False alarm resistant fire detector with improved performance
First Claim
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1. A fire detector having a low rate of generating false alarms, said fire detector comprising:
- a CO2 fire detector module;
a smoke detector module adapted to measure a second property that is indicative of the presence of a fire;
an AND gate, having an output, having an input connected to an output of the CO2 fire detector module and having an input connected to an output of the second fire detector module;
a clock, connected to said smoke detector, for measuring a duration of each interval in which the smoke detector measures a smoke level exceeding a preselected threshold level; and
temporal rate of change logic having an input connected to the output of the CO2 fire detector module and having an output indicating a temporal rate of change of carbon dioxide concentration.
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Abstract
A fire detector having a greatly reduced frequency of generating false alarms. An AND gate is responsive to outputs from first and second fire detector modules that are responsive to the detection of first and second characteristics of a fire, respectively, to signal the detection of a fire if both of these characteristics have been detected. At least one override path is included to enable the occurrence of a particular type of fire to be signalled that would not otherwise be signalled by the output of said AND gate.
79 Citations
4 Claims
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1. A fire detector having a low rate of generating false alarms, said fire detector comprising:
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a CO2 fire detector module; a smoke detector module adapted to measure a second property that is indicative of the presence of a fire; an AND gate, having an output, having an input connected to an output of the CO2 fire detector module and having an input connected to an output of the second fire detector module; a clock, connected to said smoke detector, for measuring a duration of each interval in which the smoke detector measures a smoke level exceeding a preselected threshold level; and temporal rate of change logic having an input connected to the output of the CO2 fire detector module and having an output indicating a temporal rate of change of carbon dioxide concentration. - View Dependent Claims (2, 3, 4)
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Specification