APG stocks the TST261SO, an AS568-261 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 6.734 in (171.04 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 7.012 in (178.1 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
Expect good resistance to nearly all industrial chemicals, solvents, and steam. PTFE (Teflon) delivers near-universal chemical inertness and excellent dielectric properties. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Applications involving molten alkali metals or elemental fluorine at temperature call for a different compound.
Typical settings include aggressive-media pipelines, chemical processing, and laboratory equipment.
Stocked as TST261SO and sold individually. Check the compound against your process media, pressure and temperature before committing to a design. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
Description 261 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 6.734 inch (171.04 mm)
Actual Outside Diameter 7.012 inch (178.1 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings