Method of detecting fire in an early stage
First Claim
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1. A fire alarm for the early detection of fires comprising:
- a first sensing means for sensing a first fire related phenomenon having a first electrical output, where said first sensing means is sensitive to temperature fluctuations having frequency components in the range of 0.1 to 20 Hz;
a second sensing means for sensing a second fire related phenomenon, different from the first fire related phenomenon, having a second electrical output;
a means for combining the first and second electrical output from the first and the second sensing means respectively for generating a third output;
and a housing containing the first sensing means having means for optimizing the flow of air to the first sensing means.
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Abstract
To improve probability of detection in the early stages of fires, a fire alarm (1) with a temperature sensor (3) is proposed, having a structural member (12) that causes the sensor (3) to react only to temperature changes in the ambient air, and which change with a frequency of from 0.1 to 20 Hz. The fire alarm (1) becomes particularly insensitive to errors when there is a second fire sensor (7) that reacts to fire aerosol, there being a threshold value circuit (9) that lowers the threshold value for the fire aerosol sensor (7) when the temperature sensor (3) exceeds a preset threshold value.
29 Citations
25 Claims
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1. A fire alarm for the early detection of fires comprising:
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a first sensing means for sensing a first fire related phenomenon having a first electrical output, where said first sensing means is sensitive to temperature fluctuations having frequency components in the range of 0.1 to 20 Hz; a second sensing means for sensing a second fire related phenomenon, different from the first fire related phenomenon, having a second electrical output; a means for combining the first and second electrical output from the first and the second sensing means respectively for generating a third output; and a housing containing the first sensing means having means for optimizing the flow of air to the first sensing means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fire alarm for the early detection of fires comprising:
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a first sensing means for sensing a first fire related phenomenon having a first electrical output; a second sensing means for sensing a second fire related phenomenon, different from the first fire related phenomenon, having a second electrical output; a means for combining the first and the second electrical output from the first and the second sensing means respectively for generating a third output; a housing containing the first sensing means having means for optimizing the flow of air to the first sensing means; and a measuring chamber (24), where the first sensing means forms one wall of the measuring chamber (24) in the housing, the measuring chamber having a volume not larger than the sensing means. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A fire alarm for the early detection of fires comprising:
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a first sensing means for sensing a first fire related phenomenon having a first electrical output; a second sensing means for sensing a second fire related phenomenon, different from the first fire related phenomenon, having a second electrical output; a means for combining the first and the second electrical output from the first and the second sensing means respectively for generating a third output, where the means for combining the first and the second electrical output is a band pass filter; and a housing containing the first sensing means having means for optimizing the flow of air to the first sensing means.
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19. A fire alarm for the early detection of fires comprising:
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a first sensing means for sensing a first fire related phenomenon having a first electrical output; a second sensing means for sensing a second fire related phenomenon, different from the first fire related phenomenon, having a second electrical output; a means for combining the first and the second electrical output from the first and the second sensing means respectively for generating a third output, where the means for combining the first and the second electrical output can be configured to analyze only the first electrical output for generating the third output; and a housing containing the first sensing means having means for optimizing the flow of air to the first sensing means.
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20. Method for early detection of fires comprising:
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(a) sensing temperature variations as a first fire related phenomenon with a temperature sensing means having a first electrical output (3), (b) sensing a second fire related phenomenon with a sensing means having a second electrical output (7), (c) combining the first and second electrical output into a third output, (d) providing a means for optimizing the flow of air to the temperature sensing means for the first fire related phenomenon. - View Dependent Claims (21, 22)
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23. Method for early detection of fires comprising the detection of variations in the temperature of ambient air with a temperature sensing means, said temperature sensing means being able to detect temperature variations having frequency components in the range of 0.1 Hz to 20 Hz.
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24. A fire alarm for the early detection of fires comprising a detector for temperature variations, said detector being able to detect temperature variations having frequency components in the range of 0.1 Hz to 20 Hz.
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25. A fire alarm for the early detection of fires comprising:
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a first sensing means for sensing a first fire related phenomenon having a first electrical output; a second sensing means for sensing a second fire related phenomenon, different from the first fire related phenomenon, having a second electrical output; a means for combining the first and the second electrical output from the first and the second sensing means respectively for generating a third output, where the means for combining the first and second electrical output compares individually the output from the first and the second sensing means to a threshold before generating the third output, and where exceeding the threshold for the first sensing means lowers the threshold for the second sensing means; and a housing containing the first sensing means having means for optimizing the flow of air to the first sensing means.
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Specification