Engineered for demanding hydraulic and pneumatic sealing applications, this Buna-N (Nitrile) back-up ring delivers superior extrusion resistance in high-pressure systems. With a 90 Shore A durometer hardness rating, it provides the rigidity needed to prevent primary O-ring extrusion into clearance gaps — extending seal life and maintaining system integrity under sustained pressure.
Key Features
Material: Buna-N (Nitrile Rubber, NBR)
Durometer: 90 Shore A — high hardness for maximum extrusion resistance
Application: Hydraulic cylinders, pneumatic actuators, high-pressure fluid power systems
Compatibility: Petroleum-based oils, hydraulic fluids, water, and many industrial fluids
AS568 Compatible: Sized to complement standard AS568 O-ring dash numbers
Temperature Range: -40°F to +250°F (-40°C to +121°C)
Pressure Rating: Suitable for high-pressure dynamic and static sealing applications
Why Use a Back-Up Ring?
In high-pressure hydraulic systems, O-rings can extrude into the clearance gap between mating components, causing premature seal failure. A 90 durometer Buna-N back-up ring is installed on the low-pressure side of the O-ring to block this gap, dramatically increasing the pressure rating of the seal assembly and extending service life.
