6 replies to this topic

[Brightonnk]

Hi everyone.. I've done a quick google search but can't find what im looking for.

What does it mean by a 'control valve sizing' and what does a 'control valve sizing program do'... what does the program size?

When i googe it i find programs to do it for me but im not even sure what its meant to do..?

Hope someone can help me!

Thanks

[Bobby Strain]

Go to the Emerson site. All you need is there.

Bobby

[Brightonnk]

Thanks,

is this it.. http://www.documenta.../book/cvh99.pdf

[katmar]

I hope that you know that flow through an orifice results in a pressure drop, and that for a given flow rate the smaller the orifice the larger the pressure drop? Once you have mastered that concept, think of a control valve as a variable area orifice. As the valve opens and closes the flow area through the valve changes and, again for a given flow rate, the pressure drop will vary.

Valve sizing is simply the process of matching your available pressure drop with the actual pressure drop through the valve at a given flow (or range of flows). The Emerson book you found (which used to be on every engineer's bookshelf, but now sits inside their computers) will tell you how to calculate the size of the valve (called its Cv, and explained in that book) for the pressure drop you require. The maximum Cv of the valve depends on the size of the valve and the valve's internals (also in that book). The Cv of a particular valve at any time depends on its degree of opening - you guessed it, also in the book. The relationship between the valve opening and the resulting Cv is called the valve characteristic.

By adjusting the position of the valve you change the Cv and the pressure drop, thus allowing you to change the flow rate through the valve and your equipment.

[Brightonnk]

Thank you- you've told me everything I need to know!

[Shivshankar]

Hi,

Check below link

http://www.cheresour...ve-calculation/

http://www.isa-is.or...rary_valves.htm


Regards
Shivshankar

[Brightonnk]

So many great websites- Im spoilt for choice! Thanks everyone