| 摘要 |
PURPOSE:To monitor deterioration degree of the catalytic action of an electrode, and to compensate deterioration of the output of a gas sensor, by raising voltage of the working electrode of a controlled potential electrolysis cell, and correcting a value of current flowing through electrolyte due to electrolysis. CONSTITUTION:A controlled potential electrolysis cell 1 is composed of an ion-conductive electrolyte 2, such as aq. soln. contg. H or OH ions, a working electrode 40 made of fine metallic particles e-g Pt-black and a fluorinated carbon resin, or the like on one side, a gas-permeable opposite electrode 41 in contact with a gas, and a reference electrode 42, etc. When the potential difference between the terminals 50, 52 of the electrodes 40, 42 are controlled to a prescribed potential through a battery 62 and an operation amplifier 60, etc., a current proportional to gas concn. flows between the terminal 52 and that 51 of the electrode 41, and its signal is sent through an operation amplifier 61 to a calculator 63. The initial current value of this controlled potential reaction is stored at the calculator 63, voltage of the battery 62 is periodically raised, similar measurement is made to accord the measured value with the stored initial current value by control, thus permitting compensation of deterioration of gas sensor output, by monitoring the deterioration degree of the catalytic action of the electrode. |
