Pressure rating of series pumps

[Sawsan311]

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,

 

[LittleInch]

A drawing would help and this often comes up with booster pump / main pump systems.

So long as there is somewhere for the flow or pressure to go if it every goes backwards through the pump then no.

Are there NRVs on the pump discharges? If not why not?

But 2 oo3 series pump is rather odd - never seen that before now.

Also is it equal pressure?

What sort of pressures are we talking here?

You really need a HAZOP to work this out

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