6 replies to this topic

[panagiotis]

Hello engineers!
I was trying to understand how the variable speed pump works!
And then a new doubt was created, which is very fundamental.

A pump increases the flowrate in a system or the pressure?

Why increase in the speed of the pump increases the flowrate of the pump?

There are so many different opinions in Google. But, I would love to hear your opinion and understanding on this basic fundamental knowledge.

Edited by panagiotis, 11 October 2022 - 02:06 PM.

[breizh]

Hi,

Let you study these documents and also pump's curves @ different RPM. 

Centrifugal Pump converts kinetic energy to movement thus flow.

Good luck

Breizh 

[panagiotis]

Hi Breizh,
Thanks for sharing these documents with me.

[ali99]

Good morning / evening Gents, 

 

could you please resend the document, it will be useful for me.

 

Thanks.

[breizh]

Hi,

Document attached 

Breizh

[ali99]

Hi Breizh,
Thanks for sharing these documents with me.

[StealthProg]

Increasing centrifugal pump speed increases the pressure, which overcomes the pressure drop in the pipework and therefore increases flowrate, pressure drop is proportional to V^2.  You have to remove the flow control valve for a variable speed drive to work (or leave it fully open).  When the flow control valve is in place with a fixed speed pump, some of the energy is wasted and increases the enthalpy (temperature) of the fluid.  The flow/pressure drop relationship is balance by the valve opening wheaeas with a variable speed drive it's balanced by the speed of the pump.