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# Butterfly Valve Minimum DP

05/28/2011 8:42 AM

Hi Wookies,

For a 30" Butterfly valve what is the minimum dP allowed for operation?

Thanks.

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#1

### Re: Butterfly Valve Minimum DP

05/28/2011 11:59 AM

Zero.

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#2

### Re: Butterfly Valve Minimum DP

05/28/2011 10:50 PM

According to H. D. Baumann in the book Control Valve Primer a dP of 5 psi is reccommended. This is if you are using this valve as a final control element. Minimun dP should be 1 psi to enable fluid flow through the valve.

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David Rodrigues
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#3

### Re: Butterfly Valve Minimum DP

05/29/2011 12:49 AM

Yep Butterfly Valve is for control function.

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#5

### Re: Butterfly Valve Minimum DP

05/30/2011 1:49 AM

Too bad you didn't say that part the first time. For useful control, you do need some dP through the valve, but for operability you don't.

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#4

### Re: Butterfly Valve Minimum DP

05/29/2011 12:53 AM

Actually this is a study for my project, we are determining the lowest possible dP value for a 30" Butterfly Control Valve and/or the size of a Butterfly Control Valve for a 0.12 dP.

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#6

### Re: Butterfly Valve Minimum DP

05/30/2011 4:47 PM

What type of butterfly valve? Symmetric, single/double/triple offset, fishtail profile?

If you need to use it as "control valve" and not "on-off" one, some flow should pass through the valve. What about Cv?

The results of the effective process control must depend not only on valve geometry, but on the control instrumentation used too (dead band, hysteresis....).

Kind regards

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