Back-up rings are the most common anti-extrusion devices in dynamic sealing. They provide simple solutions to safely increase system pressure or solve an existing seal extrusion problem. Back-up rings function by positioning a more robust material adjacent to the extrusion gap, taking the seal’s place and providing a barrier against high pressures. Back-ups can be used to offset the reduced pressure rating effects of wear rings or to improve seal life at increased pressures. They can also be used to protect seals against pressure spikes, or to ensure seal performance at higher temperatures.

Ptfe Backup Ring supplied by Seals is available in the following material specification such as virgin PTFE, which is used mainly for o-rings, backup rings and for machined parts used in special applications requiring chemical inertness and limited strength. Even they are ideal for use in cryogenic applications.

Bronze filled Ptfe is used in dynamic sealing applications, where the bronze filler gives improved wear resistance, hardness and compressive strength. The electrical properties and chemical resistance are reduced. Graphite filled Ptfe has significant increased thermal conductivity, reduced level of creep. They are self-lubricating, therefore suitable for high-speed applications, without the need for exterior lubrication and applications, which need to remove thermal energy and/or static electricity.

Glass filled Ptfe is used, where there is a need for improved wear and increased coefficient of friction. They are ideal for high dynamic applications E.g. High rotation pumps. These high-performance Ptfe seals are said to provide exceptional life, high chemical resistance, and lower friction that versus conventional elastomer seals. Ptfe seal handles wide variations in pressure and temperature and surface speeds.