Fire detection system with multiple output signals
First Claim
1. A fire detection system comprising:
- a control unit for providing an energizing potential difference;
a pair of conductors connected to receive the energizing potential difference from the control unit;
a plurality of fire detectors, each connected in parallel accross said conductor pair, and each of which signals an alarm in the same manner, by presenting a low impedance across said conductor pair; and
circuit means in said control unit, coupled to said conductor pair to receive status information from the detectors over the same conductor pair which supplies the energizing potential difference to the detectors, which control unit is effective to provide a first alarm output signal when a first one of the detectors is alarmed, and to provide a second alarm output signal when any of the remaining detectors is subsequently alarmed.
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Accused Products
Abstract
A fire detection system includes a single conductor pair for both supplying the energizing voltage to all of the fire detectors in the protected area and receiving back status information regarding the individual detector operation. The system provides individual, successive alarm outputs to regulate successive functions such as "evacuate the area", "dump the fire extinguishing material", and "call in the local fire department", as successive ones of the detectors are alarmed. The system includes a voltage regulator for supplying a well regulated voltage to the detectors, which regulator is switched into a current limiting mode to prevent an inaccurate first alarm signal if the conductor pair is short circuited. This system also provides a trouble-indicating output signal if the system loses supply voltage or experiences a ripple voltage beyond a preset amplitude.
39 Citations
9 Claims
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1. A fire detection system comprising:
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a control unit for providing an energizing potential difference; a pair of conductors connected to receive the energizing potential difference from the control unit; a plurality of fire detectors, each connected in parallel accross said conductor pair, and each of which signals an alarm in the same manner, by presenting a low impedance across said conductor pair; and circuit means in said control unit, coupled to said conductor pair to receive status information from the detectors over the same conductor pair which supplies the energizing potential difference to the detectors, which control unit is effective to provide a first alarm output signal when a first one of the detectors is alarmed, and to provide a second alarm output signal when any of the remaining detectors is subsequently alarmed. - View Dependent Claims (2, 3, 4, 5)
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6. A fire detection system comprising:
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two, and only two, conductors extending throughout an area to be protected; a plurality of fire detectors, each coupled between the conductor pair at different physical locations throughout the area, and each of which signals an alarm in the same manner, by presenting a low impedance across said conductor pair; termination means exhibiting a capacitive reactance and coupled to the end of said conductor pair; a control unit connected to supply a d-c potential difference between said conductors; and circuit means in said control unit, coupled to said conductor pair to receive detector status information over the same two conductors which pass the d-c energizing potential difference to the detectors, which control unit is effective to provide a first alarm output signal when the first one of the detectors is alarmed, and to provide a second alarm output signal when any of the remaining detectors is subsequently alarmed. - View Dependent Claims (7, 8, 9)
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Specification