discharge pressure centrifugal pump 5

[Muud]

I am trying to determine the discharge pressure of a centrifugal pump in a closed water system.

The centrifugal pump sucks the water from the bottom of an open tank (open top and under atmospheric pressure) and circulates it through different small vessels before finally driving the water back into the same open tank (but through a different inlet).

From the pump performance data I can see head at discharge at specific flow rate. Since in this case there is no elevation difference as water is taken and recirculated back to same tank I guess the static head will be zero. I believe if I just take the discharge head and by dividing it by 2.31 the result will be the discharge pressure of pump. Is this way of calculating the discharge pressure in this closed loop system correct?

 

[LittleInch]

The bypass line should be sized for the minimum flow required for the pump. For your pump I would have thought this was about 8-10 m3/hr.

If you then calculate what the diameter of the bypass line should be for the length you have assuming you have 40m differential head you can then ignore the control valve or orifice size. It might be a small diameter...

Or you can add a flow meter or spot measure it somehow and adjust the control valve to get to about 10 m3/hr. Your differential pressure is pretty constant so once you get 8 -10 m3/hr going through the bypass line you shouldn't have to adjust it anymore.

If you do that I can't see any problem in the piping layout you have now and I suspect your bubbles / vortexing etc will disappear.

When your measured flow through the meter exceeds 10 m3/hr, just shut the bypass line.

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