APG stocks the TST167SO, an AS568-167 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 6.987 in (177.47 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 7.193 in (182.7 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
It resists nearly all industrial chemicals, solvents, and steam. That behavior comes from the compound itself: PTFE (Teflon) offers excellent dielectric properties and near-universal chemical inertness. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It is not the right choice where elemental fluorine at temperature or molten alkali metals are present.
You will find this material specified across laboratory equipment, aggressive-media pipelines, and pharmaceutical and biotech.
Stocked as TST167SO and sold individually. Nominal inside diameter is listed as 7 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.
Description 167 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.103 inch (2.62 mm)
Actual Inside Diameter 6.987 inch (177.47 mm)
Actual Outside Diameter 7.193 inch (182.7 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings