This back-up ring is supplied in AS568-316 white PTFE (Teflon) 55 Shore D with an inside diameter of 0.85 in (21.59 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.27 in (32.26 mm), catalogued under part number TST316SO. 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 here for very wide continuous service temperature range and near-universal chemical inertness. It resists strong acids and bases, steam, and oxidizing media. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Applications involving molten alkali metals or elemental fluorine at temperature call for a different compound.
Common environments for this compound include semiconductor fabrication, pharmaceutical and biotech, and aggressive-media pipelines.
TST316SO ships individually. Nominal inside diameter is listed as 7/8 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Description 316 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 0.85 inch (21.59 mm)
Actual Outside Diameter 1.27 inch (32.26 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings