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單項(xiàng)選擇題

Reduced capacity, accompanied by vibration and noise at the suction of a centrifugal pump is a result of （）.

A.cavitation
B.water hammer
C.fluid friction
D.steam knock

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單項(xiàng)選擇題

The refrigerant leaves the evaporator of a refrigeration system as a low pressure （）.

A.sub-cooled liquid
B.high temperature liquid
C.oil saturated liquid
D.superheated vapor

單項(xiàng)選擇題

When operating with a negative suction head, which of the following types of pumps will require priming?（）

A.Reciprocating
B.Centrifugal
C.Rotary
D.Gear