單項(xiàng)選擇題

Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.

A.has continuously for a long period
B.suction pressure is below normal
C.oil level is below normal
D.starts after a long idle period

你可能感興趣的試題

單項(xiàng)選擇題

Strainers are commonly used in hydraulic systems to （）.

A.protect the pump from fine soluble contaminants
B.prevent solid particles from entering the pump
C.prevent solid particles from entering the filter
D.protect the directional control valves

單項(xiàng)選擇題

On which of the following heated surfaces of a flash type evaporator would you be more likely to find soft scale formation?（）

A.Feed-water heater internal tube surfaces
B.Internal distillate cooler tubes
C.Flash chamber vertical surfaces
D.Distilling condenser tubes