Part number TST373SO is an AS568-373 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 8.975 in (227.97 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 9.395 in (238.63 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
PTFE (Teflon) is specified for a very wide continuous service temperature range and near-universal chemical inertness. The compound resists strong acids and bases, oxidizing media, and nearly all industrial chemicals. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Applications involving molten alkali metals or service requiring elastic recovery call for a different compound.
Typical settings include pharmaceutical and biotech, aggressive-media pipelines, and food and beverage.
Order part number TST373SO, sold individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.
Description 373 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 8.975 inch (227.97 mm)
Actual Outside Diameter 9.395 inch (238.63 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings