APG stocks the TSP219, an AS568-219 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 1.296 in (32.92 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.574 in (39.98 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.
It resists strong acids and bases, solvents, and nearly all industrial chemicals. That behavior comes from the compound itself: PTFE (Teflon) is widely chosen for a very wide continuous service temperature range and excellent dielectric properties. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Exposure to molten alkali metals or service requiring elastic recovery will shorten service life.
Typical settings include aggressive-media pipelines, food and beverage, and pharmaceutical and biotech.
Order part number TSP219, sold individually. Nominal inside diameter is listed as 1 5/16 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation.
Description 2107-219 PTFE SPIRAL B/U FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 1.296 inch (32.92 mm)
Actual Outside Diameter 1.574 inch (39.98 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings