8-156 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90156, an AS568-156 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 4.237 in (107.62 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.443 in (112.85 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, Viton® (FKM) delivers outstanding high-temperature capability and the industry benchmark where nitrile reaches its thermal limit. It resists aggressive chemicals, chlorinated solvents, and aromatic hydrocarbons. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C). It should not be specified for service in amines or hot water and steam.

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

VBU90156 ships individually. Nominal inside diameter is listed as 4 1/4 inch. Check the compound against your process media, pressure and temperature before committing to a design.