Ordered as TST353, this is an AS568-353 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 4.975 in (126.37 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.395 in (137.03 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
Expect good resistance to solvents, steam, and strong acids and bases. PTFE (Teflon) is widely chosen for one of the lowest coefficients of friction of any solid and near-universal chemical inertness. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Applications involving molten alkali metals or service requiring elastic recovery call for a different compound.
Common environments for this compound include aggressive-media pipelines, pharmaceutical and biotech, and laboratory equipment.
Order part number TST353, sold individually. Nominal inside diameter is listed as 5 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.
Description 2103-353 PTFE S/T BUP FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 4.975 inch (126.37 mm)
Actual Outside Diameter 5.395 inch (137.03 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings