Sealing helium gas in medical devices

[mk2000]

Dear all

I am interested in information and design guides for sealing system design. I would like a handbook/design guide where it would tell me how I should approach the problem and what are best practices. Can anyone help me with a site/book/paper especially if it contains information about medical applications?

Thank you
MK

 

[bogiedreamer]

There are very few information regarding sealing principles and practices. Generally, companies guard their sealing technologies and do not publish them. It seems like you need to use a PTFE seal energized by a a 316 SS spring. PTFE seals are superier to Orings in term of life and friction. However, PTFE seals are machined and are generally more expensive. Minimum orders is about $1000. If you purchase it in high volume, then cost is less of an issue.
Check out this website: OmniSeal.com

* note: I work for this company so my advise could be biased. It is up to you to do more research but this website is a start. Not much information in term of education though.

 

[israelkk]

Are you talking on dynamic or static seal?
What is the sealing requirements?
How much cubic centimeter of helium leak is allowed per second/minute etc.?
What is the gas pressure?
What is the environment temperature?
Are you sealing an orifice in a valve or piston? If it is an orifice what is the orifice diameter? If it is a piston what is the piston diameter?

 

[IRstuff]

We use metal only with soldered or welded seals for cryocoolers. The charge is usually good for at least 5 years.

TTFN

 

[longeron]

Parker Hannifin has a great free handbook for O-Rings... parker.com

 

[RichardMc]

Information about seals for medical applications can be found at class-vi-o-rings.com. There is information about USP Class VI and other standards for medical grade seals.

Richard McInteer

http://www.class-vi-o-rings.com