Ordered as VBU90035, this is an AS568-035 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 2.239 in (56.87 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 2.379 in (60.43 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
Viton® (FKM) offers the industry benchmark where nitrile reaches its thermal limit, excellent resistance to compression set and permeation. Expect good resistance to aromatic hydrocarbons, aggressive chemicals, and many acids. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C). Verify compatibility before use with amines or low-molecular-weight organic acids.
You will find this material specified across chemical processing, semiconductor equipment, and aerospace.
Reference part number VBU90035 when ordering; the item is sold individually. 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.
description 8-035 BLACK FKM 90D BACK-UP RING
Actual_CS 0.07 inch (1.78 mm)
Actual_ID 2.239 inch (56.87 mm)
Actual_OD 2.379 inch (60.43 mm)
ProductCode Description O-Rings - Backup Rings