The TST281 is an AS568-281 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 14.984 in (380.59 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 15.262 in (387.65 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
It resists steam, nearly all industrial chemicals, and solvents. That behavior comes from the compound itself: PTFE (Teflon) is specified for near-universal chemical inertness and a very wide continuous service temperature range. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Applications involving molten alkali metals or elemental fluorine at temperature call for a different compound.
Common environments for this compound include food and beverage, chemical processing, and laboratory equipment.
Stocked as TST281 and sold individually. Nominal inside diameter is listed as 15 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.
Description 2103-281 PTFE S/T BUP FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 14.984 inch (380.59 mm)
Actual Outside Diameter 15.262 inch (387.65 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings