Ordered as TST368, this is an AS568-368 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 7.725 in (196.22 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 8.145 in (206.88 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
PTFE (Teflon) is known for one of the lowest coefficients of friction of any solid and a very wide continuous service temperature range. It resists solvents, steam, and nearly all industrial chemicals. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Exposure to elemental fluorine at temperature or service requiring elastic recovery will shorten service life.
Common environments for this compound include laboratory equipment, semiconductor fabrication, and pharmaceutical and biotech.
Order part number TST368, 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 2103-368 PTFE S/T BUP FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 7.725 inch (196.22 mm)
Actual Outside Diameter 8.145 inch (206.88 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings