| 摘要 |
PURPOSE:To make it possible to ensure the issuance of warning at a specified smoke concentration and to make it possible to detect time deterioration of a light emitting element, by setting the lightness of the inner surface of a black box, which detects the intrusion of smoke and issues warning, in a specified range. CONSTITUTION:A fault signal detecting circuit 8 is provided. A black box 5 has a labyrinth structure, into which smoke can intrude. In the black box 5, a light emitting element 3 and a light receiving element 4, into which the beam from the light emitting element does not directly enter, are provided. When smoke invades into the black box 5, scattering of light due to smoke particulates is detected by the light receiving element 4, and the presence of the smoke is detected. Then warning and the like are generated. The inner surface of the black box 5 of this scattered light type smoke detector is set in the range of Munsell values 2-5. The issuance of warning is ensured at the smoke concentration of about 10%/m in this smoke detector having such a black box 5. Time deterioration of the light emitting element 3, which cannot be detected in the conventional detector, can also be detected. |
