EP0148949A1
Expired / Lapsed
EP
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Fire sensor apparatus
Assignee: Nohmi Bosai Ltd
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Filing: 1984-03-29
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Granted: —
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Expires: 2004-03-29
Abstract
Abstract A fire sensor apparatus is provided with a fire sensor which has a built-in microcomputer and in which fire detection levels can be varied according to changes in environmental conditions (noise level) in the area in which it is installed. A signal from a sensor (1) is digitized in an A-D converter (3) and is input to a comparator (12). A CPU (5) determines the current time from a clock (4) and removes from a memory accumulated data on operating leveland noise level at the corresponding time in the past. The CPU (5) sets an operating level for the time concerned by executing a predetermined calculation, and compares this operating level with the signal from the sensor (1). An abnormal state is indicated at (14) or the accumulated data is renewed, according to the result of the comparison. Thus it is possible to set an appropriate operating level according to changes in noise level, and fire detection can be effected with a suitable detection sensitivity.
Inventors
- 👤 Yoshiaki C/O Nohmi Bosai Kogyo Co. Ltd. Okayama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 04:20
CPC Classifications
G; G08; G08B; G08B17/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
130 words
A fire sensing apparatus characterized by comprizing a physical quantities mesuring means for converting the physical quantities of the phenomena of a fire such as smoke, heat, light and so on into digital electric signals, means for storing said measured physical quantities and means for producing accumulated past data from said measured physical quantities, means for determining a set sensitivity at the current point in time on the basis of said accumulated past data, means for comparatively descriminating said determined set sensitivity and the physical quantities currently input, and means for outputting according to the results of said comparative discrimination, whereby the fire detection level is varied in response to variations in the environmental conditions of its installation location and fire can be detected with a continually constant fire sensitivity.
Claim 2
Dependent Claim
130 words
A fire sensing apparatus characterized by comprizing a physical quantities mesuring means for converting the physical quantities of the phenomena of a fire such as smoke, heat, light and so on into digital electric signals, means for storing said measured physical quantities and means for producing accumulated past data from said measured physical quantities, means for determining a set sensitivity at the current point in time on the basis of said accumulated past data, means for comparatively descriminating said determined set sensitivity and the physical quantities currently input, and means for outputting according to the results of said comparative discrimination, whereby the fire detection level is varied in response to variations in the environmental conditions of its installation location and fire can be detected with a continually constant fire sensitivity.
Claim 3
Dependent Claim
38 words
A fire sensing apparatus as described in claim 1, wherein the means for storing measured physical quantities includes means for reading said measured physical quantities as information into days of the week and times by a clock portion.
Claim 4
Dependent Claim
65 words
A fire sensing apparatus as described in claim 1, wherein the means for determining the set sensitivity at a current point in time on the basis of the accumulated past data includes means for obtaining physical quantities according to currently anticipated environmental conditions such as an average value by means of a simple averaging computation or a weighted averaging computation of the accumulated past data.
Claim 5
Dependent Claim
133 words
A fire sensing apparatus as described in either claim 1 or claim 3, wherein a set sensitivity as a standard value is set to be a fire discrimination level when there is no measured physical quantities of phenomena similar to a fire phenomenon, in other words noise components, and on the other hand, is set to be a fire detection level, when there are existing noise components to be determined as fire, an average value of said noise component being obtained at separated time periods or at separated time periods of the days of the week on the basis of the accumulated past data, and the reference value that is to discriminate a fire at those time periods is produced by adding the average value of said noise component to said standard value.
Claim 6
Dependent Claim
175 words
A fire sensing apparatus as described in claim 1, wherein the means for determining sensitivity at a current point in time on the basis of the accumulated past data includes means for providing an upper limit set value, a lower limit set value and a reference set value between an upper limit value and a lower limit value of an operating level, means for obtaining a maximum value, a minimum value and an average value of the accumulated data from the accumulated data of environmental noise, and means for obtaining the set sensitivity at the current point in time by means of computing (where, is constant) with the upper limit set value A, the reference set value B, the lower limit set value C, the maximum value D of the accumulated data, the average value E of the accumulated data, the minimum value F of the accumulated data and the accumulated data X corresponding to the current point in time in the accumulated data of the environmental noise which are obtained from said respective means.
References Cited (Backward Citations)
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