| 摘要 |
PURPOSE:To obtain the gas sensor which necessitates no constant-potential applying device by using a gas electrode of a silver catalyst being active to a deoxidation reaction of oxygen and being inactive to an oxidation reaction of combustible gas, for a positive electrode, and using a gas electrode of a platinum catalyst being active to an oxidation reaction of combustible gas, for a negative electrode. CONSTITUTION:A container body 1 made of an ABS resin is provided with a positive electrode 2 formed integrally by bringing silver to a electrodeposition to porous carbon and bringing a porous polyfluoroethylene film to pressure welding to its outside, and a negative electrode 3 formed by bringing platinum to electrodeposition to porous carbon. As for as electrolyte, a mixed water solution of acetic acid and potassium acetate is used. Also, on the outside of the negative electrode 3, a diaphragm 5 consisting of a tetrafluoroethylene- hexafluoropropylene copolymer film is provided. The positive electrode 2 and the negative electrode 3 are closed in the outside through a detection resistance 6. In such a state, when this galvanic cell type combustible gas sensor is placed in mixed gas of air and combustible gas, only a deoxidation reaction of oxygen occurs in the positive electrode 2, and accordingly, only an oxidation reaction of gas occurs in the negative electrode 4, therefore, by measuring a voltage across the resistor 6 generated by a movement of an electron which follows the reaction, concentration of gas can be known. |
