APG stocks the TST203SO, an AS568-203 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 0.296 in (7.52 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.574 in (14.58 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
This material stands up to strong acids and bases, solvents, and oxidizing media. That behavior comes from the compound itself: PTFE (Teflon) is specified for a very wide continuous service temperature range and non-stick, non-contaminating surface characteristics. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where service requiring elastic recovery or elemental fluorine at temperature are present.
Typical settings include food and beverage, aggressive-media pipelines, and semiconductor fabrication.
Stocked as TST203SO and sold individually. Nominal inside diameter is listed as 5/16 inch. Review your operating media and conditions against this specification before installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Description 203 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 0.296 inch (7.52 mm)
Actual Outside Diameter 0.574 inch (14.58 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings