Importance

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Abstract

A highly accurate, long life, low cost gas sensor is disclosed, particularly useful for measuring oxygen in an environment. The gas sensor has a first, sensing electrode and a second, counting electrode. Dual electrolytes are electrically serially connected between the first and second electrodes. One of the electrolytes is an ion conducting solid electrolyte, the second is a liquid electrolyte. In response to an electric current an electrical characteristic is produced, and the electrical characteristic changes in response to changes in the concentration of a gas such as oxygen introduced at the first, sensing electrode. The solid electrolyte can be a perfluorinated polymer which advantageously controls the rate of the electrochemical reaction to give the sensor a long life without need for continuous recalibration. A dense liquid impermeable membrane may be positioned over the first electrode so that only gas reaches the first electrode and all gas that reaches the first electrode passes through the membrane. Advantageously, the solid electrolyte isolates the liquid electrolyte from the first, sensing electrode. The liquid electrolyte may comprise an acidic solution, a basic solution or a salt solution.

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First Claim