Flame detection device and flame detection system

Abstract

This system enables the estimation of the distance to the fire source with a simple configuration, and also allows for the accurate identification of fire flames when detecting flames. [Solution] The flame detection device 12 includes a light receiving unit 14 that receives light including radiant light from a flame and outputs a light receiving signal based on the received light, a flame source diameter estimation unit 1820 that estimates the flame source diameter D1, a flame source distance estimation unit 1830 that estimates the flame source distance X1 from the flame detection device 12 to the flame detected, and a flame determination unit 1840 that determines whether it is a fire flame and detects the flame. The flame source diameter estimation unit 1820 calculates a fluctuation frequency n1 from the light receiving signal and estimates the flame source diameter D1 from the calculated fluctuation frequency n1, and the flame source distance estimation unit 1830 estimates the flame source distance X1 using the amount of light received by the light receiving unit 14, the fluctuation frequency n1 and the flame source diameter D1.

Description

Technical Field

[0001] The present invention relates to a flame detection device and a flame detection system that receive radiant light from a flame existing in a monitoring area to detect the flame.

Background Art

[0002] Conventionally, a flame detection device that receives radiant light from a flame generated by a fire to detect the flame in order to detect a fire occurring in a monitoring area is known. The flame detection device receives infrared rays in one or a plurality of wavelength bands having a center wavelength in the resonance emission wavelength band of CO2 generated during a fire, for example, around 4.5 μm or around 5.0 μm, and uses the amount of received infrared rays in that wavelength band or the frequency characteristics of the received light signal based on the received infrared rays to detect the flame. (Patent Documents 1, 2).

[0003] Also, in order to estimate the distance from the ignition source to a fire (flame), a flame detection device that estimates the distance from the ignition source using an image captured by an imaging device such as a scanning type flame detection device or a camera is known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in order to make it possible to estimate the distance from the ignition source, it is necessary to add an imaging device or change to a scanning type flame detection device, resulting in a problem that the configuration of the flame detection device becomes complicated and the cost increases.

[0006] Furthermore, conventional flame detection devices have the problem of being unable to correctly distinguish between flames from a fire and flames from non-fire sources, such as flames artificially created by matches or lighters near the device, or from flames from a fire that occur far away from the device.

[0007] The present invention aims to provide a flame detection device and flame detection system that enable estimation of the distance to a fire source with a simple configuration and that can correctly identify the flames of a fire when detecting flames. [Means for solving the problem]

[0008] (Flame detection device) The present invention is a flame detection device that detects a flame by receiving radiation from a flame present in a monitoring area, A light receiving unit that receives light including radiant light from a flame and outputs a light receiving signal based on the received light, A flame source diameter estimation unit that estimates the diameter of the flame source (D1), A fire source distance estimation unit estimates the fire source distance (X1) from the flame detection device to the detected flame, A flame detection unit that determines whether the flames are from a fire and detects the flames, Equipped with, The fire source diameter estimation unit calculates the fluctuation frequency (n1) from the received light signal, and estimates the fire source diameter (D1) from the calculated fluctuation frequency (n1). The fire source distance estimation unit is characterized by estimating the fire source distance (X1) using the amount of light received by the light receiving unit (Q1), the fluctuation frequency (n1), and the fire source diameter (D1).

[0009] (Estimation process for fire source diameter and fire source distance) The first relationship between fluctuation frequency (n) and fire source diameter (D), The second relationship between the diameter of the ignition source (D) and the amount of heat radiated from the flame (Y), The third relationship between heat generation (Y) and light reception (Q), The fourth relationship between the amount of light received (Q) and the distance to the fire source (X), Standard ignition source diameter (D0), Reference ignition source distance (X0), The reference light received amount (Q0) is the amount of light received when the light receiving unit receives radiation from a flame with a reference flame diameter (D0) located at a reference flame source distance (X0), The reference heat output (Y0) calculated using the reference ignition source diameter (D0) and the second relational equation, Set it up, The fire source diameter estimation unit estimates the fire source diameter (D1) from the fluctuation frequency (n1) using the first relational equation. The fire source distance estimation unit is, Using the flame source diameter (D1) and the second relational equation, the heat output (Y1) of the detected flame is calculated. Using the reference light reception amount (Q0), reference heat generation amount (Y0), heat generation amount (Y1), and the third relational equation, we calculate the assumed light reception amount (Q2) assuming that the flame is detected at a distance of the reference ignition source distance (X0). The ignition source distance (X1) is estimated using the amount of light received (Q1), the assumed amount of light received (Q2), the reference ignition source distance (X0), and the fourth relation.

[0010] (Judgment by the flame judgment unit 1) The flame detection unit determines whether the flame is from a fire based on the diameter of the ignition source (D1), and if it determines that it is from a fire, it performs a predetermined alarm action.

[0011] (Judgment by the flame judgment unit 2) The flame detection unit determines that the flame is not from a fire and does not perform the prescribed alarm action if the amount of light received (Q1) is above a predetermined value but the diameter of the ignition source (D1) is below a predetermined value.

[0012] (liquid fire) The flames detected include those caused by liquid fires.

[0013] (Flame detection system) A flame detection system in which multiple flame detection devices are installed in the monitoring area, and each of the flame detection devices is capable of communicating with a higher-level device, Each flame detection device is installed such that a portion of its detectable area overlaps with the detectable area of ​​another flame detection device. When the upper device estimates the fire source distance (X1) with a plurality of flame detection devices, it is characterized by estimating the fire occurrence position based on the positions of the flame detection devices that estimated the fire source distance (X1) and the plurality of estimated fire source distances (X1).

[0014] (Alarm operation of the upper device) The upper device changes the alarm operation according to the size of the fire source diameter (D1) estimated by the flame detection device. [Effect of the invention]

[0015] (Effect of the flame detection device) The present invention is a flame detection device that receives the radiation light from the flame existing in the monitoring area to detect the flame, and includes a light receiving unit that receives the light including the radiation light from the flame and outputs a light receiving signal based on the received light, a fire source diameter estimating unit that estimates the fire source diameter (D1) of the flame, a fire source distance estimating unit that estimates the fire source distance (X1) from the flame detection device to the detected flame, and a flame judging unit that judges whether it is a fire flame and detects the flame. The fire source diameter estimating unit calculates the fluctuation frequency (n1) from the light receiving signal and estimates the fire source diameter (D1) from the calculated fluctuation frequency (n1). The fire source distance estimating unit estimates the fire source distance (X1) using the light receiving amount (Q1), the fluctuation frequency (n1), and the fire source diameter (D1) of the light received by the light receiving unit. Therefore, it is possible to detect the flame after estimating the fire source diameter and the fire source distance with a simple configuration without using a photographing device or a scanning type flame detection device, etc.

[0016] In addition, since the fire source diameter and the fire source distance are estimated, it is possible to grasp the situation of the fire in the monitoring area, and it is possible to take appropriate measures according to the scale and location of the fire.

[0017] (Effect of the estimation process of the fire source diameter and the fire source distance) Furthermore, a first relational expression between fluctuation frequency (n) and fire source diameter (D), a second relational expression between fire source diameter (D) and the amount of heat radiated from the flame (Y), a third relational expression between heat radiated (Y) and the amount of light received (Q), a fourth relational expression between the amount of light received (Q) and fire source distance (X), a reference fire source diameter (D0), a reference fire source distance (X0), a reference amount of light received (Q0) which is the amount of light received when the light receiving unit receives the radiated light from a flame of reference fire source diameter (D0) located at a distance of reference fire source distance (X0), and a reference heat radiated (Y0) calculated using the reference fire source diameter (D0) and the second relational expression are set, the fire source diameter estimation unit estimates the fire source diameter (D1) from the fluctuation frequency (n1) using the first relational expression, and the fire source distance estimation unit estimates the fire source diameter (D1) and the second relational expression. Using the second relational equation, the heat output (Y1) of the detected flame is calculated. Using the reference light output (Q0), reference heat output (Y0), heat output (Y1), and the third relational equation, the assumed light output (Q2) is calculated assuming the flame is located at a distance of the reference ignition source distance (X0). The ignition source distance (X1) is then estimated using the light output (Q1), assumed light output (Q2), reference ignition source distance (X0), and the fourth relational equation. As a result, the ignition source distance estimation unit can estimate the ignition source distance (X1) simply by acquiring in real time the light output (Q1) from the flame actually generated in the monitoring area and the ignition source diameter (D1) estimated by the ignition source diameter estimation unit, and performing calculations using the pre-set information.

[0018] (Effect of judgment 1 by the flame judgment unit) Furthermore, the flame detection unit determines whether a flame is from a fire based on the diameter of the ignition source (D1), and if it determines that it is a fire flame, it performs a predetermined alarm action. This makes it possible to correctly determine that a flame is from a fire and perform an alarm action even when the amount of radiation (Q1) received from a flame that originates far from the flame detection device is low.

[0019] (Effect of judgment 2 by the flame judgment unit) Furthermore, the flame detection unit is designed to not perform a predetermined alarm action if the received light amount (Q1) is above a predetermined value but the flame source diameter (D1) is below a predetermined value, thus preventing the device from mistakenly identifying flames caused by non-fire factors, such as those artificially generated by matches or lighters near the flame detection device, as fire flames and triggering false fire alarms.

[0020] (Effectiveness of the flame detection system) Furthermore, the aforementioned flame detection system is configured such that multiple flame detection devices are installed in the monitoring area, and each flame detection device is capable of communicating with a higher-level device. Each flame detection device is installed such that a portion of its detectable area overlaps with the detectable area of ​​other flame detection devices. When multiple flame detection devices estimate the fire source distance (X1), the higher-level device estimates the location of the flame based on the position of the flame detection device that estimated the fire source distance (X1) and the multiple estimated fire source distances (X1). By overlapping a portion of the detectable areas of multiple flame detection devices and having the flame detection devices monitor the monitoring area, it becomes possible to accurately identify the location of the flame (location of the fire).

[0021] (Effect of alarm operation by higher-level device) Furthermore, the higher-level device is designed to change its alarm operation according to the size of the fire source diameter (D1) estimated by the flame detection device, enabling appropriate action depending on the scale of the flame (fire). [Brief explanation of the drawing]

[0022] [Figure 1] This is a diagram illustrating the overview of the flame detection system. [Figure 2] This is an explanatory diagram showing the relationship between the monitoring area inside the tunnel and the detection area of ​​the flame detection device. [Figure 3] This is an explanatory diagram showing the functional configuration of a flame detection device. [Figure 4] This is an explanatory diagram showing the external appearance of the flame detection device. [Figure 5] This is an explanatory diagram showing the relationship between the diameter of the ignition source and the fluctuation frequency. [Figure 6]This is an explanatory diagram showing the relationship between the diameter of the ignition source and the amount of heat generated. [Figure 7] This is an explanatory diagram showing the monitoring area inside the tunnel where the fire occurred. [Figure 8] This is an explanatory diagram illustrating an example of how a flame detection system works, presented as a flowchart. [Modes for carrying out the invention]

[0023] Embodiments of the flame detection device and flame detection system according to the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments.

[0024] [Basic Concepts of the Embodiment] First, the basic concepts of the embodiment will be explained. The embodiment generally relates to a flame detection device that detects flames by receiving radiant light from flames present in a monitoring area, and a flame detection system in which multiple flame detection devices are installed in the monitoring area, and each flame detection device is capable of communicating with a higher-level device.

[0025] Here, the "monitoring area" is the area that is monitored for a fire that produces flames, and is a concept that includes a certain area of ​​outdoor or indoor space, such as the area inside a building or tunnel.

[0026] The "superior device" is a device positioned above the flame detection device, which places all connected terminal devices and equipment, including all flame detection devices, under its monitoring and control. This concept includes devices that can be treated as equivalent in terms of their functions, such as disaster prevention receiving panels, central monitoring devices, receivers, and control panels. The communication method, whether wireless or wired, is irrelevant as long as it is able to communicate with the flame detection device.

[0027] A "flame detection device" is a device that detects flames by receiving radiation from a flame, such as infrared radiation in wavelength bands centered around 4.5 μm or 5.0 μm, converting the received infrared radiation into an electrical signal (a received light signal) through photoelectric conversion, and determining whether or not it is a fire flame based on the signal level (amount of received light) and frequency characteristics of the received light signal. This concept includes devices that can be treated as equivalent in terms of their functions, such as "flame detectors," "flame sensors," and "fire detection devices." Furthermore, while the type of fire that generates the flame detected by a flame detection device can be arbitrary, it includes, for example, "liquid fires" caused by flammable liquids such as gasoline.

[0028] Furthermore, the "flame detection device" of the embodiment is characterized by comprising a "light receiving unit," a "flame source diameter estimation unit," a "flame source distance estimation unit," and a "flame judgment unit," and detecting a flame after estimating the flame source diameter and flame source distance.

[0029] The "light receiving unit" receives light, including light emitted from the flame, and outputs a light receiving signal based on the received light. It may consist of a single photosensor element (light receiving element unit) that receives light in a predetermined wavelength band, or it may consist of multiple photosensor elements that receive light in multiple wavelength bands. However, the present invention enables the detection of a flame after estimating the diameter and distance of the fire source with a simple configuration, and can be realized with a single photosensor element. Therefore, the explanation will be based on the premise of a flame detection device consisting of a single photosensor element. It should be noted that the present invention does not prevent the flame detection device from consisting of multiple photosensor elements that receive light in multiple wavelength bands.

[0030] The "fire source diameter estimation unit" performs frequency analysis, such as a Fourier transform, on the received light signal. From the frequency spectrum obtained through the frequency analysis, it calculates the peak frequency with the highest spectral intensity as the fluctuation frequency (n1), and estimates the fire source diameter (D1) from the calculated fluctuation frequency (n1).

[0031] Here, the fluctuation frequency (n) and the flame source diameter (D) can be expressed by the following first relation (Equation 1), so the flame source diameter (D) can be estimated by knowing the fluctuation frequency (n). The inventor of this application derived the first relation based on "Spectral Analysis of Flame Length Variation, Kunihiro Yamashita; Fire and Disaster Management Agency Report No. 53, 1982.3" (hereinafter referred to as Reference 1).

[0032]

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[0033] Furthermore, the area where the flame is generated is not necessarily circular. The flame source diameter (D) indicates the length of the diameter when the area where the flame is generated is treated as a pseudo-circle, if the area is not circular.

[0034] The "fire source distance estimation unit" estimates the fire source distance (X1) using the amount of light received by the light receiving unit (Q1), the fluctuation frequency (n1), and the fire source diameter (D1), and the estimation process is as follows.

[0035] First, the second to fourth relational equations are used in the estimation process of the fire source distance.

[0036] The second relation expresses the relationship between the diameter of the flame source (D) and the amount of heat radiated from the flame (Y), and can be expressed as the following equation 2. The inventors of this application derived the second relation based on "Estimation of heat generation amount by the frequency of flame fluctuations, Takashi Ono et al.; H3 Illuminating Engineering Institute of Japan National Convention" (hereinafter referred to as Reference 2).

[0037]

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[0038] Next, the third relation expresses the relationship between the amount of heat generated (Y) and the amount of light received (Q). Since the amount of heat generated (Y) and the amount of light received (Q) are proportional, it can be expressed as the following equation 3.

[0039]

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[0040] Next, the fourth relation expresses the relationship between the amount of light received (Q) and the distance to the fire source (X). Since the amount of light received (Q) is inversely proportional to the square of the distance to the fire source (X), it can be expressed as the following equation 4.

[0041]

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[0042] Furthermore, prior to the estimation process of the ignition source distance, the following reference data are set: reference ignition source diameter (D0), reference ignition source distance (X0), reference light received amount (Q0), and reference heat generation amount (Y0). The reference ignition source diameter (D0) and reference ignition source distance (X0) are information that can be arbitrarily set during the preparation stage before the flame detection operation by the flame detection device. The reference light received amount (Q0) is the amount of light received when the light receiving unit receives radiation from a flame with a reference ignition source diameter (D0) located at a distance of the reference ignition source distance (X0). This information is set by actual measurement, for example, when adjusting the sensitivity of the flame detection device after determining the installation location of the flame detection device, the reference ignition source diameter (D0), and the reference ignition source distance (X0). The reference heat generation amount (Y0) is information that is calculated and set using the set reference ignition source diameter (D0) and the second relational equation.

[0043] Then, with these relational equations and reference data set, the fire source distance estimation unit first calculates the heat output (Y1) of the detected flame using the fire source diameter (D1) estimated by the fire source diameter estimation unit and the second relational equation.

[0044] Next, the fire source distance estimation unit uses the reference light received amount (Q0), reference heat generated (Y0), heat generated (Y1), and the third relational equation to calculate the assumed light received amount (Q2), which is given as equation 5, assuming that the flame is detected at a distance of the reference fire source distance (X0).

[0045]

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[0046] Finally, the fire source distance estimation unit estimates the fire source distance (X1) as equation 6 using the amount of light received (Q1), the assumed amount of light received (Q2), the reference fire source distance (X0), and the fourth relation.

[0047]

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[0048] For explanatory purposes, the symbol "n" represents the fluctuation frequency, "D" represents the ignition source diameter, "X" represents the ignition source distance, "Q" represents the amount of light received, and "Y" represents the amount of heat generated. When limiting the data to specific items such as reference data (reference ignition source diameter D0 or reference ignition source distance X0, etc.) or estimated / calculated data (ignition source diameter D1 or ignition source distance X1, etc.), these symbols are combined with numbers to represent them.

[0049] The "flame detection unit" detects flames and determines whether they are fire flames. This determination is made based on the diameter of the ignition source (D1), and if it determines that the flames are fire flames, it performs a predetermined alarm action. Furthermore, if the amount of light received (Q1) is above a predetermined value, but the diameter of the ignition source (D1) is below a predetermined value, the "flame detection unit" will determine that the flames are not fire flames and will not perform the predetermined alarm action.

[0050] This enables the flame detection device to correctly identify flames originating at a distance as fire flames and activate an alarm, while also preventing it from mistakenly identifying flames caused by non-fire factors, such as those artificially created by matches or lighters near the device, as fire flames and triggering false fire alarms.

[0051] Furthermore, the "prescribed alarm operation" in the flame detection device includes not only alarms performed by the device itself, such as alarms made by sound or display, but also operations such as signal output to cause other devices to perform alarm operations, as in a higher-level device.

[0052] Furthermore, in a flame detection system equipped with multiple flame detection devices and a higher-level device, each "flame detection device" is installed such that a portion of its detectable area overlaps with the detectable area of ​​other flame detection devices. The "higher-level device" estimates the location of the flame (location of the fire) based on the position of the flame detection device that estimated the flame source distance (X1) and the multiple estimated flame source distances (X1) when the fire source distance (X1) is estimated by multiple flame detection devices, thereby enabling accurate identification of the location of the flame (location of the fire).

[0053] Furthermore, the "higher-level device" changes its alarm operation according to the size of the fire source diameter (D1) estimated by the flame detection device. For example, if the alarm operation is changed in two stages, in the case of a small flame, the device will primarily focus on on-site confirmation and initial fire suppression, and will issue an alarm to the floor where the fire occurred. In the case of a large flame, the device will consider the danger level high and will issue an alarm to all floors, automatically contact the fire department, close fire doors, activate fire extinguishing systems, activate smoke control systems, and display evacuation guidance signs. Of course, the alarm operation can be changed in three or more stages instead of just two.

[0054] The following describes a specific embodiment. In the specific embodiment shown below, the monitoring area is a "tunnel," the fire generating flames is a "liquid fire," the light emitted from the flames received by the light receiving unit is "infrared radiation in a wavelength band centered on 4.5 μm," and the higher-level device is a "disaster prevention receiving panel."

[0055] [Specific details of the embodiment] The embodiments of the flame detection system will be described in the following sections. a. Overview of the flame detection system b. Flame detection device b1. Functional configuration of the flame detection device b2.Fire source diameter estimation part b3.Fire source distance estimation part b4.Flame Judgment Department c. Disaster prevention receiver panel d. Operation of the flame detection system e. Variations of the invention

[0056] [a. Overview of the flame detection system] First, we will explain the overview of the flame detection system. In this explanation, please refer to Figure 1, which shows an overview of the flame detection system, and Figure 2, which shows the relationship between the monitoring area in the tunnel and the detectable area of ​​the flame detection device.

[0057] As shown in Figure 1, an uphill tunnel 1a and a downhill tunnel 1b are constructed as tunnels, and flame detection devices 12 are installed at predetermined intervals, for example, every 50 meters, on the walls laid along the longitudinal direction of the tunnels inside the uphill tunnel 1a and the downhill tunnel 1b.

[0058] The flame detection device 12 has two sets of light-receiving units, and when installed in a tunnel, it has detectable areas on both the left and right sides in the longitudinal direction of the tunnel where flames can be detected, and is installed so that its detectable area overlaps with a portion of the detectable area of ​​an adjacent flame detection device 12.

[0059] The detectable area of ​​the flame detection device 12 corresponds to one of the regions when the monitoring area within the uphill tunnel 1a is divided into regions AR1, AR2, ... ARi-1, ARi, ARi+1, ... at 50-meter intervals along the length of the tunnel, as shown in the uphill tunnel 1a in Figure 2. The flame detection device 12 will be installed at each boundary of adjacent regions.

[0060] For example, a flame detection device 12 installed at the boundary between regions AR1 and AR2 will detect flames with its left light-receiving unit detecting region AR1 as the detection area and its right light-receiving unit detecting region AR2 as the detection area. Since region AR2 is also the detection area of ​​the left light-receiving unit of the flame detection device 12 installed at the boundary between regions AR2 and AR3, flames in region AR2 will be detected by both flame detection devices 12. In other words, each region except for the leftmost region AR1 and the rightmost region ARn will be monitored redundantly by two flame detection devices 12.

[0061] Furthermore, the flame detection device 12 is connected to signal lines 10a and 10b that are drawn out from the disaster prevention receiving panel 10, which functions as a higher-level device, to the uphill tunnel 1a and the downhill tunnel 1b, enabling the transmission and reception of signals between the disaster prevention receiver 610 and the flame detection device 12.

[0062] Furthermore, each flame detection device 12 is assigned a unique address to allow for individual identification. When a flame detection device 12 determines that a flame is from a fire and detects a flame, it transmits a fire determination signal to the disaster prevention receiving panel 10, which includes its own unique address and identification information indicating which light-receiving unit received infrared radiation from the flame (i.e., whether the flame was detected in the left or right detection area).

[0063] [b. Flame detection device] Next, I will explain the flame detection device.

[0064] (b1. Functional configuration of the flame detection device) First, the functional configuration of the flame detection device will be explained. This explanation will refer to Figure 3, which shows the functional configuration of the flame detection device, and Figure 4, which shows the external appearance of the flame detection device.

[0065] The flame detection device 12 includes two light-receiving units 14L, 14R, two light-transmitting windows 15L, 15R, two amplification processing units 16L, 16R, a control unit 18, a transmission unit 20, and a storage unit 22, corresponding to the left and right detectable areas. When the flame detection device 12 is installed as shown in Figure 2, the light-receiving unit 14L, the light-transmitting window 15L, and the amplification processing unit 16L correspond to the detectable area located on the left side, while the light-receiving unit 14R, the light-transmitting window 15R, and the amplification processing unit 16R correspond to the detectable area located on the right side. When distinction is not necessary, they are referred to as the light-receiving unit 14, the light-transmitting window 15, and the amplification processing unit 16.

[0066] The light-receiving unit 14 receives infrared light in a predetermined wavelength band centered on 4.5 μm from a flame in a corresponding detectable area, converts it into a photoelectric signal which is an electrical signal, and outputs it to the amplification processing unit 16. For example, it includes an optical wavelength filter 1410 and a light-receiving element unit 1420 that correspond to infrared light in a predetermined wavelength band centered on 4.5 μm.

[0067] The light-transmitting window 15 is made of a light-transmitting material that transmits infrared light, such as sapphire glass. As shown in Figure 4, the light-transmitting window 15L and light-transmitting window 15R are provided in the sensor housing 1220 located at the top of the housing 1210. The light-receiving units 14L and 14R are located inside the sensor housing 1220 corresponding to the positions of the light-transmitting window 15L and light-transmitting window 15R, respectively. Light from outside the flame detection device 12 to the light-receiving unit 14 is incident through the light-transmitting window 15.

[0068] The amplification processing unit 16 includes, for example, a pre-filter 1610, a pre-amplifier 1620, a main amplifier 1630, and a final stage amplifier 1640. The pre-filter 1610 allows the received light signal from the light receiving unit 14 to pass through a predetermined frequency band corresponding to the frequency of the flame flicker component. The pre-amplifier 1620 amplifies the received light signal that has passed through the pre-filter 1610, and the main amplifier 1630 further amplifies the received light signal amplified by the pre-amplifier 1620 and outputs the received light signal. The final stage amplifier 1640 amplifies the received light signal output from the main amplifier 1630 to a signal level suitable for processing in the control unit 18 and outputs it to the control unit 18.

[0069] The control unit 18 is provided in common with the light receiving units 14L and 14R and is a computer circuit equipped with, for example, a CPU, memory, various input / output ports, etc. as hardware, and is equipped with A / D conversion ports 1810L and 1810R which serve as input ports for the light received signal output from the amplification processing unit 16, and functions realized by the control unit 18 include a fire source diameter estimation unit 1820, a fire source distance estimation unit 1830, and a flame determination unit 1840.

[0070] The A / D conversion port 1810L is provided as an input port for the received light signal output from the final stage amplifier 1640 of the amplification processing unit 16L, and converts the received light signal (analog data) into digital data and outputs it to the various functional units of the control unit 18. Similarly, the A / D conversion port 1810R is provided as an input port for the received light signal output from the final stage amplifier 1640 of the amplification processing unit 16R. When there is no need to distinguish between the A / D conversion ports 1810L and 1810R, they are referred to as the A / D conversion port 1810.

[0071] The flame source diameter estimation unit 1820 calculates the fluctuation frequency from the digital data of the received signal output from the A / D conversion port 1810, and estimates the flame source diameter of the detected flame from the calculated fluctuation frequency.

[0072] The fire source distance estimation unit 1830 estimates the fire source distance to the flame detected by the flame detection device 12 using the digital data of the received signal output from the A / D conversion port 1810 and the fire source diameter D of the flame estimated by the fire source diameter estimation unit 1820.

[0073] The flame determination unit 1840 detects a flame by determining whether it is a fire flame, using the signal level (amount of light received) of the received light signal calculated using the digital data of the received signal output from the A / D conversion port 1810, and the fire source diameter D estimated by the fire source diameter estimation unit 1820. Details of the fire source diameter estimation unit 1820, the fire source distance estimation unit 1830, and the flame determination unit 1840 will be described later.

[0074] The transmission unit 20 transmits and receives signals to and from the disaster prevention receiving panel 10. When the flame determination unit 1840 of the control unit 18 determines that there is a fire, it transmits a fire determination signal to the disaster prevention receiving panel 10, for example, as a response signal to a call signal from the disaster prevention receiving panel 10 that matches its own address. This signal includes fire determination information such as the fire source diameter D estimated by the fire source diameter estimation unit 1820, the fire source distance X estimated by the fire source distance estimation unit 1830, and the determination result from the flame determination unit 1840, as well as the aforementioned identification information.

[0075] The memory unit 22 stores necessary information such as the digital data of the received light signal converted by the A / D conversion port 1810, setting information necessary for estimation processing by the fire source diameter estimation unit 1820 and fire source distance estimation unit 1830 and judgment processing by the flame judgment unit 1840, and the estimation results by the fire source diameter estimation unit 1820 and fire source distance estimation unit 1830 and the judgment results by the flame judgment unit 1840.

[0076] (b2.Fire source diameter estimation part) Next, the ignition source diameter estimation unit will be explained. In this explanation, please refer to Figure 5, which shows the relationship between the ignition source diameter and the fluctuation frequency.

[0077] The A / D conversion port 1810 of the control unit 18 samples the received light signal (analog data) output from the final stage amplifier 1640 of the amplification processing unit 16 at a predetermined sampling frequency, for example, 64 Hz, performs A / D conversion, and generates time-series data (digital data) for the intensity (signal level) of 64 received light signals per second.

[0078] The fire source diameter estimation unit 1820 performs a predetermined frequency analysis, such as a Fourier transform, on the time-series data output from the A / D conversion port 1810 in 2-second units (128 data units) to obtain a frequency spectrum. The fire source diameter estimation unit 1820 then calculates the peak frequency, which is the highest intensity in the frequency spectrum obtained by the frequency analysis, as the flame fluctuation frequency n1. Note that the calculation of the fluctuation frequency n1 may be based on multiple units of digital data, rather than on a single unit of digital data (2 seconds of digital data).

[0079] Next, the flame source diameter estimation unit 1820 estimates the flame source diameter D1 from the calculated fluctuation frequency n1. In this estimation process, the inventors of the present invention refer to the data described in Reference 1 (Spectral Analysis of Flame Length Fluctuations, Kunihiro Yamashita; Fire and Disaster Management Agency Report No. 53, March 1982). However, this estimation process does not necessarily have to be based on the data in Reference 1; any appropriate data may be used.

[0080] Reference 1 describes the combustion of heptane as a liquid fire, and Table 3 shows data on flame fluctuation frequencies for six different combustion vessel diameters D (=fire source diameter D): 0.09m, 0.2m, 0.3m, 0.4m, 0.7m, and 1.0m. Figure 5(A) of this application is an extraction of the portion of Table 3 showing diameter D and fluctuation frequency n. Then, plotting the diameter D and fluctuation frequency n shown in Figure 5(A) on a graph with the X-axis being the logarithm of diameter D and the Y-axis being the logarithm of fluctuation frequency n, as shown in Figure 5(B), and finding an approximate straight line using the least squares method, the first relational equation (approximation formula) expressed by the following equation 7 holds true. Note that when using Reference 1, a is approximately 2.01 and b is approximately -2.15, but it is not necessary to use the data from Reference 1, so we will use a and b in this explanation.

[0081]

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[0082] In other words, by pre-storing the first relational expression in the memory unit 22 during the preparation phase before the flame detection device 12 starts its flame detection operation, the fire source diameter estimation unit 1820 can estimate the fire source diameter D1 using the calculated fluctuation frequency n1 and the first relational expression stored in the memory unit 22 after the fluctuation frequency n1 has been calculated.

[0083] (b3.Fire source distance estimation part) Next, the ignition source distance estimation unit will be explained. For this explanation, please refer to Figure 6, which shows the relationship between the ignition source diameter and the amount of heat generated.

[0084] In this embodiment, when the ignition source distance X is estimated by the ignition source distance estimation unit 1830, reference data is set in advance, and the reference data consists of a reference ignition source diameter D0, a reference ignition source distance X0, a reference light reception amount Q0, and a reference heat generation amount Y0, which are stored in the storage unit 22.

[0085] To set the reference data, first, set the reference ignition source diameter D0 and reference ignition source distance X0 to arbitrary values. Here, for example, we set the reference ignition source diameter D0 to 0.2m and the reference ignition source distance X0 to 2.0m.

[0086] Next, the reference light reception amount Q0 is set. The reference light reception amount Q0 is the amount of infrared radiation received by the light receiving unit 14 when infrared radiation from a flame with a reference flame source diameter D0 (=0.2m) located at a reference flame source distance X0 (=2.0m) away from the flame detection device 12 is received by the light receiving unit 14. For example, when adjusting the sensitivity after installing the flame detection device 12 in a tunnel, a flame with a reference flame source diameter D0 (=0.2m) located at a reference flame source distance X0 (=2.0m) is experimentally generated, and the amount of light received by the flame detection device 12 is measured. The measured amount of light received is then set as the reference light reception amount Q0.

[0087] Furthermore, the received light quantity Q (reference received light quantity Q0) is the sum of the intensities of the received light signals in the time-series data obtained over a predetermined period of time, for example, every 2 seconds, output from the A / D conversion port 1810.

[0088] Finally, the reference heat output Y0 is set, and the inventors of this application refer to the data on container diameter (=fire source diameter D) and heat output described in Reference 2 (Estimation of heat output by the frequency of flame fluctuations, Takashi Ono et al.; H3 Illuminating Engineering Institute of Japan National Convention). However, it is not necessary to rely on the data in Reference 2, and any appropriate data may be used.

[0089] Reference 2 shows the relationship between the container diameter and the amount of heat generated when ethanol is burned as a liquid fire in Figure 2 (shown as Figure 6 in this application). It states that the curve shown in Figure 2 (Figure 6 in this application) can be approximated by a cubic polynomial using the least squares method, and that the second relationship (approximation formula) expressed by the following equation 8 holds between the ignition source diameter D and the amount of heat generated Y.

[0090]

number

[0091] Therefore, the reference heat output Y0 is calculated and set using the second relational expression when the reference ignition source diameter D0 is set, by storing the second relational expression in the memory unit 22.

[0092] Then, with these reference data set in advance, the fire source distance estimation process performed by the fire source distance estimation unit 1830 is as follows.

[0093] First, the fire source distance estimation unit 1830 calculates the heat output Y1 using the second relational equation from the fire source diameter D1 estimated by the fire source diameter estimation unit 1820. This heat output Y1 is the heat output of the flame that is actually being generated.

[0094] Next, since the amount of heat generated Y and the amount of light received Q are in a proportional relationship, the fire source distance estimation unit 1830 uses this relationship to calculate the assumed amount of light received Q2, assuming that there is a flame with a heat generated Y1 (an actual flame) at a distance of X0 from the reference fire source.

[0095] Specifically, the third relationship, expressed by the following equation 9, holds between the amount of heat generated Y and the amount of light received Q.

[0096]

number

[0097] Since the heat generation amount Y0 (a pre-set reference heat generation amount) and the calculated heat generation amount Y1, as well as the light reception amount Q0 (a pre-set reference light reception amount), have already been obtained, the ignition source distance estimation unit 1830 can use these three obtained values ​​and the third relational equation to calculate the assumed light reception amount Q2 as equation 10. The third relational equation is also stored in the memory unit 22 in advance.

[0098]

number

[0099] Next, the fire source distance estimation unit 1830 calculates the amount of light received Q1 from the time-series data output from the A / D conversion port 1810. Since the amount of light received Q is inversely proportional to the square of the fire source distance X, the fire source distance estimation unit 1830 uses this relationship to estimate the fire source distance X1 (the distance from the flame detection device 12 to the location where the flame is actually generated).

[0100] Specifically, the fourth relationship, expressed by the following equation 11, holds between the amount of light received Q and the distance X from the fire source.

[0101]

number

[0102] Since the reference ignition distance X0, which is set in advance as the ignition distance, and the calculated received light amount Q1 and assumed received light amount Q2 are obtained, the ignition distance estimation unit 1830 can estimate the ignition distance X1 as equation 12 using these three obtained values ​​and the fourth relational expression.

[0103]

number

[0104] (b4.Flame Judgment Department) Next, I will explain the flame detection unit.

[0105] Here, if the flame determination unit 1840 were to detect a fire by determining whether or not it is a fire flame based on the amount of infrared light received by the light receiving unit 14, there is a risk that the flame determination unit 1840 might mistakenly determine that it is not a fire flame because the amount of light received Q1 would be low for a fire flame that occurred far from the flame detection device 12. Also, there is a risk that the flame determination unit 1840 might mistakenly determine it to be a fire flame because the amount of light received would be high for small flames from non-fire sources such as lighters or matches that are artificially generated near the flame detection device 12.

[0106] Therefore, the flame determination unit 1840 uses the flame source diameter D1 estimated by the flame source diameter estimation unit 1820 to determine whether or not it is a fire flame and detects the flame. For example, if the flame source diameter D1 estimated by the flame source diameter estimation unit 1820 is greater than or equal to a predetermined value, it is determined to be a fire flame that requires action, and if the flame source diameter D1 does not exceed the predetermined value, it is determined to be a small flame of a non-fire cause that does not require action.

[0107] As a result, fire flames and flames from non-fire sources are determined by the flame source diameter D1, which does not depend on the distance X1 from the fire source. This allows the flame detection device 12 to correctly identify fire flames from a fire that occurred far away from it, even if the amount of infrared radiation Q1 received from fire flames that occurred far away from it is low. It also prevents the device from mistakenly identifying small flames from non-fire sources near the flame detection device 12 as fire flames, even if the amount of infrared radiation Q1 received from flames from non-fire sources near it is high.

[0108] Furthermore, since the flame diameter D1 is estimated from the fluctuation frequency n1, it is also acceptable to use the fluctuation frequency n1 instead of the flame diameter D1 to determine whether it is a fire flame. The concept of using the flame diameter D1 to determine whether it is a fire includes using the fluctuation frequency n1, which is used to estimate the flame diameter D1, in the determination.

[0109] Then, if the flame determination unit 1840 determines that the flames are from a fire and detects them, it will perform a predetermined alarm operation by transmitting a fire determination signal from the transmission unit 20 to the disaster prevention receiving panel 10. This signal includes fire determination information such as the fire source diameter D1 estimated by the fire source diameter estimation unit 1820, the fire source distance X1 estimated by the fire source distance estimation unit 1830, and the determination result from the flame determination unit 1840, as well as identification information indicating its own address and the infrared receiving units 14R and 14L that received the infrared light.

[0110] [c. Disaster Prevention Receiving Panel] Next, we will explain the disaster prevention receiving panel. For this explanation, please refer to Figure 7, which shows the monitoring area inside the tunnel where the fire occurred.

[0111] The disaster prevention receiving panel 10 identifies the location of the flame (location of the fire) based on the fire judgment signal received from the flame detection device 12 and performs a predetermined alarm operation.

[0112] For example, as shown in Figure 8, if a flame occurs in region ARi, the flame detection devices 12 installed at the boundary between regions ARi-1 and ARi, and the flame detection devices 12 installed at the boundary between regions ARi and ARi+1, receive infrared radiation from the flame, determine that it is a fire, detect the flame, and transmit a fire detection signal to the fire prevention receiving panel 10. The fire source distance X1 is defined as the distance from the flame detection device 12 installed at the boundary between regions ARi-1 and ARi to the flame generation location 30, and the fire source distance from the flame detection device 12 installed at the boundary between regions ARi and ARi+1 to the flame generation location 30, and X12 is defined as the distance from the fire source to the flame generation location 30.

[0113] Therefore, the disaster prevention receiving panel 10 receives a fire judgment signal from a flame detection device 12 installed at the boundary between areas ARi-1 and ARi, which includes fire judgment information including the distance from the fire source X11 and the diameter of the fire source D1, as well as identification information indicating the address of the flame detection device 12 and the right-side light receiving unit 14R that receives infrared rays. At the same time, it receives a fire judgment signal from a flame detection device 12 installed at the boundary between areas ARi-1 and ARi, which includes fire judgment information including the distance from the fire source X12 and the diameter of the fire source D1, as well as identification information indicating the address of the flame detection device 12 and the left-side light receiving unit 14L that receives infrared rays.

[0114] Furthermore, since the installation locations and spacing (50m) of the two flame detection devices 12, as well as the distances X11 and X12 to the two fire sources, the disaster prevention receiving panel 10 can identify the location where flames originated in area ARi, i.e., the location of the fire, by using known trigonometry or the like. This is a particularly significant advantage when multiple flame detection devices 12 are installed in large spaces such as arenas, and an effect equivalent to that of conventional large-scale and expensive devices such as infrared cameras and scanning fire source detection devices can be obtained with a minimum of two flame detection devices 12.

[0115] Furthermore, the fire alarm receiver 10 changes its alarm operation according to the size of the fire source diameter D1 included in the fire judgment signal. For example, if the fire source diameter D1 included in the fire judgment signal does not exceed a predetermined value and the fire alarm receiver 10 determines that it is a small fire, it will issue a notification focused on on-site confirmation and initial firefighting, or an alarm to the floor where the fire occurred, as the danger level is low. On the other hand, if the fire source diameter D1 included in the fire judgment signal is greater than or equal to a predetermined value and the fire alarm receiver 10 determines that it is a large fire, it will issue an alarm to all floors, automatically contact the fire station, close fire doors, activate fire extinguishing equipment, activate smoke control equipment, display evacuation guidance, etc., as the danger level is high, and will perform an alarm operation appropriate to the scale of the fire.

[0116] [d. Operation of the flame detection system] Next, we will explain the operation of the flame detection system. For this explanation, please refer to Figure 8, which shows an example of the operation of the flame detection system in a flowchart.

[0117] As shown in Figure 8, in the preparation stage before starting the flame detection operation, the flame detection device 12 sets the reference flame source diameter D0, reference flame source distance X0, reference light reception amount Q0, and reference heat generation amount Y0 as reference data and stores them in the storage unit 22 (step S1).

[0118] After the reference data has been set, the flame detection device 12 starts the flame detection operation, and at a predetermined estimation processing timing, the fire source diameter estimation unit 1820 calculates the fluctuation frequency n1 from the time series data (digital data of the received light signal) obtained in predetermined time units output from the A / D conversion port 1810, and estimates the fire source diameter D1 from the calculated fluctuation frequency n1 and the first relational expression (steps S2 to S5).

[0119] Here, the predetermined estimation processing timing is arbitrary. For example, any condition can be set as the estimation processing timing, such as when the amount of received light exceeds a predetermined value, when a predetermined amount of time has elapsed and one unit of time-series data necessary for estimation processing is available, or when an estimation processing instruction is received from an external source.

[0120] Next, the flame detection device 12 determines whether the flame is from a fire based on the flame source diameter D1 estimated by the flame source diameter estimation unit 1820, with the flame determination unit 1840 determining whether the flame is from a fire. If the flame source diameter D1 is greater than or equal to a predetermined value, the flame source distance estimation unit 1830 estimates the flame source distance X1 using the flame source diameter D1 estimated by the flame source diameter estimation unit 1820 and set reference data, and the flame determination unit 1840 determines that it is from a fire (steps S2 to S9).

[0121] Next, if the flame detection device 12 determines that the flames are from a fire, it transmits a fire determination signal from the transmission unit 20 to the fire prevention receiving panel 10, which includes fire determination information such as the fire source diameter D1 estimated by the fire source diameter estimation unit 1820, the fire source distance X1 estimated by the fire source distance estimation unit 1830, and the determination result from the flame determination unit 1840, as well as identification information indicating its own address and the infrared receiving units 14R and 14L that received the infrared light (step S9).

[0122] On the other hand, if the flame source diameter D1 is below a predetermined value, the flame determination unit 1840 determines that the flame is not caused by a fire, and the process returns to before step S2 (step S10).

[0123] Next, the fire prevention receiving panel 10, which receives a fire judgment signal from the flame detection device 12, identifies the flame detection device 12, which it determined to be a fire flame, and the light receiving units 14R and 14L, which received infrared rays from the flame, based on the identification information contained in the fire judgment signal. It then identifies the location of the flame from the fire source distance X1 of the fire judgment information contained in the fire judgment signal (step S11). Furthermore, the disaster prevention receiving panel 10 performs alarm actions according to the fire source diameter D1 of the fire judgment information included in the fire judgment signal. For example, if the fire source diameter D1 does not exceed a predetermined value and it is determined to be a small fire, the danger level is low and the panel will issue a notification focused on on-site confirmation and initial fire suppression, as well as an alarm to the floor where the fire occurred. If the fire source diameter D1 is above a predetermined value and it is determined to be a large fire, the panel will issue an alarm to all floors, automatically contact the fire station, close fire doors, activate fire extinguishing equipment, activate smoke control equipment, display evacuation guidance, etc., as the danger level is high (step S12).

[0124] [e. Variations of the present invention] Modifications of the flame detection system according to the present invention will now be described. In addition to the embodiments described above, the flame detection system of the present invention includes the following modifications.

[0125] (Flame detection device alarm activated) In the above embodiment, when the flame determination unit determines that the flames are those of a fire, the flame detection device transmits a fire determination signal to a higher-level device as an alarm operation, but it is not limited to this. For example, the flame detection device may be equipped with a notification unit that notifies by sound or indicator light, and when the flame determination unit determines that the flames are those of a fire, the notification unit notifies that the flames have been determined to be those of a fire as an alarm operation.

[0126] (Operation of the flame detection device when it determines that the flame is not caused by a fire source) In the above embodiment, if the flame determination unit determines that the flame is not caused by a fire, the fire source distance estimation unit 1830 does not estimate the fire source distance X1. However, the fire source distance estimation unit 1830 may also estimate the fire source distance X1.

[0127] Furthermore, in the above embodiment, if the flame determination unit determines that the flame is not caused by a fire, no signal is transmitted to the disaster prevention receiving panel 10. However, the transmission unit 20 may transmit a non-fire detection signal to the disaster prevention receiving panel 10, which includes non-fire determination information such as the fire source diameter D1 estimated by the fire source diameter estimation unit 1820, the fire source distance X1 estimated by the fire source distance estimation unit 1830, and the determination result from the flame determination unit 1840, as well as identification information indicating its own address and the infrared receiving units 14R and 14L that received the infrared light.

[0128] (others) Furthermore, the present invention includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the numerical values ​​shown in the above embodiments. [Explanation of Symbols]

[0129] 1a: Upbound tunnel 1b: Downbound tunnel 10: Disaster Prevention Receiving Panel 10a, 10b: Signaling circuits 12: Flame detection device 1210: Cabinet 1220: Sensor housing 14,14L,14R: Light receiving part 1410: Optical wavelength filter 1420: Photodetector section 15,15L,15R: Translucent window 16, 16L, 16R: Amplification and processing unit 1610: Pre-filter 1620: Preamplifier 1630: Main amplifier 1640: Final stage amplifier 18: Control Unit 1810, 1810L, 1810R: A / D conversion port 1820: Fire source diameter estimation part 1830:Fire source distance estimation part 1840: Flame Judgment Department 20: Transmission section 22: Storage part 30: Flame origin location

Claims

1. A flame detection device that detects flames by receiving radiation from flames present in a monitoring area, A light receiving unit that receives light including radiant light from a flame and outputs a light receiving signal based on the received light, A flame source diameter estimation unit that estimates the diameter of the flame source (D1), A fire source distance estimation unit estimates the fire source distance (X1) from the flame detected by the flame detection device, A flame detection unit that determines whether the flames are from a fire and detects the flames, Equipped with, The fire source diameter estimation unit calculates a fluctuation frequency (n1) from the received light signal, and estimates the fire source diameter (D1) from the calculated fluctuation frequency (n1). The flame detection device is characterized in that the fire source distance estimation unit estimates the fire source distance (X1) using the amount of light received by the light receiving unit (Q1), the fluctuation frequency (n1), and the fire source diameter (D1).

2. A flame detection device according to claim 1, The first relationship between the fluctuation frequency (n) and the fire source diameter (D), The second relationship between the diameter of the ignition source (D) and the amount of heat radiated from the flame (Y), The third relational expression between the amount of heat generated (Y) and the amount of light received (Q), The fourth relation between the amount of light received (Q) and the distance to the fire source (X), Standard ignition source diameter (D0), Reference ignition source distance (X0), The reference light received amount (Q0) is the amount of light received when the light receiving unit receives radiation from a flame with a reference flame diameter (D0) located at a distance (X0) from the reference flame source, The reference heat output (Y0) calculated using the reference ignition source diameter (D0) and the second relational expression, Set it up, The fire source diameter estimation unit estimates the fire source diameter (D1) from the fluctuation frequency (n1) using the first relational expression, The fire source distance estimation unit, Using the flame source diameter (D1) and the second relational equation, the heat output (Y1) of the detected flame is calculated. Using the aforementioned reference light reception amount (Q0), the reference heat generation amount (Y0), the heat generation amount (Y1), and the third relational expression, the assumed light reception amount (Q2) is calculated assuming that a flame is detected at a distance of the reference fire source distance (X0). A flame detection device characterized by estimating the ignition source distance (X1) using the amount of light received (Q1), the assumed amount of light received (Q2), the reference ignition source distance (X0), and the fourth relational expression.

3. A flame detection device according to claim 1, The flame detection device is characterized in that the flame determination unit determines whether the flame is from the fire based on the diameter of the fire source (D1), and performs a predetermined alarm operation if it determines that the flame is from the fire.

4. A flame detection device according to claim 3, The flame detection device is characterized in that, when the amount of light received (Q1) is greater than or equal to a predetermined value, but the diameter of the fire source (D1) is less than or equal to a predetermined value, the flame determination unit determines that it is not a flame from the fire and does not perform a predetermined alarm operation.

5. A flame detection device according to claim 1, A flame detection device characterized by detecting flames that include those caused by liquid fires.

6. A flame detection system comprising a plurality of flame detection devices according to any one of claims 1 to 5 installed in the monitoring area, wherein each of the flame detection devices is capable of communicating with a higher-level device, Each of the flame detection devices is installed such that a portion of its detectable area for detecting flames overlaps with the detectable area of ​​another flame detection device. The aforementioned higher-level device is a flame detection system characterized in that, when the fire source distance (X1) is estimated by a plurality of flame detection devices, it estimates the location of the flame generation based on the position of the flame detection device that estimated the fire source distance (X1) and the plurality of estimated fire source distances (X1).

7. A flame detection system according to claim 6, The aforementioned higher-level device is a flame detection system characterized by changing the alarm operation according to the size of the fire source diameter (D1) estimated by the flame detection device.

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