This back-up ring is supplied in AS568-155 white PTFE (Teflon) 55 Shore D measuring an inside diameter of 3.987 in (101.27 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.193 in (106.5 mm), catalogued under part number TST155. It installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
PTFE (Teflon) is specified for excellent dielectric properties and near-universal chemical inertness. Expect good resistance to nearly all industrial chemicals, steam, and strong acids and bases. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). It should not be specified for service in molten alkali metals or elemental fluorine at temperature.
You will find this material specified across aggressive-media pipelines, pharmaceutical and biotech, and laboratory equipment.
Order part number TST155, sold individually. Review your operating media and conditions against this specification before installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Description 2103-155 PTFE S/T BUP FDA
Actual Cross Section 0.103 inch (2.62 mm)
Actual Inside Diameter 3.987 inch (101.27 mm)
Actual Outside Diameter 4.193 inch (106.5 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings