8-220 BLACK BUNA 90D BACK-UP RING

Ordered as HB90220, this is an AS568-220 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 1.359 in (34.52 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.637 in (41.58 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Buna-N (Nitrile) is specified here for reliable performance in both static and dynamic service, most widely specified general-purpose sealing elastomer. The material holds up against petroleum-based oils, water, and greases and lubricants. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with polar solvents or automotive brake fluid.

Typical settings include general industrial maintenance, fluid power, and hydraulic and pneumatic systems.

Reference part number HB90220 when ordering; the item is sold individually. Unit weight is approximately 0.542 g and nominal inside diameter is listed as 1 3/8 inch. Check the compound against your process media, pressure and temperature before committing to a design. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.