PTFE WINDOW SEAL WITH EMI SHIELDING

摘要

A process seal (30) made of a material such as polytetrafluorethylene is used as a microwave window (31) in a radar tank level gauge (16). The periphery (32) of the process seal is surrounded by a metal containment ring (40) that is fitted to the periphery to limit the amount of expansion outwardly of the process seal material as well as provide for localized loading at the periphery for clamping pressures on the seal (30). Electromagnetic radiation shielding is provided not only by the containment ring (40), but also by an EMI shielding O-ring (46) mounted in a groove on a sealing end of the containment ring. A process environmental O-ring (41) is carried by the process seal (30) in an outer shoulder groove that is enclosed by the containment ring (40).