| 摘要 |
Fire detection system having a multiplicity of fire detectors (A11, A12,... B1, B2,... C1, C2,...) connected to a signalling centre (S). The individual fire detectors are arranged in groups (A, B, C...) according to protection areas (I, II,...), the detectors of one group being connected to one another and to the signalling centre (S) via a group line in each case. To increase the immunity to false signals, each protection area (I, II,...) is passed through by its own fire detector group (B1, B2,... C1, C2...) and by a selected fire detector group (A11, A12,... A21, A22...), common to some or all the protection areas. As a result, the installation expenditure and the susceptibility to faults can be kept particularly low. In the case of an expedient further development, the fire detectors (A11, A12,... A21. A22...) of the group (A) common to all the protection areas (I, II,...) respond to a different consequential effect of fire than the fire detectors (B1, B2,... C1, C2...) of the separate groups (B, C...) assigned to the individual monitoring areas, as a result of which the immunity to false signals can be further improved. This so-called two-group dependence can also be used analogously for increasing an alarm level, in that if one detector of only one group responds, a preliminary warning signal is triggered and, if detectors in two groups respond, the actual fire alarm is set off. <IMAGE>
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