APG stocks the TSP327, an AS568-327 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 1.725 in (43.82 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 2.145 in (54.48 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.
As a material, PTFE (Teflon) is widely chosen for excellent dielectric properties and non-stick, non-contaminating surface characteristics. It resists nearly all industrial chemicals, steam, and solvents. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). It is not the right choice where molten alkali metals or elemental fluorine at temperature are present.
You will find this material specified across semiconductor fabrication, food and beverage, and chemical processing.
Reference part number TSP327 when ordering; the item is sold individually. Check the compound against your process media, pressure and temperature before committing to a design. For a size or compound outside the standard catalog, APG can quote from a print or sample.
description 2107-327 PTFE SPIRAL B/U FDA
Actual_CS 0.21 inch (5.33 mm)
Actual_ID 1.725 inch (43.82 mm)
Actual_OD 2.145 inch (54.48 mm)
ProductCode Description O-Rings - Backup Rings