| 摘要 |
<p>The invention relates to a prevention and alarm device comprising a signal injector (1) which is disposed at the risk-prone site and receivers (3) which are installed in the houses and buildings neighbouring the risk-prone site or area. By way of a communication link, the invention employs the low- and medium-voltage electric power network (2) in the area of the risk-prone site, in a unidirectional manner. The method involves the injection of an alarm or prevention signal, in the form of a carrier current, into the power network from the risk-prone site. In this way, the houses or storage buildings equipped with the above-mentioned detector (3) can interpret the signal, raise the alarm using a siren (13) and flashlamp (14), and intervene directly on electrical systems, for example, by closing roller shutters (9) and shutting-off ventilation or air-conditioning systems (10).</p> |
