Engineering · Pumps — Centrifugal vs PD
Which statement correctly distinguishes a centrifugal pump from a positive-displacement pump?
- AA centrifugal pump delivers a fixed volume per revolution regardless of head
- BA positive-displacement pump cannot build high pressure
- CA centrifugal pump's discharge varies with head and it must not be run for long against a fully closed discharge✓ Correct
- DA centrifugal pump is self-priming in all cases
Explanation
A centrifugal pump's flow falls as head rises (per its pump curve) and overheats if run dead-headed. A positive-displacement pump moves a fixed volume per stroke/rev and can build dangerous pressure if the discharge is closed — so it needs a relief valve.
Authority: Modern Marine Engineer's Manual; pump theory
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