A.stop valves
B.check valves
C.safety valves
D.reducing valves
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A.an electric motor
B.a diesel engine
C.a compressor
D.oil
A.large size of oil globule
B.low temperature
C.high viscosity
D.high flow rate
A.with dirty water
B.with clean water
C.by oily water
D.by mixed water
A.upwards
B.downwards
C.outwards
D.forwards
A.bowl periphery
B.bowl center
C.upper surface
D.lower surface
最新試題
Which of the following statements is correct concerning heat transfer?（）
Which of the listed pumps is NOT a positive displacement pump?（）
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
The major source of chemical contaminants in hydraulic fluid is （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
A pressure drop through the refrigerant liquid line may cause （）.