axial float in multistage centrifugal pump

[pradeep4u]

Dear All,

I want to know that during assembly of multistage centrifugal pump if we get axial float less than required in the manual. What is the solution. In our KSB make 9 stage centrifugal pump minimum float is 6mm to be maintained at every stage as per manual. But if we get float less than required then what action we have to take. What happens if we get float more than 6mm in each stage.

Please guide me with your precious inputs. Thanks in advance. I am attaching cross section drawing and float measurement area for your kind reference

Regards

Pradeep

 

[electricpete]

I wonder if the float is measured as a check on proper assembly. If you don't get the expected measurement then I'd ask why. If you got the correct measurement after assembling the previous stage but you got a low measurement on the next stage, then I'd wonder if that impeller got stuck on the shaft. That could have a variety of effects, one is that if the impellers don't end up positioned correctly with respect to the stationary parts then I think that can affect pump performance.

 

[EdStainless]

The wrong amount of float will result in pressure imbalance across the impellers and excessive thrust wear.
Go back and check dimensions on the individual parts.
And then re-stack and check for free movement.
Either the parts were machined wrong or you put them together wrong.

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P.E. Metallurgy, consulting work welcomed

 

[Artisi]

Asking KSB would be good start.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)