APG stocks the TST224, an AS568-224 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 1.734 in (44.04 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 2.012 in (51.1 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
The material holds up against steam, solvents, and nearly all industrial chemicals. PTFE (Teflon) is known for excellent dielectric properties 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). Exposure to service requiring elastic recovery or elemental fluorine at temperature will shorten service life.
It sees regular use in chemical processing, laboratory equipment, and pharmaceutical and biotech.
Order part number TST224, sold individually. Nominal inside diameter is listed as 1 3/4 inch. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.
Description 2103-224 PTFE S/T BUP FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 1.734 inch (44.04 mm)
Actual Outside Diameter 2.012 inch (51.1 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings