Smoke detecting apparatus capable of detecting both smoke fine particles
First Claim
1. A smoke detecting apparatus capable of detecting both smoke and fine particles in a monitoring area, comprising:
- light emitting means for projecting a light beam onto said monitoring area;
light receiving means with an output located at a position where a light beam projected from said light emitting means is not directly received, said light receiving means receiving scattered light caused by fine particles including dust and smoke caused by fire entering said monitoring area;
amplifying means for amplifying said output from said light receiving means, said amplifying means having an output that may exceed a predetermined level a number of times;
counting means for counting the number of times that said output from said amplifying means has exceeded said predetermined level as a function of time for detecting said fine particles, said predetermined level being exceeded when fine particles are present in said monitoring area and said predetermined level being not exceeded when fine particles are not present in said monitoring area so that presence of fine particles is detected;
computing means for computing an average value of the output from said amplifying means as a function of time to detect said smoke; and
determining means for determining a contamination level of said monitoring area dependent on a count counted by said counting means and determining characteristics of a fire as a function of said average value computed by said computing means when smoke density is high and the count counted by said counting means reaches a saturation point at which further counting cannot be carried out and emitting an alarm dependent on a result determined by said determining means.
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Accused Products
Abstract
A light emitting device for projecting a light beam onto a monitor area, and a light receiving device, arranged so that a light beam is not directly received by the device, for receiving diffused light caused as a result of fine particles, such as dust, or smoke caused by a fire, entering the monitor area, are provided. Also, an amplifying device for amplifying an output from the light receiving device, and a counting device for counting the output from the amplifying device in units of time are provided. In addition, a computing device for computing an average value or an integrated value of the output from the amplifying device in units of time, and a determining device for determining the level of contamination of the monitor area on the basis of the count value of the counting device and for determining the level of the fire on the basis of the average value or the integrated value computed by the computing device, are provided. As a result, a smoke detecting apparatus consisting of a single unit capable of detecting both smoke and fine particles can be provided, the apparatus detecting a fire on the basis of an environmental abnormality.
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Citations
30 Claims
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1. A smoke detecting apparatus capable of detecting both smoke and fine particles in a monitoring area, comprising:
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light emitting means for projecting a light beam onto said monitoring area; light receiving means with an output located at a position where a light beam projected from said light emitting means is not directly received, said light receiving means receiving scattered light caused by fine particles including dust and smoke caused by fire entering said monitoring area; amplifying means for amplifying said output from said light receiving means, said amplifying means having an output that may exceed a predetermined level a number of times; counting means for counting the number of times that said output from said amplifying means has exceeded said predetermined level as a function of time for detecting said fine particles, said predetermined level being exceeded when fine particles are present in said monitoring area and said predetermined level being not exceeded when fine particles are not present in said monitoring area so that presence of fine particles is detected; computing means for computing an average value of the output from said amplifying means as a function of time to detect said smoke; and determining means for determining a contamination level of said monitoring area dependent on a count counted by said counting means and determining characteristics of a fire as a function of said average value computed by said computing means when smoke density is high and the count counted by said counting means reaches a saturation point at which further counting cannot be carried out and emitting an alarm dependent on a result determined by said determining means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A smoke detecting apparatus capable of detecting both smoke and fine particles in a monitoring area, comprising:
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light emitting means for projecting a light beam onto said monitoring area; light receiving means with an output located at a position where a light beam projected from said light emitting means is not directly received, said light receiving means receiving scattered light caused by fine particles including dust and smoke caused by fire entering said monitoring area; amplifying means for amplifying said output from said light receiving means and having an output for each predetermined level corresponding to a diameter of said fine particles; frequency computing means for differentiating the output from said amplifying means for each predetermined level corresponding to a diameter of said fine particles and counting as a function of time the predetermined levels from said output of said amplifying means over a fixed time period and computing a frequency distribution of said output of said amplifying means; storing means for prestoring the frequency distribution of the output of said light receiving means for each of said levels when smoke particles enter said monitoring area and for prestoring the frequency distribution of all other particles corresponding to a diameter for each of said levels when other fine particles enter said monitoring area; and determining means for comparing the frequency distribution computed by said frequency computing means with that stored in said storing means and distinguishing between smoke and other fine particles, and emitting an alarm dependent on a result determined by said determining means. - View Dependent Claims (30)
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Specification