APG stocks the TST284, an AS568-284 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 17.955 in (456.06 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 18.233 in (463.12 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 steam, nearly all industrial chemicals, and strong acids and bases. PTFE (Teflon) is valued for excellent dielectric properties and non-stick, non-contaminating surface characteristics. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C).
Common environments for this compound include aggressive-media pipelines, laboratory equipment, and chemical processing.
Reference part number TST284 when ordering; the item is sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application.
description 2103-284 PTFE S/T BUP FDA
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 17.955 inch (456.06 mm)
Actual_OD 18.233 inch (463.12 mm)
ProductCode Description O-Rings - Backup Rings