Ordered as TST316, this is an AS568-316 white PTFE (Teflon) 55 Shore D Back-Up Ring 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). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
As a material, PTFE (Teflon) offers non-stick, non-contaminating surface characteristics and a very wide continuous service temperature range. This material stands up to steam, strong acids and bases, and solvents. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Applications involving service requiring elastic recovery or elemental fluorine at temperature call for a different compound.
It sees regular use in food and beverage, aggressive-media pipelines, and semiconductor fabrication.
Order part number TST316, 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 2103-316 PTFE S/T BUP 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