You start a centrifugal cargo pump to discharge cargo．The pump works for a while and then loses suction．This could be caused by ______．
A.The pump running backwards
B.Incomplete priming
C.The discharge head being too high
D.All of the above
第1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 speed
B.excessive suction head
C.worn wearing rings
D.gross pump misalignment
第2题：
If it becomes necessary to pump bilges while a vessel is in port, which of the following procedures should be followed?
A.Pump only if the discharge is led to a shore tank or barge
B.Pump only during the hours of darkness
C.Pump only on the outgoing tide
D.Pump only as much as is necessary
第3题：
Throttling in the _____ line of a centrifugal pump involves the risk of the pump cavitation.
A.suction
B.exhaust
C.pressure
D.discharge
第4题：
insufficient speed
cavitation
excess discharge pressure
excessive net positive suction head B
第5题：
All of the following steps are taken in starting a centrifugal pump，EXCEPT to ______．
A.Set the relief valve
B.Check the lubrication system
C.Vent the pump casing
D.Open the pump suction and discharge valves
第6题：
It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong direction. This would cause the pump ______.
A.head capacity to improve
B.discharge to be reversed
C.efficiency to decrease
D.slippage to decrease
第7题：
If you must pump bilges while a vessel is in port，you should pump only ______．
A.If discharge is led to a shore tank or barge
B.During the hours of darkness
C.On the outgoing tide
D.As much as is necessary
第8题：
While on watch in the engine room, you hear a continuous sounding of the general alarm. Which of the following actions should you take?
A.Make an entry in the official logbook
B.Open the master control valves on the fixed CO2 system
C.Start the fire pump and check discharge pressure
D.Secure auxiliary condenser overboard discharge
第9题：
Oil is discharged from the impeller through the outlet
Gravity causes the oil to flow toward the discharge
The self-priming feature of the centrifugal pump enables it to draw its own suction as it starts
The discharge capacity varies directly with the speed of the impeller
第10题：
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
to 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