Apparatus for simultaneous detection of target gases
First Claim
1. Apparatus for the selective detection of a target gas in ambient air comprising,an electrically insulating substrate,a pair of electrodes positioned on said substrate,a gas sensor film positioned on said substrate in contact with said pair of electrodes,said film having a preselected response characteristic for a selected gas to be detected,catalytic combustion filter means integral with said gas sensor film for minimizing the effect of interference gases that are less thermochemically stable than the target gases on the response of said film for the gas to be detected by promoting combustion of interference gases on the outer layer of said film away from said electrodes, andmeans for heating said gas sensor film to a preselected elevated temperature on said substrate.
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Abstract
A gas sensing thick film is positioned on an insulating substrate in contact with a pair of electrodes. A non-porous glass layer surrounds the film to stabilize it on the substrate. A heating element maintains the film at a preselected elevated temperature. The gas sensing thick film has a response characteristic for a preselected target gas to be detected which is enhanced by impregnating the film with platinum or palladium chlorine free compounds. The response characteristic of the gas sensing film is further increased by promoting combustion of interference gases on an outer filter layer fabricated of either conductive or nonconductive material. The incorporation of an insulating material between the gas sensing film and the outer filter layer also serves to increase the relative response of the gas sensing film to a preselected target gas.
64 Citations
23 Claims
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1. Apparatus for the selective detection of a target gas in ambient air comprising,
an electrically insulating substrate, a pair of electrodes positioned on said substrate, a gas sensor film positioned on said substrate in contact with said pair of electrodes, said film having a preselected response characteristic for a selected gas to be detected, catalytic combustion filter means integral with said gas sensor film for minimizing the effect of interference gases that are less thermochemically stable than the target gases on the response of said film for the gas to be detected by promoting combustion of interference gases on the outer layer of said film away from said electrodes, and means for heating said gas sensor film to a preselected elevated temperature on said substrate.
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16. A selective gas sensing film comprising,
a heating element, a substrate positioned on said heating element, a pair of electrodes positioned in spaced relation on said substrate, a metal oxide film positioned on said substrate in contact with said pair of electrodes, and a non-porous glass layer surrounding said metal oxide film to anchor said metal oxide film to said substrate and to said pair of electrodes.
Specification