8-276 BLACK BUNA 90D BACK-UP RING

This back-up ring is supplied in AS568-276 black Buna-N (Nitrile) 90 Shore A measuring an inside diameter of 10.984 in (278.99 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 11.262 in (286.05 mm), catalogued under part number HB90276. It bridges the extrusion gap so the primary seal holds its shape under load.

The material holds up against many alcohols, water, and propane and butane. Buna-N (Nitrile) is valued for reliable performance in both static and dynamic service, low compression set under sustained load. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where automotive brake fluid or ketones are present.

Common environments for this compound include agricultural equipment, hydraulic and pneumatic systems, and general industrial maintenance.

Stocked as HB90276 and sold individually. Unit weight is approximately 4.0237 g. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.