Back-up rings are used with a primary seal such as an o-ring in both dynamic and static applications to prevent extrusion of the o-ring when it is subject to high pressures, there are excessive extrusion gaps present in the application, or the o-ring is exposed to elevated temperatures. Elevated temperatures (160°F and higher) impose a severe burden on the physical and mechanical properties of rubber O Rings which further increases their tendency to extrude.

A back-up ring is designed to fit between the O-ring and the extrusion gap and prevent the extrusion of the O-ring.

While back-up rings are used in conjunction with O-rings in both static and dynamic sealing applications, the gland they fit in must be specially designed to fit both the O-ring and the back-up. For more information on gland design please visit Hypax static or dynamic gland design guides.

Material available:
PTFE Backup Ring – Temperature range: -55 °C to + 200 °C
NBR 90 Shore – Temperature range: -40 °C to + 110 °C