JPH06282775A - Fire detector - Google Patents

Abstract

PURPOSE:To decide the degrees of flames regardless of the distance from each flame detected part and based on the relative relation between the flame degrees and the frequency components of flickering frequency bands of detected flames. CONSTITUTION:It is generally known that the flickering ways of flames differ from each other by the degree of each flame. Then it is defined from the results of experiments that the smaller degrees of flames the higher the flickering frequencies and vice versa. The output received from a flame detecting part 6 is amplified by amplifiers 1-3 of different amplifying center frequencies, and each output of amplifiers 1-3 is supplied to a deciding circuit 4. Thus the output of the amplifier 3 is relatively increased and the output of the amplifier 1 is reduced due to a fact that the smaller degrees of flames the higher the flickering frequencies. Meanwhile the output of the amplifier 1 is increased and the output of the amplifier 3 is reduced due to a fact that the larger degrees of flames the lower the flickering frequencies. Thus the circuit 4 decides the degree of each flame based on the preceding relative relation between the degrees of flames and the flickering frequencies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire detection device for detecting infrared rays or the like emitted from a flame or the like at the time of a fire to emit a fire signal, and to a fire detection device for discriminating the size of the flame regardless of the distance.

[0002]

2. Description of the Related Art In a conventional fire detecting device of this type, a wavelength component peculiar to a flame such as infrared rays, which is generally contained in a flame generated at the time of a fire, is received by a semiconductor element, and its output is a flicker frequency when the flame burns. The absolute energy of the wavelength component peculiar to the flame is amplified or amplified by an active filter or the like that amplifies the region of about 0.1 to 20 Hz, or the ratio of the received light output of a plurality of different wavelength components (for example, in Japanese Utility Model Publication 58-31
No. 278) makes a fire decision.

[0003]

As described above, in the conventional fire detection device, the wavelength component peculiar to the flame generated during a fire is detected, and the absolute energy of the wavelength component peculiar to the flame at the flicker frequency when the flame burns is detected. Since a fire is judged based on the ratio of the received output of large or small or multiple different wavelength components, it is possible to distinguish between a large flame that is far from the flame detection part of the fire detection device and a small flame that is close to the flame detection part. Is impossible, and in some cases, a large distant flame may be missed due to lack of energy, or a close small flame (the latest writer, etc.)
There was a problem that it was difficult to make a reliable fire judgment such as issuing a warning at. The present invention has been made to solve such a problem, and an object of the present invention is to obtain a fire detection device that can determine the size of a flame regardless of the distance from the flame detection unit.

[0004]

A fire detection device according to a first aspect of the present invention comprises a detection element, an extraction means for extracting a plurality of different frequency components of a flicker frequency band from the output of the detection element, and an output of the extraction means. A determination means for determining the size of the flame based on the relative relationship between each frequency component and its magnitude is provided. A fire detection device according to a second aspect of the present invention is the fire detection device according to the first aspect, wherein the determination means further comprises:
The distance to the flame is determined based on the determination result of the size of the flame and the absolute value of the output of the detection element.

[0005]

In the first aspect of the invention, the detection element detects a flame or the like, and the extraction means extracts a plurality of different frequency components in the flicker frequency band from its output. The judging means uses the property that the output of the relatively low flicker frequency component becomes large when the flame is large, and conversely the output of the relatively high flicker frequency component becomes large when the flame is small. Determine. In the second invention, the determination means determines the distance from the flame based on the determination result of the size of the flame and the absolute energy value of the flame.

[0006]

【Example】

Example 1. FIG. 1 is a block diagram showing the configuration of a radiation-type fire detector in a fire detection apparatus according to an embodiment of the present invention. 1, 2, and 3 have amplification center frequencies f ₀₁ and f, respectively.
₀₂ and f ₀₃ (f ₀₁ <f ₀₂ <f ₀₃ ), which are amplifiers made of active filters and the like, 4 is a judgment circuit, 5 is a signal transmission circuit, and 6 is a flame detection unit composed of detection elements and the like. In this embodiment, the flame detector 6 detects infrared rays emitted from a flame or the like, and the output from the flame detector 6 is amplified by amplifiers 1 to 3 having different amplification center frequencies.
The outputs of the amplifiers 1 to 3 are input to the judgment circuit 4. Then, the determination circuit 4 determines the size of the flame based on the information input from each of the amplifiers 1 to 3, and the signal transmission circuit 5 transmits the flame detection signal to the fire receiver or the like.

FIG. 2 is a diagram showing the relationship between the size of the flame and the center frequency f of the flicker of the flame, which is obtained from the results of experiments. Generally, a flame depends on the size of the flame.
It is known that the flicker is different. As a result of this experiment, it was found that the flicker frequency is high when the size of the flame is small, and the flicker frequency is low when the flame is large. This allows the size of the flame to be determined by detecting the flicker frequency. FIG. 3 is a diagram showing the amplification frequency characteristic of each of the amplifiers 1 to 3, and shows the gain with respect to the input frequency. In the figure, 7 is the amplification frequency characteristic of the amplifier 1, 8 is the amplification frequency characteristic of the amplifier 2, and 9 is the amplification frequency characteristic of the amplifier 3. As shown in the figure, the amplifiers 1, 2 and 3 have center frequencies for amplification of f ₀₁ , f ₀₂ and f ₀₃ , respectively.

FIG. 4 shows amplifiers 1 to 3 when the flame is small.
FIG. 3 is a diagram showing the output A of A, where A ₁ is the output of the amplifier 1, A
₂ indicates the output of the amplifier 2, and A ₃ indicates the output of the amplifier 3. When the flame is small, the flicker frequency is high, so that the output A _{3 of the} amplifier 3 is relatively large, and conversely, the output A ₁ of the amplifier ₁ is small and the output A _{2 of the} amplifier ₂ is an intermediate output. Fig. 5 shows amplifiers 1 to 1 when the flame is large.
It is the figure which showed the output A of 3. When the flame is large, the flicker frequency is low, so the output A _{1 of the} amplifier 1 is relatively large, whereas the output A ₃ of the amplifier ₃ is small and the output of the amplifier 2 is small.
The output A _{2 of} is an intermediate output.

From the above, for example, when the flame is large but far away, the absolute output becomes small, but the amplifier 1,
The two outputs A ₁ , A ₂ , and A ₃ have a relationship of A ₁ > A ₂ > A ₃ . The determination circuit 4 determines that a large flame is generated based on this relative relationship. Conversely, when the flame is small but near the detector, the absolute output is large, but the outputs A ₁ , A ₂ , A _{3 of} the amplifiers ₁ , ₂ , ₃ are A
The relationship is ₁ <A ₂ <A ₃ . The determination circuit 4 determines that a small flame is generated based on this relative relationship. Therefore, the determination circuit 4 can send out detailed fire data, such as sending a pre-alarm or the like when a small flame is detected and changing to a fire signal when the flame becomes large, through the signal sending circuit 5.

Further, the amplifier 1 is used to determine the distance from the flame.
The output of the amplifier or the frequency characteristic of the amplifier 2 showing the sum or peak of the outputs A ₁ , A ₂ and A ₃ of ₂ , ₃ is 0.1.
It can be estimated by expanding to ~ 20 Hz. Also, 2
By using more than one detecting element, the direction and distance of the fire point can be easily specified.

FIG. 6 is a block diagram showing a concrete example of the judgment circuit 4 in this embodiment. In the figure, 11,
Reference numerals 12 and 13 are sample and hold circuits for temporarily holding the received light amplification outputs from the amplifiers 1, 2 and 3, respectively.
Reference numerals 1, 22 and 23 denote A / D signals for the respective received light amplification outputs held by the sample hold circuits 11, 12 and 13.
It is an A / D converter that performs (analog / digital) conversion.
Reference numeral 10 is a microcomputer (MPU) having a program shown in the flowcharts of FIGS.

Next, the operation of the judgment circuit 4 will be described with reference to FIGS. 7 and 8. 7 and 8 are flowcharts showing a judgment program built in the MPU 10. First, the MPU 10 includes the sample and hold circuits 11 and 1
A holding command is output to 2 and 13, and the received light amplification outputs from the amplifiers 1, 2 and 3 are temporarily held while the MPU 10 is read (S1), and then the A / D converters 21 and 22.
And 23 sequentially output conversion commands to the A / D converter 21,
The conversion outputs F ₁ , F ₂ and F ₃ are read from 22 and 23 (S2, S3, S4).

Next, in order to determine the magnitude of the flame, the magnitude relationship between the read conversion outputs F ₁ and F ₂ is _first determined (S
5), F _1> if F _2, converts the output F ₂ and the magnitude relationship of F ₃ is determined (S5 of Y, S6). As a result, F ₂ >
If it is F ₃ , it is judged that there is a possibility of a large flame, and then the converted output F ₂ is judged to be a fire.
It is determined whether it is ₃ or more (S7). It should be noted that this determination may be performed not by the conversion output F ₂ , but by the conversion output F ₁ or F ₃ , or by the conversion outputs F ₁ , F ₂ , F ₂ .
_It may be performed at the time when ₃ is read (S2, S3, S4).

If F ₂ ≧ L _{3 as} a result of this determination, it is determined that a large flame is being generated due to a fire (Y of S7), and in order to determine at what distance the next generation is occurring,
The conversion output F ₁ is determined by the discrimination levels L ₁ and L ₂ (L ₁ > L ₂ > L
Compare with ₃ ). If F ₁ > L ₁ (Y of S8), it is determined that a large flame is generated at a short distance, and a signal to that effect is output through the signal transmission circuit 5 by adding a self-address signal, for example. (S9). On the other hand, the conversion output F ₁ is L
_{If 1} or less (N in S8) and F ₁ > L ₂ (Y in S10), it is determined that a large flame is generated at an intermediate distance,
A signal to that effect is output through the signal transmission circuit 5 (S1).
1). Then, the converted output F ₁ is below the level L ₂ (S10
If it is N), it is determined that a large flame is generated at a long distance, and a signal to that effect is output through the signal transmission circuit 5 (S12).

Meanwhile, conversion output F ₁ and results of the size relationship is determined in F _2, if F ₁ ≦ F ₂ (S5 of N), to determine whether a small flame or not, converts the output F ₂ and F The magnitude relationship of ₃ is determined (S13).

As a result, if F ₂ <F ₃ (Y in S13), it is judged that there is a possibility of a small flame, and the conversion output F ₂
Is judged to be a fire and it is judged whether or not the level is equal to or higher than the level L ₃ where there is no problem (S14). As a result of this determination, F ₂ ≧ L
If it is ₃ , it is determined that a small flame is being generated due to a fire (Y in S14), and the conversion output F ₃ is compared with the determination levels L ₁ and L ₂ in order to determine at what distance the next generation is occurring. To do. If F ₃ > L ₁ (Y in S15), it is determined that a small flame is generated at a short distance, and a signal to that effect is output through the signal transmission circuit 5 (S16).

On the other hand, if the conversion output F ₃ is less than L ₁ (N in S15) and F ₃ > L ₂ (Y in S17), it is determined that a small flame is generated at an intermediate distance, and A signal to that effect is output through the signal transmission circuit 5 (S18). And
If the conversion output F ₃ is equal to or lower than the level L ₂ (N in S17), it is determined that a small flame is generated at a long distance, and a signal to that effect is output through the signal transmission circuit 5 (S1).
9).

The magnitude relation between the read conversion outputs F ₁ and F ₂ is F ₁ ≤F ₂ (N in S5) and F ₂ ≥F ₃ (S1
3 N), or F ₁ > F ₂ (Y of S5) and F ₂ ≦
If it is F ₃ (N in S6), it is determined that there is a possibility of a medium-scale flame, and it is determined whether the converted output F ₂ is a fire or not, and it is determined whether or not it is at a level L ₃ or higher where there is no problem. (S2
0). As a result of this determination, if F ₂ ≧ L ₃ , it is determined that a medium-scale flame is being generated due to a fire (Y in S20), and in order to determine at what distance the next generation is occurring,
The converted output F ₂ is compared with the discrimination levels L ₁ and L ₂ . F ₂
If> L ₁ (Y of S21), it is determined that a medium-scale flame is generated at a short distance, and a signal to that effect is output through the signal transmission circuit 5 (S22).

On the other hand, if the converted output F ₂ is L ₁ or less (N in S21) and F ₂ > L ₂ (Y in S23), it is determined that a medium-scale flame is generated at a medium distance. A signal to that effect is output through the signal transmission circuit 5 (S24). If the conversion output F ₂ is equal to or lower than the level L ₂ (N in S23), it is determined that a medium-scale flame is generated at a long distance, and a signal to that effect is output through the signal transmission circuit 5 ( S25).

In this embodiment, an example of three amplifiers is shown, but in the present invention, the purpose can be achieved if there are two or more amplifiers. By increasing the number, more detailed flame monitoring can be performed. Is possible. Further, instead of using a plurality of amplifiers, one wide band amplifier is used, and a plurality of different frequency components are extracted from the output of the amplifier by using a plurality of band pass filters of different frequency bands. Good. Further, instead of using a plurality of amplifiers, one broadband amplifier may be used, and then a plurality of frequency components may be extracted by using a fast Fourier transform in the microcomputer.

In the above embodiment, the fire detector is provided with the flame detecting section and the judging section such as the judging circuit, and the judgment signal is sent to the receiving section of the fire receiving device (not shown). May be provided in the receiving part of the receiver or the repeater. In this case, in FIG.
The received light amplified output obtained by amplifying the output of 1 is amplified by the amplification units 1, 2 and 3, and a signal sending circuit that sends the received light amplified output to the receiving unit when called by the receiving unit by polling or the like is provided. A determination circuit may be provided.

[0022]

According to the first aspect of the present invention, a plurality of different frequency components in the flicker frequency band are extracted from the signal detected by the detection element, and the flame is detected based on the relative magnitude of the components. Since the size is discriminated, the size of the flame can be discriminated regardless of the distance from the flame. According to the second aspect of the invention, the distance to the flame is determined based on the magnitude of the flame and the absolute energy value of the flame. Therefore, the distance can be determined with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a radiant fire detector in a fire detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a size of a flame and a frequency f of flicker of the flame.

FIG. 3 is a diagram showing amplification frequency characteristics of each amplifier.

FIG. 4 is a diagram showing the output A of each amplifier when the flame is small.

FIG. 5 is a diagram showing the output A of each amplifier when the flame is large.

FIG. 6 is a block diagram showing a specific example of a determination circuit 4.

FIG. 7 is a flowchart (No. 1) showing the operation of the determination circuit 4 of FIG.

8 is a flowchart (part 2) showing the operation of the determination circuit 4 of FIG.

[Explanation of symbols]

 1 Amplifier with amplification center frequency f01 2 Amplifier with amplification center frequency f02 3 Amplifier with amplification center frequency f03 4 Judgment circuit 5 Signal transmission circuit 6 Flame detector

Claims (2)

[Claims] 1. A fire detection device for detecting a infrared ray or the like emitted from a flame or the like to emit a fire signal, and a detection element, and an extraction means for extracting a plurality of different frequency components of a flicker frequency band from the output of the detection element. And a determination means for determining the size of the flame based on the relative relationship between each frequency component of the output of the extraction means and its magnitude. 2. The determination means further determines the distance to the flame based on the determination result of the size of the flame and the absolute value of the output of the detection element. The fire detection device according to claim 1.