8-474 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90474, an AS568-474 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 24.94 in (633.48 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 25.49 in (647.45 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Viton® (FKM) is specified here for excellent resistance to compression set and permeation, outstanding high-temperature capability. This material stands up to aggressive chemicals, aromatic hydrocarbons, and petroleum oils and fuels. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Exposure to amines or low-molecular-weight organic acids will shorten service life.

You will find this material specified across oil and gas, chemical processing, and aerospace.

Stocked as VBU90474 and sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.