APG stocks the TST356, an AS568-356 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 5.35 in (135.89 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.77 in (146.56 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
PTFE (Teflon) is specified here for non-stick, non-contaminating surface characteristics and excellent dielectric properties. The compound resists solvents, oxidizing media, and nearly all industrial chemicals. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Exposure to service requiring elastic recovery or elemental fluorine at temperature will shorten service life.
Common environments for this compound include aggressive-media pipelines, chemical processing, and laboratory equipment.
This item is sold individually under part number TST356. Review your operating media and conditions against this specification before installation.
Description 2103-356 PTFE S/T BUP FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 5.35 inch (135.89 mm)
Actual Outside Diameter 5.77 inch (146.56 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings