Composite fire sensor
First Claim
1. A composite fire sensor comprising a first sensor element sensitive to a change in incident infrared rays, a second sensor element having a variable electric conductivity according to gas absorption/desorption, said first sensor element being sensitive to heat and flame, said second sensor element being sensitive to smoke and gas and both producing outputs, at least one comparator means for combining the outputs of said first and second sensor elements, said at least one comparator means adapted to change its sensitivity to produce an alarm output in response to said outputs of said first and second sensor elements, and a delay circuit for delaying said alarn output of said at least one comparator means, wherein predetermined reference voltages along with the output of the first and second sensor elements are fed to said comparator means to produce said alarm output.
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Accused Products
Abstract
A composite fire sensor comprising a first sensor element sensitive to a change in incident infrared rays, a second sensor element having a variable electric conductivity according to gas absorption/desorption, at least one comparator for combining the outputs of the first and second sensor elements, and a delay circuit for delaying the output of at least one of the comparators. Predetermined reference voltages are supplied to the comparators.
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Citations
6 Claims
- 1. A composite fire sensor comprising a first sensor element sensitive to a change in incident infrared rays, a second sensor element having a variable electric conductivity according to gas absorption/desorption, said first sensor element being sensitive to heat and flame, said second sensor element being sensitive to smoke and gas and both producing outputs, at least one comparator means for combining the outputs of said first and second sensor elements, said at least one comparator means adapted to change its sensitivity to produce an alarm output in response to said outputs of said first and second sensor elements, and a delay circuit for delaying said alarn output of said at least one comparator means, wherein predetermined reference voltages along with the output of the first and second sensor elements are fed to said comparator means to produce said alarm output.
Specification
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- Resources
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Current AssigneeDaido Denki Kogyo Kabushiki Kaisha
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Original AssigneeHiroshi Seki, Ryuichiro Kataishi
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InventorsKataishi, Ryuichiro, Seki, Hiroshi
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Primary Examiner(s)Frankfort, Charles
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Assistant Examiner(s)Will, Thomas B.
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Application NumberUS06/753,987Time in Patent Office572 DaysField of Search374/121, 374/123, 374/141, 374/161, 374/164, 374/178, 340/577, 340/578, 340/579, 340/628, 340/634, 116/5, 116/101US Class Current374/141CPC Class CodesG08B 17/00 Fire alarms; Alarms respons...G08B 29/183 Single detectors using dual...
