Back Up Rings
Backup Rings are not designed to perform any sealing activity or function in a sealing application. Backup Rings are designed as an additional product to provide back support and protection to a seal or in mostly cases, an O Ring.
The main function of a Backup Ring is to reduce up an extrusion gap in a seal housing and prevent the main seal from being forced out of the gap which can damage and finally failure of the main seal. Backup Rings are basically manufactured from extrusion-resistant high modulus materials which makes them able to withstand higher pressures than their partnering seal. This then allows seals for the use of a lower hardness material to provide better low-pressure sealing capability.
Backup Rings allow the use of O Rings in high pressure applications and in some certain instances will tolerate over twice the pressure handling capability when compared with O ring without any hold of back up ring.
SOME OF BACK UP RING WITH DIFFERENT MATERIAL