| 摘要 |
PURPOSE:To sense smoke even if in the place where the air circulates, by providing with light shielding plates having light transmitting windows, which are fit to outside plates in passages of irradiated rays of light. CONSTITUTION:Light shielding plates 5 having light transmitting windows 4 where rays are passable in the passages of the rays 3 irradiated from radiating sections 1 of light emitting diode or the like, are provided with and a smoke sensing region 7 is constituted by fixing shielding plates 5 with outside plates 6, 6 and is made to be smoke passages 8 where smoke is passable. When smoke is generated due to a fire, a light recepter 2 detects it and gives an alarm, because the rays are attenuated with smoke particles. By such arrangement, as the smoke which moves up in the air current is quickly caught and occurance of a fire is promptly sensed and also effectual places where the device is provided with, are selected without any restriction. |
