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单选题
When starting a centrifugal pump, the discharge valve should be （）.
A
closed
B
opened fully
C
cracked open
D
partly open
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单选题If a centrifugal bilge pump were continually operated with the discharge valve closed the （）.A
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primarily to lubricate the shaft sealsB
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单选题What is a characteristic of all centrifugal cargo pumps? （）A
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单选题When starting a reciprocating pump, the inlet valve should be （）.A
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单选题Which of the following will be the advantage of a centrifugal pump as compared with a reciprocating pump?（） (1) Its discharge is continuous (2) It has no internal valves (3) Upon accidental closing of discharge valve, excessive pressure will not build upA
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（1），（2），（3）D
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单选题Which method should be used to warm up the pump turbines prior to discharge（）.A
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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
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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
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单选题The usual symptoms of cavitation in a centrifugal pump is （）.A
noise and vibrationB
an increase in discharge pressureC
an increase in suction pressureD
lifting of the relief valve
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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
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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
open the priming line
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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In order to properly remove air from the casing of a centrifugal pump when starting, the pump should have a （）.A
positive headB
negative suction headC
mechanical sealD
vent valve attached to the casing at the top of the volute
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单选题A relief valve for a cargo pump is generally installed（）.A
after the discharge valveB
between the pump and discharge valveC
after the suction valveD
between the pump and suction valve
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单选题If a centrifugal pump were continually operated with the discharge valve closed, the （）.A
motor controller overload would openB
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单选题The advantage of a centrifugal pump as compared with a reciprocating pump is that （）.A
discharge is continuousB
it has no internal valvesC
upon accidental closing of discharge valve, excessive pressure will not build upD
all of the above are true
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spectacle valveC
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motor overload will openB
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单选题The simplest method to use for determining if a centrifugal pump is operating as designed, is to （）.A
closely observe the pump discharge temperatureB
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单选题A centrifugal pump attempting to develop flow against a closed discharge valve has a/an （）.A
capacity of 0%B
efficiency of 100%C
internal slippage of 0%D
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单选题When start a screw pump, the by pass valve should be （）.A
closedB
opened fullyC
cracked openD
partly open
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butterfly valveB
spectacle valveC
check valveD
globe valve
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