Part number HB90284 is an AS568-284 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 17.955 in (456.06 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 18.233 in (463.12 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
Expect good resistance to water, propane and butane, and hydraulic fluids. Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer and low compression set under sustained load. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with ketones or automotive brake fluid.
Typical settings include construction equipment, agricultural equipment, and general industrial maintenance.
HB90284 ships individually. Unit weight is approximately 6.8741 g and nominal inside diameter is listed as 18 inch. Review your operating media and conditions against this specification before installation.
Description 8-284 BLACK BUNA 90D BACK-UP RING
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 17.955 inch (456.06 mm)
Actual Outside Diameter 18.233 inch (463.12 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings