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单选题
Throttling in the （） line of a centrifugal pump involves the risk of the pump cavitation.
A
suction
B
exhaust
C
pressure
D
discharge
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Throttling in the _____ line of a centrifugal pump involves the risk of the pump cavitation.A.suctionB.exhaustC.pressureD.discharge
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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
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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
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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
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单选题In the event of failure of an auxiliary such as a lubricating pump, the standby pump is started and put on the line automatically“the line” in this sentence refers to（）A
fuel manifoldB
lubricating pipe lineC
auxiliary engine pipe lineD
generator output line
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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
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单选题Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.A
cavitationB
electrolysisC
abrasionD
corrosion
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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
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单选题All of the following steps are taken in starting a centrifugal pump，EXCEPT to（）.A
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check the lubrication systemC
vent the pump casingD
open the pump suction and discharge valves
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单选题One of the main functions of wearing rings, as used in a centrifugal pump, is to （）.A
maintain radial alignment between the pump impeller and casingB
absorb all impeller shaft end thrustC
prevent water leakage to the atmosphereD
prevent wear of the pump casing and/or impeller
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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
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change the pump to a close coupled arrangement
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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
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discharge to be reversedC
efficiency to decreaseD
slippage to decrease
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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
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单选题The most suitable pump for oily water separator feed duties is （）.A
a reciprocating pumpB
a vane pumpC
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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
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one size larger than the pump suction nozzleD
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单选题Which of the following pumps belongs to centrifugal pump?（）A
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Screw pumpC
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单选题A centrifugal pump produces the required pressure energy by means of a rotating （） provided with vanes.A
propellerB
impellerC
circumferenceD
screw
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单选题To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the （）.A
shaft and impellerB
motor and pump shaftC
casing and impeller wearing ringsD
lantern ring and impeller
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单选题When starting a centrifugal pump, the discharge valve should be （）.A
closedB
opened fullyC
cracked openD
partly open
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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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