The TST428 is an AS568-428 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 4.85 in (123.19 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 5.4 in (137.16 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
PTFE (Teflon) is specified for non-stick, non-contaminating surface characteristics and excellent dielectric properties. The material holds up against nearly all industrial chemicals, steam, and oxidizing media. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Exposure to elemental fluorine at temperature or molten alkali metals will shorten service life.
It sees regular use in aggressive-media pipelines, food and beverage, and semiconductor fabrication.
Order part number TST428, sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application.
description 2103-428 PTFE S/T BUP FDA
Actual_CS 0.275 inch (6.99 mm)
Actual_ID 4.85 inch (123.19 mm)
Actual_OD 5.4 inch (137.16 mm)
ProductCode Description O-Rings - Backup Rings