High Pressure Pump-Turbo Booster Pump

How did the phone call to the original equipment manufacturer go?

Please advise the detail of their Service Engineer's recommendations.

A booster pump defines the application of the pump. Not the type! Unable to see the application from here. So you want us to guess? You have a leak down line from the booster pump that is so great that the 36 bar is the best the pump can do.

If you don't want guesses call the OEM and get a service man in there.

My auntie Daphne is a service man. Give her a ring and she'll quote you a price for a site visit.

If your first stage inlet is at 30 and the output is 32 then how do you explain the inlet pressure to the second stage at 42?

The only way this could be happening is that you have a significant leak between the first and second stage of the pump(s).

Is there a mini-flow valve or other drain/lateral takeoff piping circuit between the first and second stage? If so; is it closed and verified as not leaking?

Is the booster pump discharge piping of the correct diameter for the application?

If all of the above is correct then more than likely the booster pump is rotating in the wrong direction or it is rotating too fast and the overspeed is causing cavitation inside the pump inlet cavity.

Look at the pump curve and adjust the speed accordingly for maximum pump operation output efficiency.

Hope this helps.

It is hard to tell with such little information, but it looks like the 42 reading is incorrect. And you have 32/30 in/out of the first stage (2 bar DP), and 36 bar inlet to 2nd stage (6 bar boost from the pump).

Is this normal? What pressure do you normally operate the 2nd stage at?

At these pressures it's hard to tell what sort of plant you have (too low for SWRO, too high for BWRO). some sort of custom plant designed specifically for your water source. So I can't even guess what your normal 2nd stage inlet pressure would be.

But if this is operating lower than normal, then it is common for booster pumps between stages to be controlled by VSD/VFD, to suction setpoint pressure rather than flow.

If the pressure transmitter on the pump suction is reading high (42 bar), then the pump would ramp down to a minimum pump speed (or perhaps even stop).

I suspect the suction PT is reading high, as a result the pump is operating at a minimum pump speed (giving only 6 bar boost).

Please check the accuracy of the pressure transmitted on the suction side of the pump. Hopefully this resolves problem.

Hope this helps,

Anthony