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單項選擇題

If a centrifugal pump vibrates and is noisy when operating, the cause could be （）.

A.worn gland sealing shaft
B.worn wearing rings
C.a bent shaft
D.reversed pump coupling

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單項選擇題

Which of the devices listed is common to all types of pumps?（）

A.A power end and fluid end
B.A propeller and educator
C.A volute and impeller
D.A turbine and piston

單項選擇題

A centrifugal pump may fail to deliver water when first started if the （）.

A.water seal pipe is plugged
B.pump is not primed
C.seal ring is improperly located
D.impeller is flooded

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