The TST157SO is an AS568-157 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 4.487 in (113.97 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.693 in (119.2 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
The material holds up against solvents, nearly all industrial chemicals, and strong acids and bases. PTFE (Teflon) offers non-stick, non-contaminating surface characteristics and a very wide continuous service temperature range. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). Exposure to molten alkali metals or service requiring elastic recovery will shorten service life.
Maintenance and OEM teams specify it across food and beverage, laboratory equipment, and aggressive-media pipelines.
Order part number TST157SO, sold individually. Nominal inside diameter is listed as 4 1/2 inch. 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 157 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.103 inch (2.62 mm)
Actual Inside Diameter 4.487 inch (113.97 mm)
Actual Outside Diameter 4.693 inch (119.2 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings