Part number TST129 is an AS568-129 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 1.549 in (39.34 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 1.755 in (44.58 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
PTFE (Teflon) is known for near-universal chemical inertness and a very wide continuous service temperature range. Expect good resistance to nearly all industrial chemicals, strong acids and bases, and steam. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Applications involving service requiring elastic recovery or elemental fluorine at temperature call for a different compound.
You will find this material specified across pharmaceutical and biotech, semiconductor fabrication, and food and beverage.
Order part number TST129, sold individually. Nominal inside diameter is listed as 1 9/16 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.
description 2103-129 PTFE S/T BUP FDA
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 1.549 inch (39.34 mm)
Actual_OD 1.755 inch (44.58 mm)
ProductCode Description O-Rings - Backup Rings