8-228 BLACK BUNA 90D BACK-UP RING

The HB90228 is an AS568-228 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 2.234 in (56.74 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 2.512 in (63.8 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Buna-N (Nitrile) is known for an economical choice for high-volume maintenance programs and the most widely specified general-purpose sealing elastomer. The material holds up against propane and butane, hydraulic fluids, and many alcohols. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in ketones or polar solvents.

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

This item is sold individually under part number HB90228. Unit weight is approximately 0.8679 g and nominal inside diameter is listed as 2 1/4 inch. Check the compound against your process media, pressure and temperature before committing to a design. For a size or compound outside the standard catalog, APG can quote from a print or sample.