Ordered as TST385SO, this is an AS568-385 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 15.955 in (405.26 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 16.375 in (415.93 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
Expect good resistance to solvents, oxidizing media, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) is widely chosen for excellent dielectric properties and a very wide continuous service temperature range. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Exposure to elemental fluorine at temperature or service requiring elastic recovery will shorten service life.
Common environments for this compound include chemical processing, semiconductor fabrication, and laboratory equipment.
Stocked as TST385SO and sold individually. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.
description 385 PTFE SOLID BACKUP RING FDA
Actual_CS 0.21 inch (5.33 mm)
Actual_ID 15.955 inch (405.26 mm)
Actual_OD 16.375 inch (415.93 mm)
ProductCode Description O-Rings - Backup Rings