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单选题
To operate a centrifugal fire pump at reduced capacity, you should （）.
A
readjust the relief valve
B
throttle the suction line
C
throttle the discharge valve
D
open the priming line
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单选题With respect to centrifugal pump impellers, which of the following descriptions represents the correct centrifugal pump classification? （）A
Single stage or multistageB
High pressure or low pressureC
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单选题Which of the following statements is correct with regards to the operation of a centrifugal cargo pump?（）A
Oil is discharged from the impeller through the outletB
Gravity causes the oil to flow toward the dischargeC
The self-priming feature of the centrifugal pump enables it to draw its own suction as it startsD
The discharge capacity varies directly with the speed of the impeller
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单选题If you heard a ‘crackling’ noise in centrifugal pump, the most probable cause of the problem would be（）A
insufficient speedB
cavitationC
excess discharge pressureD
excessive net positive suction head B
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单选题Reduced capacity, accompanied by vibration and noise at the suction of a centrifugal pump is a result of （）.A
cavitationB
water hammerC
fluid frictionD
steam knock
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单选题You are transferring fuel from the storage tanks to the day tanks by means of an electric fuel oil transfer pumpIf the pump motor catches fire, you would FIRST （）.A
secure the fuel manifoldB
shut off power to the pumpC
shut off the power ventilationD
spray water on the fire
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单选题How do you operate a portable CO2 fire extinguisher?（）A
Point the horn downB
Turn cylinder upside-downC
Break the rupture discD
Pull pin，squeeze grip
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单选题Before attempting to put out a class “C” fire involving an electric-driven centrifugal pump, you should FIRST （）.A
insulate your shoesB
ground the fire hoseC
secure its power supplyD
start the fire pump
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单选题Increasing the speed of a centrifugal pump will result in an increase in its capacity Another means of increasing the capacity of a centrifugal pump is to increase the （）.A
diameter of the discharge piping, with all other factors remaining the sameB
diameter of the suction piping, with all other factors remaining the sameC
width of the impeller onlyD
diameter of the impeller
考题
单选题Increasing the speed of a centrifugal pump will result in an increase in its capacity in its capacityAnother means of increasing the capacity pump is to increase the（）A
diameter of the discharge piping, with all other factors remaining the sameB
diameter of the suction piping, with all other factors remaining the sameC
width of the impeller onlyD
diameter of the impeller
考题
单选题All of the following steps are taken in starting a centrifugal pump，EXCEPT to（）.A
set the relief valveB
check the lubrication systemC
vent the pump casingD
open the pump suction and discharge valves
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单选题The capacity of a centrifugal pump can be increased by the installation of a larger diameter impeller Another means of increasing the pump capacity is to （）.A
increase speedB
increase the size of the cardent assemblyC
reduce wearing ring clearancesD
change the pump to a close coupled arrangement
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单选题If you were operating a centrifugal water service pump with worn wearing rings, the （）.A
pump would be very noisyB
pump would vibrate excessivelyC
pump would develop insufficient flowD
stuffing box would leak excessively
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单选题If the capacity of a centrifugal pump decreases gradually over a long period of time, you should replace the （）.A
packing glandB
mechanical sealsC
lantern ringsD
wearing rings
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单选题It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong directionThis would cause the pump （）.A
head capacity to improveB
discharge to be reversedC
efficiency to decreaseD
slippage to decrease
考题
单选题Reduced voltage applied to a motor during the starting period will （）.A
result in decreased acceleration time onlyB
lower the starting current and increase accelerating timeC
cause a greater starting torqueD
increase the starting current and pump capacity
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单选题Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?（）A
The pump delivers full capacity when started, but gradually slackens off toan abnormally low flowB
The pump packing gland overheats after short operating periodsC
The motor over-current protective device continually shuts the pump downD
Pounding noises can be heard at the pump suction chest
考题
单选题Which of the following pumps belongs to centrifugal pump?（）A
Piston pumpB
Screw pumpC
Diffuser pumpD
Water-ring pump
考题
单选题The discharge rate or capacity of a centrifugal pump will vary directly as the （）.A
change in the impeller diameterB
square of the impeller radiusC
cube of the impeller diameterD
impeller efficiency for large changes in its size
考题
单选题One of the consequences in continuing to operate a centrifugal bilge pump with the discharge valve closed, is that the （）.A
motor overload will openB
relief valve will openC
pump will overheatD
motor will overheat
考题
单选题Each fire pump on a ship must have a pressure gauge located at（）.A
the pump dischargeB
the manifold connectionC
each fire station dischargeD
the pump station
考题
单选题On modern ships, centrifugal pump with a self-primer has replaced reciprocating pump as bilge pump because（）A
centrifugal pump is cheaper than reciprocating pumpB
the size of centrifugal pump with same capacity is smaller than that of reciprocating pumpC
centrifugal pump makes maintenance easier than reciprocating pump doesD
all of the above
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单选题A centrifugal pump vibrates excessively during operationUpon disassembling the pump it is found that the impeller is out of balanceWithout an available spare, you should （）.A
drill holes through the heavy side of the impeller until it balancesB
weld counterweights to the light side of the impellerC
remove metal from the heavy side by machining in a latheD
acid wash and serape the heavy side until it balances
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单选题While on watch in the engine room, you hear a continuous sounding of the general alarmWhich of the following actions should you take FIRST?（）A
Secure the burners then proceed to your assigned boat stationB
Start the fire pump and establish flow to the fire mainC
Open the guardian valve and standby to maneuverD
Open the master control valves on the fixed CO2 system
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