8-253 BLACK FKM 90D BACK-UP RING

The VBU90253 is an AS568-253 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 5.359 in (136.12 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.637 in (143.18 mm). This back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Viton® (FKM) is widely chosen for very low compression set at elevated temperature and long service life in hot, chemically aggressive environments. The compound resists aromatic hydrocarbons, engine and transmission fluids, and chlorinated solvents. 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 ketones and esters or hot water and steam.

You will find this material specified across oil and gas, aerospace, and semiconductor equipment.

Order part number VBU90253, sold individually. Nominal inside diameter is listed as 5 3/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.