A.packing gland
B.mechanical seals
C.lantern rings
D.wearing rings
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A.through a detachable hose connection
B.after passing through an activated charcoal filter
C.after chemical analysis shows it is fit for consumption
D.through a solenoid operated three-way valve
A.worn gland sealing shaft
B.worn wearing rings
C.a bent shaft
D.reversed pump coupling
A.A power end and fluid end
B.A propeller and educator
C.A volute and impeller
D.A turbine and piston
A.water seal pipe is plugged
B.pump is not primed
C.seal ring is improperly located
D.impeller is flooded
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
最新試題
Low compressor head pressure in a refrigeration system can be caused by（）.
Which of the following statements is correct concerning heat transfer?（）
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
A pressure drop through the refrigerant liquid line may cause （）.
Which of the listed pumps is NOT a positive displacement pump?（）
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.