discharge is continuous
it has no internal valves
upon accidental closing of discharge valve, excessive pressure will not build up
all of the above are true
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:
Centrifugal pumps have what advantage(s)over reciprocating pumps ________.
A.They are less expensive
B.They are smaller for equivalent pumping ability
C.They pump more cargo in less time
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:
reduce radial thrust to the impeller
double the liquid velocity through the pump when compared to a single volute
reduce hydraulic end thrust
provide the effect of multi-staging
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:
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:
a centrifugal fan
a direct expansion cooler
a hermetic compressor
a centrifugal pump