A double suction centrifugal pump impeller has been installed in the reverse direction, and will （）.

A . head capacity to improve B . discharge to be reversed C . efficiency to decrease D . slippage to decrease

A . centrifugal pumps B . jet pumps C . propeller pumps D . reciprocating pum

A . It pulls the stern toward the bank B . It heels the vessel toward the bank C . It pushes the entire vessel away from the bank D . It pulls the bow toward the bank

A . noise and vibration B . an increase in discharge pressure C . an increase in suction pressure D . lifting of the relief valve

A . cavitation B . electrolysis C . abrasion D . corrosio

A . two or more impellers housed together in one casing and mounted on a single shaft B . a single stepped impeller mounted in a progressively staged casing C . a large radial clearance between the impeller and casing to prevent overheating due to D . an increase in the discharge velocity of the liquid with a corresponding decrease in pressure through the stage

A . one B . two C . three D . four

A . (1)-(2)-(4)-(3)-(5) B . (1)-(4)-(2)-(3)-(5) C . (1)-(3)-(2)-(4)-(5) D . (1)-(5)-(4)-(2)-(3)

A . reduce radial thrust to the impeller B . double the liquid velocity through the pump when compared to a single volute C . reduce hydraulic end thrust D . provide the effect of multi-staging

A . cooling water B . fuel oil C . sea water D . diesel intake air

A . air chamber B . head lank C . primer D . prime mover

A . Bends in the piping B . Slowing the pumping rate C . Pipeline valves D . Backing rings for pipe weld

A . insufficient lubrication B . insufficient refrigerant C . excess refrigerant D . excessive opening of the expansion valve

A . They are self-priming B . Decreasing the speed of rotation will decrease the discharge pressure C . Opening the discharge valve wider will increase the discharge pressure D . All of the above

A . The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow B . The pump packing gland overheats after short operating periods C . The motor over-current protective device continually shuts the pump down D . Pounding noises can be heard at the pump suction chest

A . backwards B . forwards C . upward D . downward

A . one size smaller than the pump suction nozzle B . the same size as the pump suction nozzle C . one size larger than the pump suction nozzle D . installed with a short radius elbow at the pum

A . closed B . opened fully C . cracked open D . partly ope

A . priming water B . power supply C . packing gland D . bearing lubricatio

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

A . between the suction and discharge B . below the liquid supply C . above the liquid supply D . any of the above

A . reclaims water B . purges air without losing refrigerant C . purges air with some loss of refrigerant D . purges lube oil from the refrigerant

A . centerline of the pump and the level of the liquid in the suction well when the source of liquid is below the pump B . centerline of the pump and the suction liquid level when the source of liquid is above the pump C . centerline of the pump and the level of the discharge liquid D . liquid levels of the suction and discharge

A . readjust the relief valve B . throttle the suction line C . throttle the discharge valve D . open the priming line