8-247 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90247, an AS568-247 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 4.609 in (117.07 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.887 in (124.13 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Buna-N (Nitrile) offers the most widely specified general-purpose sealing elastomer and an economical choice for high-volume maintenance programs. The compound resists petroleum-based oils, propane and butane, and greases and lubricants. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in ozone and direct sunlight or automotive brake fluid.

You will find this material specified across fluid power, construction equipment, and hydraulic and pneumatic systems.

This item is sold individually under part number HB90247. Unit weight is approximately 1.7563 g and nominal inside diameter is listed as 4 5/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.