| 摘要 |
PURPOSE:To enable the realization of a small and inexpensive sensor by measuring the concentration of carbon dioxide to be inspected using an Na<+> conducting solid electrolyte by a direct interpolation formula to secure a high accuracy and a high stability. CONSTITUTION:An electrically insulating material 1 is a tubular body with both ends thereof opened and a heating element 6 is arranged on an outer surface thereof while an anode electrode 4 on the inner surface thereof. A block of an Na<+> conducting solid electrolyte is inserted into a hollow part of the insulating material so as not to contact the inner surface thereof directly. The electrolyte 2 has a cathode electrode 3 formed at one end 2b thereof and a layer 5 of Na2CO3 is provided to bridge between the other end thereof and the electrode 4. When a gas to be inspected having carbon dioxide contacts this sensor, an electromotive force is generated between the electrodes 3 and 4 in proportion to the concentration of the carbon dioxide (partial pressure). If a relationship between the gas and the electromotive force is prepared by a calibration curve, the concentration of carbon dioxide in the gas to be inspected can be learned from the electromotive force when the sensor is inserted into the gas to be inspected. Thus, the electrolyte 2 and the electrode 4 are so arranged as not to contact each other directly, thereby achieving a higher accuracy and stability. |
