We are fabricating piping components for refrigeration service. These components must be leak checked at 15 bar (218 psig). We are using a gas test media that is 25% helium and experiencing difficulty on maintaining a seal on the flanged connections.
Do you know anyone or any references that could assist us with resolving this sealing problem?
2 Comments
Dr. Peter Mason
August 1, 2008What materials are used to form the seal?
Many materials allow diffusion of GHe fairly rapidly. Viton O rings are usually the seal of choice. What is your detection technique?
By way of comment, vacuum leak checking is far more sensitive to small leaks. Of course, it would not show up leaks that result from the applied pressure, so you would have to do the pressure test in any case.
Ed Bonnema, Meyer Tool and Mfg.
August 1, 2008Good references for vacuum seals are: A. Roth “Vacuum Sealing Techniques” and A. Roth “Vacuum Technology.” Is it possible that the helium is permeating through your seal? If you are re-using o-rings they could even be saturated with helium.