8-047 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90047, an AS568-047 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 4.489 in (114.02 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 4.629 in (117.58 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Buna-N (Nitrile) is specified here for reliable performance in both static and dynamic service, strong abrasion and tear resistance. The compound resists propane and butane, petroleum-based oils, and water. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or automotive brake fluid.

You will find this material specified across general industrial maintenance, hydraulic and pneumatic systems, and automotive.

Reference part number HB90047 when ordering; the item is sold individually. Unit weight is approximately 0.782 g and nominal inside diameter is listed as 4 1/2 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.