Part number TST373 is an AS568-373 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 8.975 in (227.97 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 9.395 in (238.63 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
The compound resists oxidizing media, solvents, and strong acids and bases. PTFE (Teflon) is widely chosen for a very wide continuous service temperature range and one of the lowest coefficients of friction of any solid. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Applications involving elemental fluorine at temperature or molten alkali metals call for a different compound.
Maintenance and OEM teams specify it across food and beverage, pharmaceutical and biotech, and semiconductor fabrication.
This item is sold individually under part number TST373. Nominal inside diameter is listed as 9 inch. Review your operating media and conditions against this specification before installation.
description 2103-373 PTFE S/T BUP FDA
Actual_CS 0.21 inch (5.33 mm)
Actual_ID 8.975 inch (227.97 mm)
Actual_OD 9.395 inch (238.63 mm)
ProductCode Description O-Rings - Backup Rings