TST231 is an AS568-231 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 2.609 in (66.27 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 2.887 in (73.33 mm). In service, 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 non-stick, non-contaminating surface characteristics. The compound resists steam, strong acids and bases, and solvents. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Verify compatibility before use with service requiring elastic recovery or elemental fluorine at temperature.
It sees regular use in aggressive-media pipelines, chemical processing, and pharmaceutical and biotech.
Stocked as TST231 and sold individually. Nominal inside diameter is listed as 2 5/8 inch. Review your operating media and conditions against this specification before installation.
Description *2103-231 PTFE S/T BUP FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 2.609 inch (66.27 mm)
Actual Outside Diameter 2.887 inch (73.33 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings