*8-277 TEFLON SOLID BACKUP RINGS FDA

Ordered as TST277SO, this is an AS568-277 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 11.484 in (291.69 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 11.762 in (298.75 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

PTFE (Teflon) is specified here for non-stick, non-contaminating surface characteristics and one of the lowest coefficients of friction of any solid. The compound resists oxidizing media, steam, and nearly all industrial chemicals. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It is not the right choice where elemental fluorine at temperature or molten alkali metals are present.

It sees regular use in pharmaceutical and biotech, aggressive-media pipelines, and laboratory equipment.

TST277SO ships individually. Nominal inside diameter is listed as 11 1/2 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.