309 PTFE SOLID BACKUP RING FDA

The TST309SO is an AS568-309 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 0.412 in (10.46 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 0.832 in (21.13 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

PTFE (Teflon) is known for near-universal chemical inertness and excellent dielectric properties. Expect good resistance to strong acids and bases, steam, and oxidizing media. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Applications involving molten alkali metals or elemental fluorine at temperature call for a different compound.

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

TST309SO ships individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.