In a sealing application, backup rings provide added extrusion resistance and prevent damage to O-rings and seals when subjected to high pressures, larger extrusion gaps, and/or high temperatures.
A backup ring is made of a hard, extrusion–resistant material such as high durometer nitrile, Viton (FFKM), or PTFE. They are designed to fit between the O-ring and the extrusion gap and prevent extrusion of the O-ring. If unsure about the precise size of the gap, it is always best to use two backup rings per one O-ring.
NCS offers backup rings, contoured backup rings, and PTFE (Teflon®) backup rings. Our PTFE backup rings include solid (uncut), single turn (scarf cut), and spiral (multi-turn) rings.