9K Backup Ring

Chesterton 9K Anti-Extrusion Rings, often referred to as back-up rings, have no intended sealing function. 9K provides protection to pressurized dynamic and static seals (including O-Rings) from extruding into equipment clearances while under  pressure, thus protecting seal components from premature failure and prolonging their service life. Protection is provided by tight fit of the anti-extrusion rings in the seal groove to minimize the extrusion gap.

9K anti‑extrusion rings are recommended when hydraulic system pressure exceeds the seal’s extrusion‑resistance limits, when fluid pressure spikes rise above normal operating levels, or when system temperatures become high enough to reduce the seal’s ability to resist extrusion. They are also advisable in applications where nonmetallic bearing bands are used, as these can increase radial clearance and enlarge the extrusion gap.

9K anti-extrusion rings are available in various extrusion-resistant materials and custom profiles. Split design options are available for ease of installation.

Each ring is individually manufactured and provides excellent performance, as a supporting element to piston, rod, and face seals that are generally found in static or dynamic applications.