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Question: In a multistage centrifual pump can the impellers be of same size or it should be different?

(Posted by: krish p on 2007-07-21 11:03:33)

In a multistage centrifugal pump do the impellers are always different in size or can it have same size also?

Posted by: jdsheth2004 on 2007-07-21, 12:00:06

*In a multistage centrifual pump the impellers can be of same size . *To balance the load,manufacturers taking utmost care: 1.They keep the impeller of the same size. 2.Discharge of the first stage enters the suction of the second stage 180 degree opposite . 3.They also keep the pressure balancing holes to keep the impeller exactly in the centre of the impeller housings. 4.Even , to keep the balancing , it is advisable to keep the keyways of the couple halves 180 degree opposite. *Another advantage is that , you will get a interchangeability between the impellers and its housings in some cases. Please have a look on the following link: animatedsoftware.com/ pumpglos/ impmulti.htm

Posted by: Emil Alexandrescu on 2007-07-21, 11:09:19

In most old models they were the same size. And these models are still fashionable - if they don't have to meet tough performance criteria.

Posted by: Norrie on 2007-07-21, 12:21:57

In a multistage centrifugal pump, all impellers are the same size as there is no actual compression of the liquid taking place. It's simply the velocity from each stage being changed to pressure in the casing diaphragm diffusers. The liquid then enters the 'Return Passage' which feeds the liquid into the 'EYE' of the next impeller and the process is repeated through the stages. The number of stages and the pump speed decide the discharge pressure. Volume flow, depends on the physical size of the pump.

Posted by: William F on 2007-07-22, 12:35:07

I can only speak for fabricated blowers and impellers in that can be the same size. They work on the principle that air has weight and when fan spins centrifugal forces fling air molecules away from the center, compression is just the by product of internal resistance and in most cases not desirable. W