Ordered as TST140, this is an AS568-140 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 2.237 in (56.82 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.443 in (62.05 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
Expect good resistance to steam, strong acids and bases, and solvents. PTFE (Teflon) is known for near-universal chemical inertness and a very wide continuous service temperature range. Continuous operating temperature is published at -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.
It sees regular use in aggressive-media pipelines, semiconductor fabrication, and chemical processing.
Order part number TST140, sold individually. Nominal inside diameter is listed as 2 1/4 inch. Review your operating media and conditions against this specification before installation.
Description 2103-140 PTFE S/T BUP FDA
Actual Cross Section 0.103 inch (2.62 mm)
Actual Inside Diameter 2.237 inch (56.82 mm)
Actual Outside Diameter 2.443 inch (62.05 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings