The TST432 is an AS568-432 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 5.35 in (135.89 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 5.9 in (149.86 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
It resists nearly all industrial chemicals, steam, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) offers excellent dielectric properties and one of the lowest coefficients of friction of any solid. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). It is not the right choice where service requiring elastic recovery or elemental fluorine at temperature are present.
It sees regular use in aggressive-media pipelines, chemical processing, and food and beverage.
Order part number TST432, sold individually. Nominal inside diameter is listed as 5 3/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. For a size or compound outside the standard catalog, APG can quote from a print or sample.
description 2103-432 PTFE S/T BUP FDA
Actual_CS 0.275 inch (6.99 mm)
Actual_ID 5.35 inch (135.89 mm)
Actual_OD 5.9 inch (149.86 mm)
ProductCode Description O-Rings - Backup Rings