Back-up rings (Anti-extrusion rings) are installed to prevent the extrusion of elastomeric o-rings and Quad rings (X-Rings) under extreme pressure into the clearance gap of the groove.
Back-up rings are typically installed where the system pressure exceeds 10 MPa (1,500psi).The o-ring groove has to be widened to accommodate the back-up ring, 2 back-up rings ( 1 either side of the o-ring) are installed in double acting applications.
Back-up rings are normally supplied as a spiral ring with 2 turns for ease of fitting, they can also be supplied as solid rings or solid with a scarf split if required.
Back-up Ring Materials
ERIKS back-up rings are manufactured from virgin PTFE, but can also be supplied in a range of filled PTFE's or PEEK depending on the application.