| 摘要 |
PURPOSE:To detect low-density smoke in a clean room with high sensitivity by sucking air from the clean room into a dark box, and irradiating the inside of the dark box with light from a light emitting element and detecting scattered light from smoke particles by a photodetecting element. CONSTITUTION:The air in the clean room is sucked into the dark box 5 continuously through a suction port 6 and discharged from a discharge port 8. The inside of the dark box 5 is irradiated with the light from the light emitting element 10 and the light is photodetected by the photodetecting element 12 to detect scattered light from smoke particles. Its detection value is inputted to a control circuit 14 and a warning is transmitted to a fire receiving board 15 and disaster prevention device 15 when the detection value exceeds a specific value. Thus, the air in the clean room is sucked positively to detect even low- density smoke right after firebreaks out.
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