JP2017020794A - Flame detection device and boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration that enables quick detection of deterioration in flame detection devices, and enables effective prevention of faulty determinations arising from the deterioration of flame detection units therein.SOLUTION: A flame detection device 100 comprises: a UV phototube 110 in which a current flows when detecting light of flames; a control unit 80 that determines presence or absence of the flame on the basis of a current level to be acquired from the UV phototube 110; and a storage unit 90 that stores a determination current level. The control unit 80 includes: a deterioration determination unit that executes a deterioration determination of the UV phototube 110; and a timing determination unit that, when detecting that the current level of the UV phototube 110 is present in a prescribed range where the current level thereof is set higher than a determination current level and lower than a normal current level, causes the deterioration determination unit to execute the deterioration determination.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flame detection device that performs deterioration determination of a flame detection unit and a boiler including the flame detection device.

  2. Description of the Related Art Conventionally, in a flame detection device used for a combustion device or the like, a configuration is known in which a deterioration detection unit such as an ultraviolet phototube is subjected to deterioration determination by itself using a light shielding unit that blocks light incidence. For example, Patent Document 1 and Patent Document 2 disclose techniques relating to this type of deterioration determination. Patent Document 1 discloses a control method for performing a self-diagnosis of a flame detection unit every time a predetermined combustion time elapses during combustion. Patent Document 2 discloses control for shortening the operation time when the light shielding means is operated at predetermined time intervals to be shorter than the non-operation time.

JP 2004-138302 A JP 2002-303420 A

  In the flame detection apparatus as described above, when deterioration progresses, it is erroneously determined that there is a flame despite the absence of flame. If it is determined that there is a flame, there will be a situation in which fuel continues to be supplied to the fuel device despite the absence of flame. In order to avoid such a situation, it is preferable that the deterioration of the flame detector is detected promptly. In this regard, in the configurations disclosed in Patent Document 1 and Patent Document 2, it is possible to perform deterioration determination even during flame combustion. However, even if deterioration has progressed to the use limit where frequent misjudgment frequently occurs, the deterioration cannot be detected unless the next deterioration determination is made, and the deterioration is detected quickly. There was room for improvement.

  An object of the present invention is to provide a configuration that can quickly detect deterioration in a flame detection device and can effectively prevent erroneous determination caused by deterioration of a flame detection unit.

  The present invention includes a flame detection unit through which a current flows when a flame light is detected, a control unit that determines the presence / absence of a flame based on a current level acquired from the flame detection unit, and a state in which the flame is normally detected. A storage unit that stores a determination current level that is set lower than a normal current level and that serves as a reference for determining the presence or absence of a flame, and the control unit includes a deterioration determination unit that performs a deterioration determination of the flame detection unit. A timing determination unit that, when detecting that the current level of the flame detection unit is within a predetermined range set higher than the determination current level and lower than the normal current level, causes the deterioration determination unit to execute the deterioration determination And a flame detection device.

  When the current level enters the predetermined range, the control unit starts counting a preset misfire confirmation time, and performs a misfire determination when the current level falls below the determination current level during the misfire confirmation time. It is preferable to further include a misfire determination unit, and the timing determination unit performs the deterioration determination when the current level does not fall below the determination current level during the misfire confirmation time.

  The flame detection device further includes a light shielding device that physically blocks between a flame to be detected and the flame detection unit, and the deterioration determination unit performs the deterioration determination in a state where light is blocked by the light blocking device, It is preferable to determine whether or not it is a false flame detection due to self-discharge of the flame detector.

  In addition, the present invention includes the flame detection device and a combustion device in which flame is detected by the flame detection device, and when the abnormality of the flame detection unit is determined by the deterioration determination unit, the combustion The present invention relates to a boiler that stops supply of fuel to an apparatus.

  According to the flame detection device of the present invention, it is possible to quickly detect deterioration, and it is possible to effectively prevent erroneous determination caused by deterioration of the flame detection unit.

It is a figure showing typically composition of a boiler to which a flame detection device concerning one embodiment of the present invention is applied. It is a block diagram which shows typically the structure which concerns on the deterioration determination of the control part of this embodiment. It is a graph which shows typically the change of the current level when misfire determination is carried out. It is a graph which shows typically the fluctuation | variation of the current level when the misdetection of the flame arises by self-discharge. It is a graph which shows typically the fluctuation | variation of a current level when a current level falls to the predetermined range by dirt. It is a flowchart which shows the flow of the deterioration determination performed based on the change of an electric current level. It is a flowchart which shows the flow of the deterioration determination performed based on the change of the electric current level in a modification.

  Hereinafter, a preferred embodiment of the flame detection device of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a configuration of a boiler 1 to which a flame detection apparatus 100 according to an embodiment of the present invention is applied. FIG. 2 is a block diagram schematically illustrating a configuration related to deterioration determination of the control unit 80 of the present embodiment.

  First, the overall configuration of the boiler 1 will be described. As shown in FIG. 1, the boiler 1 includes a boiler body 10, a burner 11, a fuel valve 12, a blower 13, a control device 70, and a flame detection device 100. The boiler 1 includes a fuel supply line L10 and an air supply line L20 as main lines. The “line” in the present specification is a general term for lines capable of flowing a fluid such as a flow path, a path, and a pipeline.

  The boiler body 10 is a housing that includes a plurality of water pipes, a lower header, and an upper header. The boiler body 10 is formed with a combustion chamber for heating water in the water pipe.

  The burner 11 is a combustion device provided in the combustion chamber of the boiler body 10. Fuel required for combustion is supplied by a fuel supply line L10 connected to a fuel supply source. The fuel valve 12 is an on / off valve that opens and closes the flow path of the fuel supply line L10. The blower 13 supplies air used for combustion of the burner 11 through the air supply line L20.

  The control device 70 is a computer to which various sensors and valves to be controlled are electrically connected. The control device 70 according to the present embodiment notifies a control unit 80 that performs various controls such as combustion control and flame detection, a storage unit 90 that stores various types of information related to control, and various types of information such as abnormalities. A notification unit 95. As the notification unit 95, an appropriate device that displays a sound generation or a video for notifying abnormality such as a buzzer, a light, and a touch panel display can be adopted.

  The flame detection device 100 is a device for detecting the presence or absence of flame in the burner 11. The flame detection device 100 includes an ultraviolet photoelectric tube 110 as a flame detection unit, and a shutter device 111 used for determining deterioration of the ultraviolet photoelectric tube 110.

  The ultraviolet photoelectric tube 110 is a flame detection unit that detects a flame using the photoelectric effect. The ultraviolet photoelectric tube 110 has a light receiving portion through which a discharge current flows when ultraviolet light is incident while a driving voltage is applied. The ultraviolet photoelectric tube 110 is electrically connected to the control unit 80, and the control unit 80 determines the flame state based on the current (flame signal) flowing through the ultraviolet photoelectric tube 110.

  In the present embodiment, the ratio of the number of times the current is detected with respect to the number of drive voltages applied in a predetermined time is calculated as the current level. For example, when the drive voltage is applied 200 times within a predetermined time and the current (flame signal) is detected 180 times, the current level is calculated as 0.9.

  The storage unit 90 includes a predetermined range of current levels used in misfire determination and deterioration determination described later, a determination current level serving as a reference for determining the presence or absence of flame, a misfire confirmation time and a misfire determination time serving as a reference for performing misfire determination, and the like. Are stored. Details of the misfire determination and the deterioration determination process will be described later.

  Next, the shutter device 111 will be described. The shutter device 111 is a light shielding device capable of physically shielding between the light receiving unit and the flame. The shutter device 111 according to the present embodiment includes a shielding member made of a non-translucent material and a drive unit that moves the shielding member. The shutter device 111 positions the shielding member at an open position where the light receiving unit is exposed in a state where the flame is detected, and moves the shielding member to a closed position covering the light receiving unit when determining deterioration. The control of the shutter device 111 is performed by the control unit 80.

  Next, misfire determination and deterioration determination by the ultraviolet phototube 110 will be described. As illustrated in FIG. 2, the control unit 80 includes a deterioration determination unit 81 and a timing determination unit 82.

  The deterioration determination unit 81 executes the deterioration determination of the ultraviolet phototube 110 based on a preset procedure. The deterioration determining unit 81 monitors the current of the ultraviolet phototube 110 with the light shielding portion of the shutter device 111 positioned at the closed position. If the current level exceeds the deterioration reference value, the deterioration of the ultraviolet phototube 110 is limited to the use limit. It is determined that it has reached.

  The timing determination unit 82 sets a timing for executing the deterioration determination by the deterioration determination unit 81. The timing determination unit 82 according to the present embodiment performs deterioration determination based on the time schedule and performs deterioration determination based on the current level of the ultraviolet photoelectric tube 110. In addition, the timing determination unit 82 constantly monitors the current level of the ultraviolet photoelectric tube 110 and performs the deterioration determination even when a predetermined condition is satisfied.

  The misfire determination unit 83 determines whether or not misfire has occurred based on the current level. The misfire determination unit 83 monitors the current of the ultraviolet photoelectric tube 110 and determines that a misfire has occurred when the current level falls below the misfire reference value.

  First, a case where deterioration determination is performed based on a time schedule will be described. The timing determination unit 82 causes the deterioration determination unit 81 to periodically perform deterioration determination based on a preset time schedule. Thereby, the deterioration of the ultraviolet phototube 110 is periodically determined.

  Next, a case where the deterioration determination is performed based on the current level of the ultraviolet phototube 110 will be described. FIG. 3 is a graph schematically showing the fluctuation of the current level when the misfire is determined. Note that the graph of FIG. 3 schematically shows the fluctuation of the current level, and the fluctuation of the current level that always occurs is omitted.

  A misfire determination or a deterioration determination is performed with the current level being in a predetermined range as a trigger. As shown in FIG. 3, the predetermined range is a range lower than a current level (hereinafter referred to as a normal current level) in a state where the ultraviolet phototube 110 in a state where there is no influence of deterioration or dirt normally detects a flame. Is set. For example, when the normal current level is set to a range of 1.0 to 0.9, the predetermined range is set to a range lower than 0.9.

  The determination current level is a current level that serves as a reference for performing misfire determination. The determination current level of the present embodiment is a lower limit value within a predetermined range. When the current level falls below the determination current level, the control unit 80 enters a misfire determination time and determines whether or not a misfire has occurred.

  The misfire confirmation time is a predetermined time provided to determine whether or not to perform misfire determination. In the present embodiment, the control unit 80 counts the misfire confirmation time when it falls below the upper limit of the predetermined range, and enters the misfire judgment time for making the misfire judgment if the judgment current level falls below this misfire confirmation time. The misfire determination time is a time for determining whether or not a misfire has occurred. If the current level falls below the misfire reference value during the misfire determination time, it is determined that a misfire has occurred. During the misfire determination time, deterioration determination described later is not performed, and the light receiving portion of the ultraviolet phototube 110 is not shielded by the shutter device 111.

  As shown in FIG. 3, the predetermined range is a criterion for determining whether or not to make a misfire determination. In a normal state (a state in which no deterioration has occurred) of the ultraviolet phototube 110, when the flame of the burner 11 is misfired, the current level decreases and reaches a predetermined range. When the predetermined range is reached, the misfire confirmation time is counted. If the current level falls below the determination current level during the misfire confirmation time, a misfire determination is performed. When the ultraviolet phototube 110 is misfired in a normal state, the current level is lower than the determination current level. Therefore, a misfire determination time is entered, and it is determined whether or not a misfire has occurred.

  Next, processing when the current level stays within a predetermined range for a predetermined time or more will be described. FIG. 4 is a graph schematically showing fluctuations in the current level when an erroneous flame detection occurs due to self-discharge. FIG. 5 is a graph schematically showing fluctuations in the current level when the current level is reduced to a predetermined range due to contamination. Also in FIGS. 4 and 5, like the case of FIG. 3, current level fluctuations that occur constantly are omitted.

  The reason why the current level of the ultraviolet phototube 110 stays within a predetermined range is that the current level of the ultraviolet phototube 110 is caused by self-discharge due to deterioration of the ultraviolet phototube 110 (see FIG. 4) and due to contamination of the light receiving portion of the ultraviolet phototube 110. The case of entering the predetermined range (see FIG. 5) is considered.

  First, the case where the current level of the ultraviolet phototube 110 falls within a predetermined range due to self-discharge will be described. As shown in FIG. 4, when the flame of the burner 11 is misfired in a state where deterioration that causes misjudgment has progressed, the current level is lower than the normal current level, but the shutter device 111 is in a light shielding state. However, it does not fall below the judgment current level due to the effect of self-discharge. That is, when the current level is in a predetermined range due to misfiring in a state where the deterioration of the ultraviolet phototube 110 is in progress, even if the light receiving portion of the ultraviolet phototube 110 is shielded by the shutter device 111, there is a flame due to self-discharge. It is determined. When a flame is erroneously detected due to deterioration of the ultraviolet phototube 110, it is desirable to stop the supply of fuel gas promptly from the viewpoint of safety.

  Next, a case where the current level of the ultraviolet phototube 110 falls within a predetermined range due to contamination of the light receiving portion of the ultraviolet phototube 110 will be described. As shown in FIG. 5, even when the light receiving portion of the ultraviolet phototube 110 becomes dirty, the amount of incident ultraviolet rays of the flame gradually decreases, the current level gradually decreases, and eventually the current level decreases to a predetermined range. If the contamination of the light receiving portion of the UV photoelectric tube 110 progresses and falls below the determination current level, it is determined that there is no flame despite the presence of a flame. In this case, the supply of fuel gas is stopped. Therefore, the fuel gas will not continue to be supplied despite the absence of flame. Therefore, compared with the case where the current level of the ultraviolet photocell 110 falls within a predetermined range due to self-discharge, it is less necessary to stop the supply of fuel gas immediately.

  As described above, when the current level falls from the normal current level range to the predetermined range due to self-discharge due to deterioration of the ultraviolet phototube 110, it is determined that there is a flame even if a misfire has occurred. In this case, the fuel gas may continue to be supplied from the fuel supply line L10 despite the absence of flame. From the viewpoint of safety, it is preferable to detect such a state promptly. On the other hand, as described above, the current level may fall from the range of the normal current level to the predetermined range due to contamination of the light receiving unit.

  The control unit 80 according to the present embodiment performs deterioration determination using the shutter device 111 when the current level is within the predetermined range even after the misfire confirmation time has elapsed after entering the predetermined range. As shown in FIG. 4, even when light is shielded by the shutter device 111, if the current level is within a predetermined range that exceeds the determination current level, it is determined that the ultraviolet photoelectric tube 110 caused by self-discharge has reached the use limit. To do.

  On the other hand, there is a possibility that the deterioration of the ultraviolet phototube 110 is not caused only by the current level being in the predetermined range. Therefore, the timing determination unit 82 has entered the predetermined range and the misfire confirmation time has elapsed. Is used as a trigger to cause the deterioration determination unit 81 to perform deterioration determination, thereby identifying the cause of the current level entering the predetermined range. As shown in FIG. 5, when the current level enters a predetermined range due to contamination of the ultraviolet phototube 110, the current level is greatly reduced when the light receiving portion of the ultraviolet phototube 110 is shielded by the shutter device 111. As described above, when the light is blocked by the shutter device 111 and falls below the determination current level and out of the predetermined range, it is determined that the light receiving portion is contaminated. Depending on the difference in the behavior of the current level, it is possible to specify whether the cause of the current level being in the predetermined range is self-discharge or contamination of the ultraviolet photoelectric tube 110.

  Further, the timing determination unit 82 of the present embodiment performs deterioration determination timing control that prevents the deterioration determination from being repeated, in addition to the above-described control regarding deterioration determination. This timing control will be described.

  In the deterioration determination, even if the current level has increased to some extent due to self-discharge, the current level may not exceed the determination current level. Since the flame can be detected even in such a state, it can be said that the ultraviolet phototube 110 is slightly deteriorated (the light deterioration indicated by the one-dot chain line in FIG. 5). In this case, even if the shutter device 111 performs light shielding, the deterioration determination is not performed, and when the light shielding is released, the current level again enters a predetermined range. The timing determination unit 82 according to the present embodiment performs timing control so that the deterioration determination is performed after the elapse of a predetermined time when the current level falls within a predetermined range but is below the determination current level in a light-shielded state. Thereby, the deterioration determination is prevented and repeated, and the deterioration determination is performed at a timing at which the deterioration is considered to be further progressing. Therefore, the deterioration determination can be appropriately performed.

  Next, a flow of processing for monitoring the current level of the ultraviolet phototube 110 and executing the misfire determination and the deterioration determination of the ultraviolet phototube 110 will be described. FIG. 6 is a flowchart showing a flow of deterioration determination performed based on a change in current level. In FIG. 5, the process of performing the deterioration determination based on the preset schedule and the timing control are omitted, and this flowchart schematically shows the process leading to the deterioration determination.

  The timing determination unit 82 monitors the current level of the ultraviolet photocell 110 and determines whether it is within a predetermined range (S101).

  When the current level falls within the predetermined range, the misfire confirmation time is counted, and it is determined whether or not the current level has fallen below the determination current level during the misfire confirmation time (S102).

  If the current level falls below the determination current level during the misfire confirmation time in the process of S102, a misfire determination process is performed (S103). In this embodiment, when the current level falls below the misfire reference value during the misfire confirmation time, it is determined that misfire has occurred (S104). The method of misfire determination can be changed as appropriate. If it is determined in the process of S104 that the vehicle is misfired, the abnormality is notified by the notification unit 95, and the process proceeds to the process of controlling the fuel valve 12 to stop the supply of fuel gas (S107). If there is no misfire, the process returns to S101.

  In the process of S102, when the current level does not fall below the determination current level during the misfire confirmation time, the deterioration determination unit 81 executes the deterioration determination process (S105). In the deterioration determination process, the above-described deterioration determination is performed by moving the light shielding portion of the shutter device 111 to the closed position (S106).

  As a result of the deterioration determination in S106, when it is determined that the deterioration of the ultraviolet photoelectric tube 110 has reached the use limit, the fuel valve 12 is controlled to the closed position and the supply of fuel gas is stopped (S107). As a result, it is possible to reliably prevent a situation in which fuel gas continues to be supplied despite a misfire. Note that if the result of the deterioration determination in S103 is that the deterioration state is not reached, the fuel gas supply is not stopped.

  According to the flame detection apparatus 100 of the present embodiment described above, the following effects can be obtained. The flame detection apparatus 100 according to the present embodiment includes an ultraviolet photoelectric tube 110 through which a current flows when flame light is detected, a control unit 80 that determines presence / absence of flame based on a current level acquired from the ultraviolet photoelectric tube 110, and a determination current level. And a storage unit 90 for storing. The control unit 80 detects that the current level of the ultraviolet photocell 110 is within a predetermined range that is set higher than the determination current level and lower than the normal current level. Then, it has the timing determination part 82 which makes the deterioration determination part 81 perform deterioration determination. With this configuration, it is possible to quickly detect deterioration of the ultraviolet phototube 110 that causes erroneous determination. Moreover, since the deterioration of the ultraviolet photoelectric tube 110 can be detected quickly, it is possible to effectively reduce the time during which a false detection of a flame that is determined to be present despite the absence of a flame occurs.

  When the current level enters the predetermined range, the control unit 80 starts counting a preset misfire confirmation time, and performs misfire determination when the current level falls below the determination current level during the misfire confirmation time. A part 83 is further provided. In addition, the timing determination unit 82 causes the deterioration determination to be performed when the current level does not fall below the determination current level during the misfire confirmation time. As a result, when the current level falls to a predetermined range and falls below the determination current level during the misfire confirmation time, the misfire determination is performed before the deterioration determination is performed. Therefore, it is possible to avoid the situation where the misfire determination is performed after the deterioration determination is performed, and it is possible to realize the rapid detection of the misfire as well as the rapid detection of the deterioration of the ultraviolet photoelectric tube 110.

  The flame detection device 100 further includes a shutter device 111 that physically blocks between the flame to be detected and the ultraviolet photoelectric tube 110. The deterioration determination unit 81 performs deterioration determination in a state where light is blocked by the shutter device 111, and determines whether or not the flame is erroneously detected due to self-discharge of the ultraviolet phototube 110. With this configuration, it is possible to accurately specify whether the cause that the current level has entered the predetermined range is due to deterioration or contamination. Therefore, it is possible to perform control in accordance with the situation of the ultraviolet photoelectric tube 110. In addition, since the deterioration determination can be detected promptly, the interval for periodically performing the deterioration determination can be increased, which can contribute to extending the useful life of the shutter device 111.

  The flame detection apparatus 100 of this embodiment detects the flame of the burner 11 with which the boiler 1 is provided. The boiler 1 stops supplying fuel to the burner 11 when the deterioration determination unit 81 determines that the ultraviolet phototube 110 is abnormal. Thereby, it is possible to reliably prevent the situation in which the fuel gas is continuously supplied in spite of the absence of the flame, and the boiler 1 can be stably operated.

  As mentioned above, although one preferable embodiment of the flame detection apparatus 100 of this invention was described, this invention is not restrict | limited to the above-mentioned embodiment, It can change suitably.

  The flow of control described with reference to FIG. 6 of the above embodiment is an example, and can be changed as appropriate. For example, the deterioration determination and the misfire determination may be separately controlled, and the misfire confirmation process using the predetermined range as a trigger from the process of FIG. 6 may be omitted. FIG. 7 is a flowchart showing a flow of deterioration determination performed based on a change in current level in the modification. In the flowchart shown in FIG. 7, the processes related to the determination process (S102), the misfire determination process (S103), and the misfire determination (S104) regarding whether or not the current level falls below the determination current level during the misfire confirmation time are omitted. . In this modification, the misfire determination is processed in a separate flow regardless of whether or not the predetermined range is entered. Thus, the flow of control for performing the deterioration determination of the present invention can be appropriately changed according to the circumstances.

  In the above embodiment, the ratio of the number of times the current is detected with respect to the number of times of the drive voltage applied for the predetermined time is calculated as the current level, and the deterioration determination is performed based on the current level. It is not limited. For example, the number of discharge currents and the current value may be set as the current level, and the deterioration determination may be performed based on the change in the current level. Thus, the calculation method or acquisition method of the current level to be detected can be changed as appropriate according to circumstances.

  In the above-described embodiment, the deterioration determination is performed using the shutter device 111. However, the deterioration determination is not limited to this method, and may be appropriately configured to physically block between the light receiving portion of the ultraviolet phototube 110 and the flame. Can be changed. Moreover, it is good also as a structure which performs degradation determination by methods other than the light shielding by the shutter apparatus 111. FIG. For example, a deterioration determination voltage lower than the discharge start voltage at the time of non-deterioration may be applied to the ultraviolet phototube 110, and it may be determined that the ultraviolet phototube has deteriorated when a flame signal is output when the deterioration determination voltage is applied. Thus, the deterioration determination method can be changed as appropriate according to circumstances.

  In the above embodiment, even if the current level is not within the predetermined range, the deterioration determination is periodically performed based on a preset time schedule. It can be omitted.

  In the above embodiment, the present invention has been described by taking the flame detection device 100 applied to the boiler 1 as an example. However, the flame detection device 100 of the present invention is applied to various devices in which flames other than the boiler 1 need to be detected. can do.

1 Boiler 11 Burner (combustion device)
DESCRIPTION OF SYMBOLS 80 Control part 90 Memory | storage part 81 Degradation determination part 82 Timing determination part 83 Misfire determination part 110 Ultraviolet photoelectric tube 111 Shutter apparatus (light-shielding device)

Claims (4)

A flame detection unit through which an electric current flows when detecting the light of the flame,
A controller that determines the presence or absence of flame based on the current level acquired from the flame detector;
A storage unit that stores a determination current level that is set lower than a normal current level in a state in which a flame is normally detected and serves as a reference for determining the presence or absence of a flame;
With
The controller is
A deterioration determination unit for performing deterioration determination of the flame detection unit;
A timing determination unit that executes the deterioration determination by the deterioration determination unit when detecting that the current level of the flame detection unit is within a predetermined range that is higher than the determination current level and lower than the normal current level; ,
A flame detection device. The controller is
A misfire determination unit that starts counting a preset misfire confirmation time when the current level enters the predetermined range, and performs a misfire determination when the current level falls below the determination current level during the misfire confirmation time; Have
The flame detection device according to claim 1, wherein the timing determination unit causes the deterioration determination to be executed when a current level does not fall below the determination current level during a misfire confirmation time. A light-shielding device that physically shields between the flame to be detected and the flame detector;
The deterioration determination unit
The flame detection device according to claim 1, wherein the deterioration determination is performed in a state where light is blocked by the light shielding device, and it is determined whether or not a flame is erroneously detected by self-discharge of the flame detection unit. The flame detection device according to any one of claims 1 to 3,
A combustion device in which flame is detected by the flame detection device;
With
The boiler which stops supply of the fuel to the said combustion apparatus, when the abnormality of the said flame | frame detection part is determined by the said deterioration determination part.

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