Back up ring



Back up rings are used in high pressure seal applications, along with higher durometer O-ring material.

The backup ring is used to prevent extrusion of the O-ring through the close clearance between the O-ring groove and the shaft.

Teflon® is a common back up ring material.

The seal loses some of its flexibility with the installation of this back up ring, but at the higher system pressures, flexibility is not all that important.