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What is an impeller of pump?
- Oct 30, 2018 -

What is an impeller  of pump?

A standard centrifugal pump impeller is constructed of a group of elongated, solid-walled chambers attached together in the shape of a circular ring. The ring is spun quickly and the liquid that enters the inside end of the chambers is flung out at high speed from the other end. Figure No. 1 above shows a section through centrifugal pump wet-end showing regions of low and high pressures.

The longer the chamber (i.e. a bigger diameter), the faster the liquid leaves the ring for a given speed. Alternately the faster the ring is spun the faster the liquid is flung out. High tip speeds produce higher pressures. The pressure generated in a centrifugal pump is the result of the high-speed liquid hitting and stopping at the volute wall and so changing its energy of motion (momentum) into pressure energy. The pressure then forces the liquid out the discharge nozzle.

To stop the pressure from returning to the suction inlet and back through the chambers, the gap between the impeller and the volute is made very small at the suction nozzle inlet. Usually wear rings are fitted to the impeller. When the wear from the small amount of leakage that does occur gets too bad they are changed over for new.


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