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 sh

The discharge flow of a reciprocating pump is ______.

A.steady

B.in pulsation

C.continuous

D.large

The amount of fuel delivered by a helical plunger fuel injection pump is controlled by ______.

A.varying the pump discharge pressure

B.varying the pump return pressure

C.rotation of the pump plunger

D.rotation of the pump barrel

Which of the following terms is used to identify the pressure of the liquid entering a pump?

A.Suction head

B.Pump head

C.Discharge head

D.Total head

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

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

Which method should be used to warm up the pump turbines prior to discharge ________．

A.Lock the turbine rotor and slowly bleed in steam until operating temperature is reached

B.Run the pump at high speed with the discharge valves closed

C.Run the turbine at slow speed with the pump disconnected

D.Shut the discharge valve and run the pump at slow speed

Throttling in the _____ line of a centrifugal pump involves the risk of the pump cavitation.

A.suction

B.exhaust

C.pressure

D.discharge

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