7 replies to this topic

[syfq88]

Dear all,

 

For those who have done some control valve sizing, is there a correlation for CV rated, CV flow coefficient and stroke opening of Control valve?

 

Say that. 

Characteristic is linear, Cv rated is 15 and Cv flow coefficient is 12.158. what will be the stroke opening for control valve then? 

 

[fallah]

Hi,

 

Appears you are talking about on-off control valves...In general stroke opening (closing) time for such valves is one second per one inch valve size...

 

But, actually the stroke opening (closing) time for a valve would be specified based on process/safety requirements to adjust the required rate opening (closing)...

[syfq88]

Dear Fallah,

 

Thank you for your response. This is not an on/off control valve. by stroke opening i am referring to the control valve opening 

[ankur2061]

syfq88,

 

As I understand, the information you are looking for is % opening corresponding to a particular valve  Cv. This information should be available from the valve manufacturer depending on the type of control valve i.e globe, plug, butterfly etc. The best place is to look at the manufacturer's data from his catalog for the given valve size. You may interpolate the valve % opening if valve % opening data is given for 2 values of valve Cv and your valve Cv falls between these values.

 

Regards,

Ankur. 

[Ajay S. Satpute]

Hi,

 

Below link shall help you.

 

http://www.cheresour...lve/#entry82430

 

Regards.

 

Ajay S. Satpute

[fallah]

Hi,

 

Below link shall help you.

 

http://www.cheresour...lve/#entry82430

 

 

Hi,

 

The link is about "typical curves of on-off valve", while OP has previously declared (post No. 3) that the valve isn't an on-off control valve...!

[Ajay S. Satpute]

Fallah,

 

ON/OFF or NOT, control valve basics remain the same. I still believe the link suggested is quite valid.

 

Have a nice day!!!

 

Regards.

 

Ajay S. Satpute

[sheiko]

If the valve is linear, the % opening is equal to 12.158/15 = 81%