Some valve specifications, such as ANSI/FCI 70-2, specify an allowable leakage rate through a valve as a percentage of rated valve capacity. The definition of "rated valve capacity" is vague. The leakage rate is measured with the valve closed so the pressure differential is the test pressure. If I use the same test pressure as the pressure differential across the full open valve, I can use the Flow Coefficient of the valve, Cv, to calculate an expected flowrate through the open valve. This flowrate is huge and will certainly choke. Is anyone aware of a better definition of rated valve capacity?
Red Flag Submitted
Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.
Reply To This Thread
Posting in the Eng-Tips forums is a member-only feature.