单选题If a centrifugal pump vibrates and is noisy when operating, the cause could be （）.Aworn gland sealing shaftBworn wearing ringsCa bent shaftDreversed pump coupling
单选题
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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