Part number TST429 is an AS568-429 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 4.975 in (126.37 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 5.525 in (140.34 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
As a material, PTFE (Teflon) is specified for a very wide continuous service temperature range and excellent dielectric properties. Expect good resistance to solvents, oxidizing media, and strong acids and bases. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It should not be specified for service in service requiring elastic recovery or elemental fluorine at temperature.
It sees regular use in aggressive-media pipelines, food and beverage, and pharmaceutical and biotech.
Stocked as TST429 and sold individually. Nominal inside diameter is listed as 5 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
Description 2103-429 PTFE S/T BUP FDA
Actual Cross Section 0.275 inch (6.99 mm)
Actual Inside Diameter 4.975 inch (126.37 mm)
Actual Outside Diameter 5.525 inch (140.34 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings