444 PTFE SOLID BACKUP RING FDA

This back-up ring is supplied in AS568-444 white PTFE (Teflon) 55 Shore D with an inside diameter of 7.725 in (196.22 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 8.275 in (210.19 mm), catalogued under part number TST444SO. It bridges the extrusion gap so the primary seal holds its shape under load.

It resists strong acids and bases, steam, and nearly all industrial chemicals. That behavior comes from the compound itself: PTFE (Teflon) is known for one of the lowest coefficients of friction of any solid and a very wide continuous service temperature range. The material carries a published service range of -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.

You will find this material specified across laboratory equipment, chemical processing, and pharmaceutical and biotech.

Order part number TST444SO, sold individually. Nominal inside diameter is listed as 7 3/4 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.