155 PTFE SOLID BACKUP RING FDA

Part number TST155SO is an AS568-155 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 3.987 in (101.27 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.193 in (106.5 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

PTFE (Teflon) is specified here for near-universal chemical inertness and very wide continuous service temperature range. It resists nearly all industrial chemicals, oxidizing media, and steam. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where elemental fluorine at temperature or molten alkali metals are present.

It sees regular use in aggressive-media pipelines, laboratory equipment, and food and beverage.

Reference part number TST155SO when ordering; the item is sold individually. Nominal inside diameter is listed as 4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.