A.water seal pipe is plugged
B.pump is not primed
C.seal ring is improperly located
D.impeller is flooded
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A.Close radial clearance between impeller hub and casing
B.Low rotational speed of impeller
C.Removable end plate
D.Replaceable impeller and casing wearing rings
A.fill the unit with saltwater
B.fill the unit with de-scaling compound
C.completely drain the unit
D.tightly seal the unit to exclude air
A.dischargeendbeingsmallerthanthesuctionend
B.smallsizeofimpeller
C.lackofmovingparts
D.easeatwhichthewearingringsmaybechanged
A.fusion
B.vaporization
C.sublimation
D.condensation
A.Overcoming sliding friction
B.Overcoming rolling friction
C.Overcoming fluid friction
D.Overcoming oil wedge friction
最新試題
The output volume of a positive fixed displacement pump can be changed only by （）.
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
A salinity indicator is used to determine the （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
A salinity indicator is used to determine the （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
Thermostatic expansion valves can be adjusted for （）.
The general purpose of a heat exchanger is to （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.