Central smoke alarm and annunciator
First Claim
1. In a system having a plurality of remote electronic smoke detectors, each detector having a low electrical current idle condition, a steady high electrical current alarm condition, and a periodic high electrical current test condition, the centralized smoke and fault alarm system comprising:
- a plurality of current sensing means at a central location for monitoring separately the current to each of said smoke detectors, each of said current sensing means producing a first output signal responsive to said steady high current alarm condition and a second output signal responsive to the absence of said periodic high current test condition of its associated smoke detector;
a plurality of alarm indicators wherein each of said current sensing means is connected to one of said indicators, each of said indicators for identifying the location of its associated smoke detector, for producing a smoke alarm indication responsive to said first output signal and for producing a fault indication responsive to said second output signal; and
a common alarm connected to said plurality of current sensing means for producing a common audible and visual alarm signal in response to a smoke alarm or a fault alarm from any of said plurality of remote smoke detectors.
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Abstract
A central smoke detection system for a building having multiple rooms utilizes low cost commercial smoke detectors in each room. Each detector includes a steady high current alarm mode, a low current idle mode and a high pulse current test mode. A central power source supplies power to the detectors via one common lead and a separate power lead to each detector. A resistor in each power lead at the central location provides for monitoring of the mode of each smoke detector. A central monitor operates a visual smoke alarm responsive to the steady high current mode which indicates the room in which a detector is in the alarm mode and a visual fault alarm responsive to the absence of the high test pulse current indicating the room in which a detector is inoperative. A common central smoke and fault alarm, both audible and visual is also provided.
26 Citations
14 Claims
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1. In a system having a plurality of remote electronic smoke detectors, each detector having a low electrical current idle condition, a steady high electrical current alarm condition, and a periodic high electrical current test condition, the centralized smoke and fault alarm system comprising:
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a plurality of current sensing means at a central location for monitoring separately the current to each of said smoke detectors, each of said current sensing means producing a first output signal responsive to said steady high current alarm condition and a second output signal responsive to the absence of said periodic high current test condition of its associated smoke detector; a plurality of alarm indicators wherein each of said current sensing means is connected to one of said indicators, each of said indicators for identifying the location of its associated smoke detector, for producing a smoke alarm indication responsive to said first output signal and for producing a fault indication responsive to said second output signal; and a common alarm connected to said plurality of current sensing means for producing a common audible and visual alarm signal in response to a smoke alarm or a fault alarm from any of said plurality of remote smoke detectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A central smoke detection, alarm and annunciation system for a building having multiple rooms with each room having an electronic smoke detector, said detector drawing a very low current in a non-alarm condition, a steady high current in an alarm condition, and producing a periodic high current test pulse, comprising:
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a common direct current power supply having a common power bus connecting to each said detector in each of said rooms and a separate return power lead from each said detector; a resistor in each said separate return power lead for producing a voltage thereacross, said non-alarm condition producing a very low non-alarm voltage, said alarm condition producing a steady higher alarm voltage, and said test pulse producing a higher test voltage pulse; a monitor circuit connected across each said resistor for monitoring for said steady alarm voltage and said test voltage pulse; a visual indicator connected to the output of each said monitor circuit, said indicator including an identification of the room location of the smoke detector associated therewith, said monitor circuit causing said indicator to flash at a first rate responsive to said alarm voltage indicative of a smoke alarm, and causing said indicator to flash at a second rate responsive to the absence of said test voltage pulse indicative of a fault in the smoke detector associated therewith; and a common visual alarm control and a common audible alarm control each connected to the output of said monitor circuit and responsive to a smoke alarm output therefrom or a fault alarm output therefrom for producing a common visual and audible alarm. - View Dependent Claims (14)
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Specification