251 PTFE SOLID BACKUP RING FDA

APG stocks the TST251SO, an AS568-251 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 5.109 in (129.77 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.387 in (136.83 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

PTFE (Teflon) is widely chosen for a very wide continuous service temperature range and non-stick, non-contaminating surface characteristics. The compound resists strong acids and bases, oxidizing media, and solvents. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Exposure to elemental fluorine at temperature or molten alkali metals will shorten service life.

You will find this material specified across aggressive-media pipelines, laboratory equipment, and pharmaceutical and biotech.

Stocked as TST251SO and sold individually. Check the compound against your process media, pressure and temperature before committing to a design.