8-331 BLACK FKM 90D BACK-UP RING

Part number VBU90331 is an AS568-331 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 2.225 in (56.52 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 2.645 in (67.18 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Viton® (FKM) is widely chosen for excellent resistance to compression set and permeation, outstanding high-temperature capability. It resists aggressive chemicals, aromatic hydrocarbons, and many acids. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C). It should not be specified for service in hot water and steam or low-molecular-weight organic acids.

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

Stocked as VBU90331 and sold individually. Unit weight is approximately 2.685 g. Application requirements vary, so validate compatibility with your process conditions prior to installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.