8-139 BLACK FKM 90D BACK-UP RING

Part number VBU90139 is an AS568-139 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 2.175 in (55.25 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.381 in (60.48 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Viton® (FKM) delivers very low compression set at elevated temperature and outstanding high-temperature capability. The material holds up against petroleum oils and fuels, engine and transmission fluids, and aromatic hydrocarbons. 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.

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

This item is sold individually under part number VBU90139. Unit weight is approximately 0.859 g and nominal inside diameter is listed as 2 3/16 inch. 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.