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Cv for standard Globe Valves

Cv for standard Globe Valves

Cv for standard Globe Valves

(OP)
Hi does anyone know a source for Cv values for standard cast steel globe valves? My project is using 250NPS to 400NPS valves.

Thanks

RE: Cv for standard Globe Valves

manufacturer's literature is the only place that really matters.  

If you estimate 15D^2 you won't be horribly wrong.  
1":15
2":60
3":135
etc.  

RE: Cv for standard Globe Valves

JimCasey is correct.

To get the Cv for a particular valve, you need to go to the manufacturer.

Oh, by the way, the Cv is more dependent on the port size than body size (yes, the body size also matters, but a bit less).

For a Fisher 1" D body:

Port   Cv
1/4"   1.66
3/8"   4.03
1/2"   6.51
3/4"   12.3


"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
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RE: Cv for standard Globe Valves

The manufacturer determines the Cv by lab testing, usually to the ISA S75 standards.

I agree with the others, only obtain the information from the individual manufacturer. (I have many years experience in this.)

Paul
www.ostand.com

RE: Cv for standard Globe Valves

(OP)
Thanks

The valve sizes are 250 - 400mm.

The valves are standard isolation API 600 type globe valves, not control valves.

I can not find data from the manufactures. but since they are all the same pattern they maybe genic data avaible

cheers.

RE: Cv for standard Globe Valves

If the valve is throttling a gas, you will also need to know the Xt as well as the Cv ( based on ISA nomenclature)to predict the flowrate.

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