*318 PTFE SOLID BACKUP RING FDA

Ordered as TST318SO, this is an AS568-318 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 0.975 in (24.77 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.395 in (35.43 mm). The back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Expect good resistance to solvents, oxidizing media, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) is specified for near-universal chemical inertness and one of the lowest coefficients of friction of any solid. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service.

It sees regular use in chemical processing, food and beverage, and pharmaceutical and biotech.

Reference part number TST318SO when ordering; the item is sold individually. Nominal inside diameter is listed as 1 inch. 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.