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单选题
A centrifugal bilge pump requires priming （）.
A
primarily to lubricate the shaft seals
B
due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller
C
to initially unload the pump by having its head pressure equal to discharge pressure
D
in order to overcome the potential energy of water in the discharge line
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更多 “单选题A centrifugal bilge pump requires priming （）.A primarily to lubricate the shaft sealsB due to the inability of this type of pump to lift water to cover the suction (eye) of the impellerC to initially unload the pump by having its head pressure equal to discharge pressureD in order to overcome the potential energy of water in the discharge line” 相关考题
考题
Throttling in the _____ line of a centrifugal pump involves the risk of the pump cavitation.A.suctionB.exhaustC.pressureD.discharge
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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
Open or close coupledD
Horizontal or vertical
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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The bilge system has been performing well; however, the aft starboard engine room bilgewell suddenly fails to be pumped outWhich of the following should be done first to determine the cause?（）A
Open the bilge pump for inspectionB
Remove each of the manifold valvesC
Remove only the manifold valve to the affected bilge-wellD
Attempt to pump out another bilge well to determine if the entire system is affected
考题
单选题Which one is not the component of a typical, marine pattern self-contained unit?（）A
a centrifugal fanB
a direct expansion coolerC
a hermetic compressorD
a centrifugal pump
考题
单选题If a centrifugal bilge pump were continually operated with the discharge valve closed the （）.A
motor overload would openB
relief valve would openC
pump would eventually overheatD
motor would overheat
考题
单选题The （）pump is usually used as the bilge feed pump to an oily water separator.A
turbineB
screwC
vaneD
ejector
考题
单选题Most pump manufacturers recommended that the discharge piping for centrifugal pumps be （）.A
one size larger than the pump discharge nozzleB
the same size as the pump discharge nozzleC
one size smaller than the pump discharge nozzleD
installed with a short radius elbow at the pump
考题
单选题Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.A
cavitationB
electrolysisC
abrasionD
corrosion
考题
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
考题
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
考题
单选题If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably（）.A
excessive pump speedB
excessive suction headC
worn wearing ringsD
gross pump misalignment
考题
单选题To operate a centrifugal fire pump at reduced capacity, you should （）.A
readjust the relief valveB
throttle the suction lineC
throttle the discharge valveD
open the priming line
考题
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The purpose of the wearing rings used in a centrifugal pump is to （）.A
prevent an internal explosion in the pump when it is overheatedB
enable a visual inspection of the pump while it is runningC
insure a proper alignment of the pump coupling to the driverD
accommodate for friction between the impeller and the easing
考题
单选题Which of the listed statements is correct concerning the starting of centrifugal pumps?（）A
They should always be started with the discharge valve closedB
They should always be started with the discharge valve openedC
A priming pump is always required to flood the impeller suctionD
They should always be started with the sealing line valves closed
考题
单选题The most suitable pump for oily water separator feed duties is （）.A
a reciprocating pumpB
a vane pumpC
a centrifugal pumpD
a triple screw pump
考题
单选题Most pump manufacturers recommend that the suction piping dimension for centrifugal pumps be （）.A
one size smaller than the pump suction nozzleB
the same size as the pump suction nozzleC
one size larger than the pump suction nozzleD
installed with a short radius elbow at the pump
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
考题
单选题A simple pumping system consists of a suction branch, a pump and （）.A
a priming deviceB
a discharge branchC
a filterD
a suction valve
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