5 replies to this topic

[aanita]

How can I calculate gas flow through a control valve from it's opening, when pressure and all other operating parameters are normal.
Best regards.

[katmar]

Your valve supplier will be able to provide you with either a graph or table that correlates the valve's opening with its effective Cv. This curve is known as the valve's characteristic curve. This will allow you to calculate the Cv for the known opening. And once you have the Cv you simply use the standard valve sizing formula to calculate the flow.

I have done this myself and it does give a good indication of flow, but be aware that the characteristic curves are fairly generic and it can be difficult to read the valve opening exactly, so you will get limited accuracy.

[aanita]

Your valve supplier will be able to provide you with either a graph or table that correlates the valve's opening with its effective Cv. This curve is known as the valve's characteristic curve. This will allow you to calculate the Cv for the known opening. And once you have the Cv you simply use the standard valve sizing formula to calculate the flow.

I have done this myself and it does give a good indication of flow, but be aware that the characteristic curves are fairly generic and it can be difficult to read the valve opening exactly, so you will get limited accuracy.

Thankyou very much for your time.

[Andrei]

Two very useful free resources:
http://www.emersonpr...umentation.html
http://www.emersonpr...tvuesizing.html
In Fisher Control Valve Handbook you can find the "Fisher Formula" pretty much a standard for pressure drops/flow calcs across valves.

[latexman]

In my opinion, Crane's Technical Paper No. 410 is a reference that should be on every engineer's desk that does fluid flow calculations. It is concise, yet handles the basics thoroughly. While it may not have all the information to solve your problem, it will give you an understanding of what you need and how to use it. It's available for purchase on the internet for a very modest fee in an English or SI version. Google it.

[Qalander (Chem)]

In my opinion, Crane's Technical Paper No. 410 is a reference that should be on every engineer's desk that does fluid flow calculations. It is concise, yet handles the basics thoroughly. While it may not have all the information to solve your problem, it will give you an understanding of what you need and how to use it. It's available for purchase on the internet for a very modest fee in an English or SI version. Google it.

Just a general comment, I think almost all

university/ technical colleges/polytechnics and engineering school

libraries have this valubale consulting resource alongwith

many other impotant titles

available usually in hard copies and even soft copies shape
for neeful consulting reference.
Best regards
Qalander