8-247 BLACK FKM 90D BACK-UP RING

This back-up ring is supplied in AS568-247 black Viton® (FKM) 90 Shore A 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), catalogued under part number VBU90247. It bridges the extrusion gap so the primary seal holds its shape under load.

Viton® (FKM) is specified here for outstanding high-temperature capability and industry benchmark where nitrile reaches its thermal limit. Expect good resistance to petroleum oils and fuels, aggressive chemicals, and engine and transmission fluids. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Exposure to low-molecular-weight organic acids or ketones and esters will shorten service life.

You will find this material specified across high-temperature process equipment, chemical processing, and aerospace.

This item is sold individually under part number VBU90247. Unit weight is approximately 2.324 g and nominal inside diameter is listed as 4 5/8 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.