Fisher Regulator Sizing
Fisher Regulator Sizing
(OP)
I am sizing a Fisher regulator for air and I have calculated the Cv required . The product data sheet(s) however give me "wide open flow" and C1. I understand the definition of C1 but but how does this relate to my calculation? Is my criteria that I nedd to be below the wide open flow coefficient? How can I get the available Cv the valve?





RE: Fisher Regulator Sizing
Did they give Cg? They should have, C1 and Cg are both needed in Fisher's universal gas sizing equation.
Good luck,
Latexman
RE: Fisher Regulator Sizing
RE: Fisher Regulator Sizing
You have [Cv = Cg/C1]wide open, right? You also calculated [Cv]required, right? Seems to me:
% open = [Cv]required / [Cv]wide open
Is the CV ~ 50% open (ideal) or at least within the 20-80% or 25-75% open range?
Good luck,
Latexman
RE: Fisher Regulator Sizing
That's a good point, I see what you mean. So if the wide open Cv is just that - 100% valve opened, it is the same thing as the term "rated Cv" for any other control valve.
RE: Fisher Regulator Sizing
The wide open Cv or Cg is used for safety relief valve sizing only, not for sizing the valve itself.
All of the Fisher data sheets have charts for capacity and these are what I use to size them, then use the wide open Cv to size the relief (full disclosure: I work for the Fisher local business partner - rep). I would call your rep and have them size it, it is their job.
FYI: Cg is the gas flow coefficient, Cv is the universal flow coefficient, and C1 is the ratio of Cg/Cv
RE: Fisher Regulator Sizing
rmw
RE: Fisher Regulator Sizing
Good luck,
Latexman