| 摘要 |
PURPOSE:To detect only a large amount of smoke and to reduce erroneous operation, by providing light sources, which emit two or more parallel light beams, whose intensities are different by 10 times or more, and providing a light detecting part, which compares the transmittances of the light beams through a smoke atmosphere. CONSTITUTION:Light sources are halogen lamps 1a and 1b of 100V and 150W. A voltage of 100V is applied to one lamp, and 80V is applied to the other. The ratio of the light intensities of the lamps is 15 times. The light beams from the halogen lamps are guided to an optical system comprising convex lenses 6, which are fixed with a supporting tool 3, through light guides 2a and 2b. The light beams become the two parallel light beams and enter into an optical system comprising convex lenses 6, which are fixed with a supporting tool 4 on the light receiving side. The light beams are further guided through light guides 5a and 5b and inputted into power meters 7a and 7b. The output voltages of the power meters 7a and 7b are inputted into an operating device 8. The operating device computes and compares the transmittances of the two parallel light beams. When there is the difference of 10% or more in the transmittances, a relay 9 is actuated with output power, and a warning light 10 is lighted. |
