342 PTFE SOLID BACKUP RING FDA

APG stocks the TST342SO, an AS568-342 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 3.6 in (91.44 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.02 in (102.11 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

PTFE (Teflon) is specified here for one of the lowest coefficients of friction of any solid and very wide continuous service temperature range. It resists oxidizing media, nearly all industrial chemicals, and solvents. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). It is not the right choice where molten alkali metals or service requiring elastic recovery are present.

Maintenance and OEM teams specify it across laboratory equipment, aggressive-media pipelines, and pharmaceutical and biotech.

TST342SO ships individually. Nominal inside diameter is listed as 3 5/8 inch. Check the compound against your process media, pressure and temperature before committing to a design.