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單項(xiàng)選擇題

Noise in a refrigeration compressor can be caused by （）.

A.worn bearings and piston pins
B.slugging due to flooding back
C.too much oil in circulation
D.All of the above

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單項(xiàng)選擇題

The air charge leaving an intercooler, or after-cooler of an air compressor can be expected to be （）.

A.superheated
B.super-cooled
C.at or below the dew point
D.All of the above

單項(xiàng)選擇題

Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should （）.

A.open the steam line mot valve
B.drain the steam cylinder
C.close the steam cylinder drains
D.open the liquid cylinder drains