Impeller

A rotating component with blades or vanes that transfers energy between a shaft and a fluid.

In centrifugal pumps the impeller accelerates fluid so the casing can convert velocity into pressure. Flexible-vane impellers are widely used in engine raw-water and utility pumps, while propellers and waterjet impellers apply related principles but have distinct arrangements and names.

Condition and failure modes depend on type. Flexible impellers can harden, crack, lose vanes or run dry; rigid impellers can suffer erosion, corrosion, fouling and cavitation. Lost fragments should be recovered from downstream passages, and replacement material and rotation must suit the pump and fluid.