| 摘要 |
PURPOSE:To preserve a sensor alone for a long period of time, to easily calibrate the output thereof and to obtain high reliability by coating the opening part of the housing part having the sensor received therein with a thermoplastic material. CONSTITUTION:The gas sensing part of a sensor detecting carbon dioxide under heating at 300 - 500 deg.C is included in a housing part 7 and, in such a state that a detection part 1 is not heated, an opening part 11 is closed by a bimetal plate 8 and a seal material 10 and further covered with a cover material 15 to be perfectly shielded from the outside atmosphere. Therefore, the interior of the housing part 7 always becomes a dry state by the hygroscopicity of a silica gel sheet 12 and the deterioration of a sensing part 1 is prevented. When the sensing part 1 becomes a heated state, the temp. of the housing part 7 and that of the bimetal plate 8 rise by the heat of a heater 2 and the bimetal plate 8 is operated. Since the cover material 15 is fixed to the bimetal plate 8 at this time, it is damaged by the operation of the bimetal plate 8. As a result, the opening part 1 becomes an open state and the interior of the housing part 7 is brought into contact with the outside atmosphere to become a measuring state. |
