This back-up ring is supplied in AS568-241 black Buna-N (Nitrile) 90 Shore A with an inside diameter of 3.859 in (98.02 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.137 in (105.08 mm), catalogued under part number HB90241. It allows a standard o-ring to operate at higher pressures than it could unsupported.
Buna-N (Nitrile) is valued for strong abrasion and tear resistance, reliable performance in both static and dynamic service. The compound resists greases and lubricants, hydraulic fluids, and water. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Applications involving automotive brake fluid or ozone and direct sunlight call for a different compound.
Common environments for this compound include automotive, general industrial maintenance, and construction equipment.
HB90241 ships individually. Unit weight is approximately 1.4111 g and nominal inside diameter is listed as 3 7/8 inch. 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.
description 8-241 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 3.859 inch (98.02 mm)
Actual_OD 4.137 inch (105.08 mm)
ProductCode Description O-Rings - Backup Rings