| 摘要 |
PURPOSE:To detect propane gas, coal gas, etc., leaking at the normal temperature without wrong information by emitting infrared light of specific wavelength from a light source, by detecting it by a photodetector, and then by detecting the gas that resides in a gas stay space between the both. CONSTITUTION:Light from LED emitting monochromatic light of 34mum or light source 1 emitting white light, etc., including a wavelength range of 34mum passes through air penetration hole 5, where surrounding air is sucked, by pump 4 and then passes through a gas stay space, where air including gas is reserved, before reaching photodetector 3 consisting of a light-voltage converting element such as a thermistor. When gas is included in the sucked air, light of wavelength according with the gas is absorbed and the light reaches photodetector 3. According to the absorptivity of the light, photodetector 3 detects the density of the gas in the air. Consequently, fine gas of low density can be detected. |
