Abnormality detector

Abstract

To enable detecting hydrogen flames with high accuracy.SOLUTION: An abnormality detector includes: a first band filter that transmits infrared light in a first band being at least a part of a range from 3.9 μm to 6.0 μm; a second band filter that transmits infrared light in a second band being at least a part of the range from 3.9 μm to 6.0 μm, and different from the first band; a detection unit that has a first detection element detecting the infrared light passing through the first band, and converting the detected infrared light to an electric signal, and a second detection element detecting the infrared light passing through the second band filter, and converting the detected infrared light to an electric signal; and a determination unit that determines whether to detect hydrogen flames on the basis of a value of the electric signal detected by the first detection element and a value of the electric signal detected by the second detection element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anomaly detector. [Background technology]

[0002] Conventionally, the main detectors used for hydrogen flames are optical detection methods using optical sensors, which are roughly divided into three types according to the wavelength band of light detected by the sensor (ultraviolet type, infrared type, and combined ultraviolet and infrared type). However, hydrogen flames do not accompany carbon dioxide resonance radiation (4.5 μm) that originates from flames of hydrocarbon compounds, making fire detection using this band difficult.

[0003] When hydrogen (and combustible gases) burn, "light emission from OH radicals (ultraviolet light)," "light emission from high-temperature water vapor (near-infrared light)," and "light emission from condensation formed when the high-temperature water vapor is cooled (far-infrared light)" are generated (Figure 4). Detectors generally detect one or more of these bands.

[0004] The most widely used type is the ultraviolet detection type, which detects the ultraviolet band of 185 to 260 nm, a wavelength band that is included in the radiation spectrum from hydrogen flames but not in sunlight (Patent Documents 5 and 7). The advantages of the ultraviolet detection type are that the detection element is inexpensive and the flame detection speed is fast.

[0005] There are only a few detectors that use infrared detection, but methods are used to detect one or more wavelength bands of 930 to 950 nm, 1.3 to 1.5 μm, and 2.6 to 3.1 μm, which are the emission spectrum of high-temperature water vapor (Patent Documents 2, 4, 6, 8). There is also a method of detecting the emission spectrum (heat rays) of condensation formed when high-temperature water vapor is cooled using thermography (7 to 14 μm). While the infrared band has the advantage of high detection sensitivity, many high-performance products use microbolometers or CCD image sensors, and detectors tend to be expensive.

[0006] The ultraviolet / infrared combined type detects both the ultraviolet band (185-260 nm) and the infrared band (carbon dioxide resonance radiation band: 4.5 μm) separately, making it possible to detect both hydrogen flames and hydrocarbon flames, and this type is widely used in flame detectors (Patent Documents 1 and 3). In this case, multiple sensors and optical windows corresponding to each band are required, and the detectors tend to be expensive. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 1983-084388 A [Patent Document 2] JP 2006-267097 A [Patent Document 3] JP 2006-338419 A [Patent Document 4] JP 2013-36974 A [Patent Document 5] JP 2018-25477 A [Patent Document 6] JP 2018-132457 A [Patent Document 7] Restated WO2005-045379 publication [Patent Document 8] U.S. Patent No. 7,119,697 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the case of hydrogen flames, the carbon dioxide resonance radiation (4.5 μm) derived from the flames of hydrocarbon compounds does not appear as a spectral feature (peak), making flame detection using only this band difficult.

[0009] The present invention has been made to solve the above problems, and has an object to provide an anomaly detector that can detect hydrogen flames with high accuracy. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, an anomaly detector according to an embodiment of the present invention includes a first band filter that transmits infrared light of a first band, which is at least a part of the range from 3.9 μm to 6.0 μm; a second band filter that transmits infrared light of a second band, which is at least a part of the range from 3.9 μm to 6.0 μm and is different from the first band; a detection unit including a first detection element that detects infrared light that has transmitted through the first band filter and converts it into an electrical signal; and a second detection element that detects infrared light that has transmitted through the second band filter and converts it into an electrical signal; and a judgment unit that judges whether or not a hydrogen flame has been detected based on the value of the electrical signal detected by the first detection element and the value of the electrical signal detected by the second detection element. Effect of the Invention

[0011] According to the anomaly detector of one aspect of the present invention, it is possible to obtain the effect of being able to detect a hydrogen flame with high accuracy. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a configuration of an anomaly detector according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram showing a configuration of a calculation processing unit of the anomaly detector according to the embodiment of the present invention. FIG. [Diagram 3] 2 is a block diagram showing a configuration of a determination unit of the anomaly detector according to the embodiment of the present invention. FIG. [Figure 4] 1 is a graph showing the radiation spectrum of a hydrogen flame. [Diagram 5] 1 is a graph showing the amount of change in an IR signal when a hydrogen flame is detected. [Figure 6] 1 is a graph showing the radiant energy of a black body by wavelength. [Figure 7] 1 is a graph showing the slope of the signal change amount at 4.0 μm, 4.5 μm, and 5.0 μm for hot air and hydrogen flame. [Figure 8]5 is a flowchart showing a flame determination processing routine in a calculation processing unit of the abnormality detector according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, "A or / and B" is synonymous with "at least one of A and B." In other words, "A or / and B" means that it may be only A, only B, or a combination of A and B. In addition, in this specification, the same concept as "A or / and B" is also applied when three or more things are expressed by connecting them with "or / and."

[0014] <Outline of the embodiment of the present invention> In an embodiment of the present invention, hydrogen flames are monitored and detected in the infrared wavelength bands (4.0 μm, 5.0 μm, and 4.5 μm) used to detect flames accompanied by carbon dioxide resonance radiation.

[0015] In addition, because flames accompanied by carbon dioxide resonance radiation and hydrogen flames are monitored and detected in the same wavelength band, the number of sensors and optical windows required is reduced, making it possible to realize an inexpensive flame detector.

[0016] In the radiation spectrum of a hydrogen flame (Figure 4), the infrared range has higher radiation energy than the ultraviolet range, so in principle it is possible to detect smaller flames at greater distances compared to methods that use ultraviolet light to detect hydrogen flames.

[0017] <System configuration> An anomaly detector according to an embodiment of the present invention will now be described.

[0018] As shown in FIG. 1, an anomaly detector 10 according to an embodiment of the present invention includes a first sensor 12 that detects infrared light of a first band existing within an infrared wavelength range of 3.9 μm to 6.0 μm (e.g., the center of the first band is 4.0 μm), a second sensor 14 that detects infrared light of a second band existing within the range of 3.9 μm to 6.0 μm and different from the first band (e.g., the center of the second band is 5.0 μm), and a third sensor 16 that detects infrared light of a band around 4.5 μm, which is the carbon dioxide resonance radiation band emitted by flames.

[0019] Furthermore, the anomaly detector 10 includes an amplifier 18 that amplifies the signal from the first sensor 12, an amplifier 20 that amplifies the signal from the second sensor 14, an amplifier 22 that amplifies the signal from the third sensor 16, a switch 24 that switches the signals from the amplifiers 18, 20, 22, and an AD conversion unit 26 that converts the signal from the switch 24 into a digital value. The anomaly detector 10 also includes an arithmetic processing unit 28 that performs pre-processing for flame detection and processing to detect a flame, and an external output unit 30.

[0020] The first sensor 12 includes a filter 12A that transmits infrared light in a band around 4.0 μm, and a detection element 12B that detects the infrared light that has transmitted through the filter 12A and converts it into an electrical signal of a direct current component.

[0021] The second sensor 14 includes a filter 14A that transmits infrared light in a band around 5.0 μm, and a detection element 14B that detects the infrared light that has transmitted through the filter 14A and converts it into an electrical signal of a DC component.

[0022] The third sensor 16 is equipped with a filter 16A that transmits infrared light in the band around 4.5 μm, which is the carbon dioxide resonance radiation band emitted by the flame, and a detection element 16B that detects the infrared light that has transmitted through the filter 16A and converts it into an electrical signal with a DC component.

[0023] It also includes an optical lens 11 disposed in front of filters 12A, 14A, and 16A.

[0024] Moreover, the optical lens 11 is composed of one or more lenses. It is preferable that the optical lens 11 is composed of two or more lenses. This is to focus the detection element on a flat surface as much as possible for the wide monitoring angle of the detection element. Also, in order to reduce loss due to lens reflection, it is possible to increase the sensitivity of the detection element by evaporating an anti-reflection film (AR coating) on ​​the lens. Lens materials include sapphire, chalcogenide glass, silicon, germanium, etc.

[0025] The detection element is composed of a thermopile, but it may also be composed of other photovoltaic type elements such as InAsSb elements, microbolometer elements that use resistance changes, or photoconductive type elements such as PbSe. Compared to thermopiles and microbolometers, other elements have extremely fast infrared detection speeds. For this reason, even with the same circuit configuration, it is possible to configure an anomaly detector that can detect flames extremely quickly by increasing the AD conversion speed.

[0026] The amplifiers 18, 20, and 22 amplify the electrical signal of the detection element 12B of the first sensor 12, the electrical signal of the detection element 14B of the second sensor 14, and the electrical signal of the detection element 16B of the third sensor 16, respectively, independently.

[0027] The switch 24 includes a switch section (not shown) that sequentially switches the electric signals amplified individually by the amplifiers 18, 20, 22 at a fixed time to combine them into one electric signal, and outputs the combined electric signal by the switch section. Note that instead of providing the switch 24, an AD conversion section may be provided for each of the amplifiers 18, 20, 22 to convert the amplified electric signals into digital values ​​individually and output them to the arithmetic processing section 28.

[0028] The calculation processing unit 28 is composed of a CPU. When the calculation processing unit 28 is explained in terms of functional blocks divided into each function realization means, as shown in Fig. 2, the calculation processing unit 28 includes a signal acquisition unit 40, a correction coefficient setting unit 42, a correction unit 44, an average calculation unit 50, a change amount calculation unit 52, a determination unit 54, and an output information control unit 56.

[0029] The signal acquisition unit 40 acquires the value of the electrical signal from the detection element 12B of the first sensor 12, the value of the electrical signal from the detection element 14B of the second sensor 14, and the value of the electrical signal from the detection element 16B of the third sensor 16 from the signal output from the AD conversion unit 26.

[0030] The correction coefficient setting unit 42 sets in advance a correction coefficient for equalizing the variation in sensitivity between the detection elements of the first sensor 12, the detection elements of the second sensor 14, and the detection elements of the third sensor 16, a correction coefficient for equalizing the variation in sensitivity between individual anomaly detectors 10, and a correction coefficient for performing offset correction. Note that each correction coefficient is set based on the value of each electrical signal acquired by the signal acquiring unit 40 when infrared reference light is irradiated from a reference light source such as a blackbody furnace.

[0031] The correction unit 44 corrects the values ​​of the electrical signals from the detection elements of the first sensor 12, the second sensor 14, and the third sensor 16 acquired by the signal acquisition unit 40 using the correction coefficient set by the correction coefficient setting unit 42, and outputs the corrected values ​​to the calculation processing unit 28.

[0032] The average calculation unit 50 calculates, for a detection element of the first sensor 12, a moving average value (e.g., an average value for the past 100 seconds) of the value of the electrical signal from that detection element corrected by the correction unit 44 as the monitored environment signal value of the signal from that detection element of the first sensor 12. Similarly, for a detection element of the second sensor 14, the average calculation unit 50 calculates a moving average value of the value of the electrical signal from that detection element corrected by the correction unit 44 as the monitored environment signal value of the signal from that detection element of the second sensor 14. Similarly, for a detection element of the third sensor 16, the average calculation unit 50 calculates a moving average value of the value of the electrical signal from that detection element corrected by the correction unit 44 as the monitored environment signal value of the signal from that detection element of the third sensor 16.

[0033] The change amount calculation unit 52 calculates, for a detection element of the first sensor 12, the difference between the live value of the electrical signal from the detection element corrected by the correction unit 44 and the monitored environment signal value of the signal of the detection element calculated by the average calculation unit 50 as a first change amount. Similarly, for a detection element of the second sensor 14, the change amount calculation unit 52 calculates, for a detection element of the second sensor 14, the difference between the live value of the electrical signal from the detection element corrected by the correction unit 44 and the monitored environment signal value of the signal of the detection element calculated by the average calculation unit 50 as a second change amount. Similarly, for a detection element of the third sensor 16, the change amount calculation unit 52 calculates, for a detection element of the third sensor 16, the difference between the live value of the electrical signal from the detection element corrected by the correction unit 44 and the monitored environment signal value of the signal of the detection element calculated by the average calculation unit 50 as a third change amount.

[0034] Here, the principle of detecting a hydrogen flame will be described.

[0035] As an example of the above-mentioned change amount, if the center of the band of filter 12A of first sensor 12 is 4.0 μm and the center of the band of filter 14A of second sensor 14 is 5.0 μm, and the horizontal axis is wavelength and the vertical axis is change amount, the distribution (spectrum) of the change amount of the signal caused by the hydrogen flame shows an upward sloping linearity (Figure 5).

[0036] This linearity shows a slope that is specific to hydrogen flames, regardless of the flame scale, etc., so it is possible to detect hydrogen flames based on the value of this slope.

[0037] Furthermore, the anomaly detector is configured to include a third sensor 16 that detects infrared light in a third band (4.5 μm) that includes the peak wavelength of the carbon dioxide resonance radiation band and converts it into an electrical signal. A third change amount similarly obtained from detection element 16B of the third sensor 16 is also used to determine the slope, enabling hydrogen flames to be detected with greater accuracy (Figure 5).

[0038] Furthermore, in the distribution of change (spectrum) in this band, the Stefan-Boltzmann law shows a similar upward-sloping linearity even for low-temperature radiators (especially hot air at 40 to 60°C) (Figure 6).

[0039] However, the two (hydrogen flame / low-temperature radiator) can be distinguished based on either or both of the following two points (1) and (2):

[0040] (1) The slope of the line connecting the first change amount and the second change amount, the slope of the line connecting the first change amount and the third change amount, and the slope of the line connecting the second change amount and the third change amount are identified based on a preset threshold value ( FIG. 7 , Table 1).

[0041] (2) Identification is performed by setting a threshold value for the value of the electrical signal from detection elements 12B, 14B, and 16B (as shown in FIG. 6, the electrical signal value itself of a radiator at 40 to 60° C. is very small).

[0042] [Table 1]

[0043] The configuration of the above anomaly detector is the same as that of the conventional technology for detecting flames accompanied by carbon dioxide resonance radiation (e.g., JP 2018-044792 A, JP 2020-094916 A), and therefore detection of flames accompanied by carbon dioxide resonance radiation is possible as in the conventional technology.

[0044] Therefore, in flame judgment, both a method similar to the conventional technique and the hydrogen flame detection method according to this embodiment are carried out, and if a flame is judged by either one or both, a flame output is performed.

[0045] By using the above method, it is possible to identify whether the flame is hydrogen or hydrocarbon based on which method was used to determine the flame, and output information on the flame material along with the flame output. In addition, when a hydrogen flame and a flame accompanied by carbon dioxide resonance radiation occur simultaneously, it is possible to output both information that the flame is a hydrogen flame and information that the flame is accompanied by carbon dioxide resonance radiation.

[0046] The above system allows you to select fire extinguishing tactics according to the type of fire, making fire extinguishing more effective.

[0047] Furthermore, since the configuration of the anomaly detector according to this embodiment is the same as that of the conventional technology, a hydrogen flame detection function can be added to a flame sensor developed based on the conventional technology simply by updating the firmware.

[0048] According to the above-described principle, in this embodiment, the determination unit 54 determines whether or not a hydrogen flame has been detected based on the value of the electric signal detected by the detection element 12B of the first sensor 12 and the value of the electric signal detected by the detection element 14B of the second sensor 14. Specifically, the determination unit 54 compares the first change amount and the second change amount calculated by the change amount calculation unit 52 with a determination threshold value to determine whether or not a hydrogen flame has been detected. Alternatively, the determination unit 54 determines whether or not a hydrogen flame has been detected based on the difference between the first change amount and the second change amount and / or the ratio between the first change amount and the second change amount.

[0049] More specifically, based on the value of the electrical signal detected by detection element 12B of the first sensor 12, the value of the electrical signal detected by detection element 14B of the second sensor 14, and the value of the electrical signal detected by detection element 16B of the third sensor 16, the judgment unit 54 judges and detects whether the flame is derived from a substance that generates carbon dioxide resonance radiation during combustion, or a hydrogen flame, or an abnormal temperature.

[0050] As an example, the judgment section 54 includes a first flame judgment section 60, a second flame judgment section 62, a flame position judgment section 64, and a scale judgment section 66, as shown in FIG.

[0051] The first flame judgment unit 60 judges and detects whether or not it is a hydrogen flame using any one or more of the following: a first ratio, which is the ratio between the first amount of change (4.0 μm) and the second amount of change (5.0 μm); a second ratio, which is the ratio between the first amount of change (4.0 μm) and the third amount of change; and a third ratio, which is the ratio between the second amount of change (5.0 μm) and the third amount of change (4.5 μm). As an example, the first flame judgment unit 60 judges that it is a hydrogen flame when the first ratio is 3.0 or more and 5.0 or less, the second ratio is 1.5 or more and 2.5 or less, and the third ratio is 1.5 or more. It is also possible to judge that it is a hydrogen flame when any one or more of the conditions of the first ratio being 3.0 or more and 5.0 or less, the second ratio being 1.5 or more and 2.5 or less, and the third ratio being 1.5 or more are satisfied.

[0052] The second flame judgment unit 62 judges and detects whether the flame is derived from a substance that generates carbon dioxide resonance radiation during combustion using one or more of the first ratio, which is the ratio between the first change amount (4.0 μm) and the second change amount (5.0 μm), the second ratio, which is the ratio between the first change amount (4.0 μm) and the third change amount (4.0 μm), and the third ratio, which is the ratio between the second change amount (5.0 μm) and the third change amount (4.5 μm).

[0053] Alternatively, the second flame judgment unit 62 may judge that a flame originating from a substance that accompanies carbon dioxide resonance radiation during combustion has been detected when at least one of the value of the third change amount (near 4.5 μm), the value of the first change amount (near 4.0 μm), and the value of the second change amount (near 5.0 μm) calculated by the change amount calculation unit 52 is equal to or greater than the threshold value E, and the ratio of the calculated value (noise amount) near 4.5 μm obtained from the approximation line of the value of the first change amount and the value of the second change amount to the third change amount, when compared with the threshold value, satisfies a predetermined condition.

[0054] The flame position determination unit 64, for example, treats the detection elements of the first sensor 12, the second sensor 14, or the third sensor 16 as an array sensor in which the detection elements are arranged in a two-dimensional manner, and determines a predetermined position for a detection element determined to have detected a hydrogen flame as the hydrogen flame position, and determines a predetermined position for a detection element determined to have detected a flame derived from a substance that generates carbon dioxide resonance radiation during combustion as the flame position derived from the substance that generates carbon dioxide resonance radiation during combustion.

[0055] The predetermined positions for the detection elements may be set by measuring the detection position in real space for each detection element using a position measuring device when installing the anomaly detector 10.

[0056] The scale determination unit 66 treats detection element 12B of the first sensor 12, detection element 14B of the second sensor 14, or detection element 16B of the third sensor 16 as an array sensor arranged in a two-dimensional shape, and determines the scale, which is the spatial size of the flame, based on the first change amount, the second change amount, or the third change amount and a predetermined first change amount, second change amount, or the third change amount corresponding to a reference scale, which is the spatial size of the flame.

[0057] Specifically, the scale determining unit 66 first obtains a predetermined distance from the detection element that has been determined to have detected a flame as the distance to the flame position.

[0058] The predetermined distance for the detection elements may be set by measuring the distance to the detection position in real space for each detection element using a laser range finder or the like when installing the anomaly detector 10.

[0059] Then, the scale determining unit 66 obtains a correction coefficient corresponding to the obtained distance based on the obtained distance.

[0060] Specifically, the correction coefficient d is calculated by the following formula.

[0061] d=(D / D0) 2

[0062] Here, D is the acquired distance between the anomaly detector 10 and the flame position, and D0 is the distance used in the definition of the reference scale, and is, for example, 60 m.

[0063] Then, the scale determination unit 66 corrects the value of the first change amount, the second change amount, or the third change amount for which it is determined that a flame has been detected, using the acquired correction coefficient d. Specifically, the scale determination unit 66 multiplies the value of the first change amount, the second change amount, or the third change amount for the detection element determined to have detected a flame by the correction coefficient d.

[0064] Then, the scale determination unit 66 determines the scale W, which is the spatial size of the flame, based on the result of multiplying the value v of the first change amount, the second change amount, or the third change amount of the detection element that is determined to have detected a flame by a correction coefficient d, and the value v0 of the first change amount, the second change amount, or the third change amount when the flame is at a predetermined reference scale.

[0065] Specifically, the scale W is calculated according to the following formula:

[0066] W=v d / v0

[0067] Here, v0 is the first change amount, the second change amount, or the third change amount obtained in the detection element when the distance between the flame of the reference scale is a predetermined distance (the distance used in the definition of the reference scale).

[0068] When a hydrogen flame or a flame originating from a substance that accompanies carbon dioxide resonance radiation during combustion is detected, the output information control unit 56 controls the external output unit 30 to report the flame position together with the type of flame.

[0069] <Function of anomaly detector> Next, the operation of the anomaly detector 10 according to the embodiment of the present invention will be described.

[0070] First, a correction coefficient is set in advance for the anomaly detector 10 before installation. Specifically, when the first sensor 12, the second sensor 14, and the third sensor 16 are irradiated with reference infrared light from a reference light source such as a blackbody furnace, the correction coefficient setting unit 42 of the anomaly detector 10 sets correction coefficients for the detection element 12B of the first sensor 12, the detection element 14B of the second sensor 14, and the detection element 16B of the third sensor 16.

[0071] The abnormality detector 10 in which the correction coefficient has been set is installed at a location where a flame judgment is to be performed. Then, when electrical signals are output from the detection element 12B of the first sensor 12, the detection element 14B of the second sensor 14, and the detection element 16B of the third sensor 16 of the abnormality detector 10 and the values ​​of the signals are input to the arithmetic processing unit 28 via the amplifiers 18, 20, 22, the switch 24, and the AD conversion unit 26, the arithmetic processing unit 28 of the abnormality detector 10 repeatedly executes the flame judgment processing routine shown in Fig. 8 at regular intervals.

[0072] In step S100, the signal acquisition unit 40 acquires the value of the electrical signal from the detection element 12B of the first sensor 12, the value of the electrical signal from the detection element 14B of the second sensor 14, and the value of the electrical signal from the detection element 16B of the third sensor 16 from the signal output from the AD conversion unit 26.

[0073] In the next step S102, the correction unit 44 corrects the value of the electrical signal from detection element 12B of the first sensor 12, the value of the electrical signal from detection element 14B of the second sensor 14, and the value of the electrical signal from detection element 16B of the third sensor 16, which were acquired in step S100, using a preset correction coefficient.

[0074] Then, in step S104, the average calculation unit 50 calculates moving average values ​​for each of the electrical signal values ​​from detection element 12B of the first sensor 12, the electrical signal values ​​from detection element 14B of the second sensor 14, and the electrical signal values ​​from detection element 16B of the third sensor 16, based on the sensor values ​​corrected in step S102 above and sensor values ​​previously corrected in step S102 above.

[0075] In step S106, the change amount calculation unit 52 calculates a first change amount, a second change amount, and a third change amount for each of the value of the electrical signal from the detection element 12B of the first sensor 12, the value of the electrical signal from the detection element 14B of the second sensor 14, and the value of the electrical signal from the detection element 16B of the third sensor 16, based on the sensor values ​​corrected in step S102 and the moving average values ​​calculated in step S104.

[0076] Then, in step S108, the judgment unit 54 judges and detects whether the flame is derived from a substance that involves carbon dioxide resonance radiation during combustion, based on the first change amount, the second change amount, and the third change amount calculated in step S106 above.

[0077] Then, in step S110, the determination unit 54 determines and detects whether or not it is a hydrogen flame, based on the first change amount, the second change amount, and the third change amount calculated in step S106 above.

[0078] In step S112, it is determined whether or not the flame is determined to be a hydrogen flame or a flame originating from a substance that generates carbon dioxide resonance radiation during combustion in step S108 or S110. If it is determined that the flame is not originating from a substance that generates carbon dioxide resonance radiation during combustion and is determined to be a hydrogen flame, the flame determination process routine is terminated. On the other hand, if it is determined that the flame is originating from a substance that generates carbon dioxide resonance radiation during combustion or is determined to be a hydrogen flame, the process proceeds to step S114.

[0079] In step S114, the flame position determination unit 64 determines the position of a hydrogen flame or the position of a flame resulting from a substance that involves carbon dioxide resonance radiation during combustion.

[0080] In step S116, the scale determination unit 66 determines the scale, which is the spatial size of the flame, based on the first change amount, the second change amount, or the third change amount and a previously obtained first change amount, the second change amount, or the third change amount corresponding to a reference scale, which is the spatial size of the flame.

[0081] In step S118, when a hydrogen flame or a flame originating from a substance that generates carbon dioxide resonance radiation during combustion is detected, the output information control unit 56 controls the external output unit 30 to report the flame position together with the type of flame, and ends the flame determination processing routine. At this time, the external output unit 30 may output the flame type to a fire extinguishing control device that is capable of different fire extinguishing tactics. In this case, when the type of flame is a hydrogen flame, the fire extinguishing control device performs water curtain and main valve closing control, for example, and when the type of flame is a flame originating from a substance that generates carbon dioxide resonance radiation, for example, activates a fire extinguisher.

[0082] As described above, the anomaly detector according to the embodiment of the present invention judges whether or not a hydrogen flame has been detected based on the value of an electrical signal detected by a detection element that detects infrared light that has passed through a first band filter that transmits infrared light in a first band that is at least a part of the range from 3.9 μm to 6.0 μm and converts it into an electrical signal, and the value of an electrical signal detected by a detection element that detects infrared light that has passed through a second band filter that transmits infrared light in a second band that is at least a part of the range from 3.9 μm to 6.0 μm and different from the first band and converts it into an electrical signal. This makes it possible to detect a hydrogen flame with high accuracy.

[0083] In addition, by using the same detection element to monitor / detect flames accompanied by carbon dioxide resonance radiation and hydrogen flames, the number of elements and related parts can be reduced, making it possible to realize an inexpensive flame detector.

[0084] The hydrogen flame detection function can be added to conventional flame detectors by simply updating the firmware without changing the explosion-proof structure, providing a safer flame monitoring environment at low cost. In particular, since the hydrogen flame monitoring function can be added without changing the explosion-proof structure, it is effective for anomaly detectors with the same structure.

[0085] Compared to methods that use ultraviolet light to detect hydrogen flames, this method is capable of detecting smaller flames at greater distances, providing a safer monitoring environment.

[0086] Compared to methods that use ultraviolet light to detect hydrogen flames, this method has the same sensitivity and can provide a monitoring environment at a lower cost.

[0087] <Modification> The present invention is not limited to the above-described embodiment, and various modifications and applications are possible without departing from the spirit and scope of the present invention.

[0088] For example, in the above embodiment, the detection element 12B of the first sensor 12, the detection element 14B of the second sensor 14, and the detection element 16B of the third sensor 16 may be configured as an array sensor arranged two-dimensionally, and for each detection element of the array sensor of the first sensor 12, it may be determined and detected whether it is a flame derived from a substance that generates carbon dioxide resonance radiation during combustion or a hydrogen flame based on the value of the electric signal detected by the detection element of the first sensor 12, the value of the electric signal detected by the corresponding detection element of the second sensor 14, and the value of the electric signal detected by the corresponding detection element of the third sensor 16. In this way, by configuring the detection elements as an array sensor, it may be configured to be able to detect the position where a hydrogen flame and / or a flame that generates carbon dioxide resonance radiation is determined.

[0089] In addition, in the above embodiment, the configuration may further include an array sensor in which a bandpass filter that transmits infrared light in a predetermined band and detection elements that detect the infrared light that has transmitted through the bandpass filter and convert it into an electrical signal are arranged in a two-dimensional manner, and when the determination unit 54 determines that a flame has been detected, the position of a flame originating from a substance that generates carbon dioxide resonance radiation during combustion and / or a hydrogen flame may be determined based on the value of the electrical signal detected by each detection element of the array sensor. Also, abnormal temperature may be detected instead of flames from a substance that generates carbon dioxide resonance radiation during combustion. In this case, three array sensors detect infrared light in a band around 4.5 μm in the carbon dioxide resonance radiation band, infrared light in a band around 4.0 μm in a band with a shorter wavelength than the carbon dioxide resonance radiation band, and infrared light in a band around 5.0 μm in a band with a longer wavelength than the carbon dioxide resonance radiation band, and convert them into electric signals of DC components. The abnormality detector determines whether or not abnormal temperature is detected based on any one or more of the first change amount, the second change amount, and the third change amount. For example, based on the relationship between the ratio of the first change amount and the second change amount and the temperature, the temperature is estimated from the ratio of the first change amount and the second change amount, and whether or not abnormal temperature is detected is determined. Note that the temperature may be estimated based on the ratio of the third change amount and the first change amount to determine whether abnormal temperature is detected, or the temperature may be estimated based on the ratio of the third change amount and the second change amount to determine whether abnormal temperature is detected. Also, based on the first change amount, the second change amount, and the third change amount, it may be determined whether or not a flame originating from a substance that accompanies carbon dioxide resonance radiation during combustion has been detected, and based on any one or more of the first change amount, the second change amount, and the third change amount, it may be determined whether or not an abnormal temperature has been detected by estimating the temperature. Furthermore, when a temperature abnormality occurs, the fire extinguishing control device may, for example, activate a water spray device or a cooling water sprinkler device.

[0090] Also, a hydrogen flame may be detected from signal values ​​obtained from two types of infrared wavelength bands in the range from 3.9 μm to 6.0 μm, based on the radiation spectrum of the hydrogen flame.

[0091] Furthermore, by combining a plurality of anomaly detectors, the distance from the anomaly detector to the flame and the scale of the flame may be calculated based on the principle of triangulation. [Explanation of symbols]

[0092] 10 Anomaly detector 11 Optical Lenses 12 First Sensor 12A, 14A, 16A Filters 12B, 14B, 16B Detector element 14 Second Sensor 16 3rd Sensor 28 Processing Unit 30 External output section 40 Signal Acquisition Unit 42 Correction coefficient setting section 44 Correction section 50 Average calculation section 52 Change amount calculation unit 54 Judgment section 56 Output information control section 60 Flame judgment section 62 Flame judgment section 64 Flame position determination section 66 Size Judgment Department

Claims

1. a first band filter that transmits infrared light in a first band that is at least a portion of the range from 3.9 μm to 6.0 μm; a second band filter that transmits infrared light in a second band that is at least a portion of the range from 3.9 μm to 6.0 μm and is different from the first band; a detection unit including a first detection element that detects the infrared light transmitted through the first band filter and converts the infrared light into an electrical signal, and a second detection element that detects the infrared light transmitted through the second band filter and converts the infrared light into an electrical signal; a determination unit that determines whether or not a hydrogen flame has been detected based on a value of the electric signal detected by the first detection element and a value of the electric signal detected by the second detection element; An anomaly detector including:

2. an average calculation unit that calculates a first average value of the electrical signals detected by the first detection elements and a second average value of the electrical signals detected by the second detection elements; a change amount calculation unit that calculates a first change amount from the first average value of the electrical signal detected by the first detection element and a second change amount from the second average value of the electrical signal detected by the second detection element, The determination unit compares the first change amount and the second change amount calculated by the change amount calculation unit with a determination threshold value to determine whether or not a hydrogen flame has been detected. The anomaly detector according to claim 1.

3. 3. The anomaly detector according to claim 2, wherein the determination unit determines whether or not a hydrogen flame has been detected based on a difference between the first change amount and the second change amount and / or a ratio between the first change amount and the second change amount.

4. 4. The anomaly detector according to claim 3, wherein the determination unit determines that a hydrogen flame exists when a ratio of the first change amount to the second change amount is equal to or greater than 3.0 and equal to or less than 5.

0.

5. 2. The anomaly detector of claim 1, wherein the first band is centered at 4.0 μm and the second band is centered at 5.0 μm.

6. The detection unit further includes a third detection element that detects infrared light in a third band including a peak wavelength of the carbon dioxide resonance radiation band and converts the infrared light into an electrical signal, 2. The anomaly detector according to claim 1, wherein the determination unit determines and detects whether the flame is derived from a substance that generates carbon dioxide resonance radiation during combustion, and / or whether it is a hydrogen flame, and / or whether there is an abnormal temperature, based on the value of the electrical signal detected by the first detection element, the value of the electrical signal detected by the second detection element, and the value of the electrical signal detected by the third detection element.

7. an average calculation unit that calculates a first average value of the electrical signals detected by the first detection elements, a second average value of the electrical signals detected by the second detection elements, and a third average value of the electrical signals detected by the third detection elements; a change amount calculation unit that calculates a first change amount of the electrical signal detected by the first detection element from the first average value, a second change amount of the electrical signal detected by the second detection element from the second average value, and a third change amount of the electrical signal detected by the third detection element from the third average value, The determination unit is 7. The anomaly detector as claimed in claim 6, which determines and detects whether the flame is derived from a substance that generates carbon dioxide resonance radiation during combustion, and / or whether it is a hydrogen flame, and / or whether it is an abnormal temperature, using any one or more of a first ratio which is a ratio between the first change amount and the second change amount, a second ratio which is a ratio between the first change amount and the third change amount, and a third ratio which is a ratio between the second change amount and the third change amount.

8. The determination unit is the first ratio being equal to or greater than 3.0 and equal to or less than 5.0; The second ratio is equal to or greater than 1.5 and equal to or less than 2.5; and 8. The anomaly detector according to claim 7, which judges that a hydrogen flame exists when any one or more of the conditions that the third ratio is 1.5 or more are satisfied.

9. a fourth band filter that transmits a predetermined band of infrared light; the detection unit includes an array sensor in which fourth detection elements are two-dimensionally arranged to detect the infrared light transmitted through the fourth band filter and convert the infrared light into an electrical signal; When it is determined that the flame or abnormal temperature has been detected, the location of the flame originating from a substance that accompanies carbon dioxide resonance radiation during combustion, or / and the hydrogen flame, or / and the abnormal temperature are determined based on the value of the electrical signal detected by each fourth detection element of the array sensor. The anomaly detector according to claim 1.

10. any one or more of the first detection elements, the second detection elements, and the third detection elements are array sensors arranged two-dimensionally; The determination unit determines the location of a flame originating from a substance that accompanies carbon dioxide resonance radiation during combustion, or / and a hydrogen flame, or / and an abnormal temperature. The anomaly detector according to claim 6.

11. the first detection element, the second detection element, or the third detection element is an array sensor arranged two-dimensionally; 8. The anomaly detector according to claim 7, further comprising a scale determination unit that determines the scale, which is the spatial size of the flame or abnormal temperature, based on the first change amount, the second change amount, or the third change amount and the first change amount, the second change amount, or the third change amount that is found in advance and corresponds to a reference scale, which is the spatial size of the flame or abnormal temperature.

12. The anomaly detector according to any one of claims 1 to 11, further comprising an output unit that outputs a determination result by the determination unit to a fire extinguishing control device capable of implementing different fire extinguishing tactics.

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