Centrifugal Pumps 1

[SENGUTTUVAN]

Hi
I would like to know that for centrifugal pumps , for an open valve start up ( auto start pumps) , whether it should be designed for End of Curve. That is , NPSHR should be less than NPSHA even at its end of curve. My Process dept is insisting to select a vendor who can satisfy the above condition. I am arguing that it need not be designed for that since centrifugal pumps can be started with discharge valve in open condition and no problem will happen for both the pump as well as the drive motor. Can U please throw some light on this " When a centrifugal pump should be designed for the End of curve operation.

 

[nickelkid]

I have not seen the "end of curve" requirement before, but this requirement is fairly common:

From rated capacity up to 125% of best efficiency point the NPSHR shall not exceed the NPSHA.

Have you any accumulated data on the cost impact of "End of curve"?

 

[Artisi]

Think you will find the answer in the pump engineering forum where you have already ask the same question.