JPH0581578A - Fire alarm - Google Patents

Abstract

PURPOSE:To improve the efficiency of judging fire by judging the kind of smoke at the time occurring fire. CONSTITUTION:Through the use of a principle saying that there is a correlation peculiar to each smoke between scattering angles formed by an optical axis of light emitting means 8 and light receiving means 10, 12, 14 and 16 and the light receiving output of the light receiving means 10,12 14 and 16, the feature of smoke can be known based on the light receiving output of the respective scattering angles. Then, the kind of smoke at the time of occurring fire is judged 18 by comparing light receiving output with characteristic data of the respective kinds of smoke which is previously stored in a storage means 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire alarm device for detecting the type of smoke from the scattered light of smoke produced during a fire.

[0002]

2. Description of the Related Art A scattered light type smoke detector is known as a detector for judging a fire from scattered light of smoke produced during a fire. As shown in FIG. 6, the light emitting element 2 such as a light emitting diode is arranged toward the center portion X of the smoke detection chamber (smoke detection space) and at a predetermined angle θ with respect to the optical axis of the light emitting element 2. A light receiving element 4 such as a photodiode having an aligned optical axis is arranged, and the light emitting element 2 constantly radiates light having directivity in the optical axis direction,
The light receiving element 4 has a configuration of collecting scattered light via a condenser lens (not shown) provided on the light receiving surface.

During normal times when a fire does not occur, the smoke does not enter the smoke detection chamber, so the intensity of the scattered light that reaches the light-collecting element 4 is small. The intensity of the scattered light that arrives increases. Since the intensity of scattered light incident on the light receiving element 4 has a correlation with the concentration of the smoke 6, it is determined that a fire has occurred when the output signal of the light receiving element 4 exceeds a predetermined threshold level.

[0004]

The conventional scattered-light type smoke detector does not have a function of judging the type of smoke, but merely the concentration of smoke entering the smoke detection chamber and a uniform threshold value. The existence of fire was judged by comparing with the level. However, in reality, the color of smoke and the diameter of particles vary depending on the material of the combustion material such as plastic and wood, so even if the smoke concentration in the smoke detection chamber is the same, the light receiving element may be changed depending on the type of smoke. This causes a phenomenon that the intensity of the scattered light that reaches is different. From this, it is not possible to judge a fire based on a uniform threshold level regardless of the type of smoke.
There were problems such as judging non-fire as a fire and delaying the fire judgment.

Generally, such a fact, for example, a scattered light smoke detector installed in a room filled with cigarettes is
It is empirically known that a cigarette smoke causes a malfunction even if it is not a fire. In addition, there is a problem that the intensity of scattered light becomes small with respect to black smoke generated by the combustion of oil or the like, and the fire judgment is delayed.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a fire alarm device for performing accurate fire detection according to the type of smoke to be detected. And

[0007]

In order to achieve such an object, the present invention receives a light emitting means for irradiating light toward a smoke detecting space and a scattered light due to smoke existing in the smoke detecting space. In a fire alarm device comprising a light receiving means and determining the presence of smoke by the light output of the light receiving means, the light receiving means when the scattering angle formed by the optical axis of the light emitting means and the optical axis of the light receiving means is changed. Of the light-receiving output of the light-receiving means of the light-receiving means obtained for each scattering angle between the optical axis of the light-emitting means and the optical axis of the light-receiving means. A determination unit for determining the type of smoke is provided by comparing and collating the received light output with the characteristic data in the storage unit.

[0008]

According to the fire alarm device of the present invention having such a structure, the peculiar correlation for each smoke between the scattering angle formed by the optical axes of the light emitting means and the light receiving means and the light receiving output of the light receiving means. Therefore, the characteristics of smoke can be known based on the received light output for each scattering angle. Then, by comparing the received light output with the characteristic data for each type of smoke stored in advance in the storage means, the type of smoke at the time of fire can be determined.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the structure will be described with reference to FIG. 1. Reference numeral 8 denotes a light emitting element including a light emitting diode having directivity, and its optical axis Q is directed toward the central portion X of the smoke detection chamber to emit light. Reference numerals 10, 12, 14, and 16 are light receiving elements each including a photodiode, etc., and an angle θ1 formed by the optical axis of the first light receiving element 10 and the optical axis Q of the light emitting element 8 is 30 °, and the second light receiving element The angle Q2 formed by the optical axis 12 and the optical axis Q of the light emitting element 8 is 60 °, the angle θ3 formed by the third light receiving element 14 and the optical axis Q of the light emitting element 8 is 90 °, and the fourth light receiving The angle θ4 formed by the element 16 and the optical axis Q of the light emitting element 8 is set to 120 °.

Reference numeral 18 denotes each of the light receiving elements 10, 12, 14,
16 is a determination unit that receives output signals S1, S2, S3, S4 from the output signal 16, and further compares these signals S1 to S4 with the data α of the reference data storage unit 20 to determine whether or not a fire has occurred and the type of smoke. When a fire occurs, information data β indicating the fire occurrence and the type of smoke is output. Incidentally, the judging unit 1
8 and the reference data storage unit 20 are applied with a microprocessor having a memory function.

Next, the principle for detecting the type of smoke in this embodiment will be described. As a result of many experiments and studies, the inventor of the present application has found that when the angle (hereinafter referred to as a scattering angle) θ formed by the light emitting element and the light receiving element is different, the light receiving element The received light intensity is different,
It was confirmed that such a correlation between the scattering angle θ and the received light intensity has unique characteristics for each type of smoke.

FIG. 2 shows an example of the result of such an experiment. However, the horizontal axis represents the scattering angle θ, and the vertical axis represents the output voltage (hereinafter referred to as light reception output) output from the light receiving element when the smoke detection chamber is filled with smoke of a predetermined concentration (1.0% / m), The measurement result A for smoke generated when the filter paper is burned, the measurement result B for smoke of cotton wick, the measurement result C for smoke of incense stick, and the measurement result D for smoke of kerosene are shown.

Furthermore, the scattering angle θ for kerosene and cotton wick
The chamber output for each is shown in a table as shown in FIG. The values shown in parentheses in FIG. 3 are values obtained by normalizing the other outputs with the chamber output being 1.0 when the scattering angle θ is 30 °. As is apparent from FIGS. 2 and 3, each smoke type has its own characteristics. Then, the reference data storage unit 2
In FIG. 0, normalized data for each scattering angle θ of various types of smoke is stored in advance, and the determination unit 18 uses the change patterns of the detection signals S1 to S4 from the light receiving elements 10 to 16 and the reference data. By determining the correlation with the data in the storage unit 20 by the pattern matching method and determining the most correlated smoke type, the type of smoke 22 that has entered the smoke detection chamber is determined.

Further, a threshold value is previously determined for each type of smoke in the determination unit 18, and for example, it is determined that a fire occurs when the chamber output when the scattering angle θ is 30 ° exceeds the threshold value. To do. That is, the presence / absence of a fire is determined for each type of smoke based on an individual standard. In this way, by determining the type of smoke and determining the fire based on the threshold value set for each type of smoke, it is possible to accurately determine whether or not a fire has occurred.

For example, the chamber output of white smoke emitted from filter paper or cotton wick and the chamber output of black smoke emitted from kerosene have an inherent difference as shown in FIG. By setting the threshold value for judgment to a value larger than the threshold value for judging fire that produces black smoke, the accuracy of judgment is better than when a conventional uniform threshold value is used as a reference. Is improved. That is, it is possible to reduce non-fire alarms due to cigarettes, steam, etc., and it is possible to detect a fire more quickly than in the case of black smoke generated by the combustion of oil or the like.

Next, another embodiment will be described with reference to FIG.
In FIG. 4, the same or corresponding parts as in FIG. In this embodiment, instead of installing a plurality of light receiving elements for each scattering angle θ, the carrier mechanism 24 is moved to face the smoke detection chamber at scattering angles θ of 30 °, 60 °, 90 ° and 120 °. One light receiving element 24 is provided.

Then, the light receiving element 24 has these scattering angles θ.
And the timing of inputting the detection output S of the light receiving element 24 to the determination unit 18 are performed in synchronization with the clock signal CK of the timing circuit 28.
Indicates the type of smoke by comparing the detection output S for the total scattering angle θ with the smoke data stored in advance in the reference data storage unit 20 by the pattern matching method, and is set in advance for each type of smoke. Whether or not there is a fire is determined by comparing it with the threshold value.

According to this embodiment, the number of light receiving elements can be reduced. FIG. 5 is a structural explanatory view showing still another embodiment of the present invention, which is characterized in that a plurality of light emitting elements 8a to 8d are provided. In such an embodiment, the light emitting elements 8a to 8d are sequentially caused to emit light, the light receiving element 10a receives light in synchronization with the light emitting elements 8a to 8d, and the received light data is compared with the smoke data stored in advance to generate smoke. Determine the type.

Incidentally, in the embodiment shown in FIGS. 1, 4 and 5,
Although four scattering angles θ of 30 °, 60 °, 90 °, and 120 ° are applied, the measurement may be performed for each finer angle. Also, by applying at least two scattering angles θ,
Since the smoke feature for determining the smoke type can be detected, two scattering angles θ may be applied when there are few types of smoke when a fire occurs. By applying such a small scattering angle θ, the signal processing speed can be improved.

Further, in these embodiments, a means for judging the type of smoke is incorporated in a light emitting element and a light receiving element together with an optical system, and is used as a known scattered light type smoke sensing. Although shown, the signal processing parts such as the judgment part and the reference data storage part may be separated so as to be provided in the receiver or the repeater. By doing so, the sensor portion for detecting smoke can be made smaller and lighter, and can be easily applied to a conventional fire alarm system such as a boring method.

[0021]

As described above, according to the present invention, there is a unique correlation for each smoke between the scattering angle formed by the optical axes of the light emitting means and the light receiving means and the light receiving output of the light receiving means. From
The characteristics of smoke can be known based on the received light output for each scattering angle. Then, by comparing the received light output with the characteristic data for each type of smoke stored in the storage means in advance, the type of smoke at the time of fire can be determined.

As a result, in the past, the presence or absence of a fire was judged based on a uniform judgment standard for all smokes, whereas the present invention sets a judgment standard for each smoke and determines whether or not there is a fire. By determining the presence or absence, it is possible to reduce erroneous determination and improve the accuracy of the fire alarm device.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the principle of smoke discrimination of the present invention.

FIG. 3 is another explanatory view for explaining the principle of smoke discrimination of the present invention.

FIG. 4 is a structural explanatory view showing the structure of another embodiment of the present invention.

FIG. 5 is a configuration explanatory view showing a configuration of still another embodiment of the present invention.

FIG. 6 is a configuration explanatory view for explaining a configuration of a conventional scattered light type smoke sensor.

[Explanation of symbols]

 Light emitting elements 10, 10a, 12, 14, 16, 24; Light receiving element 18; Judgment unit 20; Reference data storage unit 22; Smoke 26; Conveyance mechanism 28; Timing circuit

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[Procedure amendment]

[Submission date] October 25, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (3)

[Claims] 1. A light emitting means for irradiating light toward a smoke detecting space, and a light receiving means for receiving scattered light due to smoke existing in the smoke detecting space, the presence of the smoke being detected by a light receiving output of the light receiving means. In the fire alarm device for determination, the light-receiving output of the light-receiving means when the scattering angle formed by the optical axis of the light-emitting means and the optical axis of the light-receiving means is changed is experimentally obtained in advance, and a plurality of smoke-type output signals for each type of smoke By comparing and collating the storage means for storing as characteristic data, the light reception output of the light receiving means obtained for each scattering angle formed by the optical axis of the light emitting means and the optical axis of the light receiving means, and the characteristic data in the storage means. A fire alarm device comprising: a determination unit that determines the type of smoke. 2. The fire alarm device according to claim 1, further comprising a conveying means for changing the scattering angle by moving the light emitting means or the light receiving means relatively. 3. A plurality of said light receiving means are installed corresponding to each of a plurality of predetermined scattering angles, and said judging means judges the type of smoke based on the light receiving output of each light receiving means. The fire alarm device according to claim 1.