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Flowrate throught butterfly valves

Flowrate throught butterfly valves

Flowrate throught butterfly valves

(OP)
S!
I'd like to know how can I calculate/estimate the air flow through a butterfly valve as a function of the rotation angle/opening. The catalog comes with the Cv as a function of rotation angle. Can I use the sizing equation in terms of flow, not in Cv?

RE: Flowrate throught butterfly valves

I'm not sure I'm understanding the question, but Cv is used to calculate flow. It gives the relationship between flow and pressure drop. Flow is proportional to absolute inlet pressure. Hence if you know inlet pressure and valve rotation angle, the Cv figures you have can be used to calculate flow.


Regards
Seán Moran
www.expertise-limited.co.uk
  

RE: Flowrate throught butterfly valves

Find an equation that is in the form flow = f(Cv and other variables).  Develop an equation for Cv = f(rotation angle).  Then use algebraic substitution to get flow = f(rotation angle and other variables).

Good luck,
Latexman

RE: Flowrate throught butterfly valves

waterex, as you've said, its diff pressure and actual flowrate (at pipe conditions not STP), so forget the absolute inlet pressure bit entirely.

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: Flowrate throught butterfly valves

(OP)
S!
Thanks a lot, guys.

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