Ordered as TST168, this is an AS568-168 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 7.237 in (183.82 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 7.443 in (189.05 mm). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
PTFE (Teflon) is valued for excellent dielectric properties and one of the lowest coefficients of friction of any solid. The compound resists nearly all industrial chemicals, solvents, and strong acids and bases. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Applications involving service requiring elastic recovery or molten alkali metals call for a different compound.
Maintenance and OEM teams specify it across pharmaceutical and biotech, semiconductor fabrication, and food and beverage.
Reference part number TST168 when ordering; the item is sold individually. Nominal inside diameter is listed as 7 1/4 inch. Check the compound against your process media, pressure and temperature before committing to a design.
description 2103-168 PTFE S/T BUP FDA
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 7.237 inch (183.82 mm)
Actual_OD 7.443 inch (189.05 mm)
ProductCode Description O-Rings - Backup Rings