4 replies to this topic

[SawsanAli311]

Dear All, 

 

For 3 pumps being in series, any one of the pumps can be in standby and hence each pump will have a forward bypass equipped with two dissimilar check valves.The bypass is interlocked with pumps inlet and outlet isolation such that it is never opened as long as the pump is in operation.

 

Do you agree that the design pressure rating of all pumps starting from the first pump shall be equal to the combined differential head of the system, since any loss of any pump will cause the upstream preceding pump's to experience the full system shut off pressure specifically under common blocked outlet scenario. No credit is given to the favorable action of the minimum flow control nor to the two check valves on the bypass since they don't serve overpressure protection purpose unless they are tested or inspected+ since the bypass itself is isolated while pump is in operation. 

 

Thanks 

 

Regards, 

[Sharma Varun]

please upload a sketch & give brief description of process, is it a Pipeline application?

[thorium90]

Im curious why there is a need for such a complication of using 3 pumps in series if the pressure can be achieved by just one pump.

[breizh]

Hi,

A sketch  will save thousand of words and will be understood by peers .

good luck

Breizh 

[Technical Bard]

If you do have pumps in series, the downstream design pressure shall be the combined differential heads at zero flow, plus the design pressure of the suction of the first pump.  The interstage pressures should be set based on the sum of the differentials to that point.