8-345 BLACK FKM 90D BACK-UP RING

The VBU90345 is an AS568-345 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 3.975 in (100.97 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.395 in (111.63 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Viton® (FKM) is specified here for long service life in hot, chemically aggressive environments and outstanding high-temperature capability. The material holds up against aromatic hydrocarbons, aggressive chemicals, and engine and transmission fluids. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C). Applications involving hot water and steam or low-molecular-weight organic acids call for a different compound.

Common environments for this compound include high-temperature process equipment, oil and gas, and chemical processing.

Order part number VBU90345, sold individually. Unit weight is approximately 4.7267 g. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.