Ordered as TST171, this is an AS568-171 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 7.987 in (202.87 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 8.193 in (208.1 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.
As a material, PTFE (Teflon) is known for near-universal chemical inertness and non-stick, non-contaminating surface characteristics. Expect good resistance to oxidizing media, solvents, and steam. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Exposure to molten alkali metals or elemental fluorine at temperature will shorten service life.
It sees regular use in chemical processing, laboratory equipment, and food and beverage.
Reference part number TST171 when ordering; the item is sold individually. Nominal inside diameter is listed as 8 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.
description 2103-171 PTFE S/T BUP FDA
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 7.987 inch (202.87 mm)
Actual_OD 8.193 inch (208.1 mm)
ProductCode Description O-Rings - Backup Rings