Inflammation detection device

Abstract

To enable accurate fire determination by performing dirt correction for each light receiving element even when dirt of a translucent window is uneven.SOLUTION: A flame detector comprises flame detection units 12a and 12b that receive infrared energy emitted from a combustion flame by flame detection sensors 16a and 16b through a translucent window 18 and output a flame light reception signal, and a non-flame detection unit 12c that receives the infrared energy emitted from a flame other than the combustion flame by a non-flame detection sensor 16c through the translucent window and output non-flame light reception signal. A test control unit 38 emits test light from a test light source through the translucent window to obtain a light reduction rate due to dirt of the translucent window for each detection unit. A fire determination unit 36 corrects the flame light reception signal and the non-flame light reception signal based on this, detects the presence or absence of the combustion flame based on each corrected light reception signal to determine fire, and outputs a fouling warning or a fouling announcement warning to a reception device in accordance with the light reduction rate of the flame light reception signal or a difference between the flame light reception signals.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a flame detection device that detects infrared radiation generated by CO2 resonance during flaming combustion and determines the presence or absence of a flame.

Background Art

[0002] Conventionally, in a flame detection device that detects infrared energy generated by flaming combustion and detects the presence or absence of a flame, there are well-known flame detection devices and flame detection methods that detect the infrared intensity in the resonance radiation wavelength band of CO2 generated during flaming combustion to detect the presence or absence of a flame.

[0003] Here, the two-wavelength type flame detection device in the prior art will be briefly described. FIG. 16 is a conceptual diagram showing the infrared spectrum in the infrared wavelength region of a combustion flame and other typical radiators, where the horizontal axis represents the wavelength of infrared rays and the vertical axis represents the relative intensity of infrared rays.

[0004] As shown in FIG. 16, in the spectral characteristics 100 of a combustion flame, there is a peak in the relative intensity of infrared rays associated with the resonance radiation of CO2 in the wavelength band near 4.5 μm. Also, as a characteristic wavelength existing near this peak wavelength, for example, there is a wavelength band with a low relative intensity of infrared rays near 5.0 μm on the long wavelength side. Hereinafter, unless otherwise specified, the CO2 resonance radiation band refers to the 4.5 μm band.

[0005] In a two-wavelength type flame detection device, for example, the infrared energy in the wavelength band near 4.5 μm and the wavelength band near 5.0 μm is selectively transmitted by a narrow-band optical wavelength band-pass filter, and the infrared energy is detected by a detection sensor for each, and after photoelectric conversion, predetermined processing such as amplification is performed to obtain an electric signal corresponding to the energy amount (hereinafter referred to as a "light reception signal"). The relative ratio of the light reception signal levels in the above respective wavelength bands is taken and compared with a predetermined threshold value to determine the presence or absence of a flame.

[0006] This enables discrimination between infrared radiators other than flames, such as high-temperature radiators like sunlight shown in spectral characteristic 102, relatively low-temperature radiators shown in spectral characteristic 10.5, and low-temperature radiators such as the human body shown in spectral characteristic 106, and flames.

[0007] In addition, the flame detection device detects infrared energy generated by a flaming combustion through a light-transmissive window and monitors the presence or absence of a flame. As a self-test for monitoring the contamination of the light-transmissive window to maintain the flame monitoring function, a contamination test is being conducted.

[0008] When the contamination test receives a test signal regularly transmitted from the fire alarm control panel, test light that becomes simulated flame light is made to enter the light-transmissive window from a test light source provided outside the flame detector, received by the detection unit, and the received light signal at this time is compared and calculated with the initial state without contamination to obtain a light reduction rate. When the light reduction rate exceeds a predetermined contamination threshold value, a contamination alarm signal is transmitted to the fire alarm control panel to output a contamination alarm.

[0009] Also, contamination correction is performed to obtain a received light signal corresponding to the case without contamination by multiplying the reciprocal of (1 - light reduction rate) by the received light signal, and the presence or absence of a flame is determined based on the contamination-corrected received light signal.

[0010] Furthermore, when the contamination of the light-transmissive window progresses and the light reduction rate becomes, for example, 0.7 or more, a fouling failure is detected, a fouling alarm is output from the receiving device to prompt the establishment of a cleaning plan, and since the correction of the received light signal has reached the limit, the determination of the presence or absence of a flame based on the received light signal is not performed.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0012] However, in such a soiling test for measuring the light attenuation rate of a conventional light-transmitting window and correcting the received light signal for soiling, for example, based on the flame received light signal from a light receiving element that receives infrared energy in the flame wavelength band near 4.5 μm, the light attenuation rate by the light-transmitting window is obtained as a representative value, and the soiling correction of the flame received light signal is performed. At the same time, the soiling correction of the non-flame received light signal from a non-flame light receiving element that receives infrared energy in the non-flame wavelength band near 5.0 μm is also performed. However, there is unevenness in the soiling of the light-transmitting window, and the light attenuation rate may vary for each light receiving element. Nevertheless, when performing soiling correction of the received light signal from other light receiving elements using the light attenuation rate of a specific light receiving element as a representative value, accurate soiling correction cannot be achieved, and there is a possibility that accurate fire detection cannot be performed based on the soiling-corrected received light signal.

[0013] An object of the present invention is to provide a flame detection device that can perform accurate fire detection by performing soiling correction based on the light attenuation rate for each light receiving element even when there is unevenness in the soiling of the light-transmitting window.

Means for Solving the Problems

[0014] (Flame Detection Device) The present invention is a flame detection device that observes infrared energy radiated from a monitoring area, detects the presence or absence of a combustion flame, and determines a fire, a plurality of detection units that receive infrared energy radiated from the monitoring area through a light-transmitting window and output a received light signal, a test control unit that irradiates test light from a test light source to the plurality of detection units through the light-transmitting window, and for each of all the detection units, compares the received light signal by the test light with the initial state to obtain the light attenuation rate with respect to the initial state of the infrared energy transmitted through the portion corresponding to each detection unit of the light-transmitting window, Based on the light reduction rate obtained for each detection unit, the light reception signals for each of all the detection units are corrected, and a fire determination unit determines whether there is a fire by detecting the presence or absence of a combustion flame based on each of the corrected light reception signals. It is provided with The plurality of detection units include a plurality of flame detection units that detect infrared rays radiated from a flame and one or more non-flame detection units that detect infrared rays radiated from sources other than the flame. The fire determination unit is characterized in that it causes the receiving device to output a contamination warning or a contamination pre-warning according to the light reduction rate of the light reception signals from the plurality of flame detection units or the difference between the light reception signals.

[0015] Further, when the light reception signal of any one of the plurality of detection units reaches a predetermined correction limit, the fire determination unit excludes the light reception signal that has reached the correction limit from the fire determination elements, and performs a fire determination using, as the fire determination elements, at least the light reception signals from the flame detection units that have not reached the correction limit.

[0016] (Contamination warning or contamination pre-warning) When the light reception signals from at least one or more flame detection units reach the correction limit, the fire determination unit causes the receiving device to output a predetermined failure warning. [Advantages of the Invention]

[0017] (Basic advantages) The present invention is a flame detection device that observes the infrared energy radiated from a combustion flame to determine and detect the presence or absence of a combustion flame. The device includes a plurality of detection units that receive the infrared energy radiated from a combustion flame through a light-transmitting window and output a light reception signal, a test control unit that irradiates a test light through the light-transmitting window from a test light source to obtain the light reduction rate with respect to the initial state for each detection unit, and a fire determination unit that corrects the light reception signal for each detection unit based on the light reduction rate obtained for each detection unit, and determines whether there is a fire by detecting the presence or absence of a combustion flame based on each of the corrected light reception signals. Therefore, by obtaining the light reduction rate for each detection unit and performing dirt correction on the light reception signal, even if there is unevenness in the dirt on the light-transmitting window, the dirt correction of each light reception signal can be correctly performed, and an accurate fire determination can be made based on the corrected light reception signal.

[0018] (Effect of Fire Judgment According to Correction Status) The fire judgment unit makes different fire judgments according to the correction status of the received light signal. For example, when the received light signal of any one of the detection units reaches a predetermined correction limit, the fire judgment unit makes a fire judgment based on the other received light signals that have not reached the correction limit. Therefore, in the case of a two-wavelength method, for example, when the received light signal of the non-flame detection unit reaches the correction limit due to partial contamination of the light-transmitting window, the fire judgment is switched to a one-wavelength fire judgment based only on the received light signal of the flame detection unit that has not reached the correction limit. Even if a contamination failure or a contamination warning failure is detected based on the correction limit, flame detection can be continued by a limited fire judgment, and the reliability of the flame detection device can be improved.

[0019] (Effect of Contamination Alarm or Contamination Warning Alarm) In addition, since the fire judgment unit detects a predetermined failure according to the correction status of the received light signal and outputs an alarm to the receiving device, when any one of the received light signals from each detection unit reaches a predetermined correction limit, a contamination alarm or a contamination warning alarm is output from the receiving device, for example. The fact that the partial contamination of the light-transmitting window has advanced and locally reached the correction limit is notified by the contamination alarm or the contamination warning alarm from the receiving device, which enables the administrator or the like to be prompted to formulate a cleaning plan for the flame detection device.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

[0021] [Flame Detection Device] (Device Overview) FIG. 1 is a block diagram showing an embodiment of the flame detection unit incorporated in the flame detection device, taking a two-wavelength type flame detection device as an example. The flame detection device of this embodiment shall be a fire detection device that detects the presence or absence of a flame in the monitoring area.

[0022] As shown in FIG. 1, the detection unit of the flame detection device 10 of the present embodiment incorporates two sets, namely a flame detection unit 11-1 and another flame detection unit 11-2 (not shown) with the same configuration.

[0023] The flame detection unit 11-1 is composed of flame detection units 12a, 12b, a non-flame detection unit 12c, a fire determination unit 36 provided in an MPU (Microprocessor Unit) 15, and a test control unit 38.

[0024] The flame detection units 12a, 12b observe the infrared energy radiated from the combustion flame existing in the monitoring area, receive infrared rays in a predetermined wavelength band centered on 4.5 μm radiated along with the CO2 resonance from the combustion flame, perform photoelectric conversion, and output flame received signals E1, E2.

[0025] The flame detection units 12a, 12b are provided with flame detection sensors 16a, 16b, pre-filters 24a, 24b, pre-amplifiers 26a, 26b, and main amplifiers 28a, 28b. The flame received signals E1, E2 output from the main amplifiers 28a, 28b are further amplified by final-stage amplifiers 30a, 30b to become flame received signals E1', E2', and are converted into digital received signals at the A / D conversion ports 35a, 35b of the MPU (Microprocessor Unit) 15 and taken in. For the convenience of explanation, the same reference signs are used for each received signal before and after A / D conversion. The same applies to the received signals E4', E5' described later.

[0026] In addition, the flame received signals E1', E2' output from the flame detection units 12a, 12b and read from the A / D conversion ports 35a, 35b are added by the fire determination unit 36 of the MPU 15 and used as an added received signal (added flame received signal) E3 for fire determination.

[0027] The non-flame detection unit 12c observes the infrared energy radiated from heat sources other than the combustion flame existing in the monitoring area, receives infrared energy in a wavelength band of approximately 5.0 μm to 7.0 μm, converts it into an electrical signal, and outputs a non-flame received signal E4.

[0028] The non-flame detection unit 12c is provided with a non-flame detection sensor 16c, a pre-filter 24c, a pre-amplifier 26c, and a main amplifier 28c. The non-flame light reception signal E4 output from the main amplifier 28c is further amplified by the final-stage amplifier 30c to become the non-flame light reception signal E4', and is converted into a digital light reception signal at the A / D conversion port 35c of the MPU 15 and captured. On the front side (monitoring area side) of the flame detection units 12a and 12b and the non-flame detection unit 12c, a light-transmitting window 18 made of, for example, sapphire glass is arranged, which transmits infrared rays in a predetermined wavelength band.

[0029] When the signal level of the added light reception signal E3 obtained by adding the flame light reception signals E1' and E2', for example, the integrated value ΣE3 of the added light reception signal E3 over a predetermined period is equal to or greater than a predetermined threshold value or exceeds the predetermined threshold value, the ratio ΣE3 / Σ4' of the integrated values of the added light reception signal E3 and the non-flame light reception signal E4' over the same period is calculated, and when this ratio is equal to or greater than another threshold value or exceeds it, it is determined that there is a flame (satisfying the first requirement described later).

[0030] In the following description, when it is not necessary to distinguish between the flame light reception signal and the non-flame light reception signal, or when they are collectively referred to, they may simply be called the light reception signal.

[0031] (Outline of the dirt test) A test light source 60-1 that functions as a test light source is provided for the light-transmitting window 18 of the flame detection unit 11-1. The test light source 60-1 is arranged at the central convex portion 54 on the front surface of the housing (case body) 50 of the flame detection device 10, which will be clarified in the following description. During the dirt test, which is one item of the self-test, test light that becomes flame-simulating light by driving the test light source 60-1 is output from the light-transmitting test window 56-1, and this test light is received by the flame detection sensors 16a and 16b and the non-flame detection sensor 16c arranged inside the light-transmitting window 18.

[0032] A test light source 60-2 and a test window 56-2 used for the dirt test of the light-transmitting window 18 of another flame detection unit 11-2 are similarly arranged at the central convex portion 54.

[0033] For the test light sources 60-1 and 60-2, for example, a krypton lamp is used. In addition, the test light source 60-1 is provided with a reflection hood 70 that functions as a reflector for reflecting the test light toward the test window 56-1 side, that is, toward each detection sensor. On the other hand, the reflection hood 70 outputs the test light of the test light source 60-1 only from the test window 56-1 and is not transmitted to the test window 56-2 side. Similarly, the test light source 60-2 is also provided with a reflection hood 70 to output the test light only from the test window 56-2. The two reflection hoods 70 corresponding to the test light sources 60-1 and 60-2 may be integrated.

[0034] The dirt test of the light-transmitting window 18 is individually performed based on each of the flame reception signals E1’ and E2’ from the flame detection units 12a and 12b and the non-flame reception signal E4’ from the non-flame detection unit 12c. When the test control unit 38 provided in the MPU 15 receives a test signal periodically transmitted from a fire receiving panel, which is a receiving device not shown, it sequentially drives the test light sources 60-1 and 60-2 to output test light (for the flame detection unit 11-1 side in FIG. 1, the test will be carried out by driving the test light source 60-1), reads the flame reception signals E1’ and E2’ and the non-flame reception signal E4’ output from the final-stage amplifiers 30a, 30b, and 30c, calculates the light reduction rates D1, D2, and D4 by comparison operation with the initial state (state without dirt), and outputs them to the fire determination unit 36.

[0035] The fire determination unit 36 corrects (dirt correction) by multiplying 1 / (1-D1), 1 / (1-D2), and 1 / (1-D4) by the flame reception signals E1’, E2’, and the non-flame reception signal E4’, respectively. At the same time, the added reception signal E3 is corrected by adding the corrected flame reception signals E1’ and E2’, and this, together with the corrected E4’, is used for fire determination. For the sake of convenience of explanation, the same symbols are used here for the signals before and after correction.

[0036] In addition, when the light extinction rates D1, D2, and D4 calculated by the test control unit 38 reach a predetermined threshold value, for example, the threshold value Dth = 0.7 or more, or exceed the threshold value Dth = 0.7, the fire determination unit 36 determines that the received light signal has reached the correction limit, detects a fouling failure or a fouling warning failure, outputs a fouling alarm or a fouling warning alarm from the fire receiving panel, and prompts the administrator to formulate measures such as a cleaning plan for the flame detection device 10 through these alarms.

[0037] In addition, when the fire determination unit 36 determines that the non-flame received light signals E4’ have reached the correction limit although the flame received light signals E1’ and E2’ have not reached the correction limit, a limited fire determination is performed within the possible range.

[0038] (Device Appearance and Sensor Unit) FIG. 2 is an explanatory diagram showing the appearance of the flame detection device, FIG. 3 is an explanatory diagram showing the flame detection device of FIG. 2 from the front, and FIG. 4 is an explanatory diagram showing the test light source and the test window of the central convex portion and the flame detection portion inside the light-transmitting window in a partial cross-section when the flame detection device of FIG. 2 is viewed from below.

[0039] As shown in FIGS. 2 to 4, in the sensor housing portion 52 of the front cover disposed on the front surface of the housing 50 of the flame detection device 10, corresponding to two sets of flame detection units including the flame detection portion 11-1 of FIG. 1, an infrared light-transmitting window 18 is provided.

[0040] In the following description, the test windows 56-1 and 56-2 may also be referred to as the test window 56.

[0041] In each of the light-transmitting windows 18, the flame detection sensors 16a and 16b of the flame detection units 12a and 12b and the non-flame detection sensor 16c of the non-flame detection unit 12c in the flame detection portion 11-1 shown in FIG. 1 and the other flame detection portion 11-2 are arranged.

[0042] In addition, between the light-transmitting windows 18 provided in the sensor housing portion 52, a central convex portion 54 is formed to protrude. The central convex portion 54 incorporates test light sources 60-1 and 60-2, and test windows 56-1 and 56-2 are arranged on the left and right side walls.

[0043] The test light source 60-1 outputs test light toward the light-transmitting window 18 from the test window 56-1. Also, the test light source 60-2 outputs test light toward the light-transmitting window 18 from the test window 56-2.

[0044] As shown in FIG. 5, a sensor unit is incorporated inside the pair of light-transmitting windows 18 shown in FIGS. 2 and 3. The sensor unit is composed of a unit body 62 and a unit cover 64, and a circuit board 48 is fixed and housed inside with screws 68.

[0045] Flame detection sensors 16a and 16b are arranged adjacent to each other on the circuit board 48. Light-receiving openings 66a and 66b are formed at positions of the unit cover 64 facing the flame detection sensors 16a and 16b, so that the light passing through the light-transmitting window 18 from the monitoring area side can be received by the flame detection sensors 16a and 16b.

[0046] Also, a non-flame detection sensor 16c is arranged on the circuit board 48, and a light-receiving opening 66c is formed at a position of the unit cover 64 facing the non-flame detection sensor 16c, so that the light passing through the light-transmitting window 18 from the monitoring area side can be received by the non-flame detection sensor 16c.

[0047] (Configuration of the flame detection units 12a and 12b) In the flame detection units 12a and 12b shown in FIG. 1, the flame detection sensors 16a and 16b convert infrared energy having an infrared wavelength band centered at approximately 4.5 μm, which is radiated due to CO2 resonance from a combustion flame, into an electric signal and output it as a light-receiving signal. The pre-filters 24a and 24b selectively pass only the signal components in a predetermined frequency band corresponding to the frequency of the flame flicker from the light-receiving signals output from the flame detection sensors 16a and 16b. The pre-amplifiers 26a and 26b amplify the signal components passing through the pre-filters 24a and 24b at the first stage, and the main amplifiers 28a and 28b further amplify them to output flame light-receiving signals E1 and E2. Then, the final-stage amplifiers 30a and 30b amplify this to a signal level suitable for the flame determination process and output flame light-receiving signals E1' and E2'.

[0048] Here, the flame detection sensors 16a and 16b include optical wavelength filters 20a and 20b, and light receiving element sections 22a and 22b.

[0049] The flame light receiving signals E1' and E2' output from the flame detection units 12a and 12b via the final - stage amplifiers 30a and 30b are converted into digital light receiving signals E1' and E2' by the A / D conversion ports 35a and 35b provided in the MPU15 and then read.

[0050] Also, the flame light receiving signals E1' and E2' output from the flame detection units 12a and 12b and read from the A / D conversion ports 35a and 35b are added by the fire determination section 36 of the MPU15, and a determination of the presence or absence of a flame is executed based on this added light receiving signal E3. Hereinafter, each configuration will be specifically described.

[0051] In this embodiment, the flame light receiving signals E1' and E2' are not used for determining the presence or absence of a flame, but they may be used for determination as appropriate.

[0052] (Flame detection sensors 16a, 16b) FIG. 6 is an explanatory diagram showing a schematic configuration of the flame detection sensor, and FIG. 7 is a circuit diagram showing an equivalent circuit of the flame detection sensor of FIG. 6.

[0053] As shown in FIG. 6, the flame detection sensor 16a includes a pyroelectric body 45 supported and arranged on the surface of a substrate 40, a light receiving electrode 25 provided thereon, a light receiving element section 22a including an FET 27 and a high - resistance (not shown) arranged on the back side of the substrate 40, a terminal 42 provided through the base 37 while supporting the substrate 40 on the base 37, and a cover member 44 provided with an optical wavelength filter 20a in front of (above in the figure) the light receiving element section 22a, and has a package configuration.

[0054] Also, as shown in FIG. 7, the equivalent circuit of the light receiving element section 22a connects the gate of the FET 27 to the gate terminal G via, for example, a parallel circuit of the pyroelectric body 45 and a high - resistance 29, and connects the drain and source of the FET 27 to the drain terminal D and the source terminal S, respectively.

[0055] Here, the optical wavelength filter 20a selectively transmits a predetermined wavelength band centered at 4.5 μm, and can be formed on a substrate such as silicon or sapphire by a known method, respectively. Further, the flame detection sensor 16b of the flame detection unit 12b also has the same structure as the flame detection sensor 16a.

[0056] Furthermore, the non-flame detection sensor 16c of the non-flame detection unit 12c also has the same structure as the flame detection sensor 16a, but is different in that a cut-on filter (long-wave pass filter) that preferably transmits infrared rays in a predetermined wavelength band exceeding approximately 5.0 μm is used as the optical wavelength filter 20c.

[0057] (Translucent window 18) As shown in FIGS. 2 and 3, the translucent window 18 is on the upper surface side corresponding to the monitoring area side of the sensor unit in FIG. 6 in which the flame detection sensors 16a and 16b and the non-flame detection sensor 16c are housed, and is provided on the front side of the flame detection sensors 16a and 16b and the non-flame detection sensor 16c. It is disposed in a predetermined opening of the sensor housing portion 52 and is formed of an infrared-translucent member such as sapphire glass as described above.

[0058] Therefore, the light-receiving limited field of view of the flame detection sensors 16a and 16b and the non-flame detection sensor 16c is restricted by the edge portion of the translucent window 18, thereby setting a detection area within a visual field range having a predetermined spread angle.

[0059] Here, the sapphire glass constituting the translucent window 18 functions as a filter member having a short-wave pass characteristic of preferably transmitting infrared rays in a wavelength band of approximately 7.0 μm or less, in other words, a long-wave cut characteristic of blocking infrared rays having a wavelength longer than approximately 7.0 μm. Further, in the present embodiment, the translucent window 18 is shared by the flame detection sensors 16a and 16b and the non-flame detection sensor 16c.

[0060] (Pre-filter 24a, 24b, 24c) The pre-filters 24a and 24b of the flame detection units 12a and 12b in FIG. 1 function as frequency selection units, and are, for example, active filters that allow only signal components in a specific frequency band used for flame determination processing to pass through from the received light signals output from the light receiving element units 22a and 22b of the flame detection sensors 16a and 16b, and output received light signals composed of signal components in a specific frequency band to the subsequent pre-amplifiers 26a and 26b.

[0061] Similarly, the pre-filter 24c is, for example, an active filter that allows only signal components in a specific frequency band used for flame determination processing to pass through from the received light signal output from the light receiving element unit 22c of the non-flame detection sensor 16c, and outputs a received light signal composed of signal components in a specific frequency band to the subsequent pre-amplifier 26c.

[0062] Such a frequency selection filter is appropriately arranged not only as a pre-filter but also from the pre-amplifier to the final-stage amplifier, and is configured to amplify the signal while performing frequency selection (extraction).

[0063] (Pre-amplifiers 26a, 26b, 26c and main amplifiers 28a, 28b, 28c) The pre-amplifiers 26a and 26b perform primary amplification of the received light signal input via the pre-filters 24a and 24b at a predetermined amplification factor, and the main amplifiers 28a and 28b amplify each flame received light signal from the pre-amplifiers 26a and 26b and output them as flame received light signals E1 and E2.

[0064] The final-stage amplifiers 30a and 30b finally adjust and amplify the flame received light signals E1 and E2 to a signal level suitable for flame determination processing, and output them as flame received light signals E1' and E2' to the A / D conversion ports 35a and 35b of the MPU 15.

[0065] Similarly, the pre-amplifier 26c performs primary amplification of the non-flame received light signal output via the pre-filter 24c at a predetermined amplification factor, and the main amplifier 28c and the final-stage amplifier 30c amplify the non-flame received light signal from the pre-amplifier 26c to a signal level suitable for the flame determination processing described later, and output them as non-flame received light signals E4 and non-flame received light signal E4'.

[0066] (A / D conversion ports 35a, 35b) The A / D conversion ports 35a and 35b are A / D converters provided as input ports of the MPU 15, and convert the flame reception signals E1’ and E2’ into digital signals suitable for digital processing by the fire determination unit 36 and read them in.

[0067] (Non-flame detection unit 12c) The non-flame detection unit 12c includes a non-flame detection sensor 16c that converts infrared energy in a predetermined wavelength band different from that of the flame detection sensors 16a and 16b into an electric signal and outputs it. That is, the flame detection units 12a and 12b output the flame reception signals E1 and E2 obtained by converting infrared energy in a wavelength band centered at approximately 4.5 μm, which is radiated by combustion flames due to CO2 resonance, into an electric signal, while the non-flame detection unit 12c outputs a non-flame reception signal E4 obtained by converting infrared energy in a wavelength band of approximately 5.0 μm to 7.0 μm into an electric signal.

[0068] Further, the non-flame detection unit 12c includes, following the non-flame detection sensor 16c, a pre-filter 24c that allows only signal components in a predetermined frequency band to pass through from the received light signal output from the non-flame detection sensor 16c, a pre-amplifier 26c that pre-amplifies the signal components that have passed through the pre-filter 24c, and a main amplifier 28c that amplifies the output from the pre-amplifier 26c.

[0069] The non-flame reception signal E4 output from the main amplifier 28c of the non-flame detection unit 12c is further adjusted and amplified by the final-stage amplifier 30c to become the non-flame reception signal E4’, is converted into a digital signal by the A / D conversion port 35c of the MPU 15, read in as the non-flame reception signal E4’, and used for flame determination processing by the fire determination unit 36.

[0070] (Configuration of the non-flame detection sensor 16c) The non-flame detection sensor 16c includes an optical wavelength filter 20c which is a long-pass filter composed of a cut-on filter that transmits infrared rays in a predetermined wavelength band exceeding approximately 5.0 μm well, and a light receiving element unit 22c having an equivalent circuit similar to FIG. 7 that receives the light transmitted through the optical wavelength filter 20c and converts it into an electrical signal for output. With a structure similar to that shown in FIG. 6, it has a packaged configuration.

[0071] (Wavelength transmission characteristics of the non-flame detection sensor 16c) FIG. 8 is a characteristic diagram showing the transmittance at each wavelength of the optical wavelength filter and the light-transmitting window applied to the embodiment of FIG. 1.

[0072] As shown in FIG. 8, the sapphire glass which is the light-transmitting window 18 of FIG. 1 has a transmittance characteristic 80 having a short-wave pass characteristic (or long-wave cut characteristic) in which infrared rays below approximately 7.0 μm are transmitted well.

[0073] Also, a transmittance characteristic 82 that selectively transmits infrared energy in a wavelength band near the center wavelength is obtained by the band-pass filter having a center wavelength of approximately 4.5 μm that constitutes the optical wavelength filters 20a and 20b. By combining these, a band-pass filter having a combined transmittance characteristic 84 with a center wavelength of approximately 4.5 μm is configured.

[0074] On the other hand, a transmittance characteristic 86 having a cut-on filter characteristic that selectively transmits infrared rays in a predetermined wavelength band exceeding approximately 5.0 μm is obtained by the long-pass filter that constitutes the optical wavelength filter 20c. By combining this with the transmittance characteristic 80 of the sapphire glass, a wide-band band-pass filter having a combined transmittance characteristic 88 that selectively transmits infrared rays in a wavelength band of approximately 5.0 μm to 7.0 μm is configured.

[0075] (Fire determination unit 36) FIG. 9 is a signal waveform diagram showing a flame light reception signal output from the flame detection unit of FIG. 1 when observing infrared energy radiated from a combustion flame. FIG. 9(A) shows the signal waveform of the flame light reception signal E1' from the A / D conversion port 35a, and FIG. 9(B) shows the signal waveform of the flame light reception signal E2' from the A / D conversion port 35b.

[0076] FIGS. 9(A) and (B) are obtained simultaneously via the flame detection units 12a and 12b having the same configuration and have similarity. Also, if the amplification factors of the final-stage amplifiers 30a and 30b are the same, they will have almost the same waveform. The added light reception signal E3 has a waveform obtained by adding and synthesizing FIGS. 9(A) and 9(B).

[0077] Also, the flame light reception signals E1' and E2' are corrected (soot correction) by the fire determination unit 36 based on the light attenuation rates D1 and D2 of the flame detection units 12a and 12b detected by the test control unit 38. The added light reception signal E3 is corrected by adding the corrected flame light reception signals E1' and E2'.

[0078] In this embodiment, A / D conversion is performed by sampling the light reception signal at 64 Hz, that is, 64 digital data points are obtained per second for each signal.

[0079] The fire determination unit 36 obtains a flame integration value ΣE3, which is the sum of the absolute values of the differences from the reference potential in units of T = 2 seconds (128 data) for the flame light reception signal shown in FIG. 9. When the flame integration value ΣE3 is equal to or greater than a predetermined threshold value, it proceeds to the relative ratio determination described below.

[0080] When the flame integration value ΣE3 is equal to or greater than a predetermined threshold value, the fire determination unit 36 obtains a non-flame integration value ΣE4' in the same manner as when obtaining the flame integration value ΣE3 for the same 2 seconds at this time.

[0081] Next, the fire determination unit 36 calculates the relative ratio (ΣE3 / ΣE4') between the flame integration value ΣE3 and the non-flame integration value ΣE4'. If the relative ratio (ΣE3 / ΣE4') exceeds a preset threshold value, it is determined that there is a flame, and it is considered that the first requirement for the presence of a flame is satisfied.

[0082] Further, for the added light reception signal E3, the fire determination unit 36 performs a fast Fourier transform on the same two seconds (128 data) used for calculating the flame integration value ΣE3 and analyzes the result. For example, if there is a main component in the frequency band of 8 Hz or less, it is considered that the second requirement for determining the presence of a flame is satisfied. When both the first requirement and the second requirement are satisfied, it is determined that there is a flame.

[0083] FIG. 10 is an explanatory diagram showing the frequency distribution of the added light reception signal E3 obtained from the flame detection unit of FIG. 1 when observing the infrared rays radiated from the combustion flame. As described above, the fire determination unit 36 performs a fast Fourier transform on the T = 2 seconds (128 data) of the added light reception signal E3 to obtain, for example, the frequency distribution shown in FIG. 10.

[0084] As shown in FIG. 10, when observing the infrared rays radiated from the combustion flame on the frequency axis, a frequency distribution showing high intensity in the frequency band FL on the lower frequency side than approximately 8 Hz is obtained. Therefore, it can be seen that the main component of the frequency of the added light reception signal E3 exists in the frequency band FL up to 8 Hz. On the other hand, in the high frequency band FH exceeding 8 Hz and up to 16 Hz, a distribution with relatively low intensity is shown. Such distribution characteristics are the characteristics of the signal when observing a flame. Thus, for the flame determination based on the frequency distribution of the added light reception signal E3, for example, the relative intensity integration value ΣFL on the lower frequency side in the range up to 8 Hz and the range from exceeding 8 Hz to up to 16 Hz

[0085] and the relative intensity integration value ΣFH on the high frequency side are obtained. When the ratio ΣFL / ΣFH of the two values is equal to or less than a preset threshold value, it is determined that the light reception output corresponding to the flame has not been detected, and it is considered that the second requirement for determining the presence of a flame has not been satisfied. On the other hand, when ΣFL / ΣFH exceeds the threshold value, it is considered that the second requirement for determining the presence of a flame has been satisfied. The fire determination unit 36 repeats the above determinations every T = 2 seconds. (Test control unit 38)

[0086] (Test control unit 38) FIG. 11 is a time chart showing drive signals for pulse driving a test light source. FIG. 11(A) shows the drive signal E11 for the test light source 60-1, and FIG. 11(B) shows the drive signal E12 for the test light source 60-2.

[0087] When the test control unit 38 receives a test signal periodically transmitted by the fire receiving panel, it outputs the drive signals E11 and E12 shown in FIG. 11 to the test light sources 60-1 and 60-2 to drive them to emit light, and outputs test light to the light-transmitting window 18 to perform a contamination test.

[0088] The test control unit 38 outputs the drive signals E11 and E12 for a period T1, for example, T1 = 2 seconds. The period of the drive signals E11 and E12 is T2, and further, the drive signals E11 and E12 have a phase shift of (T2 / 2).

[0089] Thus, when the drive signal E11 is at the H level and the test light source 60-1 is emitting light, the drive signal E12 is at the L level and the test light source 60-2 is turned off. Also, when the drive signal E11 is at the L level and the test light source 60-1 is turned off, the drive signal E12 is at the H level and the test light source 60-2 is turned on. Test light is alternately output from the test windows 56-1 and 56-2 toward the light-transmitting window 18.

[0090] Therefore, the test time for the contamination test of both sides of the light-transmitting window 18 by the test control unit 38 is T1+(T2 / 2), which is the drive period T1 plus the phase shift (T2 / 2).

[0091] On the other hand, when the tests for the two sets of light-transmitting windows 18 are performed in order, for example, after performing the drive in FIG. 11(A) to test the contamination of the light-transmitting window 18, subsequently performing the drive in FIG. 11(B) to test the contamination of the light-transmitting window 18, the total test time for one flame detection device 10 is, for example, T = 4 seconds. However, in this embodiment, it can be completed in a time of just over 2 seconds, which is approximately half of the conventional time.

[0092] Therefore, when performing the contamination tests of a large number of flame detection devices 10 in sequence by transmitting test signals from the fire receiving panel, the time during which a control load due to the contamination test is applied to the fire receiving panel can be shortened to about half of that in the prior art, and the time during which a control burden is applied to the fire receiving panel can be shortened as much as possible to maintain the original fire monitoring function.

[0093] Note that the pulse driving of the test light source may not be based on the driving signal in FIG. 11, and the driving signals E11 and E12 may be output in sequence at a period T.

[0094] [Contamination Test Control] When the test control unit 38 provided in the MPU 15 in FIG. 1 receives a test signal from the fire receiving panel, it drives the test light sources 60-1 and 60-2 to emit light according to the driving signal shown in FIG. 11, and irradiates the flame detection units 11-1 and 11-2 with test light through the corresponding light-transmitting windows 18 to perform a contamination test.

[0095] For example, the test control unit 38 drives the test light source 60-1 to emit light with the driving signal E11 in FIG. 11, so as to output flame-simulating light corresponding to a fire flame through the test window 56-1 and make it incident on the flame detection sensors 16a and 16b and the non-flame detection sensor 16c through the corresponding light-transmitting window 18. The flame-simulating light from the test light source 60-1 includes the wavelength bands received by the flame detection sensors 16a and 16b and the non-flame detection sensor, and is, for example, light having a fluctuation frequency of 2 to 8 Hz specific to a flame as the frequency band extracted by the pre-filters 24a, 24b, and 24c.

[0096] The light-transmitting window 18 is not contaminated at the time of factory shipment, and the received light levels of the flame received light signals E1', E2' and the non-flame received light signal E4' obtained in the contamination test at that time are stored in the memory of the MPU 15 as the reference received light levels respectively, and are used for the calculation of the light reduction rates D1, D2, and D4.

[0097] That is, the test control unit 38 obtains the light attenuation rates D1, D2, and D4 from the flame light reception signals E1’, E2’ and the non-flame light reception signal E4’ read by driving the light emission of the test light source 60-1 and the respective reference light reception levels stored in the memory. The light attenuation rates D1, D2, and D4 are 0 at the time of shipment. However, as the operation period elapses in the installation environment, dirt adheres to the light-transmitting window 18, the light attenuation rate gradually increases, and since there are unevennesses in the dirt, each light attenuation rate can be a different value due to differences in the degree of partial dirtiness.

[0098] Subsequently, the fire determination unit 36 performs dirt correction on the flame light reception signals E1’, E2’ and the non-flame light reception signal E4’ corrected by the light attenuation rates D1, D2, and D4 obtained by the dirt test of the test control unit 38 Corrected E1’ = E1’ / (1 - D1) Corrected E2’ = E2’ / (1 - D2) Corrected E4’ = E4’ / (1 - D4) and determines a fire based on the received values of the dirt-corrected flame light reception signals E1’, E2’ and the non-flame light reception signal E4’. Here, the dirt-corrected flame light reception signals E1’ and E2’ are added, and even when E1’ + E2’ = E3, it is also used for fire determination.

[0099] Note that it is also possible to detect the light attenuation rate D3 for the added light reception signal E3 and perform dirt correction so that the corrected E3 = E3 / (1 - D3).

[0100] [Dirt damage processing] The fire determination unit 36 is preset with a threshold value Dth that is a light attenuation rate corresponding to the dirt correction limit, for example, the threshold value Dth = 0.7. When the light attenuation rates D1, D2, and D4 obtained by the dirt test of the test control unit 38 are equal to or exceed the threshold value, or when they exceed the threshold value, it is determined as a dirt damage or a dirt warning damage as the dirt correction limit (for example, a state where the entire predetermined monitoring area cannot be monitored even after correction), and control is performed to transmit a dirt warning signal or a dirt warning signal to the fire receiving panel to output a dirt warning or a dirt warning.

[0101] FIG. 12 is an explanatory diagram showing in a list form the relationship among an effective light reception signal, a fire determination, and an alarm with respect to a soiled state in the embodiment of FIG. 1.

[0102] FIG. 12 shows the flame detection sensors 16a and 16b and the non-flame detection sensor 16c as a sensor soiled state (the soiled state of the portions of the light-transmissive window 18 corresponding to the respective sensors). As a correction state, a ○ mark indicates that the correction limit has not been reached, and a × mark indicates that the correction limit has been reached.

[0103] Also, with respect to the flame light reception signals E1' and E2' and the non-flame light reception signal E4', a ○ mark indicates that the light reduction rate has not reached the correction limit and is a valid signal, and a × mark indicates that the light reduction rate has reached the correction limit and is invalid.

[0104] Also, the fire determination shows the fire determination by the added signal E3 obtained by adding the flame light reception signals E1' and E2' and the non-flame light reception signal E4' (addition·two wavelengths), and shows the limited fire determination by only the added signal E3 obtained by adding the flame light reception signals E1' and E2' (addition·one wavelength). Further, the alarm is either a soiling alarm or a soiling pre-alarm. FIG. 12 divides the sensor soiled state into modes 1 and 2, as follows.

[0105] (Mode 1) In mode 1, the light reception signals of the flame detection sensors 16a and 16b and the non-flame detection sensor 16c have not reached the correction limit, and all of the flame light reception signals E1' and E2' and the non-flame light reception signal E4' are obtained effectively. Therefore, the fire determination is the original fire determination by (addition·two wavelengths) using the added light reception signal E3 of the flame light reception signals E1' and E2', no soiling failure has occurred, and there is no alarm.

[0106] (Mode 2) Mode 2 is the case where only the non-flame light reception signal E4' of the non-flame detection sensor 16c has reached the correction limit. For this reason, since the non-flame light reception signal E4' is invalid and the flame light reception signals E1' and E2' are valid, the fire determination is a limited fire determination by (addition·one wavelength) (degenerate with respect to (addition·two wavelengths)) using the added light reception signal E3 of the flame light reception signals E1' and E2'.

[0107] In this case, it is assumed that the first requirement for the presence of a flame is satisfied when the flame integral value ΣE3 is equal to or greater than a predetermined threshold value, and the determination based on the relative ratio (ΣE3 / ΣE4’) between the flame integral value ΣE3 and the non-flame integral value ΣE4’ is not performed.

[0108] Also, in the failure processing, when the non-flame detection sensor 16c has reached the correction limit, a contamination failure or a contamination warning failure is detected, and the fire receiving panel is notified to output a contamination warning or a contamination warning. The contamination warning and the contamination warning are selected according to, for example, the correction degree of the flame detection sensors 16a and 16b, that is, the light extinction rate. Specifically, each light extinction rate is compared with a predetermined threshold value, for example, Dth1 (for example, 0.5). When both or one of the light extinction rates is equal to or greater than Dth1 or exceeds this value, although the correction limit has not been reached, it is determined that the correction limit will be reached soon, and a contamination warning is issued. Similarly, when compared with another threshold value Dth2 (for example, 0.3), if the light extinction rate is less than or equal to Dth2, a contamination warning is issued.

[0109] Also, for example, it may be selected according to the difference between the received light signals E1’ and E2’. In this case, when the difference is equal to or greater than a predetermined threshold value or larger than this, a contamination warning is issued, and when the difference is less than or equal to the predetermined threshold value, a contamination warning is issued. Of course, both the light extinction rates and the difference between the received light signals may be combined for determination and selection.

[0110] When either one or both of the flame received light signals E1’ and E2’ have reached the correction limit, the fire determination unit 36 detects a contamination failure and notifies the fire receiving panel to output a contamination warning.

[0111] [Contamination test control] FIG. 13 is a flowchart showing the contamination test control in the embodiment of FIG. 1, and is a control operation by the MPU 15.

[0112] As shown in FIG. 13, when the MPU 15 determines in step S1 that it has received a test signal from the fire receiving panel, it proceeds to step S2, where it drives the test lamp to emit light and irradiates each detection sensor with test light through the test window and the light-transmitting window.

[0113] Subsequently, the MPU 15 individually calculates the light attenuation rate based on the received light signals from each detection sensor (detection unit) in step S3, and determines in step S4 whether there is a detection sensor (detection unit) that has reached or exceeded a predetermined threshold value Dth and reached the correction limit. If there is a detection sensor (detection unit) that has reached the correction limit, it proceeds to step S5, where it detects fouling or a fouling warning and outputs a fouling alarm or a fouling warning alarm from the fire receiving panel. Furthermore, it proceeds to step S6, where it performs a limited fire determination using the added received light signal E3 of the flame received light signals E1' and E2' in mode 2 of FIG. 12 (addition · one wavelength).

[0114] [Flame detection device with three-wavelength method] FIG. 14 is a block diagram showing an embodiment of a three-wavelength flame detection unit incorporated in a flame detection device.

[0115] As shown in FIG. 14, the detection unit of the flame detection device 10 of this embodiment incorporates two sets, namely a flame detection unit 11-1 and another flame detection unit 11-2 (not shown) having the same configuration.

[0116] The flame detection unit 11-1 is composed of a flame detection unit 12a, non-flame detection units 12c and 12d, a fire determination unit 36 and a test control unit 38 provided in the MPU 15.

[0117] The flame detection unit 12a is the same as the non-flame detection unit 12a in FIG. 1, and observes the infrared energy radiated from the combustion flame existing in the monitoring area. It receives the infrared energy in a predetermined wavelength band centered on 4.5 μm radiated along with the CO2 resonance from the combustion flame, performs photoelectric conversion, and outputs a flame received light signal E1.

[0118] The non-flame detection unit 12c is the same as the flame detection unit 12c in FIG. 1, and observes the infrared energy radiated from heat sources other than the combustion flame existing in the monitoring area. It receives infrared energy in the wavelength band of approximately 5.0 μm to 7.0 μm and outputs a non-flame received light signal E4 that is converted into an electrical signal.

[0119] In contrast, the non-flame detection unit 12d is basically the same as the non-flame detection unit 12c except that the optical wavelength filter 20d is different from that of the non-flame detection unit 12c (however, the amplification factors of each amplifier are appropriately different). The optical wavelength filter 20d of the non-flame detection unit 12d receives infrared energy in a wavelength band different from that of the optical wavelength filter 20c of the non-flame detection unit 12c, for example, in the vicinity of 2.3 μm (for example, 2.1 to 2.5 μm), and outputs a non-flame received light signal E5 that is converted into an electrical signal. The other structure of the non-flame detection sensor 16d is the same as that of the flame detection sensor 16a shown in FIG. 6. The equivalent circuit of the light receiving element unit 22d is also the same as that of the light receiving element unit 22a shown in FIG. 7.

[0120] The non-flame received light signal E5’ is adjusted and amplified by the final-stage amplifier 30d to become the non-flame received light signal E5’, which is input to the A / D conversion port 35d.

[0121] The flame received light signal E1’ and the non-flame received light signals E4’, E5’ are converted into digital received light signals at the A / D conversion ports 35a, 35c, 35d of the MPU15 and captured.

[0122] When the test control unit 38 provided in the MPU15 receives the test signals periodically transmitted from the fire receiving panel, it sequentially drives the test light sources 60-1, 60-2 to output test light, reads the flame received light signal E1’ and the non-flame received light signals E4’, E5’ output from the final-stage amplifiers 30a, 30c, 30d, and calculates the light reduction rates D1, D4, D5 by comparison operations with the initial states (clean states).

[0123] Further, the fire determination unit 36 provided in the MPU 15 multiplies the reciprocals 1 / (1−D1), 1 / (1−D4), and 1 / (1−D5) of the light extinction ratios D1, D4, and D5 calculated by the test control unit 38 by the flame reception light signal E1' and the non-flame reception light signals E4' and E5' respectively for dirt correction, and performs fire determination in a three-wavelength method based on the dirt-corrected flame reception light signal E1' and non-flame reception light signals E4' and E5'.

[0124] For the three-wavelength fire determination by the fire determination unit 36, when the flame integration value ΣE1' is equal to or greater than a predetermined threshold value, the relative ratio (ΣE1' / ΣE4') between the flame integration value ΣE1' and the non-flame integration value ΣE4' is calculated. If the relative ratio (ΣE1' / ΣE4') is equal to or greater than the threshold value, it is considered as the first requirement for the presence of a flame. Subsequently, the relative ratio (ΣE1' / ΣE5') between the flame integration value ΣE1' and the non-flame integration value ΣE5' is calculated. If the relative ratio (ΣE1' / ΣE5') is equal to or greater than the threshold value, it is considered as the third requirement for the presence of a flame. Furthermore, all three requirements for determining the presence of a flame based on the frequency distribution of the flame reception light signal E1', i.e., the second requirement, are satisfied, and if this occurs continuously for a predetermined number of times, the determination of the presence of a flame is confirmed and a fire detection signal is output to the outside.

[0125] In addition, when any one of the light extinction ratios D1, D4, and D5 calculated by the test control unit 38 is equal to or greater than a predetermined threshold value, or reaches the correction limit equal to or greater than the predetermined threshold value, for example, when it is equal to or greater than the threshold value of 0.7 or exceeds the threshold value of 0.7, the fire determination unit 36 detects a fouling failure or a fouling warning failure, transmits a fouling alarm signal or a fouling warning alarm signal to the fire receiving panel to output a fouling alarm or a fouling warning alarm, and prompts the administrator to formulate a cleaning plan or the like for the flame detection device 10.

[0126] In addition, when it is determined that either one or both of the non-flame reception light signals E4' and E5' reach the correction limit while the flame reception light signal E1' does not reach the correction limit in the test control unit 38, the fire determination unit 36 performs a limited fire determination based on the flame reception light signal E1' or based on the flame reception light signal E1' and the non-flame reception light signal E4' or E5' that has not reached the correction limit.

[0127] FIG. 15 is an explanatory diagram showing in a list form the relationship among the effective light reception signals, fire determination, and alarms with respect to the fouling state in the embodiment of FIG. 14. As the fouling state (the fouling state of the portions of the light-transmissive window 18 corresponding to the respective sensors), the flame detection sensor 16a and the non-flame detection sensors 16c and 16d are shown. As the effective light reception signals, the flame light reception signal E1' and the non-flame light reception signals E4' and E5' are shown. The fire determination indicates three wavelengths, two wavelengths, and one wavelength. Further, the alarm becomes a fouling alarm or a fouling warning alarm, and the fouling state is divided into modes 1 to 4 as follows.

[0128] (Mode 1) In mode 1, the light reception signals of neither the flame detection sensor 16a nor the non-flame detection sensors 16c and 16d have reached the correction limit, and all of the flame light reception signal E1' and the non-flame light reception signals E4' and E5' are obtained effectively. Therefore, the fire determination is the original fire determination based on (three wavelengths), no fouling failure has occurred, and there is no alarm.

[0129] (Mode 2) Mode 2 is the case where only the light reception signal of the non-flame detection sensor 16d has reached the correction limit. For this reason, the non-flame light reception signal E5' is invalid, and since the flame light reception signal E1' and the non-flame light reception signal E4' are valid, the fire determination becomes a limited fire determination (degenerate with respect to (three wavelengths)) based on (two wavelengths).

[0130] (Two-wavelength) fire determination calculates the relative ratio (ΣE2' / ΣE4') between the flame integral value ΣE1' and the non-flame integral value ΣE4' when the flame integral value ΣE1' is equal to or greater than a predetermined threshold value, and when the relative ratio (ΣE1' / ΣE4') is equal to or greater than the threshold value, it satisfies both the first requirement of determining that there is a flame and the second requirement of determining the presence of a flame based on the frequency distribution of the flame light reception signal E1' (both conditions are satisfied), and when this continues for a predetermined number of consecutive times, it determines the presence of a flame and outputs a fire detection signal to the outside.

[0131] Also, for the failure processing, since the non-flame detection sensor 16d has reached the correction limit, it detects a fouling failure or a fouling warning failure, notifies the fire receiving panel, and outputs a fouling alarm or a fouling warning alarm.

[0132] The fouling alarm and the fouling warning alarm are selected according to, for example, the correction degree of the flame detection sensor 16a, that is, the light extinction rate. Specifically, the light extinction rate is compared with a predetermined threshold value, for example, Dth1 (for example, 0.5). When the light extinction rate is equal to or greater than Dth1 or exceeds this value, although the correction limit has not been reached, it is determined that the correction limit will be reached soon, and a fouling alarm is issued. Similarly, when compared with another threshold value Dth2 (for example, 0.3), if the light extinction rate is less than or equal to Dth2, a fouling warning alarm is issued. The same applies to modes 3 and 4.

[0133] (Mode 3) Mode 3 is the case where only the received light signal of the non-flame detection sensor 16c reaches the correction limit. Therefore, since the non-flame received light signal E4’ is invalid and the flame received light signal E1’ and the non-flame received light signal E5’ are valid, the fire determination is a limited fire determination by (two wavelengths).

[0134] (Two wavelengths) For fire determination, when the flame integral value ΣE1’ is equal to or greater than a predetermined threshold value or exceeds it, the relative ratio (ΣE1’ / ΣE5’) between the flame integral value ΣE1’ and the non-flame integral value ΣE5’ is calculated. When the relative ratio (ΣE1’ / ΣE5’) is equal to or greater than the threshold value, it satisfies both the third requirement of having a flame and the second requirement of determining the presence of a flame based on the frequency distribution of the flame received light signal E1’. And when this occurs continuously for a predetermined number of times, the determination of a flame is confirmed and a fire detection signal is output to the outside.

[0135] In addition, for the failure process, since the received light signal of the non-flame detection sensor 16c reaches the correction limit, a fouling failure or a fouling warning failure is detected and notified to the fire receiving panel to output a fouling alarm or a fouling warning alarm.

[0136] (Mode 4) Mode 4 is the case where the received light signals of the non-flame detection sensors 16c and 16d reach the correction limit. Therefore, since the non-flame received light signals E4’ and E5’ are invalid and only the flame received light signal E1’ is valid, the fire determination is a limited fire determination by (one wavelength).

[0137] For the fire determination of (1 wavelength), when the flame integral value ΣE1’ is equal to or exceeds the threshold value, it is considered that the first requirement for the presence of flame is satisfied. If both of the second requirements for the presence of flame based on the frequency distribution of the flame light reception signal E1’ are satisfied, and this occurs continuously for a predetermined number of times, the determination of the presence of flame is confirmed and a fire detection signal is output externally.

[0138] In addition, for the failure processing, when the light reception signals of the non-flame detection sensors 16c and 16d reach the correction limit, a contamination failure or a contamination warning failure is detected, and the fire receiving panel is notified to output a contamination alarm or a contamination warning alarm.

[0139] When the light reception signal of the flame detection sensor 16a (flame light reception signal E1’) reaches the correction limit, the fire determination unit 36 detects a contamination failure, notifies the fire receiving panel, and outputs a contamination alarm.

[0140] [Modification Example of the Present Invention] (Average of Light Reception Signals) In the above embodiment of FIG. 1, the fire determination unit 36 determines the presence or absence of a flame using the added light reception signal E3 obtained by adding the flame light reception signals E1’ and E2’ from the flame detection units 12a and 12b. However, the present invention is not limited to this. For example, the average of the flame light reception signals E1’ and E2’ from the flame detection units 12a and 12b may be obtained, the average light reception signal may be captured, and the fire determination unit 36 may determine the presence or absence of a flame.

[0141] (Wavelength Method) In addition, the above embodiment takes the 1-wavelength method (multiple detection units), 2-wavelength method, and 3-wavelength method as examples, but other types of flame detection devices may also be used. Further, the present invention may be applied to a flame detection device that observes radiation energy other than infrared rays.

[0142] (Correction of Light Reception Signals for Factors Other than Contamination) In addition, the operations and effects of the present invention include those not described above. For example, not only when there is dirt or uneven dirt on the light-transmitting window 18, but also when the received light signal decreases due to a failure or deterioration of the detection sensor of the detection unit, the received light signal is corrected based on the light attenuation rate for each detection unit in the same manner, and a dirt warning signal or a dirt pre-warning signal is transmitted to the fire receiving panel according to the degree of signal decrease to notify. The administrator can then clean the light-transmitting window 18 in response to this, and if the dirt or pre-dirt state is not resolved, it can be estimated that there is an abnormality such as in the detection sensor of the detection unit.

[0143] (Others) In addition, the present invention includes appropriate modifications that do not impair its object and advantages, and furthermore, is not limited by the numerical values shown in the above embodiments.

Explanation of Reference Numerals

[0144] 10: Flame detection device 11-1: Flame detection unit 12a, 12b: Flame detection units 12c, 12d: Non-flame detection units 15: MPU 16a, 16b: Flame detection sensors 16c, 16d: Non-flame detection sensors 18: Light-transmitting window 20a, 20b, 20c, 20d: Optical wavelength filters 22a, 22b, 22c, 22d: Light-receiving element parts 24a, 24b, 24c, 24d: Pre-filters 25: Light-receiving electrode 26a, 26b, 26c, 26d: Preamps 27: FET 28a, 28b, 28c, 28d: Main amplifiers 30a, 30b, 30c, 30d: Final-stage amplifiers 35a, 35b, 35c, 35d: A / D conversion ports 36: Fire determination unit 38: Test control unit 45: Pyroelectric body 50: Housing 52: Sensor housing part 54: Central convex part 56-1, 56-2: Test window 60, 60-1, 60-2: Test light source 70: Reflection hood

Claims

1. An infrared energy radiated from a monitoring area is observed, and a flame detection device that detects the presence or absence of a combustion flame and determines a fire, a plurality of detection units that receive the infrared energy radiated from the monitoring area through a light-transmitting window and output a received light signal, a test control unit that irradiates the plurality of detection units with test light through the light-transmitting window from a test light source, and for each of all the detection units, compares the received light signal by the test light with an initial state and obtains a light reduction rate with respect to the initial state of the infrared energy transmitted through a portion corresponding to each detection unit of the light-transmitting window, a fire determination unit that corrects the received light signal for each of all the detection units based on the light reduction rate obtained for each detection unit, and detects the presence or absence of a combustion flame based on each corrected received light signal and determines a fire, comprising, the plurality of detection units include a plurality of flame detection units that detect infrared rays radiated from a flame and one or more non-flame detection units that detect infrared rays radiated from sources other than the flame, the fire determination unit, causes a receiving device to output a contamination warning or a contamination pre-warning according to the light reduction rate of the received light signal from the plurality of flame detection units or the difference of the received light signal, when any of the received light signals of the plurality of detection units reaches a predetermined correction limit, the received light signal that has reached the correction limit is excluded from the fire determination elements, and a fire determination is made using, as the fire determination elements, at least the received light signals from the flame detection units that have not reached the correction limit. A flame detection device characterized by this.

2. The flame detection device according to claim 1, wherein the fire determination unit causes a receiving device to output a predetermined failure warning when at least one received light signal from the flame detection units reaches the correction limit. A flame detection device characterized by this.

Images