1 reply to this topic

[Ilyes]

1-Does anyone know how to determine minimum flow of level control valve located at pump discarge because I have case of max=110% norm=100% min=39%, why is it 39% in the process Datasheet.
(While the pump minimum flow =50% in the process DS I don't know if it's from pump vendor because there's minimum circulation control valve too, so why is it 50% for the centrifugal pump too?.
2- how to calculate for the above control valve the ∆p of max, normal, minimum flow of a control valve to fill it in the process Datasheet (is it by conell method).

[breizh]

Hi,

Not knowing your process, I guess the value of 39% is defined based on the NPSH of the pump to prevent cavitation.

check for NPSH a.

Minimum flow is based on the manufacturer recommendation to prevent damages (thermal and mechanical).

Ring the pump manufacturer representative to get confirmation.

attached documents to support your query.

https://empoweringpu...r-minimum-flow/

Control Valve Sizing Theory, Cavitation, Flashing

EDIT:

For those interested I've attached the paper referenced in your post, from J.R Connell.

Methodology could be applied to your case.

Good luck 

Breizh

Attached Files

•  Valvesizing reference.pdf   910.26KB   0 downloads
•  realistic-control-valve-pressure-drops-pdf-free.pdf   1.09MB   0 downloads
•  valves_arv.pdf   1.77MB   4 downloads
•  valve sizing emerson.pdf   1.13MB   2 downloads
•  minimum flow centrifugal pump.pdf   217.72KB   2 downloads
•  flow recirculation.pdf   3.28MB   2 downloads