| 摘要 |
1,129,402. Photo-electric smoke or particle detector. WALTER KIDDE CO. Ltd. Feb. 24, 1967, [Feb. 24, 19661 No.8293/66. Heading G1A. A smoke detector comprises a main container 10 having openings 15 for the passage of air to be monitored, a sealed chamber 11 and a light source 24 in the container the main light-sensitive cell or cells 17 being housed in the sealed chamber and having a beam of light from the source directed past their active surfaces by a lens 19. There may be four cells arranged to define a passage through which the light is directed and a pyramidal light deflector 21 having a light absorptive surface is positioned at the end of the passage. A further cell 25 having an adjustable light attenuator is provided to cancel the standing scattered light on the main cell. The lamp may be enclosed and have a lens 16b, or may be exposed to the stream of air, the former arrangement being suitable for tungsten-iodine, or quartz-iodine lamps. A bulb failure indicator may be actuated by a thyristor in the circuit or by a further photo cell. The container may be earthed to prevent static build-up. |
