Ordered as TST042, this is an AS568-042 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 3.239 in (82.27 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 3.379 in (85.83 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
As a material, PTFE (Teflon) is known for a very wide continuous service temperature range and non-stick, non-contaminating surface characteristics. It resists oxidizing media, strong acids and bases, and nearly all industrial chemicals. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C).
Typical settings include food and beverage, pharmaceutical and biotech, and semiconductor fabrication.
TST042 ships individually. Nominal inside diameter is listed as 3 1/4 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Description 2103-042 PTFE S/T BUP FDA
Actual Cross Section 0.07 inch (1.78 mm)
Actual Inside Diameter 3.239 inch (82.27 mm)
Actual Outside Diameter 3.379 inch (85.83 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings