Ordered as TST138, this is an AS568-138 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 2.112 in (53.64 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.318 in (58.88 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
The material holds up against solvents, steam, and strong acids and bases. PTFE (Teflon) is widely chosen for one of the lowest coefficients of friction of any solid and a very wide continuous service temperature range. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Exposure to elemental fluorine at temperature or service requiring elastic recovery will shorten service life.
Common environments for this compound include aggressive-media pipelines, food and beverage, and semiconductor fabrication.
Order part number TST138, sold individually. Check the compound against your process media, pressure and temperature before committing to a design. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
description 2103-138 PTFE S/T BUP FDA
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 2.112 inch (53.64 mm)
Actual_OD 2.318 inch (58.88 mm)
ProductCode Description O-Rings - Backup Rings