The Foxboro Company

John R Martin

Richard A Anderson

Robert J Gardner

A monitoring system for testing the integrity of seal structures, filled with an electrically non-conductive fluid and for validating measurements of a measurement device. The monitoring system includes electrodes disposed in the fluid for measuring an electrical property of the fluid. The system indicates when the measured electrical property changes, which indicates contamination of the fluid.

Pressure sensing device having fill fluid contamination detector

A compliant sealing material with low or no gas permeability and low spring rate is made by coating a metal such as gold, on the surface of a polymer sheet. The metal acts as a complete gas barrier on an atomic level, and the polymer provides structural integrity and mounting attributes without detrimentally increasing compliance. A small number of metal atoms injected at a moderate energy into the near surface of the polymer act as link sites for joining subsequent lower energy atoms forming an impermeable layer. The total heat delivery to the polymer is minimized thereby preserving integrity and continuity. The material is particularly useful in micromechanical devices where high flexibility is needed with complete sealing.

Method of making a compliant fluid-impermeable element

Compliant diaphragm material

A nonporous composite electrode, particularly suitable for use in electromagnetic flowmeters, includes a non-metallic, electrically conductive element consisting of a fused mass of polymeric material, such as perfluoroalkoxy (pfa) fluoropolymer, and carbon fibers. The electrode is fabricated by stacking alternating layers of polymeric film and carbon fiber paper, subjecting the assembly to sufficient heat and pressure to intermix the two components and bond them into a coherent mass, and fusing the resultant composite material onto a mounting pin. Using a polymeric material compatible with the polymeric liner of an electromagnetic flowtube allows the finished electrode to be fused into the liner, again by application of heat and pressure, so as to achieve a seamless interface. This configuration virtually eliminates process fluid leaks around the electrode, while the electrode structure itself exhibits exceptional high temperature stability and corrosion resistance.

Composite electrode structure

A self-cleaning optical device, suitable for use in dirty process environments has a composite, multi-layered structure. A protective outer layer, exposed to the process environment, is a transparent plastic film which is resistant to the adhesion of contaminants to its surface. A light-interactive layer, either light-transmissive or light-reflective depending on the intended function of the optical device, is disposed beneath the protective plastic film layer. A semi-rigid plastic material forms a support layer to give the device structural integrity. The optical device is vibrated to shake loose collected particles from the protective plastic film. The vibrational motion is generated either externally or by excitation of piezoelectric materials incorporated into the device construction.

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Foxboro, MA, United States of America

John R Martin