240 PTFE SOLID BACKUP RING FDA

This back-up ring is supplied in AS568-240 white PTFE (Teflon) 55 Shore D measuring an inside diameter of 3.734 in (94.84 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.012 in (101.9 mm), catalogued under part number TST240SO. It allows a standard o-ring to operate at higher pressures than it could unsupported.

It resists steam, oxidizing media, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) offers a very wide continuous service temperature range and near-universal chemical inertness. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). Exposure to molten alkali metals or service requiring elastic recovery will shorten service life.

It sees regular use in laboratory equipment, aggressive-media pipelines, and semiconductor fabrication.

Reference part number TST240SO when ordering; the item is sold individually. Nominal inside diameter is listed as 3 3/4 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.