Part number VBU90228 is an AS568-228 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 2.234 in (56.74 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 2.512 in (63.8 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
As a material, Viton® (FKM) is valued for the industry benchmark where nitrile reaches its thermal limit and very low compression set at elevated temperature. The material holds up against aromatic hydrocarbons, aggressive chemicals, and many acids. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C).
Typical settings include aerospace, high-temperature process equipment, and automotive fuel systems.
Order part number VBU90228, sold individually. Unit weight is approximately 1.1641 g and nominal inside diameter is listed as 2 1/4 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
description 8-228 BLACK FKM 90D BACK-UP RING
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 2.234 inch (56.74 mm)
Actual_OD 2.512 inch (63.8 mm)
ProductCode Description O-Rings - Backup Rings