APG stocks the TST284SO, an AS568-284 white PTFE (Teflon) 55 Shore D Back-Up Ring built to 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 extends o-ring service life by supporting the seal against extrusion under high pressure.
PTFE (Teflon) is widely chosen for excellent dielectric properties and a very wide continuous service temperature range. This material stands up to oxidizing media, steam, and solvents. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where elemental fluorine at temperature or molten alkali metals are present.
You will find this material specified across aggressive-media pipelines, laboratory equipment, and pharmaceutical and biotech.
Reference part number TST284SO when ordering; the item is sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application.
description 284 PTFE SOLID BACKUP RING 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