| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect a correct concentration of a gas without time and labor required for maintenance by introducing a gas into an optical path between a light emitting part for emitting lights containing two wavelengths and a detector having a filter adapted to pass the lights alone to absorb or transmit the lights with these wavelengths. SOLUTION: Light emitted from an infrared emitting element 2a is transmitted through a glass 1j of a partition wall 1c, then, introduced into an introduction path 1h to be irradiated to carbon dioxide and subsequently transmitted through a glass 1k of a partition wall 1d. The light transmitted through the glass 1j reaches detectors 3a and 3b but that with a specified wavelength is detected as filters 3c and 3d are provided. When the lights with these wavelengths irradiate the carbon dioxide, the lights are absorbed according to the concentration thereof, which allows detecting of the concentration of the carbon dioxide based on the light with the wavelength detected by the detector 3a. At this point, even when the glass 1j is fouled, correction is possible based on the light with the wavelength detected by the detector 3b without being irradiated to the carbon dioxide to be absorbed.</p> |
