APG stocks the TST355SO, an AS568-355 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 5.225 in (132.72 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.645 in (143.38 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
The material holds up against strong acids and bases, solvents, and nearly all industrial chemicals. PTFE (Teflon) offers near-universal chemical inertness and excellent dielectric properties. The material carries a published service range of -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.
It sees regular use in laboratory equipment, chemical processing, and pharmaceutical and biotech.
This item is sold individually under part number TST355SO. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
Description 355 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 5.225 inch (132.72 mm)
Actual Outside Diameter 5.645 inch (143.38 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings