二、根据材料，回答下题：第5题：

A.discharge side of the centrifugal pump

B.suction side of the centrifugal pump

C.the lowest point of the cooling water system

D.inlet of the main engine

A centrifugal pump can’t supply water after startingYou should check ____.

A.priming water

B.power supply

C.packing gland

D.bearing lubrication

A.high steam pressure in the boiler

B.abnormally high feed-water temperature

C.abnormally high boiler water temperature

D.steam demand exceeding feed pump capacity

When starting a centrifugal pump, the discharge valve should be ____.

A.closed

B.opened fully

C.cracked open

D.partly open

A.a reciprocating pump

B.a vane pump

C.a centrifugal pump

D.a triple screw pump

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

If a centrifugal pump vibrates and is noisy when operating, the cause could be _____.

A.worn gland sealing shaft

B.worn wearing rings

C.a bent shaft

D.reversed pump coupling

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 casing

B.absorb all impeller shaft end thrust

C.prevent water leakage to the atmosphere

D.prevent wear of the pump casing and/or impeller

The purpose of the wearing rings used in a centrifugal pump is to _____.

A.prevent an internal explosion in the pump when it is overheated

B.enable a visual inspection of the pump while it is running

C.insure a proper alignment of the pump coupling to the driver

D.accommodate for friction between the impeller and the easing