PTFE SEAL RING, SHAFT SEAL, O RING, ENCAPSULATED O RING

PTFE (polytetrafluoroethylene, better known as Teflon®) and it’s derivatives like FEP and PFA, is one of the most inert and chemically resistant materials that an o-ring or seal can be made from. It has been described as the “slipperiest stuff in the world” because of its very low coefficient of friction. There are some elastomers today that approach PTFE’s chemical and heat resistance but their high cost can be a drawback. PTFE can be modified with fillers to improve its properties depending on the applications requirements.  

PTFE O-rings are typically used in static applications while PTFE lip seals (with metallic springs or rubber used as an energizer) and piston rings will be used in tough dynamic applications where pressure and heat or high cycles are a problem. PTFE also makes excellent Backup Rings that boost the sealing capabilities of an o-ring to much higher levels.  It is also possible to encapsulate an elastomeric ring with a seamless FEP tube creating a unique o-ring with the properties of both the elastomer and the PTFE.  

PTFE can be extruded, skived into thin tape or sheet, and molded by several processes depending on the outcome desired. It is also readily machineable, lending itself to special parts and configurations to suit the application at hand. Ball valve seats are a common use for PTFE both molded to near net and machined for special or low volume requirements.  

PTFE can now be processed into soft joint sealing tape and gaskets by a special “expanding” process allowing its use in applications where a flange or sealing surface is less than ideal or needs a low bolt loading such as glass flanges. 

Other engineering plastics such as: UHMW (Ultra High Molecular Weight Polyethylene), Nylon®, Delrin®, PEEK® (Polyetheretherketone), can be supplied in sealing configurations as well as machined parts. Give us a call and we will be glad to help you with any sealing problem that might require a “plastic” or PTFE solution.

Teflon, Nylon, and Delrin are registered trademarks of DuPont.

PEEK is registered trademark of Victrex PLC.