This back-up ring is supplied in AS568-139 white PTFE (Teflon) 55 Shore D built to an inside diameter of 2.175 in (55.25 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.381 in (60.48 mm), catalogued under part number TST139SO. It allows a standard o-ring to operate at higher pressures than it could unsupported.
PTFE (Teflon) is specified here for one of the lowest coefficients of friction of any solid and excellent dielectric properties. The compound resists strong acids and bases, solvents, and oxidizing media. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where service requiring elastic recovery or molten alkali metals are present.
Common environments for this compound include pharmaceutical and biotech, laboratory equipment, and food and beverage.
This item is sold individually under part number TST139SO. 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 139 PTFE SOLID BACKUP RING FDA
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 2.175 inch (55.25 mm)
Actual_OD 2.381 inch (60.48 mm)
ProductCode Description O-Rings - Backup Rings