TST240 is an AS568-240 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 3.734 in (94.84 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.012 in (101.9 mm). In service, this back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
As a material, PTFE (Teflon) delivers excellent dielectric properties and one of the lowest coefficients of friction of any solid. Expect good resistance to solvents, oxidizing media, and nearly all industrial chemicals. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). Exposure to service requiring elastic recovery or elemental fluorine at temperature will shorten service life.
Typical settings include laboratory equipment, food and beverage, and chemical processing.
Reference part number TST240 when ordering; the item is sold individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.
description 2103-240 PTFE S/T BUP FDA
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 3.734 inch (94.84 mm)
Actual_OD 4.012 inch (101.9 mm)
ProductCode Description O-Rings - Backup Rings