O-Ring Design 1

[Jack808]

I am designing an o-ring groove or gland on a pressure vessel for 150 psi helium gas. The pressure is internal and requires an axial or face seal.

I have found great guides and, right now, all of my calculations fit the desired parameters; however, I would like to increase the gland width.

None of the guides could tell me why the gland fill or gland volume has a minimum of 50%. It has been stated that this minimum is to reduce o-ring motion within the gland. I speculate that if the o-ring is ever in motion, which I hope it is not, too much room will allow the o-ring to twist and fail.

My question is:
What is the real reason for the minimum value and can I safely increase the gland width and go below the minimum of 50% gland fill?

I have attached the o-ring design guide for reference.

 

[israelkk]

Be aware that face seal gland outside diameter should be as close as possible to the O-ring outside diameter, Otherwise the internal pressure will stretch the O-ring radially which will destroy the O-ring. If the pressure comes from the outside then the gland inside diamter should be close to the O-ring inside diameter to support the O-ring from "buckle" toward its center.

 

[unclesyd]

If for some reason you have problems with your O-ring you might want to look at the Helicoflex Seals.
We use these on He, H, and O2 at high pressure with great sucess.

http://www.Helicoflex.com