Ordered as TST330, this is an AS568-330 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 2.1 in (53.34 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 2.52 in (64.01 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.
PTFE (Teflon) is widely chosen for excellent dielectric properties and one of the lowest coefficients of friction of any solid. The material holds up against oxidizing media, strong acids and bases, and steam. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where service requiring elastic recovery or molten alkali metals are present.
You will find this material specified across semiconductor fabrication, aggressive-media pipelines, and chemical processing.
This item is sold individually under part number TST330. Check the compound against your process media, pressure and temperature before committing to a design. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
description 2103-330 PTFE S/T BUP FDA
Actual_CS 0.21 inch (5.33 mm)
Actual_ID 2.1 inch (53.34 mm)
Actual_OD 2.52 inch (64.01 mm)
ProductCode Description O-Rings - Backup Rings