Rosemount Analytical Inc.

James W Thomson

Frederick M Ryan

Michael T Estvander

Michael G O'Neill

Boris Y Farber

A solid electrolyte gas analyzer is equipped with a diagnostic circuit that intermittently measures an impedance of the solid electrolyte measurement cell as an indication that the cell is in need of calibration or replacement. The diagnostic operation is performed on the cell in situ, i.e., while the solid electrolyte cell is exposed to the gas to be measured and heated to a controlled elevated temperature. Preferably the cell impedance is measured at a predetermined frequency by injecting a modulated current through the cell and measuring the resulting voltage drop.

Diagnostic method and apparatus for solid electrolyte gas analyzer

An analyzer measures properties of multiple chemical samples, and includes an optical filter element having a long axis and positioned at a location where simultaneous multiple light beams, corresponding to the chemical samples to be measured, form a diffuse light spot elongated along an axis which is substantially aligned with the filter element long axis. The analyzer also includes a light source, filter means incorporating the filter element for transmitting spectrally selected portions of the light beams, sample cell means for exposing each sample to its associated light beam, and detector means for detecting the light beams after modification by the samples and after transmission by the filter. In a preferred embodiment, optical fibers carry the light beams to and from the chemical samples.

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Murrysville, PA, United States of America

James W Thomson