239 PTFE SOLID BACKUP RING FDA

Part number TST239SO is an AS568-239 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 3.609 in (91.67 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.887 in (98.73 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

The material holds up against solvents, oxidizing media, and strong acids and bases. PTFE (Teflon) delivers excellent dielectric properties and non-stick, non-contaminating surface characteristics. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service.

You will find this material specified across semiconductor fabrication, pharmaceutical and biotech, and aggressive-media pipelines.

Reference part number TST239SO when ordering; the item is sold individually. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.