| 摘要 |
PURPOSE:To enable stable measurement of dissolved oxygen in water for a long period by constructing an oxygen sensor of a sensor element having an oxygen ion conductor and a pair of electrodes and of a porous partition wall. CONSTITUTION:A sensor element M is constructed of an oxygen ion conductor 1 formed to be of small thickness and constituted of stabilized zirconia, of porous electrodes 2A and 2B which are laminated on the counter surfaces of the conductor and whereon a prescribed voltage is impressed, etc. On the side of a stem 10 whereon the sensor element M is disposed, a mesh cover 12 (first air-permeable partition wall) covering the sensor element M wholly and preventing impurities such as dust is fitted, and moreover an air-permeable Teflon film 13 (second air-permeable partition wall) preventing the invasion of a solution and allowing a gas (oxygen gas) dissolved in the solution to pass through is fitted on the inner surface of the cover 12. A porous partition wall 14 is constructed of this cover 12 and the film 13. By this partition wall 14, it is possible to prevent the invasion of the solution and to allow only the gas to pass through, and thus the concentration of oxygen dissolved in water can be measured effectively. |
