Trade names include Teflon, Syncolon, Fluon, Poly (ethylene tetrafluoride)
Back-up rings are used in conjunction with O-Ring for both static and dynamic sealing applications.
The design of PTFE Back-up rings it used to overcome the problems of 'O'-Ring extrusion when the system pressures are greater than the sealing capabilities of an unsupported 'O'-Ring.
The use of P.T.F.E. for anti-extrusion rings has many advantages over 'hard rubber' materials, particularly at system pressures.
The cold flow characteristics of PTFE are used to full advantage in reducing the extrusion gaps to a minimum and allowing automatic compensation for wear.
The capability of specialist compounding to suit extremes of duty combined with a high resistance to virtually all chemicals, low friction and wear rates render PTFE as the ideal material for anti-extrusion devices.