APG stocks the VBU90229, an AS568-229 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 2.359 in (59.92 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 2.637 in (66.98 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
As a material, Viton® (FKM) is known for very low compression set at elevated temperature, excellent resistance to compression set and permeation. This material stands up to many acids, engine and transmission fluids, and chlorinated solvents. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C).
You will find this material specified across semiconductor equipment, aerospace, and oil and gas.
Stocked as VBU90229 and sold individually. Unit weight is approximately 1.199 g and nominal inside diameter is listed as 2 3/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
description 8-229 BLACK FKM 90D BACK-UP RING
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 2.359 inch (59.92 mm)
Actual_OD 2.637 inch (66.98 mm)
ProductCode Description O-Rings - Backup Rings