8-173 BLACK FKM 90D BACK-UP RING

Ordered as VBU90173, this is an AS568-173 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 8.487 in (215.57 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 8.693 in (220.8 mm). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

This material stands up to petroleum oils and fuels, chlorinated solvents, and aromatic hydrocarbons. Viton® (FKM) is specified for the industry benchmark where nitrile reaches its thermal limit, excellent resistance to compression set and permeation. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). It is not the right choice where hot water and steam or ketones and esters are present.

You will find this material specified across aerospace, chemical processing, and high-temperature process equipment.

VBU90173 ships individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.