205 PTFE SOLID BACKUP RING FDA

This back-up ring is supplied in AS568-205 white PTFE (Teflon) 55 Shore D built to an inside diameter of 0.421 in (10.69 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.699 in (17.75 mm), catalogued under part number TST205SO. It installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

PTFE (Teflon) is specified here for near-universal chemical inertness and non-stick, non-contaminating surface characteristics. The material holds up against nearly all industrial chemicals, oxidizing media, and strong acids and bases. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where molten alkali metals or service requiring elastic recovery are present.

Common environments for this compound include semiconductor fabrication, food and beverage, and chemical processing.

Order part number TST205SO, sold individually. Check the compound against your process media, pressure and temperature before committing to a design. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.