Seal to seal-off gases
Seal to seal-off gases
(OP)
We use O-rings for metal-to-metal seal, to seal-off liquids for a high temperature application. But elastomer are permeable to gases. What would someone use to seal-off both liquids and gases(no permeations allowed) for the same high temperature(400 degree F) application?





RE: Seal to seal-off gases
There are also elastic metal o-ring seals which has a closed hollow section or open C type section but I am not sure how good they can seal.
RE: Seal to seal-off gases
RE: Seal to seal-off gases
For example when we needed to seal a helium pressure vessel we used a coned 1100 alluminum disk that is crushed between the vessel openning and a cap.
RE: Seal to seal-off gases
RE: Seal to seal-off gases
Garlock-Helicoflex
scalleke
RE: Seal to seal-off gases
If you look at the Helicoflex on page 7 you will see that the seal is designed such that it may have an air leak at a rate up to 0.0001 cc/sec-atm. Meaning, at higher pressure difference the leak will be higher.
In the original post Vic123 says that even permeation rate is not allowed which is usually much smaller than leak rates so leak is absolutely forbidden. Therefore, I do not believe that Helicoflex will do the job.
RE: Seal to seal-off gases
Teflon has low permeability, low friction (if dynamic), and with the spring energizing the seal is an extremely effective device in sealing hard to seal gases like N2, He.
check this out
http://w