3 replies to this topic

[sidewinder]

I have an equal percentage control valve online and it has been fitted with a travel stop to limit the valve's Cv. I have a flow of 150 m3/h through it and is opened at 55%. I am not sure what the travel stop has limited the Cv of the valve to, and the installed valve Cv without the travel stop is 136.

 

I need help in calculating the operating Cv at the conditions mentioned above. Is there a way to calculate the max Cv with the fitted travel stop? 

 

Regards

 

Luthando 

[Padmakar Katre]

Hello,

Get the design data sheet for control valve and vendor details of the same, things will be clear.

[sidewinder]

Thanks Padmakar,

There has unfortunately been credibility issues with the valve documentation and I find myself having to rely on other means to determined or estimate the Cv of the valve. I also have valve flow characteristic curves but not sure how I might use them.

[ChemEng01]

Why dont you just use the control valve sizing equations. 

 

I dont know if your dealing with gas or liquid or 2 phase but if you know your flow, pressure drop, and fluid composition (specific gravity / viscosity)  you can calculate the reduced CV of the valve using the correct equation using the known flow you mentioned.

 

You can use equations and do it by hand or use an online calculator (eg http://www.hassmfg.com/vscform.pl/)

 

cheers

Edited by JRudd, 26 September 2013 - 02:46 AM.