| 摘要 |
PURPOSE: To obtain a small-sized planer electrochemical oxygen sensor not consumed by oxygen, simple and cheap to produce and having long life by providing the semipermeable membrane having specific oxygen permeability covering a hygroscopic solid electrolyte. CONSTITUTION: A solid electrolyte 58 is provided on a reference electrode 50, an opposed electrode 52 and an acting electrode 54. The electrolyte 58 is composed of a gel swollen below twice its dry vol. upon the contact with water or steam. A semipermeable membrane 60 is provided on the electrolyte 58 so as to perfectly cover the same. The membrane 60 protects the electrolyte 58 and the electrodes 50, 52, 54 from metal ions harmful to the operation of them according to circumstances but permits steam and oxygen necessary for the operation of a sensor to permeate. The membrane 60 restricts the passage of oxygen up to the electrode because enhances the non-consumption characteristics of the sensor. The membrane 60 suitable for this use has oxygen permeability of below about 8 Barrer, pref., about 0.1-5 Barrer, more pref., about 0.2-3 Barrer. |
