TSP439 is an AS568-439 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 6.475 in (164.47 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 7.025 in (178.44 mm). In service, this back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
It resists steam, solvents, and nearly all industrial chemicals. That behavior comes from the compound itself: PTFE (Teflon) is specified for non-stick, non-contaminating surface characteristics and one of the lowest coefficients of friction of any solid. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C).
It sees regular use in pharmaceutical and biotech, chemical processing, and food and beverage.
Stocked as TSP439 and sold individually. Nominal inside diameter is listed as 6 1/2 inch. Check the compound against your process media, pressure and temperature before committing to a design.
description 2107-439 PTFE SPIRAL B/U FDA
Actual_CS 0.275 inch (6.99 mm)
Actual_ID 6.475 inch (164.47 mm)
Actual_OD 7.025 inch (178.44 mm)
ProductCode Description O-Rings - Backup Rings