| 摘要 |
PROBLEM TO BE SOLVED: To surely detect total NOx concentration up to a low concentration territory by directly laminatedly joining a detection electrode and a conversion electrode formed on respective solid electrolyte base plates to be oxygen ion conductive bodies. SOLUTION: A NOx conversion electrode 1 is screen-printed on a zirconia sheet (solid electrolyte base plate) 5, a conversion pair electrode 4 is printed on the opposite face of the base plate 5, and hence a conversion electode sheet is formed. A NOx detection electrode 2 is printedly formed on a solid electrolyte base plate 6 of the same material as the base plate 5, a refererence electrode 3 is printed on the opposite face, and hence a detection electrode sheet is formed. A theobromine extinction sheet is pinched on the circumference of the electrodes 1, 2 so as not to contact with the each other sheet of the conversion electrode sheet and the detection electrode sheet, and the electrodes 1, 2 are directly joined together so as to meet with each other. By this element construction because the used zirconia sheets become to be dense quality, NOx gas goes in and out from the sides of a porous electrode or a porous alumina insulating layer. Consequently, the measuring accuracy and the noise resistance for total NOx detection are improved, and the conversion electrode 1 can be prevented from deteriorating. |
