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單項(xiàng)選擇題

To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the （）.

A.shaft and impeller
B.motor and pump shaft
C.casing and impeller wearing rings
D.lantern ring and impeller

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單項(xiàng)選擇題

In a radial piston pump, reversal and control of fluid flow are accomplished by moving the （）.

A.central valve
B.radial plunger
C.floating ring
D.cylinder body

單項(xiàng)選擇題

Increasing the moisture content of conditioned air is known as （）.

A.moisturizing
B.dehumidification
C.dampening
D.humidification