The TST243 is an AS568-243 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 4.109 in (104.37 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.387 in (111.43 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
PTFE (Teflon) is specified here for very wide continuous service temperature range and excellent dielectric properties. The compound resists steam, oxidizing media, and strong acids and bases. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service.
Common environments for this compound include chemical processing, semiconductor fabrication, and food and beverage.
Stocked as TST243 and sold individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.
Description 2103-243 PTFE S/T BUP FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 4.109 inch (104.37 mm)
Actual Outside Diameter 4.387 inch (111.43 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings