drill holes through the heavy side of the impeller until it balances
weld counterweights to the light side of the impeller
remove metal from the heavy side by machining in a lathe
acid wash and serape the heavy side until it balances
第1题：
A centrifugal pump may fail to deliver water when first started if the ______.
A.water seal pipe is plugged
B.pump is not primed
C.seal ring is properly located
D.impeller is flooded
第2题：
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：
a centrifugal fan
a direct expansion cooler
a hermetic compressor
a centrifugal pump
第5题：
Single stage or multistage
High pressure or low pressure
Open or close coupled
Horizontal or vertical
第6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7题：
worn gland sealing shaft
worn wearing rings
a bent shaft
reversed pump coupling
第8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：
one size larger than the pump discharge nozzle
the same size as the pump discharge nozzle
one size smaller than the pump discharge nozzle
installed with a short radius elbow at the pump