| 摘要 |
PURPOSE: To provide a contact-combustion-type carbon monoxide gas sensor with good gas selectivity having high sensitivity only against carbon monoxide gas. CONSTITUTION: A gas sensing element 3 and a compensating element 4 used while being built into branches of a bridge circuit are held by metallic pins 6 fixed through a base 5 of an insulator and covered with a cap. The gas sensing element 3 comprises a temperature measuring resistor and an oxidation combustion catalyst layer for coating the resistor, wherein the catalyst layer is a sintered body of a mixture ofα-ferric oxide fine powder holding a gold catalyst and aluminum oxide powder holding a platinum catalyst and a palladium catalyst. The compensating element 4 comprises a temperature measuring resistor and a metal oxide layer for coating the resistor, wherein the metal oxide layer is a sintered body of a mixture ofα-ferric oxide fine powder and aluminum oxide powder. In addition, a cap 8 comprising glass fiber filter paper and a polyfreon filter is put over the elements.
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