Ordered as TST352, this is an AS568-352 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 4.85 in (123.19 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.27 in (133.86 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
PTFE (Teflon) offers one of the lowest coefficients of friction of any solid and non-stick, non-contaminating surface characteristics. Expect good resistance to steam, solvents, and strong acids and bases. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). Verify compatibility before use with service requiring elastic recovery or molten alkali metals.
Common environments for this compound include chemical processing, aggressive-media pipelines, and semiconductor fabrication.
TST352 ships individually. Nominal inside diameter is listed as 4 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 2103-352 PTFE S/T BUP FDA
Actual_CS 0.21 inch (5.33 mm)
Actual_ID 4.85 inch (123.19 mm)
Actual_OD 5.27 inch (133.86 mm)
ProductCode Description O-Rings - Backup Rings