| 摘要 |
A fire detector and a fire alarm system wherein a plurality of fire detectors are connected across a pair of lines leading to a signal station and which is capable of detecting, at the signal station, removal of a detector head or heads from an associated socket or sockets of any one or more detectors and yet capable of keeping the succeeding fire detectors operative to send a possible fire alarm signal even after removal of the head or heads. Each of said fire detectors comprises a means for disconnecting the line connected therethrough to the succeeding detector, temporarily in the course of removal of the detector head or heads from the associated socket or sockets or periodically after the detector or detectors has or have been removed from the associated socket or sockets. The signal station comprises a means for detecting the temporary or periodical disconnection of the line. |
