Pressure changer

Could somebody please tell me how I can vary (increase/decrease)the pressure in a pump/motor setup to compensate for the high and low pressures at the various operating speeds.

 

[owlscreech]

Why not a pump discharge control valve that controls pressure?

 

[Shahin71]

If you have a positive displacement pump you need to design the motor to give max required power for the max pressure.Pressure can be reduced IF REQUIRED by resetting the built in by pass(pressure relief valve).

 

Yes, but how could I increase the pressure as well. It needs to be efficient

 

[MortenA]

Variable speed control will change the head of the pump in accordance with:

Q: flow
H: head
P: Power
N: speed

subscript
n:nominal
x:selected spped

Qx/Qn=Nx/Nn

Hx/Hn=(Nx/Nn)^2

Px/Pn=(Nx/Nn)^3

You can get variable frequency control for all pump sizes allthough the (motor control) priciple may vary.

Grundfos (eg) deliver small variable frequency control pumps with build in control, check their web page:

http://www.grundfos.com

Best regards

Morten