The TST263 is an AS568-263 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 7.234 in (183.74 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 7.512 in (190.8 mm). This 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 specified here for near-universal chemical inertness and non-stick, non-contaminating surface characteristics. It resists steam, nearly all industrial chemicals, and solvents. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). It should not be specified for service in service requiring elastic recovery or elemental fluorine at temperature.
Typical settings include laboratory equipment, food and beverage, and pharmaceutical and biotech.
TST263 ships 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. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
description 2103-263 PTFE S/T BUP FDA
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 7.234 inch (183.74 mm)
Actual_OD 7.512 inch (190.8 mm)
ProductCode Description O-Rings - Backup Rings