8-221 BLACK FKM 90D BACK-UP RING

The VBU90221 is an AS568-221 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 1.421 in (36.09 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.699 in (43.15 mm). This back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

The compound resists petroleum oils and fuels, chlorinated solvents, and aggressive chemicals. That behavior comes from the compound itself: Viton® (FKM) is known for long service life in hot, chemically aggressive environments, excellent resistance to compression set and permeation. Service temperature is rated from -15°F (-26.1°C) through 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, automotive fuel systems, and aerospace.

Order part number VBU90221, sold individually. Unit weight is approximately 0.7524 g and nominal inside diameter is listed as 1 7/16 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.