape shall be deposited perpendicularly at one end of the
crack only, no closer than 1/2-inch from the drilled hole. |
A welded overlay
of trapezoidal shape shall be deposited perpendicularly at each end of the
crack right up against each drilled hole. |
A welded overlay
of trapezoidal shape shall be deposited perpendicularly at one end of the
crack only, right up against the drilled hole. |
|
C |
In order to minimize
distortion while performing the electric arc welding process while joining
two plates with a butt weld, besides using restraint procedures, what statement
is true? |
The greater the
number of welding passes the less the distortion, and welding on only one
side of a joint with a single-V will minimize distortion.
o |
The greater the
number the welding passes the less the distortion, and symmetrical welding
on either side of a joint with a double-V will minimize distortion. |
The fewer the
number of welding passes the less the distortion, and symmetrical welding
on either side of a joint with a double-V will minimize distortion. |
The fewer the
number of welding passes the less the distortion, and welding on only one
side of a joint with a single-V will minimize distortion. |
|
B |
For long welding
runs, either the "back-step" or the "skip" welding technique
is often used. For what purpose are these techniques utilized? |
These techniques
are used to minimize internal stresses. |
These techniques
are used to help minimize distortion. |
These techniques
are used to increase weld strength. |
These techniques
are used to maximize distortion. |
|
B |
Which of the devices
shown in the illustration is designed for both inside and outside measurements?
Illustration GS-0073 |
B |
C |
A |
D |
|
B |
Which of the devices
shown in the illustration should be used with a bridge gage? Illustration
GS-0073 |
C |
A |
B |
D |
|
B |
The best tool
to use to measure the number of threads per inch on a bolt is a __________. |
pair of outside
calipers |
screw pitch gauge |
micrometer |
tap |
|
B |
The ruler indicated
in the illustration is commonly referred to as a/an __________. Illustration
GS-0023 |
Metric Scale |
Engineers Scale |
Architects Scale |
Micrometer Scale |
|
D |
To set the dividers
to the proper radius, you should use a __________. |
micrometer |
calipers |
scribing circle |
steel rule |
|
C |
The center head
of a combination square set is used to __________. |
check the angle
of thread cutting tools |
check degrees
of angle |
locate the center
on round stock |
find right angles |
|
B |
Which of the instruments
listed is used to measure the gauge of a piece of sheet metal? |
Gauge calibrator |
Wire gauge |
Inside micrometer |
Circular mil |
|
C |
To measure the
circumference of a piece of pipe, you should use a __________. |
folding rule |
hook rule |
flexible steel
rule |
machinist's steel
rule |
|
C |
The purpose of
the instrument illustrated is to __________. Illustration GS-0079 |
strip insulation
from wire |
gage resistors |
measure wire diameter |
measure insulation
thickness |
|
B |
A metal scribe
commonly found on a Combination Square measuring tool should only be used
to __________. |
remove packing |
mark on metal |
clean file teeth |
punch gasket holes |
|
B |
A dial indicator
is used to measure __________. |
positive readings
only |
shaft eccentricity |
torque of a shaft |
scribed layout
lines on vertical surfaces |
|
D |
To get an accurate
measurement using a 12 inch machinist's steel rule, you should measure __________. |
on the unmarked
edge of the rule |
on the narrow
edge of the rule |
from the zero
end on the scale |
from the one inch
graduation mark |
|
B |
If a micrometer
were opened to a distance of 0.0001 inch, you would say the reading is __________. |
one millionth
of an inch |
one ten thousandth
of an inch |
ten one thousandths
of an inch |
ten millionths
of an inch |
|
C |
To determine the
diameter of a small hole, which of the listed tools must be used with inside
calipers to get an accurate reading? |
Wire gage |
A Center gage |
Micrometer |
None of the above |
|
D |
The correct torque
value for a micrometer torque wrench is reached when __________. |
a dial lights
on the handle |
the dial is read
on the handle |
the scale is read
on the handle |
an audible click
is heard and the handle releases |
|
D |
The reading on
the micrometer scale shown in figure "D" in the illustration is
__________. Illustration GS-0081 |
0.4710 inch |
0.4715 inch |
0.4810 inch |
0.4815 inch |
|
C |
What is the reading
of the vernier micrometer caliper scale shown in figure "G" in
the illustration? Illustration GS-0083 |
0.2280 inch |
0.2340 inch |
0.2470 inch |
0.2520 inch |
|
B |
One turn of the
micrometer barrel will linearly move the spindle __________. |
0.110 inch |
0.025 inch |
0.250 inch |
0.205 inch |
|
B |
A reading of 0.625
inch on a micrometer with a 2 to 3 inch range would be equal to __________. |
3 1/8 inches |
2 5/8 inches |
2 7/16 inches |
3 9/16 inches |
|
A |
To check the thickness
of a piece of thin shim stock before using it to make a bearing shim, you
should use a __________. |
micrometer |
feeler gage |
depth gage |
machinist's rule |
|
A |
The most accurate
method of measuring the setting of an inside caliper is to use a/an __________. |
outside micrometer |
dial indicator |
engineer's scale |
thread micrometer |
|
D |
For greater accuracy,
some micrometers have a vernier scale making it possible to read in increments
of __________. |
twenty five thousands
of an inch |
one fortieth of
an inch |
five thousands
of an inch |
ten thousands
of an inch |
|
A |
Many micrometers
are equipped with a ratchet stop at the end of the thimble to __________. |
prevent the user
from closing the tool with too much force |
stop the spindle
from sliding out of the barrel |
eliminate ratchet
movement |
click at each
increment of measure |
|
B |
The reading on
the vernier caliper scale shown in figure "G" in the illustration
is __________. Illustration GS-0082 |
2.965 inches |
2.368 inches |
2.380 inches |
2.308 inches |
|
C |
If you are hand
tapping holes in cast iron, you should __________. |
start tapping
with a plug tap |
chamfer the edges
of the holes |
tap the holes
without cutting oil |
flood the tap
with mineral oil |
|
A |
When internal
threading for piping where the work permits the tap to be run entirely through
you can begin and end the tapping of the hole by using a __________. |
taper tap |
bottoming tap |
plug tap |
finishing tap |
|
D |
The proper tool
used for cutting new external threads is called a thread __________. |
tap |
chaser |
broach |
die |
|
B |
The names plug,
bottom, and taper refer to __________. |
pipe fittings |
machinist's hand
taps |
drill press parts |
measuring instruments |
|
D |
With respect to
machine shop "taps and dies", a plug tap is correctly used for
__________. |
chasing the threads
on a circular rod |
reversing the
threads in a hole |
starting the threads
on a circular rod |
the second cut
when threading a blind hole |
|
A |
If a bolt or stud
were to break off flush at the surface, which of the listed actions would
probably be the best first step to begin the process of its removal? |
Drill a hole in
the center of the broken stud. |
Heat the bolt
with an oxyacetylene torch. |
Tap the bolt with
a starting punch extractor. |
Use a tapered
screw extractor only. |
|
B |
The number of
screw threads per inch for a Standard National Coarse 1/2 inch bolt is __________. |
18 |
13 |
20 |
16 |
|
D |
The designation
'1/4-20' describes __________. |
steel plate thickness |
pipe thread die
size |
cutting torch
tips size |
machine bolt size
and threads per inch |
|
A |
The letters 'NC'
in '1/4-20 NC' indicates the bolt is __________. |
threaded with
national coarse threads |
made of nickel-cadmium
metal |
made of non-corrosive
metal |
not clad with
any coating |
|
B |
Which of the following
types of nuts would be best suited to use when it is important that a nut
not work itself loose due to vibration? |
Square nut |
Castellated nut |
Cap nut |
Wing nut |
|
D |
Which figure shown
in the illustration, is the nut lock improperly used? Illustration GS-0156 |
"A" |
"B" |
"C"
and "D" |
"C"
and "E" |
|
D |
Which of the figures
in illustration GS-0080 would be used in conjunction with figure "C"
in illustration GS-0015? Illustration GS-0080 and GS-0015 |
figure A |
figure D |
figure F |
figure K |
|
D |
What class of
screw thread is indicated with a machine screw described as 1/2-13 NC-2? |
1/2 |
13 |
NC |
2 |
|
D |
Which of the following
is true when comparing the different "class of fit" for machine
threads on bolts and nuts? |
A class 1 fit
always has fewer threads per inch. |
A class 1 fit
is tighter than a class 2 fit. |
A class 4 fit
always has more threads per inch. |
A class 2 fit
is looser than a class 4 fit. |
|
B |
Which of the figures
illustrated would be LEAST desirable for use as a set screw? Illustration
GS-0080 |
figure G |
figure A |
figure F |
figure L |
|
D |
Which of the figures
illustrated is not suitable for use as a hex head set screw? Illustration
GS-0080 |
figure C |
figure G |
figure L |
figure D |
|
D |
With regards to
the American National Screw Thread nomenclature, 'pitch' is the __________. |
number of threads
divided by the length of the threaded portion of the screw |
angle of taper
formed by the centerline of the screw and the crests of the thread |
angle formed by
adjacent flanks of a thread |
distance between
corresponding points on adjacent threads |
|
A |
The locking plates
shown in the illustration are used in many marine applications. Which figure
indicates the improper method for using these devices? Illustration GS-0156 |
"C" |
"B" |
"D" |
"A" |
|
A |
Which of the figures
illustrated is known as an Allen head set screw? Illustration GS-0080 |
figure F |
figure G |
figure B |
figure C |
|
A |
Which of the figures
in illustration GS-0080 would be used in conjunction with figure "B"
of the device shown in illustration GS-0124? Illustrations GS-0080 and GS-0124 |
figure F |
figure C |
figure B |
figure G |
|
A |
When drilling
holes larger than 1/2 inch, drilling a smaller hole first is a good practice.
This is called a pilot hole, and the pilot drill should have a diameter
__________. |
slightly larger
than the web thickness of the larger drill |
smaller than the
dead center of chisel edge of the larger drill |
small enough to
ensure the maximum cut by the larger drill |
equal to at least
1/2 the diameter of the larger drill |
|
D |
Before boring
a blind tapered hole, a good shop practice to follow is to __________. |
drill to the large
diameter of the taper |
use a tapered
reamer |
bore a straight
hole |
drill to the small
diameter of the taper |
|
C |
All straight shank
twist drills must be mounted or held in a __________. |
tapered sleeve |
morse sleeve |
drill chuck |
drill socket |
|
A |
Generally speaking,
when using a twist drill to bore a hole in metal, the harder the metal,
the greater the drill's required __________. |
included point
angle |
cutting speed |
diameter |
lip clearance |
|
D |
Failing to decrease
the feed pressure on a drill as its point begins to break through the bottom
of the work piece will cause the drill to __________. |
break cleanly
through the bottom of the work piece |
form a tapered
hole in the bottom of the work piece |
cut an elongated
hole in the bottom of the work piece |
jam in the work
piece and tend to whirl it around |
|
C |
Which material
can be drilled at the highest speed? |
Copper |
High carbon steel |
Aluminum |
Medium cast iron |
|
A |
To drill a hole
in round stock, perpendicular to the axis of the piece, the stock should
be mounted in a __________. |
V-block |
morse sleeve |
clamp |
collet |
|
D |
When drilling
blind holes with a standard drill press, the proper method of stopping the
progress of the drill boring through the work is by __________. |
moving the working
table |
adjusting the
spindle return spring |
gaging chuck motion |
using a depth
stop |
|
D |
One of the steps
required to increase the drilling speed of a drill press is to __________. |
change the terminal
connections of the drive motor |
move the drive
belt to a smaller diameter motor pulley |
change to a larger
diameter spindle |
move the drive
belt to a smaller diameter spindle pulley |
|
B |
A tapered shank
drill is removed from the drill press spindle with a __________. |
vice grip |
drill drift |
leather mallet |
taper punch |
|
D |
Before drilling
a hole in a piece of metal, the location of the hole center should be __________. |
marked with chalk |
blued |
scribed |
center punched |
|
C |
Which of the listed
metals can usually be drilled without lubrication? |
Tungsten |
Steel |
Brass |
Monel |
|
D |
If the speed of
a drill is too great, the drill will __________. |
cut faster |
not cut |
cut slower |
rapidly dull |
|
A |
The tool shown
in the illustration is called a __________. Illustration GS-0072 |
center gage |
crotch center |
drill gage |
thread gage |
|
A |
The lathe tool
shown as figure "R" in the illustration would best be used to
__________. Illustration GS-0090 |
form a right-cut
square shoulder |
perform a right-cut
rough turning operation |
perform a left-cut
rough turning operation |
form a left-cut
groove |
|
D |
In machine shop
practice, a center gage is used for checking the angle of __________. |
drill points |
screw threads |
screw thread pitch |
60° thread cutting
tools |
|
B |
Which lathe tool
shown in the illustration would best be used on a work piece to perform
a right hand facing operation? Illustration GS-0090 |
V |
R |
Q |
P |
|
D |
The lathe tool
shown as figure "N" in the illustration is commonly known as a/an
__________. Illustration GS-0090 |
curling tool |
hurling tool |
furling tool |
knurling tool |
|
D |
The angle "A"
shown on the illustrated lathe tool bit is properly called the __________.
Illustration GS-0164 |
side relief angle |
side rake angle |
working relief
angle |
nose angle |
|
C |
Which of the following
statements represents the difference between a four-jaw independent chuck
and a three-jaw universal chuck? |
The jaws on the
three-jaw chuck can be individually adjusted. |
Since the three-jaw
universal chuck is automatically self-centering, it is always more accurate
than the four-jaw independent chuck. |
The jaws on the
four-jaw chuck can be individually adjusted. |
The three-jaw
chuck will hold square, round, and irregular shapes in either a concentric
or an eccentric position. |
|
D |
The lathe tool
shown as figure "U" in the illustration is commonly known as a/an
__________. Illustration GS-0090 |
universal turning
tool |
right side end
facing tool |
left cut side-facing
tool |
cutting-off tool |
|
A |
Which of the illustrated
lathe tools would be used to produce a smooth finish cut for figure I? Illustration
GS-0009 |
A |
D |
F |
G |
|
C |
The lathe tool
shown as figure "T" in the illustration is commonly known as a/an
__________. Illustration GS-0090 |
left-cut knurling
tool |
left-cut side-facing
tool |
right-cut roughing
tool |
right-cut side-facing
tool |
|
A |
The lathe tools
shown as figure "M" in the illustration are commonly known as
__________. Illustration GS-0090 |
form tools |
curvature cutting
tools |
parting tools |
universal turning
tools |
|
D |
Which single illustrated
lathe tool could be used to turn down the stock in figure II? Illustration
GS-0009 |
C |
G |
A |
B |
|
A |
The lathe tool
shown as "Q" in the illustration is a __________. Illustration
GS-0090 |
left hand side
facing tool |
right hand turning
tool |
cutting-off tool |
universal turning
tool |
|
B |
The main difference
between a common lathe dog and a safety lathe dog is that the latter __________. |
is more easily
centered |
has a headless
set screw |
has a spring loaded
catch |
allows for misaligned
center holes |
|
C |
Which of the illustrated
figures represents the use of a right hand roughing tool? Illustration GS-0090 |
Figure P |
Figure V |
Figure T |
Figure S |
|
C |
If the distances "A"
and/or "B" as shown in the illustration are excessively increased,
the tool will __________. Illustration GS-0085 |
take a deeper
cut in the work |
take a shallow
cut |
chatter |
slip in the tool
post |
|
A |
Which of the lathe
operations listed is best done with the carriage locked in position? |
Facing work held
in a chuck. |
Threading internal
threads. |
Boring an angled
hole. |
Turning work held
between centers. |
|
C |
To properly cut
even numbered threads using the lathe thread dial indicator shown in the
illustration, you should close the lathe split or half-nut on __________.
Illustration GS-0084 |
even numbered
lines only |
odd numbered lines
only |
any line on the
dial |
any unnumbered
half line |
|
D |
Which of the following
statements best defines 'depth of cut' in lathe work? |
The chip length
that will be removed from the work in 1 minute. |
The distance to
tool point advances with each revolution of the work. |
The distance the
work piece circumference moves past the cutting tool point in 1 minute. |
The distance from
the bottom of the cut to the uncut surface of the work piece. |
|
A |
To properly cut
an odd numbered thread with a lathe using the thread dial indicator illustrated,
you should close the lathe split, or half-nut on __________. Illustration
GS-0084 |
any numbered line
on the dial |
even numbered
lines only |
odd numbered lines
only |
any line on the
dial |
|
C |
The taper produced
by a lathe taper attachment is determined by setting the __________. |
automatic cross
feed |
compound rest
angle |
guide (swivel)
bar |
tailstock off
center |
|
C |
Before power to
a lathe is turned on, it is a good shop practice to first hand feed the
carriage to ensure __________. |
the work piece
is secure in the lathe |
the carriage is
lubricated |
all locking devices
have been released |
the lathe is level |
|
C |
To obtain a 1/2
inch per foot taper on an 18 inch work piece, the tailstock of the lathe
must be set over __________. |
3/4 inch |
7/8 inch |
3/8 inch |
1/2 inch |
|
D |
Which of the following
definitions accurately describes 'tool feed' when referring to lathe work? |
The distance the
work piece circumference moves past the cutting tool point in one minute. |
The chip length
that will be removed from the work in one minute. |
The distance from
the bottom of the cut to the uncut surface of the work piece. |
The distance the
tool advances with each revolution of the work. |
|
C |
If you are machining
work held between lathe centers, and the lathe centers begin to squeal,
you should first __________. |
change the cutting
bit |
run the lathe
at a slower speed |
stop the lathe |
lubricate the
centers |
|
A |
For proper support
when turning a long thin piece of work between lathe centers, you should
use a __________. |
steady rest |
draw-in collet
chuck |
faceplate |
compound rest |
|
C |
A follower rest
should be used with a lathe to machine __________. |
work mounted on
the lathe carriage |
large diameter
stock between centers |
threads on long
slender shafts |
round stock to
a finished dimension |
|
B |
Work that cannot
readily be mounted between lathe centers is usually held in a __________. |
crotch center |
chuck |
spindle |
lathe dog |
|
B |
A workpiece has
been mounted between centers and a test cut machined at each end to check
alignment of the lathe centers. If the test cut on the tailstock end is
deeper than the test cut on the headstock end, the tailstock must be moved
__________. |
toward you to
correct alignment |
away from you
to correct alignment |
closer to the
headstock to reduce the amount of offset |
away from the
headstock to decrease the misalignment |
|
A |
Hydraulically,
servo-operated, automatic, change over valves, utilized in a two ram hydraulic
steering gear, serve to __________. |
prevent either
main pump from being hydraulically motored when idle by cross pressure flow |
prevent both units
from operating simultaneously which could result in doubling the flow of
oil and pressure leading to over pressurization of the system |
allow an alternate
main pump to start in the fully loaded condition thus developing immediate
full torque |
All of the above. |
|
B |
The rudder torque
capacity of the four ram steering gear illustrated is rated at 44,210,000
inch-pounds with one power unit in operation. If the four ram system was
able to be operated as a two ram system with both power units on line, what
would be the available torque? Illustration GS-0067 |
11,052,500 inch
pounds |
22,105,000 inch
pounds |
44,210,000 inch
pounds |
88,420,000 inch
pounds |
|
B |
The device shown
in the illustration is a/an __________. Illustration GS-0116 |
mechanical shaft
seal |
vane type steering
gear |
diesel engine
motor mount |
oil scraper ring
stuffing box for a crosshead engine |
|
C |
If it is necessary
to prevent the rudder from moving while a repair is made on the steering
system using the illustrated actuator __________. Illustration GS-0116 |
tighten the locking
screws in item "S" |
tighten the locking
pins, item "H" at each position of item "I" to keep
the rudder from swinging |
secure the valves
in the supply and return lines |
screw in the locking
pin, item "J" |
|
A |
In the illustrated
schematic, the device used to replace the six-way valve, as found on many
older type steering gears, is the component labeled as __________. Illustration
GS-0123 |
"A" |
"B" |
"F" |
"H" |
|
A |
Rudder position
is shown on the bridge by the __________. |
rudder angle indicator |
follow-up gear |
telemotor position |
Rapson slide indicator |
|
B |
Hydraulically,
servo-operated, automatic, change over valves, utilized in a two ram hydraulic
steering gear, serve to __________. |
allow an alternate
main pump to start in the fully loaded condition thus developing immediate
full torque |
prevent either
main pump from being hydraulically motored when idle by cross pressure flow |
prevent both units
from operating simultaneously which could result in doubling the flow of
oil and pressure leading to over pressurization of the system |
All of the above. |
|
B |
The rudder torque
capacity of the four ram steering gear illustrated, is rated at 44,210,000
inch-pounds with one power unit in operation. If the four ram system was
able to be operated as a two ram system with both power units on line, what
would be the available torque? Illustration GS-0067 |
11,052,500 inch
pounds |
22,105,000 inch
pounds |
44,210,000 inch
pounds |
88,420,000 inch
pounds |
|
B |
When responding
to a 'right rudder' command from the amidships position, which parts of
the steering gear system illustrated will be subjected to the highest pressure?
Illustration GS-0137 |
"C"
and "F" |
"E"
and "B" |
"F"
and "E" |
"B"
and "C" |
|
B |
In an electro-hydraulic
steering system, damage due to rudder shock is prevented by __________. |
buffer springs |
relief valves |
oil flowing through
the pumps |
dashpots |
|
A |
The device shown
in the illustration is a/an __________. Illustration GS-0116 |
vane type steering
gear |
oil scraper ring
stuffing box for a crosshead engine |
diesel engine
motor mount |
mechanical shaft
seal |
|
A |
If it is necessary
to prevent the rudder from moving while a repair is made on the steering
system using the illustrated actuator __________. Illustration GS-0116 |
secure the valves
in the supply and return lines |
screw in the locking
pin, item "J" |
tighten the locking
pins, item "H" at each position of item "I" to keep
the rudder from swinging |
tighten the locking
screws in item "S" |
|
B |
The operation
of the device shown in the illustration is dependent upon __________. Illustration
GS-0116 |
all items, similar
to "I" move as the rudder stock rotates |
all items, similar
to "N" move as the rudder stock rotates |
both "I"
and "N" move as the rudder stock rotates |
neither "I"
nor "N" move as the rudder stock rotates |
|
C |
Hydraulically,
servo-operated, automatic, change over valves, utilized in a two ram hydraulic
steering gear, serve to __________. |
allow an alternate
main pump to start in the fully loaded condition thus developing immediate
full torque
o |
prevent both units
from operating simultaneously which could result in doubling the flow of
oil
and pressure leading to over pressurization of the system |
prevent either
main pump from being hydraulically motored when idle by cross pressure flow |
All of the above. |
|
C |
If oil under pressure
is supplied to the area noted as "N" on the vane in the illustration
__________. Illustration GS-0116 |
"O"
will be hydraulically locked in place even though oil is returned to the
main pump from the area between "M" and "I" |
"O"
will rotate clockwise as oil is returned from the area between "M"
and "I" |
"O"
will rotate counter-clockwise as oil is returned from the area between "M"
and "I" |
"Q"
will rotate counter-clockwise as oil is returned from the area between "M"
and "I" |
|
A |
The action necessary
to use the steering gear room trick wheel when transferring the steering
control from the wheelhouse to local control, is to __________. |
align the trick
wheel to the rudder angle position before engaging |
set the six-way
control valve in the trick wheel position |
open the power
transfer switch before engaging the trick wheel |
always place the
rudder in the midship position to engage the trick wheel |
|
A |
A command signal
input to the steering gear has initiated rudder movement for 20° right rudder.
The follow-up mechanism at the beginning of the rudder movement will __________.
GS-0123 Illustration GS-0123 |
be in motion with
a null input |
not be in motion,
thus a null input |
be in motion providing
an input to place the variable stroke pump on maximum stroke |
be in motion providing
an input to place the variable stroke pump at null stroke |
|
A |
Rudder position
is shown on the bridge by the __________. |
rudder angle indicator |
follow-up gear |
telemotor position |
Rapson slide indicator |
|
C |
When the helm
angle position is changed, the series of corresponding events of the steering
gear will include __________.
{{{
I. rate of steering gear ram movement will be proportional to amount of
helm angle input
II. degree of tilting plate (box) angle will be proportional to the amount
of helm angle input}}} |
I only |
II only |
Both I and II |
Neither I nor
II |
|
D |
In order for heat
transfer to take place between two substances, what essential condition
must exist? |
The two substances
must be of different state of matter. |
The two substances
must be of different specific gravity. |
The two substances
must be of different pressure. |
The two substances
must be of different temperature. |
|
B |
What mode of heat
transfer is associated with the transport of thermal energy from one location
to another by fluid in motion? |
Sublimation |
Convection |
Radiation |
Conduction |
|
B |
What mode of heat
transfer is associated with the transport of thermal energy within a body
or between two bodies in direct contact? |
Radiation |
Conduction |
Sublimation |
Convection |
|
C |
What mode of heat
transfer is associated with the transport of thermal energy through a transparent
medium by means of electro-magnetic energy in the infrared spectrum? |
Conduction |
Sublimation |
Radiation |
Convection |
|
D |
Overall heat transfer
processes often involve two or more modes of heat transfer. Specifically,
when heat is being transferred from one side of an air compressor cylinder
wall to the opposite side, what mode of heat transfer is associated with
that particular part of the overall process? |
Radiation |
Natural convection |
Forced convection |
Conduction |
|
D |
What statement
is true concerning the heat transfer rates through a heat exchanger boundary
wall by conduction? |
Heat transfer
rates are inversely proportional to the temperature gradient across the
wall, and directly proportional to the area of the wall and the wall thickness. |
Heat transfer
rates are inversely proportional to the temperature gradient across the
wall and the area of the wall, and directly proportional to the wall thickness. |
Heat transfer
rates are directly proportional to the temperature gradient across the wall,
and inversely proportional to the area of the wall and the wall thickness. |
Heat transfer
rates are directly proportional to the temperature gradient across the wall
and the area of the wall, and inversely proportional to the wall thickness. |
|
A |
What statement
is true concerning heat transfer rates by the heat transfer mode of natural
convection? |
Heat transfer
rates are directly proportional to the difference in fluid densities which,
in turn, is directly proportional to the temperature gradient. |
Heat transfer
rates are inversely proportional to the difference in fluid densities which,
in turn, is directly proportional to the temperature gradient. |
Heat transfer
rates are directly proportional to the difference in fluid densities which,
in turn, is inversely proportional to the temperature gradient. |
Heat transfer
rates are inversely proportional to the difference in fluid densities which,
in turn, is inversely proportional to the temperature gradient. |
|
D |
What statement
represents the first law of thermodynamics? |
When heat is transferred
from one body to another, the internal energy given up by the first body
must be exceed the internal energy taken up by the second body. |
When heat is transferred
from one body to another, there is no mathematical relationship between
the internal energy given up by the first body and the internal energy taken
up by the second body. |
When heat is transferred
from one body to another, the internal energy given up by the first body
must be less than the internal energy taken up by the second body. |
When heat is transferred
from one body to another, the internal energy given up by the first body
must be equal to the internal energy taken up by the second body. |
|
C |
What statement
is true concerning the internal energy of a substance? |
The internal potential
and kinetic molecular energies of a substance is a function of the state
of matter of the substance, whereas the internal potential and kinetic molecular
energies of a substance are in no way related to the temperature of a substance.
o |
The internal potential
and kinetic molecular energies of a substance is a function of the temperature
of the substance, whereas the internal potential and kinetic molecular energies
of a substance are in no way related to the state of matter of a substance. |
The internal potential
molecular energy of a substance is a function of the state of matter of
the substance, whereas the internal kinetic molecular energy of a substance
is a function of the temperature of the substance. |
The internal potential
molecular energy of a substance is a function of the temperature of the
substance, whereas the internal kinetic molecular energy of a substance
is a function of the state of matter of the substance. |
|
C |
What statement
represents the second law of thermodynamics? |
When heat is transferred
from one body to another, the direction of heat flow is uni-directional
from the relatively cold body to the relatively hot body. |
When heat is transferred
from one body to another, the direction of heat flow between the two bodies
is unpredictable. |
When heat is transferred
from one body to another, the direction of heat flow is uni-directional
from the relatively hot body to the relatively cold body. |
When heat is transferred
from one body to another, the direction of heat flow is bi-directional from
the relatively hot body to the relatively cold body and from the relatively
cold body to the relatively hot body. |
|
B |
If Boyles' law
describes the relationship between the pressure and volume of ideal gases,
what statement is true? |
If the temperature
remains constant, the volume of a given mass of gas is directly proportional
to its pressure. |
If the temperature
remains constant, the volume of a given mass of gas is inversely proportional
to its pressure. |
If the pressure
remains constant, the volume of a given mass of gas is directly proportional
to its temperature. |
If the pressure
remains constant, the volume of a given mass of gas is inversely proportional
to its temperature. |
|
C |
If Charles' law
describes the relationship between the temperature and volume of ideal gases,
what statement is true? |
If the pressure
remains constant, the volume of a given mass of gas is inversely proportional
to its temperature.
o |
If the temperature
remains constant, the volume of a given mass of gas is inversely proportional
to its pressure. |
If the pressure
remains constant, the volume of a given mass of gas is directly proportional
to its temperature. |
If the temperature
remains constant, the volume of a given mass of gas is directly proportional
to its pressure. |
|
D |
What term is defined
as the quantity of heat necessary to raise the temperature of a unit mass
of a substance one degree? |
Specific volume |
Specific gravity |
Latent heat |
Specific heat |
|
C |
What statement
represents the ideal gas law? |
For a given mass
of a gas, the volume is inversely proportional to its pressure and inversely
proportional to its temperature.
|
For a given mass
of a gas, the volume is directly proportional to its pressure and directly
proportional to its temperature. |
For a given mass
of a gas, the volume is inversely proportional to its pressure and directly
proportional to its temperature. |
For a given mass
of a gas, the volume is directly proportional to its pressure and inversely
proportional to its temperature. |
|
D |
What term is defined
as the amount of heat required to convert a unit mass of a substance from
a liquid to a vapor at constant temperature and pressure? |
Latent heat of
fusion |
Specific heat
of vaporization |
Sensible heat
of vaporization |
Latent heat of
vaporization |
|
A |
What term is defined
as the rate of doing work? |
Power |
Kinetic energy |
Mechanical work |
Potential energy |
|
B |
What statement
is true concerning thermal energy in transition? |
Thermal energy
in transition is called heat which is the result of a temperature difference.
The resulting heat flow may produce two possible outcomes. Sensible heat
transfer results in a change of state of the substance. Latent heat transfer
results in a change of temperature of the substance. |
Thermal energy
in transition is called heat which is the result of a temperature difference.
The resulting heat flow may produce two possible outcomes. Sensible heat
transfer results in a change of temperature of the substance. Latent heat
transfer results in a change of state of the substance. |
Thermal energy
in transition is called heat which is the result of differences in state.
The resulting heat flow may produce two possible outcomes. Sensible heat
transfer results in a change of temperature of the substance. Latent heat
transfer results in a change of state of the substance. |
Thermal energy
in transition is called heat which is the result of differences in state.
The resulting heat flow may produce two possible outcomes. Sensible heat
transfer results in a change of state of the substance. Latent heat transfer
results in a change of temperature of the substance. |
|
B |
Which of the following
types of files is generally used for finishing? |
A double cut file |
A single cut file |
Any bastard cut
file |
Only a double
bastard cut file |
|
B |
Pushing the file
endways (or with the axis), under pressure, against the work, is called
__________. |
standard form
filing |
cross filing |
draw filing |
stroke filing |
|
A |
It is necessary
to 'chalk' a file when the metal you are filing is __________. |
aluminum |
monel |
mild steel |
stainless steel |
|
B |
Double cut files
are most effective when used for __________. |
finish work |
rough work |
draw filing |
sharpening tools |
|
C |
Which of the listed
types of files is the best for producing a fine finish on metal? |
Float |
Second cut |
Mill |
Warding |
|
B |
A metal file has
become clogged with filings and should be cleaned with a file __________. |
scraper |
card |
dressing tool |
oilstone |
|
A |
A file handle
is fitted to the file's __________. |
tang |
taper |
point |
heel |
|
C |
Heavy pressure
on the ends of a file will cause the work surface to become __________. |
smooth |
rough |
rounded |
tapered |
|
D |
A new file should
be broken in carefully by filing a piece of. |
monel stock using
heavy pressure |
brass stock using
heavy pressure |
stainless steel
stock using light pressure |
bronze stock using
light pressure |
|
A |
Which of the files
listed is tapered on all sides and used to enlarge rectangular- shaped holes
and slots? |
Square |
Round |
Half round |
None of the above |
|
D |
The terms rough,
coarse, bastard, second cut, smooth, and dead smooth refer to the __________. |
distance between
the parallel cuts of a file |
size of the file |
coarseness of
file teeth |
Both A and C are
correct. |
|
B |
To cut angle iron
and heavy pipe with a hand hacksaw, you should use a blade with what number
of teeth per inch? |
32 |
24 |
18 |
14 |
|
A |
A saw blade produced
of bonded tungsten-carbide particles and mounted in a hacksaw frame is known
as a __________. |
rod saw blade |
hardened blade |
flexible blade |
wave set blade |
|
B |
A hacksaw blade
will break if __________. |
the blade becomes
loose in the frame |
all the above |
the rate of cutting
is too great |
too much pressure
is applied to the blade |
|
D |
To properly install
a new blade in a hand hacksaw frame, the __________. |
teeth should point
toward the handle |
blade can be installed
in any position for normal use |
blade should be
kept loose in the frame |
teeth should point
away from the handle |
|
C |
Proper hacksaw
cutting is accomplished when pressure is applied only on the __________. |
front of the hacksaw
frame |
backward stroke |
forward stroke |
top of the hacksaw
frame |
|
A |
A hacksaw blade
will start a cut more easily if you __________. |
file a nick where
the cut is to be started |
turn the saw blade
at right angles to the saw frame |
coat the saw blade
with soap before starting the cut |
apply maximum
pressure at the start of the cut |
|
A |
When coming to
the end of a cut using a hand hacksaw, you should __________. |
reduce cutting
speed and pressure |
increase cutting
speed and pressure |
change to a finer
cut blade |
stop applying
the cutting fluid |
|
B |
The term referring
to the number of teeth per inch on a hacksaw blade is known as the __________. |
set |
pitch |
rake |
thread gauge |
|
B |
When using a hand
held hacksaw the correct maximum rate of speed for cutting should be __________. |
70 to 80 strokes
per minute |
40 to 50 strokes
per minute |
10 to 20 strokes
per minute |
80 to 100 strokes
per minute |
|
D |
When cutting sheet
metal too thin to be held in your hand while using a hand held hacksaw,
the sheet metal should be placed between two __________. |
pieces of sand
paper |
pieces of cloth |
blocks of steel |
blocks of wood |
|
B |
Which of the saws
listed would be more suitable for cutting metal in tight quarters or flush
to a surface where a hand held hacksaw frame could not be used? |
Coping saw |
Stab saw |
Hole saw |
Back saw |
|
D |
The open end wrench
size for a 3/4 inch American National Standard hex head machine bolt is
__________. |
1 1/2 inches |
3/4 inch |
7/8 inch |
1 1/4 inches |
|
B |
Needle nosed pliers
are best used to __________. |
tighten electrical
wire clamps |
grasp items positioned
in tight places |
cut recessed cotter
pins |
strip insulation
from electric wire or cable |
|
B |
Which of the wrenches
listed practically eliminates the possibility of its slipping off while
tightening a nut or bolt?
|
Open end wrench |
Box end wrench
o |
Crescent wrench
o |
Monkey wrench |
|
C |
Open end wrenches
are __________. |
intended for gripping
round objects |
used with a speeder
handle |
nonadjustable
solid wrenches |
not suitable for
tubing fittings |
|
B |
In order to tighten
the bolts of a crankpin bearing to the exact tension specified by the engine
manufacturer, you should use a/an __________. |
offset box end |
torque wrench |
dial wrench |
hook spanner |
|
B |
A pipe, or Stillson
wrench functions best when __________. |
the wrench jaws
are at the widest open setting |
the bite is taken
midway up the jaw teeth |
a maximum pull
is exerted with one hand |
an extension is
placed on the wrench handle |
|
B |
Large size pipe
can be easily rotated with a __________. |
strong back |
chain pipe wrench |
basin wrench |
monkey wrench |
|
D |
When using a chisel,
you should __________. |
wear gloves |
be certain it
is a nonsparking type |
hold the tool
lightly |
wear safety glasses |
|
B |
The best type
of chisel to use for cutting a keyway is the __________. |
round nose chisel |
cape chisel |
flat cold chisel |
diamond point
chisel |
|
A |
A chisel with
a mushroom head should not be used because __________. |
pieces may fly
off the chisel and injure your eyes |
it must be held
firmly by the head to strike it |
the chisel cannot
be struck squarely |
the hammer head
may be chipped |
|
D |
The temper is
likely to be drawn out from a chisel edge when you __________. |
soak it in hot
oil for lengthy periods |
hold it next to
a wet grinding wheel |
grind the cutting
angle too small |
grind it for long
periods of time with excessive pressure |
|
A |
What precautions
should be followed when using a chisel having a mushroomed head? |
Remove the ragged
edges by grinding. |
Knock off the
ragged edges with a hammer. |
Use only light
hammer blows with the chisel. |
Do not strike
the mushroomed portion. |
|
C |
Which of the chisels
listed should be used for cutting oil grooves? |
Square nose |
Diamond point |
Round nose |
Flat cold |
|
A |
Diamond point
chisels are best used for cutting __________. |
V-grooves and
inside sharp angles |
oil grooves in
bearings |
keyways having
square corners |
holes through
metal plate |
|
B |
Which of the listed
punches can be properly used to free a tapered pin 'frozen' in its hole? |
Prick punch |
Drift punch |
Center punch |
Aligning punch |
|
A |
An aligning punch
is commonly used to __________. |
line up corresponding
holes in adjacent symmetrical parts |
tighten tapered
pins |
loosen jammed
bolts |
remove snap rings |
|
B |
Some heavy duty
screwdrivers are made with a square shank to __________. |
prevent the shank
from bending |
allow turning
with a wrench |
permit striking
with a hammer |
allow it to be
used as a pry bar |
|
C |
An offset screwdriver
is best used for __________. |
tightening Allen
head screws only |
tightening or
loosening "offset type" machine screws |
screws you cannot
reach with a straight shaft screwdriver |
driving self-tapping
screws only |
|
D |
Which of the screwdriver
tips listed will fit screws with a four-way or cross type slot? |
Standard screwdriver |
Phillips screwdriver |
Reed and Prince
screwdriver |
Both B and C are
correct |
|
D |
Which of the screwdrivers
listed has a tip surrounded by parallel fluted ridges resembling the ridges
of a splined socket wrench? |
Standard |
Reed and Prince |
Phillips |
Torx |
|
B |
Which type of
screwdriver listed would have a 'Keystone' type vertical cross-sectional
tip? |
Torx |
Standard |
Phillips |
Allen |
|
D |
Which of the screwdrivers
listed is designed for the precision assembly of small parts? |
Square-shanked |
Allen head |
Ratchet |
Jeweler's |
|
C |
Which of the screwdrivers
listed is fastest and most convenient when tightening many screws? |
Square shank |
Offset |
Ratchet |
Standard |
|
C |
Which of the screwdrivers
listed is designed with the shaft made from double coil wire or tightly
coiled steel? |
Square shank |
Jeweler's |
Flexible shaft |
Ratchet |
|
A |
Screwdrivers designed
for electrical use should have __________. |
insulated handles |
larger than normal
shanks |
shorter than normal
shanks |
longer than normal
shanks |
|
B |
A grease gun is
generally used to lubricate a __________. |
main turbine bearing |
condensate pump
ball bearing |
diesel engine
wrist pin bearing |
generator crosshead
bearing |
|
A |
The tool best
suited for cutting pipeline flange gaskets to the correct size is __________. |
a gasket cutter |
a pair of tin
snips |
a jack knife |
a ball peen hammer |
|
C |
The best tool
to use when attempting to widen the opening of a flanged joint, in preparation
for renewing the gasket, is a __________. |
gasket cutter |
scraper |
flange spreader |
spud wrench |
|
C |
Ball peen hammers
are sized according to their __________. |
overall length |
face diameter |
head weight |
peen head size |
|
B |
Why should the
use of metallic or semi-metallic packing hooks or pullers be avoided on
bronze or brass shafts, rods, plungers, or sleeves? |
Bonnet corrosion
may result. |
Scoring may result. |
Valve seat will
be damaged. |
Heat transfer
is restricted. |
|
B |
The names plug,
bottom, and taper refer to __________. |
pipe fittings |
machinist's hand
taps |
measuring instruments |
drill press parts |
|
C |
If you are cutting
external threads by hand and you start the die at an angle, the threads
will __________. |
straighten out
after the third revolution |
be out of round
on the work |
be cut crooked
on the work |
be rough, weak,
and easily broken |
|
B |
With respect to
machine shop "taps and dies", a plug tap is correctly used for
__________. |
reversing the
threads in a hole |
the second cut
when threading a blind hole |
chasing the threads
on a circular rod |
starting the threads
on a circular rod |
|
D |
If you are hand
tapping holes in cast iron, you should __________. |
start tapping
with a plug tap |
chamfer the edges
of the holes |
flood the tap
with mineral oil |
tap the holes
without cutting oil |
|
C |
If a bolt or stud
were to break off flush at the surface, which of the listed actions would
probably be the best first step to begin the process of its removal? |
Use a tapered
screw extractor only. |
Heat the bolt
with an oxyacetylene torch. |
Drill a hole in
the center of the broken stud. |
Tap the bolt with
a starting punch extractor. |
|
A |
The proper tool
used for cutting new external threads is called a thread __________. |
die |
chaser |
tap |
broach |
|
A |
When internal
threading for piping where the work permits the tap to be run entirely through
you can begin and end the tapping of the hole by using a __________. |
taper tap |
bottoming tap |
plug tap |
finishing tap |
|
D |
With regards to
the American National Screw Thread nomenclature, 'pitch' is the __________. |
angle of taper
formed by the centerline of the screw and the crests of the thread |
angle formed by
adjacent flanks of a thread |
number of threads
divided by the length of the threaded portion of the screw |
distance between
corresponding points on adjacent threads |
|
A |
When should the
nut lock shown in the illustration, be replaced with standard lock washers
or other similar devices used in the industry? Illustration GS-0156 |
Replacement with
another nut locking device is unnecessary. |
Flat locks are
no longer used in the marine industry and should be replaced during the
next maintenance procedure. |
Bellevue washers
are the ideal substitute for these locking devices provided a thread locking
adhesive is used. |
When torque values
of 25 foot pounds or greater are being used, replacement with spring washers
is mandatory. |
|
C |
Which of the figures
illustrated would be LEAST desirable for use as a set screw? Illustration
GS-0080 |
figure L |
figure G |
figure A |
figure F |
|
D |
Which of the figures
illustrated is not suitable for use as a hex head set screw?
Illustration GS-0080 |
figure G |
figure L |
figure C |
figure D |
|
C |
Which of the figures
in illustration would be used in conjunction with figure "B" of
the device shown in illustration GS-0124? |
figure G |
figure B |
figure F |
figure C |
|
C |
The device "F"
shown in the illustration is best used to __________. Illustration GS-0080 |
secure tapered
pins in position |
fasten pump casing
flanges together |
assist in securing
a coupling half to its shaft |
bolt motor frames
to bedplates |
|
A |
The number of
screw threads per inch for a Standard National Coarse 1/2 inch bolt is __________. |
13 |
18 |
16 |
20 |
|
A |
The letters 'NC'
in '1/4-20 NC' indicates the bolt is __________. |
threaded with
national coarse threads |
made of nickel-cadmium
metal |
made of non-corrosive
metal |
not clad with
any coating |
|
B |
Which of the following
types of nuts would be best suited to use when it is important that a nut
not work itself loose due to vibration? |
Cap nut |
Castellated nut |
Wing nut |
Square nut |
|
D |
The locking plates
shown in the illustration are used in many marine applications. Which figure
indicates the improper method for using these devices? Illustration GS-0156 |
"A" |
"D" |
"B" |
"C" |
|
B |
What is the primary
function of the devices shown in the illustration? Illustration GS-0156 |
The transit washers
transmit the rotary motion of the cap screw to the actuating assembly. |
The locking plates
are used to prevent the fastening devices from vibrating loose. |
The grounding
straps help prevent electrolysis by improving the conductivity between the
components. |
These abrasion
resistors prevent damage to the surface around the bolt holes when tightening
the bolts. |
|
D |
A metal scribe
commonly found on a Combination Square measuring tool should only be used
to __________. |
clean file teeth |
punch gasket holes |
remove packing |
mark on metal |
|
C |
Which of the instruments
listed is used to measure the gauge of a piece of sheet metal? |
Inside micrometer |
Circular mil |
Wire gauge |
Gauge calibrator |
|
C |
The purpose of
the instrument illustrated is to __________. Illustration GS-0079 |
gage resistors |
strip insulation
from wire |
measure wire diameter |
measure insulation
thickness |
|
B |
Which of the devices
shown in the illustration should be used with a bridge gage? Illustration
GS-0073 |
C |
A |
B |
D |
|
B |
The center head
of a combination square set is used to __________. |
check the angle
of thread cutting tools |
locate the center
on round stock |
find right angles |
check degrees
of angle |
|
B |
To get an accurate
measurement using a 12 inch machinist's steel rule, you should measure __________. |
on the unmarked
edge of the rule |
from the one inch
graduation mark |
on the narrow
edge of the rule |
from the zero
end on the scale |
|
B |
To set the dividers
to the proper radius, you should use a __________. |
calipers |
steel rule |
micrometer |
scribing circle |
|
A |
A dial indicator
is used to measure __________. |
shaft eccentricity |
torque of a shaft |
scribed layout
lines on vertical surfaces |
positive readings
only |
|
D |
Which of the devices
shown in the illustration is designed for both inside and outside measurements?
Illustration GS-0073 |
A |
D |
B |
C |
|
B |
To measure the
circumference of a piece of pipe, you should use a __________. |
hook rule |
flexible steel
rule |
folding rule |
machinist's steel
rule |
|
A |
A grinding wheel
is trued with a __________. |
dressing tool |
round file |
lathe tool |
garnet stone |
|
D |
Which practices
should be followed at all times when using an electric grinding machine? |
Wear goggles or
face shield. |
Be certain that
the frame is properly grounded. |
Be properly trained
in the use of this tool. |
Each of the above
practices. |
|
B |
A coolant is usually
used when cutting metal in a power hacksaw to prevent the __________. |
heat of friction |
blade from overheating |
cut from clogging |
blade from bending |
|
D |
The blade for
a power hacksaw should be installed with the teeth __________. |
pointing toward
the motor if using a 4 or 6 tooth blade and away from the motor if using
a 10 or 14 tooth blade |
pointing either
toward or away from the motor end of the machine |
pointing away
from the motor end of the machine |
pointing toward
the motor end of the machine |
|
A |
All portable electric
tools should have a ground connection to prevent __________. |
electric shock
if the tool is shorted |
grounding the
plastic case through a short |
burning out the
motor from an overload |
overloading the
motor from a short |
|
C |
The ability of
a metal to be hammered, or rolled out is called its __________. |
ductibility |
elasticity |
malleability |
fusibility |
|
D |
Reheating a hardened
component to a temperature lower than the hardening temperature and then
cooling it is known as __________. |
case hardening |
low temperature
hardening |
annealing |
tempering |
|
D |
When hardened
metal is heat-treated by a process known as tempering, what metallurgical
properties are achieved? |
increase in brittleness |
increase in corrosion
resistance |
increase in hardening |
decrease in brittleness |
|
D |
The purpose of
annealing any metal is to make the metal __________. |
tougher |
harder |
smoother |
softer |
|
D |
Ferrous metals
are metals containing __________. |
a large percentage
of copper |
no iron |
a large percentage
of aluminum |
a large percentage
of iron |
|
C |
Which of the following
statements represents the difference between a four-jaw independent chuck
and a three-jaw universal chuck? |
The jaws on the
three-jaw chuck can be individually adjusted. |
Since the three-jaw
universal chuck is automatically self-centering, it is always more accurate
than the four-jaw independent chuck. |
The jaws on the
four-jaw chuck can be individually adjusted. |
The three-jaw
chuck will hold square, round, and irregular shapes in either a concentric
or an eccentric position. |
|
D |
The best tool
to use to measure the number of threads per inch on a bolt is a __________. |
pair of outside
calipers |
micrometer |
tap |
screw pitch gauge |
|
C |
A workpiece has
been mounted between centers and a test cut machined at each end to check
alignment of the lathe centers. If the test cut on the tailstock end is
deeper than the test cut on the headstock end, the tailstock must be moved
__________. |
closer to the
headstock to reduce the amount of offset |
toward you to
correct alignment |
away from you
to correct alignment |
away from the
headstock to decrease the misalignment |
|
D |
To commence cutting
threads with a metal lathe, you should engage the __________. |
feed-change lever |
back gear lever |
thread-chasing
dial |
split or half-nut |
|
D |
The 60° taper
angle machined on work supported by lathe centers is most easily machined
by the __________. |
taper attachment |
tailstock set
over method |
headstock set
over method |
compound rest |
|
D |
A tailstock 'dead
center' has been given that name because it __________. |
is dead centered
on the tailstock spindle |
must be removed
by clamping in the chuck |
fits into the
dead center of the work piece |
does not revolve |
|
C |
Which of the metals
listed below can be cut with the highest operating lathe speed? |
Cast iron |
Soft brass |
Aluminum |
Mild steel |
|
C |
If you are cutting
off a piece of stock in a lathe and the work piece tends to climb over the
top of the cutoff tool, you should __________. |
stop the lathe
and tighten the chuck |
increase the lathe
spindle speed |
increase the height
of the tool cutting edge |
stop the lathe
and lubricate the dead center |
|
A |
To properly cut
even numbered threads using the lathe thread dial indicator shown in the
illustration, you should close the lathe split or half-nut on __________.
Illustration GS-0084 |
any line on the
dial |
any unnumbered
half line |
odd numbered lines
only |
even numbered
lines only |
|
A |
To properly cut
an odd numbered thread with a lathe using the thread dial indicator illustrated,
you should close the lathe split, or half-nut on __________. Illustration
GS-0084 |
any numbered line
on the dial |
even numbered
lines only |
odd numbered lines
only |
any line on the
dial |
|
A |
When a lathe is
used for thread cutting, the number of threads per inch produced is determined
by the speed relationship between the __________. |
lead screw and
headstock spindle |
drive motor and
spindle |
spindle and feed
rod |
lead screw and
feed rod |
|
C |
If the distances "A"
and/or "B" as shown in the illustration are excessively increased,
the tool will __________. Illustration GS-0085 |
take a deeper
cut in the work |
slip in the tool
post |
chatter |
take a shallow
cut |
|
C |
Two separate work
pieces are to have a taper cut with the same taper per inch, using the offset
tailstock method. After the first piece is completed, the tailstock offset
must be changed if there is a change in the __________. |
diameter of the
work piece |
angle of the cutting
tool |
length of the
work piece |
none of the above |
|
C |
For proper support
when turning a long thin piece of work between lathe centers, you should
use a __________. |
compound rest |
draw-in collet
chuck |
steady rest |
faceplate |
|
D |
A follower rest
should be used with a lathe to machine __________. |
round stock to
a finished dimension |
large diameter
stock between centers |
work mounted on
the lathe carriage |
threads on long
slender shafts |
|
D |
Work that cannot
readily be mounted between lathe centers is usually held in a __________. |
spindle |
lathe dog |
crotch center |
chuck |
|
C |
The taper produced
by a lathe taper attachment is determined by setting the __________. |
automatic cross
feed |
tailstock off
center |
guide (swivel)
bar |
compound rest
angle |
|
C |
To obtain a 1/2
inch per foot taper on an 18 inch work piece, the tailstock of the lathe
must be set over __________. |
3/4 inch |
7/8 inch |
3/8 inch |
1/2 inch |
|
C |
Which single illustrated
lathe tool could be used to turn down the stock in figure II? Illustration
GS-0009 |
C |
A |
B |
G |
|
C |
The lathe tool
shown as figure "R" in the illustration would best be used to
__________. Illustration GS-0090 |
perform a left-cut
rough turning operation |
form a left-cut
groove |
form a right-cut
square shoulder |
perform a right-cut
rough turning operation |
|
D |
The lathe tool
shown as figure "T" in the illustration is commonly known as a/an
__________. Illustration GS-0090 |
left-cut knurling
tool |
right-cut side-facing
tool |
left-cut side-facing
tool |
right-cut roughing
tool |
|
C |
The lathe tools
shown as figure "M" in the illustration are commonly known as
__________. Illustration GS-0090 |
universal turning
tools |
parting tools |
form tools |
curvature cutting
tools |
|
D |
The lathe tool
shown as figure "N" in the illustration is commonly known as a/an
__________. Illustration GS-0090 |
curling tool |
hurling tool |
furling tool |
knurling tool |
|
A |
The angle "A"
shown on the illustrated lathe tool bit is properly called the __________.
Illustration GS-0164 |
nose angle |
working relief
angle |
side rake angle |
side relief angle |
|
B |
In machine shop
practice, a center gage is used for checking the angle of __________. |
drill points |
60° thread cutting
tools |
screw threads |
screw thread pitch |
|
B |
Which lathe tool
shown in the illustration would best be used on a work piece to perform
a right hand facing operation? Illustration GS-0090 |
V |
R |
Q |
P |
|
B |
If you are machining
work held between lathe centers, and the lathe centers begin to squeal,
you should first __________. |
run the lathe
at a slower speed |
stop the lathe |
change the cutting
bit |
lubricate the
centers |
|
C |
The lathe tool
shown as "Q" in the illustration is a __________. Illustration
GS-0090 |
cutting-off tool |
universal turning
tool |
left hand side
facing tool |
right hand turning
tool |
|
A |
The tool shown
in the illustration is called a __________. Illustration GS-0072 |
center gage |
crotch center |
thread gage |
drill gage |
|
C |
The main difference
between a common lathe dog and a safety lathe dog is that the latter __________. |
allows for misaligned
center holes |
has a spring loaded
catch |
has a headless
set screw |
is more easily
centered |
|
C |
Which of the illustrated
figures represents the use of a right hand roughing tool? Illustration GS-0090 |
Figure S |
Figure V |
Figure T |
Figure P |
|
C |
The lathe tool
shown as figure "U" in the illustration is commonly known as a/an
__________. Illustration GS-0090 |
left cut side-facing
tool |
right side end
facing tool |
cutting-off tool |
universal turning
tool |
|
A |
Which of the illustrated
lathe tools would be used to produce a smooth finish cut for figure I? Illustration
GS-0009 |
A |
F |
G |
D |
|
B |
To determine the
diameter of a small hole, which of the listed tools must be used with inside
calipers to get an accurate reading? |
None of the above |
Micrometer |
A Center gage |
Wire gage |
|
B |
For greater accuracy,
some micrometers have a vernier scale making it possible to read in increments
of __________. |
five thousands
of an inch |
ten thousands
of an inch |
twenty five thousands
of an inch |
one fortieth of an inch |
|
B |
Many micrometers
are equipped with a ratchet stop at the end of the thimble to __________. |
click at each
increment of measure |
prevent the user
from closing the tool with too much force |
stop the spindle
from sliding out of the barrel |
eliminate ratchet
movement |
|
D |
The reading on
the micrometer scale shown in figure "D" in the illustration is
__________. Illustration GS-0081 |
0.4710 inch |
0.4715 inch |
0.4810 inch |
0.4815 inch |
|
B |
The reading on
the vernier caliper scale shown in figure "G" in the illustration
is __________. Illustration GS-0082 |
2.308 inches |
2.368 inches |
2.380 inches |
2.965 inches |
|
C |
What is the reading
of the vernier micrometer caliper scale shown in figure "G" in
the illustration? Illustration GS-0083 |
0.2280 inch |
0.2340 inch |
0.2470 inch |
0.2520 inch |
|
A |
A reading of 0.625
inch on a micrometer with a 2 to 3 inch range would be equal to __________. |
2 5/8 inches |
2 7/16 inches |
3 1/8 inches |
3 9/16 inches |
|
C |
To measure the
diameter of a piece of round stock, you should use a __________. |
dial indicator |
wire gauge |
micrometer |
circular slide
rule |
|
C |
To check the thickness
of a piece of thin shim stock before using it to make a bearing shim, you
should use a __________. |
machinist's rule |
feeler gage |
micrometer |
depth gage |
|
D |
The correct torque
value for a micrometer torque wrench is reached when __________. |
a dial lights
on the handle |
the scale is read
on the handle |
the dial is read
on the handle |
an audible click
is heard and the handle releases |
|
A |
The rotating part
of a micrometer is the known as the __________. |
thimble |
frame |
sleeve |
anvil |
|
B |
If a micrometer
were opened to a distance of 0.0001 inch, you would say the reading is __________. |
ten millionths
of an inch |
one ten thousandth
of an inch |
one millionth
of an inch |
ten one thousandths
of an inch |
|
D |
A micrometer screw
has a pitch of __________. |
100 threads per
inch |
50 threads per
inch |
75 threads per
inch |
40 threads per
inch |
|
B |
One turn of the
micrometer barrel will linearly move the spindle __________. |
0.250 inch |
0.025 inch |
0.205 inch |
0.110 inch |
|
A |
The most accurate
method of measuring the setting of an inside caliper is to use a/an __________. |
outside micrometer |
dial indicator |
engineer's scale |
thread micrometer |
|
B |
Expansion tanks
when used in a ship's low temperature hot water heating system may be of
the open or closed type. In a closed type system, what would be the normal
temperature range of the water? |
180°F to 200°F |
220°F to 240°F |
260°F to 280°F |
320°F to 360°F |
|
A |
Expansion tanks
when used in a ship's low temperature hot water heating system may be of
the open or closed type. Referring to the illustrated central-station hookup
for a hot-water heating system drawing, what would be the normal temperature
range of the water? Illustration GS-0151 |
180⁰F to
200⁰F |
220⁰F to
240⁰F |
260⁰F to
280⁰F |
320⁰F to
360⁰F |
|
D |
Referring to the
illustrated diagram for a central-station hookup for a hot-water heating
system, what statement represents the configuration of the system? Illustration
GS-0151 |
The system is
a single zone system, with multiple circulating pumps and multiple heating
coils |
The system is
a multi-zone system, with multiple circulating pumps and multiple heating
coils. |
The system is
a single zone system, with one circulating pump and one heating coil. |
The system is
a multi-zone system, with one circulating pump and one heating coil. |
|
C |
What type of pump
is invariably used as a circulator in a hydronic heating system? |
Diaphragm pump |
Reciprocating
pump |
Centrifugal pump |
Rotary pump |
|
C |
Referring to the
illustrated drawing of the central-station hookup for a hot-water heating
system, what statement is true concerning the air separator on the heated
water outlet of the converter? Illustration GS-0151 |
The air separator
removes the entrained air introduced within the converter and ultimately
released by the expansion tank vent.
o |
The air separator
removes the entrained air introduced by the heating steam and ultimately
released by the condensate returns gravity draining to the atmospheric drains
tank. |
The air separator
removes the entrained air introduced with the makeup water at the expansion
tank and ultimately released by the heating process within the converter. |
The air separator
removes the entrained air introduced by the heated air via the zone return
lines and ultimately released by the heating process within the converter. |
|
D |
What statement
is true concerning a one-pipe hydronic heating system? |
Each heating coil
inlet temperature is different, as the hot water inlet temperature to each
heating coil progressively rises as the water passes through each successive
series-connected coil. |
Each heating coil
inlet temperature is identical, as the hot water inlet temperature to each
heating coil progressively rises as the water passes through each successive
series-connected coil. |
Each heating coil
inlet temperature is identical, as the hot water inlet temperature to each
heating coil progressively drops as the water passes through each successive
series-connected coil. |
Each heating coil
inlet temperature is different, as the hot water inlet temperature to each
heating coil progressively drops as the water passes through each successive
series-connected coil. |
|
B |
What statement
is true concerning a two-pipe hydronic heating system? |
Each heating coil
inlet temperature is identical, as each series-connected heating coil has
its own separate supply teeing off a supply main. |
Each heating coil
inlet temperature is identical, as each parallel-connected heating coil
has its own separate supply teeing off a supply main. |
Each heating coil
inlet temperature is different, as each series-connected heating coil has
its own separate supply teeing off a supply main. |
Each heating coil
inlet temperature is different, as each parallel-connected heating coil
has its own separate supply teeing off a supply main. |
|
B |
It is absolutely
essential that hydronic heating system hot water piping be kept free of
air. Assuming that a system is initially properly filled with water, what
is the primary source of air contamination? |
The introduction
of air with the convector steam supply. |
The introduction
of air via the makeup water. |
The introduction
of air via the expansion tank vent. |
The introduction
of air via the atmospheric drains tank vent. |
|
C |
What advantage
does a 4-pipe hydronic heating/cooling heating system have over a 2-pipe
hydronic heating/cooling system? |
A 4-pipe hydronic
heating/cooling system can serve twice as many zones as a 2-pipe hydronic
heating/cooling system.
|
A 4-pipe hydronic
heating/cooling system requires double the amount of piping as compared
to a 2-pipe hydronic heating/cooling system serving the same number of zones. |
A 4-pipe hydronic
heating/cooling system allows simultaneous heating and cooling of different
zones, whereas a 2-pipe hydronic heating/cooling system does not. |
A 4-pipe hydronic
heating/cooling system requires one-half the amount of piping as compared
to a 2-pipe hydronic heating/cooling system serving the same number of zones. |
|
A |
Which of the following
guidelines is considered to reflect good design practices for shipboard
steam heating systems? |
Provide a dirt
pocket and strainer ahead of the steam trap on a unit heater return. |
Provide all units
with a dirt trap and gate valve in the supply and a check valve on the return. |
Wherever possible
install vertical runs for condensate piping. |
Provide orifice-type
bypasses for all traps and automatic valves. |
|
A |
Concerning air-conditioning
system dry-expansion cooling coils, what statement is true? |
Dry expansion
cooling coils are usually the finned-coil type and horizontally installed. |
Dry expansion
cooling coils are usually the finned-coil type and vertically installed. |
Dry expansion
cooling coils are usually the bare-coil type and horizontally installed. |
Dry expansion
cooling coils are usually the bare-coil type and vertically installed. |
|
B |
Water hammer in
a steam heating system can be caused by __________. |
filling the auxiliary
boiler with cold water |
steam admitted
to a cold pipe |
filling the auxiliary
boiler with hot water |
draining a soot
blower line before cracking the steam supply valve |
|
B |
What type of fan
is most commonly used in ducted air-conditioning systems? |
Propeller fan |
Centrifugal fan |
Vane-axial fan |
Tube-axial fan |
|
B |
What type of centrifugal
fan is characterized by the highest operating efficiency? |
Forward-curved
blade fans |
Backward-curved
blade fans |
Flat blade fans |
Radial blade fans |
|
B |
What pressure
drop across an air conditioning filter is indicative of a need to replace
or clean the filter as appropriate? |
0.1 inches of
water column |
0.5 inches of
water column |
1.0 inches of
water column |
5.0 inches of
water column |
|
D |
Concerning air-conditioning
system steam heating coils, what statement is true? |
Steam heating
coils are usually the serpentine type and, if possible, vertically installed. |
Steam heating
coils are usually the header type and, if possible, horizontally installed. |
Steam heating
coils are usually the serpentine type and, if possible, horizontally installed. |
Steam heating
coils are usually the header type and, if possible, vertically installed. |
|
C |
Concerning air-conditioning
system hot-water heating coils, what statement is true? |
Steam heating
coils are usually the header type and vertically installed. |
Steam heating
coils are usually the header type and horizontally installed. |
Steam heating
coils are usually the serpentine type and horizontally installed. |
Steam heating
coils are usually the serpentine type and vertically installed. |
|
C |
What type of heating
coil is generally preferred in heating spaces with electronic equipment? |
Hot-water heating
coil |
Steam heating
coil |
Electric-resistance
heating coil |
Thermal-oil heating
coil |
|
C |
What statement
is true concerning steam-heated, hot-water heated, or electric-heated convectors? |
Convectors draw
in relatively cool air through an opening at the top and discharge relatively
warm air through an outlet grille at the bottom and are located on bulkheads
near the deck.
|
Convectors draw
in relatively cool air through an opening at the top and discharge relatively
warm air through an outlet grille at the bottom and are located on bulkheads
near the overhead. |
Convectors draw
in relatively cool air through an opening at the bottom and discharge relatively
warm air through an outlet grille at the top and are located on bulkheads
near the deck. |
Convectors draw
in relatively cool air through an opening at the bottom and discharge relatively
warm air through an outlet grille at the top and are located on bulkheads
near the overhead. |
|
A |
Concerning cargo-hold
dehumidification, what statement is true? |
Cargo hold moisture
content is reduced by supplying relatively dry air from the outside and
exhausting relatively humid air to the outside. |
Cargo hold moisture
content is reduced by supplying relatively humid air from the outside and
exhausting relatively dry air to the outside. |
Cargo hold moisture
content is increased by supplying relatively dry air from the outside and
exhausting relatively humid air to the outside. |
Cargo hold moisture
content is increased by supplying relatively humid air from the outside
and exhausting relatively dry air to the outside. |
|
C |
Which statement
is true concerning a liquid desiccant cargo-hold dehumidification system? |
Water from the
humid air inlet from the cargo hold is evaporated and driven out of the
liquid desiccant by means of a heating coil located in the humidification
chamber.
|
Water from the
humid air inlet from the cargo hold is evaporated and driven out of the
liquid desiccant by means of a cooling coil located in the humidification
chamber. |
Water vapor from
the humid air inlet from the cargo hold is condensed and absorbed into the
liquid desiccant by means of a cooling coil located in the humidification
chamber. |
Water vapor from
the humid air inlet from the cargo hold is condensed and absorbed into the
liquid desiccant by means of a heating coil located in the humidification
chamber. |
|
A |
What statement
is true concerning a liquid desiccant cargo-hold dehumidification system? |
Water absorbed
in the liquid desiccant is evaporated and driven out of the desiccant by
means of a heating coil located in the regeneration chamber. |
Water absorbed
in the liquid desiccant is condensed and absorbed into the desiccant by
means of a cooling coil located in the regeneration chamber. |
Water absorbed
in the liquid desiccant is condensed and absorbed in to the desiccant by
means of a heating coil located in the regeneration chamber. |
Water absorbed
in the liquid desiccant is evaporated and driven out of the desiccant by
means of a cooling coil located in the regeneration chamber. |
|
A |
With regard to
the cooling and heating coils and humidification and regeneration chambers
of a liquid cargo-hold dehumidification system, which statement is true? |
The chamber that
processes the cargo-hold air contains the cooling coil and is known as the
humidification chamber. The chamber that processes the outside air contains
the heating coil and is known as the regeneration chamber. |
The chamber that
processes the outside air contains the cooling coil and is known as the
humidification chamber. The chamber that processes the cargo-hold air contains
the heating coil and is known as the regeneration chamber. |
The chamber that
processes the cargo-hold air contains the heating coil and is known as the
humidification chamber. The chamber that processes the outside air contains
the cooling coil and is known as the regeneration chamber. |
The chamber that
processes the cargo-hold air contains the cooling coil and is known as the
regeneration chamber. The chamber that processes the outside air contains
the heating coil and is known as the humidification chamber. |
|
C |
To prevent damage
to dry cargoes, the cargo hold ventilation and dehumidification systems
play a key role. In terms of the maintained dew point, what statement is
true? |
The dew point
temperature of the cargo hold is normally maintained 10⁰F above the
surface temperature of the cargo or ship structure.
|
The dew point
temperature of the cargo hold is normally maintained at a constant temperature
regardless of the surface temperature of the cargo or ship structure. |
The dew point
temperature of the cargo hold is normally maintained 10⁰F below the
surface temperature of the cargo or ship structure. |
The dew point
temperature of the cargo hold is normally maintained at the surface temperature
of the cargo or ship structure. |
|
B |
To determine the
average cargo hold dew point temperature, at what location would the dew
point be measured? |
The dew point
is taken near the bottom of the cargo hold. |
The dew point
is taken at the ventilation exhaust trunk. |
The dew point
is taken at the ventilation supply trunk. |
The dew point
is taken near a central location of the cargo hold. |
|
C |
What common feature
is found on both liquid-desiccant and solid-desiccant cargo-hold dehumidification
systems? |
Both systems require
a continuous source of cooling water to absorb moisture into the desiccant. |
Both systems require
a continuous source of heat to absorb moisture into the desiccant. |
Both systems require
a continuous source of heat to drive the moisture out of the desiccant. |
Both systems require
a continuous source of cooling water to drive the moisture out of the desiccant. |
|
A |
What type of HVAC
system is ideally designed to serve a large public space? |
A single zone
system |
A terminal reheat
system |
A dual duct system |
A variable air
volume system |
|
A |
What type of HVAC
system is characterized by poor air distribution and ventilation and low
system heat loads? |
A variable air
volume system |
A single zone
system |
A dual duct system |
A terminal reheat
system |
|
D |
Referring to illustrated
diagram, what type of HVAC system is shown? Illustration GS-RA-09 |
A dual duct system |
A terminal reheat
system |
A variable air
volume system |
A single zone
system |
|
B |
Referring to illustrated
diagram, what type of HVAC system is shown? Illustration GS-RA-42 |
A single zone
system |
A terminal reheat
system |
A dual duct system |
A variable air
volume system |
|
A |
Referring to illustrated
diagram, what type of HVAC system is shown? Illustration GS-RA-43 |
A dual duct system |
A variable air
volume system |
A single zone
system |
A terminal reheat
system |
|
A |
What type of HVAC
system is characterized by a having a split supply air stream, with one
for cold air and the other for hot air? |
A dual duct system |
A single zone
system |
A terminal reheat
system |
A variable air
volume system |
|
D |
What type of HVAC
system is characterized by having control dampers in locations other than
the outside air supply, outside air exhaust, and recirculation damper applications? |
A terminal reheat
system |
A single zone
system |
A dual duct system |
A variable air
volume system |
|
A |
In the illustrated
single zone HVAC system, what prevents the simultaneous flow of steam through
the preheat coil and flow of chilled water through the cooling coil? Illustration
GS-RA-09 |
The supply air
duct thermostat controlling the steam flow is set several degrees lower
than the design off-coil temperature associated with the cooling coil. |
The supply air
duct thermostat controlling the steam flow is set equal to the design off-coil
temperature associated with the cooling coil. |
The supply air
duct thermostat controlling the steam flow is set several degrees higher
than the design off-coil temperature associated with the cooling coil. |
Simultaneous steam
flow through the preheater and chilled water flow through the cooling coil
is permitted for the purposes of space humidity control. |
|
C |
In the illustrated
single zone HVAC system, what prevents the simultaneous flow of steam through
the preheat coil and flow of chilled water through the cooling coil? Illustration
GS-RA-09 |
Simultaneous steam
flow through the preheater and chilled water flow through the cooling coil
is permitted for the purposes of space humidity control.
|
The supply air
duct thermostat controlling the steam flow is set several degrees higher
than the design off-coil temperature associated with the cooling coil. |
The supply air
duct thermostat controlling the steam flow is set several degrees lower
than the design off-coil temperature associated with the cooling coil. |
The supply air
duct thermostat controlling the steam flow is set equal to the design off-coil
temperature associated with the cooling coil. |
|
B |
In the illustrated
single zone HVAC system, what statement represents the functioning of the
diverting relay as it controls the cooling coil flow and the exhaust, outside
air and recirculation dampers? Illustration GS-RA-09 |
The diverting
relay processes the humidistat control signal as long as the space humidity
is below the humidistat set point. The diverting relay processes the room
thermostat control signal if the space humidity exceeds the humidistat set
point. |
The diverting
relay processes the room thermostat control signal as long as the space
humidity is below the humidistat set point. The diverting relay processes
the room humidistat control signal if the space humidity exceeds the humidistat
set point. |
The diverting
relay processes the room thermostat control signal as long as the space
temperature is below the thermostat set point. The diverting relay processes
the room humidistat control signal if the space temperature exceeds the
thermostat set point. |
The diverting
relay processes the humidistat control signal as long as the space temperature
is below the thermostat set point. The diverting relay processes the room
thermostat control signal if the space temperature exceeds the thermostat
set point. |
|
A |
In the illustrated
single zone HVAC system, what statement represents the relationship between
the exhaust, outside air and recirculation dampers? Illustration GS-RA-09 |
The more the exhaust
and outside air dampers are open, the more the recirculation damper is closed,
and vice versa. |
The more the exhaust
and recirculation dampers are open, the more the outside air damper is closed,
and vice versa. |
The the exhaust,
outside air, and recirculation dampers are all open or closed to the same
degree for all operating conditions. |
The more the outside
air and recirculation dampers are open, the more the exhaust damper is closed,
and vice versa. |
|
A |
In the illustrated
terminal reheat multiple zone system, what statement represents the functioning
of the winter outside air duct thermostat? Illustration GS-RA-42 |
During the heating
season, the winter thermostat senses the outside air temperature and closes
the exhaust and outside air dampers when the outside air temperature is
significantly lower than typical indoor air temperatures. |
During the heating
season, the winter thermostat senses the inside air temperature and opens
the exhaust and outside air dampers when the inside air temperature is significantly
lower than typical indoor air temperatures. |
During the heating
season, the winter thermostat senses the outside air temperature and opens
the exhaust and outside air dampers when the outside air temperature is
significantly lower than typical indoor air temperatures. |
During the heating
season, the winter thermostat senses the inside air temperature and closes
the exhaust and outside air dampers when the inside air temperature is significantly
lower than typical indoor air temperatures. |
|
A |
In the illustrated
terminal reheat multiple zone system, what statement represents the functioning
of the summer outside air duct thermostat? Illustration GS-RA-42 |
During the cooling
season, the summer thermostat senses the outside air temperature and closes
the exhaust and outside air dampers when the outside air temperature is
significantly higher than typical indoor air temperatures. |
During the cooling
season, the summer thermostat senses the outside air temperature and opens
the exhaust and outside air dampers when the outside air temperature is
significantly higher than typical indoor air temperatures. |
During the cooling
season, the summer thermostat senses the inside air temperature and closes
the exhaust and outside air dampers when the inside air temperature is significantly
higher than typical indoor air temperatures. |
During the cooling
season, the summer thermostat senses the inside air temperature and opens
the exhaust and outside air dampers when the inside air temperature is significantly
higher than typical indoor air temperatures. |
|
A |
In the illustrated
terminal reheat multiple zone system, what statement represents the functioning
of the supply air duct thermostats controlling the preheater steam flow
and the cooling coil chilled water flow? Illustration GS-RA-42 |
The thermostat
controlling the preheater steam flow is set several degrees lower than the
design cooling coil off-coil temperature to prevent simultaneous flows. |
The thermostat
controlling the preheater steam flow is set several degrees higher than
the design cooling coil off-coil temperature to prevent simultaneous flows. |
The thermostat
controlling the preheater steam flow is set at the design cooling coil off-coil
temperature to allow simultaneous flows. |
The thermostat
controlling the preheater steam flow is set at the design cooling coil off-coil
temperature to prevent simultaneous flows. |
|
A |
Referring to the
illustrated single zone HVAC system diagram, what statement is true concerning
the damper controls? Illustration GS-RA-09 |
The exhaust and
outside air dampers are normally open and the recirculation damper is normally
closed and all three dampers are controlled by a single pilot air signal. |
The exhaust and
outside air dampers are normally closed and the recirculation damper is
normally open and each damper is controlled by its own pilot air signal. |
The exhaust and
outside air dampers are normally closed and the recirculation damper is
normally open and all three dampers are controlled by a single pilot air
signal. |
The exhaust and
outside air dampers are normally open and the recirculation damper is normally
closed and each damper is controlled by its own pilot air signal. |
|
A |
Referring to the
illustrated dual duct multiple zone HVAC system, how is the space temperature
directly controlled? Illustration GS-RA-43 |
The space air
temperature is controlled by automatically proportioning the cold and hot
air streams at the mixing unit. |
The space air
temperature is controlled by automatically controlling the chilled water
flow through the cooling coil. |
The space air
temperature is controlled by automatically controlling the steam flow through
the reheat coil. |
The space air
temperature is controlled by automatically controlling the steam flow through
the preheat coil. |
|
B |
What temperature
associated with the psychrometric properties of air is measured by an ordinary
thermometer? |
The saturation
temperature |
The dry-bulb temperature |
The dew-point
temperature |
The wet-bulb temperature |
|
D |
Referring to the
illustrated psychrometric chart, suppose during the heating season where
steam is injected into the air stream, this results in sensible heat gain
and humidification. What statement represents the direction of the air conditioning
process line? Illustration GS-RA-22 |
The air conditioning
process line is diagonal with the coil outlet to the right and below the
coil inlet. |
The air conditioning
process line is diagonal with the coil outlet to the left and above the
coil inlet. |
The air conditioning
process line is diagonal with the coil outlet to the left and below the
coil inlet. |
The air conditioning
process line is diagonal with the coil outlet to the right and above the
coil inlet. |
|
A |
What temperature
associated with the psychrometric properties of air is measured with a sling
psychrometer? |
The wet-bulb temperature |
The dew-point
temperature |
The saturation
temperature |
The dry-air temperature |
|
B |
Referring to the
illustrated psychrometric chart, if the dry bulb temperature is 70⁰F
and the relative humidity is 50%, what is the absolute humidity? Illustration
GS-RA-22 |
38 grains of moisture
per pound of dry air |
45 grains of moisture
per pound of dry air |
51 grains of moisture
per pound of dry air |
58 grains of moisture
per pound of dry air |
|
B |
Referring to the
illustrated psychrometric chart, if the measured dry-bulb temperature is
80⁰F and the measured wet-bulb temperature is 70⁰F, what is
the determined relative humidity? Illustration GS-RA-22 |
45 (%) |
60 (%) |
70 (%) |
95 (%) |
|
B |
Referring to the
illustrated psychrometric chart, suppose air at a dry-bulb temperature of
60⁰F and a relative humidity of 52% passes over a heating coil, resulting
in sensible heat gain, and the off-coil temperature is now 80⁰F. What
is off-coil relative humidity? Illustration GS-RA-22 |
19 (%) |
27 (%) |
55 (%) |
70 (%) |
|
A |
Referring to the
illustrated psychrometric chart, suppose during the heating season that
air passes over a heating coil, and this results in sensible heat gain with
no change in moisture content. What statement represents the direction of
the air conditioning process line? Illustration GS- RA-22 |
The air conditioning
process line is horizontal with the coil outlet to the right of the coil
inlet. |
The air conditioning
process line is vertical with the coil outlet above the coil inlet. |
The air conditioning
process line is horizontal with the coil outlet to the left of the coil
outlet. |
The air conditioning
process line is vertical with the coil outlet below the coil inlet. |
|
B |
Referring to the
illustrated psychrometric chart, suppose during the cooling season that
air passes over a cooling coil with a mean surface temperature above the
dew point temperature, and this results in sensible heat loss with no change
in moisture content. What statement represents the direction of the air
conditioning process line? Illustration GS-RA-22 |
The air conditioning
process line is vertical with the coil outlet below the coil inlet. |
The air conditioning
process line is horizontal with the coil outlet to the left of the coil
inlet. |
The air conditioning
process line is vertical with the coil outlet above the coil inlet. |
The air conditioning
process line is horizontal with the coil outlet to the right of the coil
inlet. |
|
A |
Referring to the
illustrated psychrometric chart, suppose during the cooling season that
air passes over a cooling coil with a mean surface temperature below the
dew point temperature, and this results in sensible heat loss and dehumidification.
What statement represents the direction of the air conditioning process
line? Illustration GS-RA-22 |
The air conditioning
process line is diagonal with the coil outlet to the left and below the
coil inlet. |
The air conditioning
process line is diagonal with the coil outlet to the right and below the
coil inlet. |
The air conditioning
process line is diagonal with the coil outlet to the left and above the
coil inlet. |
The air conditioning
process line is diagonal with the coil outlet to the right and above the
coil inlet. |
|
C |
Referring to the
illustrated psychrometric chart, under what conditions are the dry-bulb,
wet-bulb, and dew point temperatures for air all equal in value? Illustration
GS-RA-22 |
When the grains
of moisture per pound of dry air is zero. |
When the relative
humidity is 0%. |
When the air is
completed saturated with moisture and the relative humidity is 100%. |
It is impossible
for the dry-bulb, wet-bulb, and dew point temperatures to be the same value. |
|
D |
What type of HVAC
system is ideally designed to serve a large public space? |
A dual duct system |
A terminal reheat
system |
A variable air
volume system |
A single zone
system |
|
C |
What type of HVAC
system is characterized by poor air distribution and ventilation and low
system heat loads? |
A terminal reheat
system |
A single zone
system |
A variable air
volume system |
A dual duct system |
|
D |
Referring to illustrated
diagram, what type of HVAC system is shown? Illustration GS-RA-09 |
A dual duct system |
A terminal reheat
system |
A variable air
volume system |
A single zone
system |
|
C |
Referring to illustrated
diagram, what type of HVAC system is shown? Illustration GS-RA-43 |
A single zone
system |
A variable air
volume system |
A dual duct system |
A terminal reheat
system |
|
B |
What type of HVAC
system is characterized by a having a split supply air stream, with one
for cold air and the other for hot air? |
A variable air
volume system |
A dual duct system |
A terminal reheat
system |
A single zone
system |
|
D |
What type of HVAC
system is characterized by having control dampers in locations other than
the outside air supply, outside air exhaust, and recirculation damper applications? |
A terminal reheat
system |
A dual duct system |
A single zone
system |
A variable air
volume system |
|
A |
In the illustrated
single zone HVAC system, what prevents the simultaneous flow of steam through
the preheat coil and flow of chilled water through the cooling coil? Illustration
GS-RA-09 |
The supply air
duct thermostat controlling the steam flow is set several degrees lower
than the design off-coil temperature associated with the cooling coil. |
The supply air
duct thermostat controlling the steam flow is set equal to the design off-coil
temperature associated with the cooling coil. |
Simultaneous steam
flow through the preheater and chilled water flow through the cooling coil
is permitted for the purposes of space humidity control. |
The supply air
duct thermostat controlling the steam flow is set several degrees higher
than the design off-coil temperature associated with the cooling coil. |
|
C |
In the illustrated
single zone HVAC system, what statement represents the relationship between
the exhaust, outside air and recirculation dampers? Illustration GS-RA-09 |
The more the exhaust
and recirculation dampers are open, the more the outside air damper is closed,
and vice versa.
|
The more the outside
air and recirculation dampers are open, the more the exhaust damper is closed,
and vice versa. |
The more the exhaust
and outside air dampers are open, the more the recirculation damper is closed,
and vice versa. |
The the exhaust,
outside air, and recirculation dampers are all open or closed to the same
degree for all operating conditions. |
|
C |
In the illustrated
terminal reheat multiple zone system, what statement represents the functioning
of the summer outside air duct thermostat? Illustration GS-RA-42 |
During the cooling
season, the summer thermostat senses the outside air temperature and opens
the exhaust and outside air dampers when the outside air temperature is
significantly higher than typical indoor air temperatures.
o |
During the cooling
season, the summer thermostat senses the inside air temperature and opens
the exhaust and outside air dampers when the inside air temperature is significantly
higher than typical indoor air temperatures. |
During the cooling
season, the summer thermostat senses the outside air temperature and closes
the exhaust and outside air dampers when the outside air temperature is
significantly higher than typical indoor air temperatures. |
During the cooling
season, the summer thermostat senses the inside air temperature and closes
the exhaust and outside air dampers when the inside air temperature is significantly
higher than typical indoor air temperatures. |
|
A |
Referring to the
illustrated dual duct multiple zone HVAC system, how is the space temperature
directly controlled? Illustration GS-RA-43 |
The space air
temperature is controlled by automatically proportioning the cold and hot
air streams at the mixing unit. |
The space air
temperature is controlled by automatically controlling the steam flow through
the preheat coil. |
The space air
temperature is controlled by automatically controlling the chilled water
flow through the cooling coil. |
The space air
temperature is controlled by automatically controlling the steam flow through
the reheat coil. |
|
A |
Expansion tanks
when used in a ship's low temperature hot water heating system may be of
the open or closed type. Referring to the illustrated central-station hookup
for a hot-water heating system drawing, what would be the normal temperature
range of the water? Illustration GS-0151 |
180⁰F to
200⁰F |
220⁰F to
240⁰F |
260⁰F to
280⁰F |
320⁰F to
360⁰F |
|
B |
What type of pump
is invariably used as a circulator in a hydronic heating system? |
Reciprocating
pump |
Centrifugal pump |
Rotary pump |
Diaphragm pump |
|
C |
What statement
is true concerning a one-pipe hydronic heating system? |
Each heating coil
inlet temperature is identical, as the hot water inlet temperature to each
heating coil progressively rises as the water passes through each successive
series-connected coil.
o |
Each heating coil
inlet temperature is identical, as the hot water inlet temperature to each
heating coil progressively drops as the water passes through each successive
series-connected coil. |
Each heating coil
inlet temperature is different, as the hot water inlet temperature to each
heating coil progressively drops as the water passes through each successive
series-connected coil. |
Each heating coil
inlet temperature is different, as the hot water inlet temperature to each
heating coil progressively rises as the water passes through each successive
series-connected coil. |
|
A |
It is absolutely
essential that hydronic heating system hot water piping be kept free of
air. Assuming that a system is initially properly filled with water, what
is the primary source of air contamination? |
The introduction
of air via the makeup water. |
The introduction
of air via the expansion tank vent. |
The introduction
of air with the convector steam supply. |
The introduction
of air via the atmospheric drains tank vent. |
|
B |
What advantage
does a 4-pipe hydronic heating/cooling heating system have over a 2-pipe
hydronic heating/cooling system? |
A 4-pipe hydronic
heating/cooling system requires double the amount of piping as compared
to a 2-pipe hydronic heating/cooling system serving the same number of zones. |
A 4-pipe hydronic
heating/cooling system allows simultaneous heating and cooling of different
zones, whereas a 2-pipe hydronic heating/cooling system does not. |
A 4-pipe hydronic
heating/cooling system can serve twice as many zones as a 2-pipe hydronic
heating/cooling system. |
A 4-pipe hydronic
heating/cooling system requires one-half the amount of piping as compared
to a 2-pipe hydronic heating/cooling system serving the same number of zones. |
|
D |
Concerning cargo-hold
dehumidification, what statement is true? |
Cargo hold moisture
content is increased by supplying relatively humid air from the outside
and exhausting relatively dry air to the outside. |
Cargo hold moisture
content is reduced by supplying relatively humid air from the outside and
exhausting relatively dry air to the outside. |
Cargo hold moisture
content is increased by supplying relatively dry air from the outside and
exhausting relatively humid air to the outside. |
Cargo hold moisture
content is reduced by supplying relatively dry air from the outside and
exhausting relatively humid air to the outside. |
|
C |
What statement
is true concerning a liquid desiccant cargo-hold dehumidification system? |
Water vapor from
the humid air inlet from the cargo hold is condensed and absorbed into the
liquid desiccant by means of a heating coil located in the humidification
chamber.
|
Water from the
humid air inlet from the cargo hold is evaporated and driven out of the
liquid desiccant by means of a cooling coil located in the humidification
chamber. |
Water vapor from
the humid air inlet from the cargo hold is condensed and absorbed into the
liquid desiccant by means of a cooling coil located in the humidification
chamber. |
Water from the
humid air inlet from the cargo hold is evaporated and driven out of the
liquid desiccant by means of a heating coil located in the humidification
chamber. |
|
A |
What statement
is true concerning a liquid desiccant cargo-hold dehumidification system? |
Water absorbed
in the liquid desiccant is evaporated and driven out of the desiccant by
means of a heating coil located in the regeneration chamber. |
Water absorbed
in the liquid desiccant is evaporated and driven out of the desiccant by
means of a cooling coil located in the regeneration chamber. |
Water absorbed
in the liquid desiccant is condensed and absorbed into the desiccant by
means of a cooling coil located in the regeneration chamber. |
Water absorbed
in the liquid desiccant is condensed and absorbed in to the desiccant by
means of a heating coil located in the regeneration chamber. |
|
C |
With regard to
the cooling and heating coils and humidification and regeneration chambers
of a liquid cargo-hold dehumidification system, what statement is true? |
The chamber that
processes the cargo-hold air contains the cooling coil and is known as the
regeneration chamber. The chamber that processes the outside air contains
the heating coil and is known as the humidification chamber.
o |
The chamber that
processes the cargo-hold air contains the heating coil and is known as the
humidification chamber. The chamber that processes the outside air contains
the cooling coil and is known as the regeneration chamber. |
The chamber that
processes the cargo-hold air contains the cooling coil and is known as the
humidification chamber. The chamber that processes the outside air contains
the heating coil and is known as the regeneration chamber. |
The chamber that
processes the outside air contains the cooling coil and is known as the
humidification chamber. The chamber that processes the cargo-hold air contains
the heating coil and is known as the regeneration chamber. |
|
C |
To prevent damage
to dry cargoes, the cargo hold ventilation and dehumidification systems
play a key role. In terms of the maintained dew point, what statement is
true? |
The dew point
temperature of the cargo hold is normally maintained at the surface temperature
of the cargo or ship structure.
|
The dew point
temperature of the cargo hold is normally maintained 10⁰F above the
surface temperature of the cargo or ship structure. |
The dew point
temperature of the cargo hold is normally maintained 10⁰F below the
surface temperature of the cargo or ship structure. |
The dew point
temperature of the cargo hold is normally maintained at a constant temperature
regardless of the surface temperature of the cargo or ship structure. |
|
A |
To determine the
average cargo hold dew point temperature, at what location would the dew
point be measured? |
The dew point
is taken at the ventilation exhaust trunk. |
The dew point
is taken at the ventilation supply trunk. |
The dew point
is taken near a central location of the cargo hold. |
The dew point
is taken near the bottom of the cargo hold. |
|
B |
What common feature
is found on both liquid-desiccant and solid-desiccant cargo-hold dehumidification
systems? |
Both systems require
a continuous source of cooling water to drive the moisture out of the
desiccant. |
Both systems require
a continuous source of heat to drive the moisture out of the desiccant. |
Both systems require
a continuous source of heat to absorb moisture into the desiccant. |
Both systems require
a continuous source of cooling water to absorb moisture into the desiccant. |
|
A |
What temperature
associated with the psychrometric properties of air is measured by an ordinary
thermometer? |
The dry-bulb temperature |
The wet-bulb temperature |
The dew-point
temperature |
The saturation
temperature |
|
B |
Referring to the
illustrated psychrometric chart, if the dry bulb temperature is 70⁰F
and the relative humidity is 40%, what is the absolute humidity? Illustration
GS-RA-22 |
38 grains of moisture
per pound of dry air |
45 grains of moisture
per pound of dry air |
51 grains of moisture
per pound of dry air |
58 grains of moisture
per pound of dry air |
|
B |
Referring to the
illustrated psychrometric chart, suppose air at a dry-bulb temperature of
60⁰F and a relative humidity of 52% passes over a heating coil, resulting
in sensible heat gain, and the off-coil temperature is now 80⁰F. What
is off-coil relative humidity? Illustration GS-RA-22 |
19 (%) |
27 (%) |
55 (%) |
70 (%) |
|
B |
Referring to the
illustrated psychrometric chart, suppose during the cooling season that
air passes over a cooling coil with a mean surface temperature above the
dew point temperature, and this results in sensible heat loss with no change
in moisture content. What statement represents the direction of the air
conditioning process line? Illustration GS-RA-22 |
The air conditioning
process line is horizontal with the coil outlet to the right of the coil
inlet. |
The air conditioning
process line is horizontal with the coil outlet to the left of the coil
inlet. |
The air conditioning
process line is vertical with the coil outlet below the coil inlet. |
The air conditioning
process line is vertical with the coil outlet above the coil inlet. |
|
B |
Referring to the
illustrated psychrometric chart, suppose during the cooling season that
air passes over a cooling coil with a mean surface temperature above the
dew point temperature, and this results in sensible heat loss with no change
in moisture content. What statement represents the direction of the air
conditioning process line? Illustration GS-RA-22 |
The air conditioning
process line is horizontal with the coil outlet to the right of the coil
inlet. |
The air conditioning
process line is horizontal with the coil outlet to the left of the coil
inlet. |
The air conditioning
process line is vertical with the coil outlet below the coil inlet. |
The air conditioning
process line is vertical with the coil outlet above the coil inlet. |
|
C |
Referring to the
illustrated psychrometric chart, under what conditions are the dry-bulb,
wet-bulb, and dew point temperatures for air all equal in value? Illustration
GS-RA-22 |
When the relative
humidity is 0%. |
It is impossible
for the dry-bulb, wet-bulb, and dew point temperatures to be the same value. |
When the air is
completed saturated with moisture and the relative humidity is 100%. |
When the grains
of moisture per pound of dry air is zero. |
|
C |
Probably the most
useful troubleshooting tools used in a predictive maintenance management
program for shipboard machinery are vibration meters, analyzers, and monitors.
What is the term that represents the distance a mass travels in a given
direction as a result of a part vibrating during its periodic or oscillatory
motion? |
Vibration frequency |
Vibration velocity |
Vibration displacement |
Vibration acceleration |
|
C |
Probably the most
useful troubleshooting tools used in a predictive maintenance management
program for shipboard machinery are vibration meters, analyzers, and monitors.
What is the term that represents the rate of change of the velocity as a
result of a part vibrating during its periodic or oscillatory motion? |
Vibration frequency |
Vibration displacement |
Vibration acceleration |
Vibration velocity |
|
A |
Probably the most
useful troubleshooting tools used in a predictive maintenance management
program for shipboard machinery are vibration meters, analyzers, and monitors.
What is the term that represents the number of vibration cycles per unit
time as a result of a part vibrating during its periodic or oscillatory
motion? |
Vibration frequency |
Vibration displacement |
Vibration acceleration |
Vibration velocity |
|
B |
What is the standard
unit of measure for vibration displacement? |
Ten thousandths
of an inch (.0001), peak to peak |
Thousandths of
an inch (.001), peak to peak. |
Hundredths of
an inch (.01), peak to peak |
Tenths of an inch
(.1), peak to peak |
|
D |
What is the most
useful measurement that represents the severity of vibration associated
with periodic or oscillatory motion? |
Vibration frequency |
Vibration acceleration |
Vibration displacement |
Vibration velocity |
|
B |
When performing
a vibration analysis for rotating machinery, what is essential? |
A baseline vibration
signature should be established as a reference, but no historical record
of periodic analyses need be maintained. Vibration amplitudes at various
frequencies are compared. |
A baseline vibration
signature should be established as a reference, and a historical record
of periodic analyses should be maintained. Vibration amplitudes at various
frequencies are compared. |
A historical record
of periodic analyses should be maintained, but no baseline vibration signature
need be established as a reference. Vibration amplitudes at various frequencies
are compared. |
A baseline vibration
signature should be established as a reference, and a historical record
of periodic analyses should be maintained. Vibration amplitudes are compared
with no need to examine frequencies. |
|
B |
In examining a
baseline vibration signature and the historical record of periodic vibration
analyses, what must be considered for the evaluation of rotating machinery? |
Minimum vibration
limits and the change in vibration levels over time. |
Maximum vibration
limits and the change in vibration levels over time. |
Change in vibration
levels over time, with no regard to maximum vibration limits. |
Maximum vibration
limits only, with no regard for the change in vibration levels over time. |
|
C |
What is meant
by a critical speed for rotating machinery? |
The critical speed
of a shaft is the speed at which it will shear due to excessive torque placed
upon it by the prime mover in driving the load.
|
The critical speed
of a shaft is the speed of rotation that is out of harmonic synchronism
with the shaft's natural vibration frequency which produces excessive vibration. |
The critical speed
of a shaft is the speed of rotation that is in harmonic synchronism with
the shaft's natural vibration frequency which produces excessive vibration. |
The critical speed
of a shaft is the speed at which it will fly apart due to excessive centrifugal
forces associated with excessive speed. |
|
D |
On a ship with
a continuously manned engine room, with a three-person watch rotation, what
is the watch and rest period rotation? |
8 hours on watch
followed by 8 hours rest |
6 hours on watch
followed by 6 hours rest |
8 hours on watch
followed by 4 hours rest |
4 hours on watch
followed by 8 hours rest |
|
D |
On a ship with
a continuously manned engine room, ratings may form part of the engineering
watch. For engine room watch ratings, what is the customary time to relieve
the watch? |
On the hour |
Thirty minutes
before the hour |
Fifteen minutes
after the hour |
Fifteen minutes
before the hour |
|
D |
On vessels exceeding
1600 GRT, who is responsible for the practical upkeep of machinery and the
manning of the engine room? |
Chief mate |
Chief engineer |
Officer in charge
of the engineering watch |
First assistant
engineer |
|
C |
In terms of the
personal safety of an engine room watch standing rating, which alarm response
would be the most immediately critical? |
M/E low lube oil
pressure alarm |
M/E high coolant
temperature alarm |
E/R fixed CO2
impending release alarm |
General emergency
alarm |
|
D |
Under which of
the listed conditions can the engine room retake the throttle control from
the bridge of an automated vessel? |
Only with the
master's permission. |
Only after the
throttle has been placed in stop. |
After a 10 minute
delay to the input command. |
Any time it is
deemed necessary. |
|
B |
On a ship with
a periodically unmanned engine room, the duty engineer is responsible for
making machinery space rounds when the engine room is unattended. How often
should these machinery space rounds be performed by the duty engineer? |
Every two hours |
Every four hours |
Every twelve hours |
Every hour |
|
C |
When entering
an unattended machinery space to conduct maintenance or a machinery space
round, what must be done? |
The master should
be telephoned at agreed to intervals. |
The first assistant
engineer should be telephoned at agreed to intervals. |
The navigational
watch officer should be telephoned at agreed to intervals. |
The chief engineer
should be telephoned at agreed to intervals. |
|
B |
On a ship with
a periodically unmanned engine room, the duty engineer is responsible for
making machinery space rounds when the engine room is unattended. Between
machinery space rounds, what is the responsibility of the duty engineer? |
The duty engineer
is only required to make periodic machinery space rounds. Acknowledgement
and response to any machinery space alarms are the responsibility of the
junior engineering officer onboard. |
The duty engineer
is on call and should be prepared to acknowledge and respond to any machinery
space alarms by remaining in range of the remote alarm stations in his or
her cabin or the various public spaces. |
The duty engineer
is only required to make periodic machinery space rounds. Acknowledgement
and response to any machinery space alarms are the responsibility of the
Chief Engineer. |
The duty engineer
is only required to make periodic machinery space rounds. Acknowledgement
and response to any machinery space alarms are the responsibility of the
First Assistant Engineer. |
|
A |
On a ship with
a periodically unmanned engine room, under what conditions must the propulsion
console be continuously manned? |
Under standby
conditions or while maneuvering |
Under standby
conditions only |
While maneuvering
only |
During the day
work period |
|
C |
Preferably when
should the bridge be informed when engine room situations may affect the
speed, maneuverability, power supply, or other essentials for the safe operation
of the ship? |
The bridge should
be informed after any changes are made, as soon as practical. |
The bridge need
not be informed of any changes being made, as it will soon be obvious. |
The bridge should
be informed before any changes are made, if at all possible. |
The bridge should
be informed simultaneously as any changes are made, if at all possible. |
