Part number TSP349 is an AS568-349 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 4.475 in (113.67 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.895 in (124.33 mm). A 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 near-universal chemical inertness and non-stick, non-contaminating surface characteristics. The material holds up against steam, nearly all industrial chemicals, and strong acids and bases. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Exposure to elemental fluorine at temperature or service requiring elastic recovery will shorten service life.
You will find this material specified across pharmaceutical and biotech, food and beverage, and aggressive-media pipelines.
Order part number TSP349, sold individually. Review your operating media and conditions against this specification before installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
Description *2107-349 PTFE SPIRAL B/U FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 4.475 inch (113.67 mm)
Actual Outside Diameter 4.895 inch (124.33 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings