Depends on the temperature that you are running at. Viton is more resilient and easier to seal, but is limited to about -40C. PTFE takes more pressure to seal and cold flows, but can handle the temperature.The lady at the terpp store (u know the one...) told me when using 100% propane it's good to upgrade to ptfe gaskets instead of the usual viton gaskets I currently run. Has anyone had any experience with this or using viton gaskets with propane?
Thanks guys you are the best.Depends on the temperature that you are running at. Viton is more resilient and easier to seal, but is limited to about -40C. PTFE takes more pressure to seal and cold flows, but can handle the temperature.
A sandwich gasket with a viton center and PTFE outer cover is the best solution.
Cold flow means when you put pressure on it, it eventually deforms by flowing away from the pressure and squishing out somewhere else.Thanks guys you are the best.
Im not using a dry ice or vaccum jackets around my columns so I would think it would be hard to get it to -40 but would hate to see what happens when the viton gaskets fail =O
What does it mean when the PTFE "cold flow"?
Lately I have been liking the very slow drip method because it freezes the columns nicely and seems to make things lighter, not to mention it's the only way to run three of the 5# terpp tubes at once on a tank holding 22# of solvent (takes an hour to run out of solvent in the tank). Never seen the outside of the tubes get below 0 degrees with a Newport 20-30% propane mix, so I would think reaching -40 would be tough, although I would like to try to the vaccum jackets here they keep the temps down well.