8-320 BLACK FKM 90D BACK-UP RING

Part number VBU90320 is an AS568-320 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 1.1 in (27.94 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.52 in (38.61 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Viton® (FKM) is specified for excellent resistance to compression set and permeation, outstanding high-temperature capability. It resists many acids, aggressive chemicals, and aromatic hydrocarbons. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). Applications involving amines or hot water and steam call for a different compound.

It sees regular use in aerospace, semiconductor equipment, and high-temperature process equipment.

Order part number VBU90320, sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.