138 PTFE SOLID BACKUP RING FDA

The TST138SO is an AS568-138 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 2.112 in (53.64 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.318 in (58.88 mm). This back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

PTFE (Teflon) is widely chosen for near-universal chemical inertness and one of the lowest coefficients of friction of any solid. The compound resists nearly all industrial chemicals, strong acids and bases, and oxidizing media. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Exposure to elemental fluorine at temperature or service requiring elastic recovery will shorten service life.

Typical settings include pharmaceutical and biotech, food and beverage, and chemical processing.

This item is sold individually under part number TST138SO. Nominal inside diameter is listed as 2 1/8 inch. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.