Ordered as TST156SO, this is an AS568-156 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 4.237 in (107.62 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.443 in (112.85 mm). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
It resists strong acids and bases, steam, and oxidizing media. That behavior comes from the compound itself: PTFE (Teflon) offers excellent dielectric properties and one of the lowest coefficients of friction of any solid. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It should not be specified for service in elemental fluorine at temperature or molten alkali metals.
It sees regular use in chemical processing, aggressive-media pipelines, and laboratory equipment.
Order part number TST156SO, sold individually. Check the compound against your process media, pressure and temperature before committing to a design.
Description 156 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.103 inch (2.62 mm)
Actual Inside Diameter 4.237 inch (107.62 mm)
Actual Outside Diameter 4.443 inch (112.85 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings