| 摘要 |
PURPOSE:To prevent the clogging of a shielding body and to prolong further the lifetime of a sensor by providing a restricted vent part so that it opens downward. CONSTITUTION:A working electrode 20, an opposite electrode 30 and a reference electrode 40 are provided on the same surface of an insulative substrate 10, and a solid-electrolyte layer 50 is so provided as to cover the electrodes 20 to 40 and spaces between them. A water tank 60 supplying water to the electrolyte layer 50 is joined to the electrolyte layer 50 by a water supplying means, while a restricted vent part securing an airflow between the electrolyte layer 50 and the outside in a restricted manner is provided. In a sensor thus constructed, a vent 81 is so provided in the base of a shielding body 80 as to open downward and to serve as the restricted vent part securing the airflow between the electrolyte layer 50 and the outside in a restricted manner. Thereby evaporation of water to the outside from the electrolyte layer 50 is controlled to make excellent the action of maintaining the water retention of the electrolyte layer 50 by the water tank 60, while a quantity of airflow from outside being necessary for detection of gas can be secured. Besides, it is made possible to prevent the deposition of oil mist or dust on the restricted vent part and to prolong the lifetime of the sensor. |
