| 摘要 |
An improved fire detector is obtained by combining a conventional smoke particle sensor (22) with a fire radicals odor sensor (17); the latter being an electronic nose tuned to respond to the presence of a family of radicals, produced by most fires, that is responsible for the odor associated with a fire. The conventional smoke particle sensor (22) is prevented from producing an alarm signal unless the tuned electronic nose (17) senses that the fire-produced radicals are increasing at a rate that exceeds a preset threshold rate C1. In another aspect of the invention, the smoke particle sensor is provided with a second, lower, threshold L1 connected to a timer so that an alarm will be produced if the lower threshold is exceeded, without interruption, for a preset time T1. The improved fire detector, using the combined sensors, has greater sensitivity and a lower false alarm rate.
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