A thermally reacting closure for sprinklers and nozzles is presented in patent application WO 03/105963 AI. The author describes in this invention a nozzle that is sealed at the end of the outlet channel by a cover plate. This cover plate is firmly connected to the nozzle body by a melt tripping device that acts as connection like soft solder. It is assumed in that invention that when the case arises the temperature in the space rises and the melt tripping device melts at a specific temperature and in this way releases the nozzle such that the extinguishing with the aid of extinguishant begins. Most sprinkler systems currently in use are based on the principle of an element installed in the sprinkler being directly heated as a consequence of the fire.
It has emerged in practice that the melting temperature of the melt tripping device can vary over the years. The temperature and fluctuations thereof in the monitored space, inter alia, play a role in this context. When the temperature rises above 30° C., it is possible for the material structure, and thus the property of the melt tripping device to vary slowly and in a creeping fashion. It is no longer possible to be sure whether the melt tripping device really does melt at the envisaged temperature. The melting point can be higher such that the response is too late, or else it can be lower such that the response is too early. Both promote damage that it is actually desired to avoid with the use of such devices.
Another problem of the invention presented in document WO 03/105963 A1 is the tripping room temperature. In principle, one would like to use the effect of the sprinklers and nozzles at the place of occurrence of blaze or fire. However, one is not sure whether the highest temperature occurs precisely where the fire or blaze would need to be extinguished. Sometimes, a local fire triggers too many sprinklers and/or nozzles, or the wrong ones, thus unnecessarily producing additional water damage.
In many cases, the beginning of a blaze cannot be detected by fire and the related development of heat, but can be detected by the development of smoke. Where there is smoke there is also certainly fire, but the high temperature governing and tripping the sprinkler occurs much later in some circumstances. This means that in many cases large amounts of damage have already occurred at the relatively late point in time at which the sprinklers and/or nozzles come into use.
For this reason, in most buildings fire alarms are installed that react to smoke, flames, temperature or a combination thereof, and trip an alarm that alarms the supervising staff before a fire breaks out. Thus, in addition to a sprinkler/nozzle system the buildings also further have an electric monitoring system.