| 摘要 |
Selective gas/smoke detection system having a number of suction lines connected separately to different measuring points in a room or rooms to be monitored and intended for taking air samples or gas samples at these measuring points, a gas or smoke detector which is connected to these lines and which reacts to the presence of a specific gas in the sample and, when a fixed threshold value is exceeded, emits a detection signal controlling an indicator and/or alarm circuit, and shut-off valves which are received in the individual suction lines and which are to be energised cyclically and periodically in a controlled manner by means of a control circuit, the detector being connected to a control unit which, in the absence of a detection signal, sets the valves in such a way that all the suction lines are simultaneously in open connection with the detector and, when a detection signal is received, changes them over to a sensing mode, the suction lines being brought into open connection with the detector cyclically one after the other or in groups.
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