4 replies to this topic

[A mukherjee]

HI all,

I want to know if there is any reason of using TEFLON gasket in the cryogenic fluid pipe lines?
What are the criteria for selecting gasket material in the pipe line?

Regards,
Arpan

[Art Montemayor]

Arpan:

I can answer your basic question very succinctly: NEVER, NEVER use Teflon as a gasket material!

Teflon has no "memory". In other words, the more stress you put into it (such as torqueing a pair of flanges in order to compress the gasket and make it seal), the more the tendency it has to just keep on deforming and it will not spring back to this original shape, resulting in leaks. This is a notoriously well-known characteristic of Teflon and the reason everyone should shy away from using it as a sealing gasket. Teflon gaskets were born to leak. God made them that way.

The guideline to use in selecting a proper gasket is to inform yourself of what gasket fabricator(s) you are going to use. When you have identified them, interview them with the fluids and the conditions you intend to employ their gaskets under and ask for their valued recommendations. Make sure that you are always including the maintenance department of your plant in ALL COMMUNICATIONS AND SPECIFICATIONS as well as in all discussions with gasket applications. If you don't you will regret it. One young engineer who failed to do this in one of the plants I supervised found the tires of his car slashed and a note stating "stop making things difficult for the maintenance department". Always keep your maintenance department informed and aware of what they have to maintain.

[breizh]

Arpan ,

This book may support your query :

http://books.google....aterial&f=false

Breizh

[A mukherjee]

The link is of great help...

[Supraton]

Hello,

we sometimes use PTFE O-rings in mechanical seals, but they are not easy to handle

Martin