Combustion apparatus

Abstract

To provide a combustion apparatus provided with a flame detector capable of detecting a combustion state.SOLUTION: A combustion apparatus 2 according to one embodiment includes: a flame ejection part 18; a flame detector 6 having a detection part 20 located in a direction in which the flame ejection part 18 ejects a flame; and a determiner 8 configured to determine a combustion state based on an output of the flame detector 6, wherein, when the detection part 20 is viewed from the flame ejection part 18 side, the detection part 20 has a shape whose width becomes narrower from one side toward the other side. Preferably, a surface of the detection part 20 facing the flame ejection part 18 is inclined in a direction away from the flame ejection part 18 from the one side toward the other side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This specification discloses a combustion device. [Background technology]

[0002] Combustion devices such as burners are sometimes equipped with flame detectors to enhance safety. A typical flame detector includes a flame rod located near the flame outlet and a detection circuit. In this device, a high voltage is applied between the flame outlet and the flame rod. When a flame from the flame outlet contacts the flame rod, an ionic current flows between the flame outlet and the flame rod. The presence of a flame is detected by the detection circuit detecting this current flow. An example of a flame detector that can stably detect a flame even when the flame is disturbed is disclosed in Japanese Utility Model Laid-Open Publication No. 57-199749. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 57-199749 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional combustion devices, flame detectors detect whether a flame is generated or not. To achieve higher safety in combustion devices, there is a demand for combustion devices that have flame detectors that can detect not only the generation or non-generation of a flame but also the combustion state.

[0005] The present inventors have an intention to provide a combustion device equipped with a flame detector capable of detecting the combustion state. [Means for solving the problem]

[0006] A combustion apparatus according to one embodiment includes a flame ejection section, a flame detector having a detection section positioned in the direction in which the flame ejection section ejects a flame, and a determiner for determining a combustion state from the output of the flame detector. When viewed from the flame ejection section side, the detection section has a shape that narrows from one side to the other. [Effects of the Invention]

[0007] The inventors discovered that the magnitude of the ion current depends on the length of the contact area between the outer edge of the flame and the flame detector. The inventors discovered that by appropriately shaping the detection part of the flame detector that actually comes into contact with the flame, the length of the contact area with the outer edge can be changed depending on the size of the flame, thereby making it possible to detect the combustion state.

[0008] In this combustion device, the detection section of the flame detector has a shape that narrows from one side to the other when viewed from the flame ejection section. This allows the magnitude of the ion current detected by the flame detector to vary depending on the size of the flame. In this combustion device, the combustion state can be determined by processing the signal from the flame detector with a determiner. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a combustion device according to one embodiment. [Figure 2] 2(a) is a perspective view of the detection unit of the combustion device of FIG. 1, FIG. 2(b) is a plan view of this detection unit, and FIG. 2(c) is a side view of this detection unit. [Figure 3] 3(a), (b) and (c) are schematic diagrams showing the state of contact between the detection unit of FIG. 2 and the flame. [Figure 4] FIG. 4 is a graph showing the relationship between the equivalence ratio of fuel and the amount of detected ions in the combustion device of FIG. [Figure 5] 5(a), (b), and (c) are schematic diagrams showing the state of contact between a conventional flame rod and a flame. [Figure 6] FIG. 6 is a graph showing the relationship between the equivalence ratio of fuel and the magnitude of the detected ion amount in a combustion device using a conventional flame rod. [Figure 7] FIG. 7 is a graph showing the relationship between the equivalence ratio of fuel and the magnitude of the amount of detected ions in a combustion device according to another embodiment. [Figure 8] 8(a) and 8(b) are perspective views of a detection unit of a combustion device according to still another embodiment. [Figure 9] FIG. 9 is a schematic diagram showing a combustion device according to yet another embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a combustion device according to yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments will be described in detail with reference to the drawings as appropriate.

[0011] 1 is a schematic diagram showing a combustion device 2 according to one embodiment. The combustion device 2 includes a combustion chamber 4, a flame detector 6, and a determiner 8. Although not shown, the combustion device 2 further includes an igniter. The combustion device 2 is a so-called burner.

[0012] The combustion chamber 4 includes a body 10 and a ceiling 12. The ceiling 12 is provided with a flame hole. As shown in FIG. 1 , gaseous fuel 14 is introduced toward the flame hole from outside the combustion chamber 4. The gaseous fuel 14 is ignited by an igniter (not shown), and a flame 16 is ejected from the flame hole toward the inside of the combustion chamber 4. In this embodiment, multiple flames 16 are ejected. In this embodiment, the flame hole and the ceiling 12 form a flame ejection section 18 of the combustion device 2. The body 10 has a cylindrical or rectangular tubular shape. The body 10 and the ceiling 12 are made of a conductive material such as metal. The body 10 and the ceiling 12 are electrically connected. The body 10 is grounded, and the ceiling 12 is also grounded via the body 10. Typical materials for the combustion chamber 4 include stainless steel and heat-resistant steel.

[0013] The flame detector 6 detects the flame 16 emitted from the flame ejection portion 18. The flame detector 6 includes a detection portion 20, a support portion 22, and a detection circuit .

[0014] The detection unit 20 is located near at least one flame hole within the combustion chamber 4. The detection unit 20 is located in the direction in which the flame 16 is ejected, as viewed from the flame ejection unit 18. The distance between the flame ejection unit 18 and the detection unit 20 is determined so that a flame 16 larger than a predetermined size will come into contact with the detection unit 20. The detection unit 20 is made of a conductive material such as metal. A typical example of the material for the detection unit 20 is alloy steel. The detection unit 20 protrudes from the tip of the support unit 22.

[0015] Fig. 2(a) is an enlarged perspective view of the detection unit 20. In this embodiment, the detection unit 20 has a quadrangular pyramid shape. Fig. 2(b) is a plan view of the detection unit 20 as seen from the flame ejection unit 18 side. In this figure, a first side surface 26 of the detection unit 20 is shown. The first side surface 26 faces the flame ejection unit 18. Fig. 2(c) is a side view of the detection unit 20, showing a second side surface 28 of the detection unit 20.

[0016] As shown in Figure 2(b), when viewed from the flame ejection portion 18 side, the detection portion 20 has a shape that narrows from one side to the other. In this embodiment, the width of the detection portion 20 narrows continuously from the support portion 22 side of the detection portion 20 toward the tip side. In this embodiment, the detection portion 20 has a triangular shape in a plan view. The detection portion 20 may also have a trapezoidal shape that narrows from one side to the other in a plan view.

[0017] The width of the detection unit 20 does not have to narrow continuously. For example, the width of the detection unit 20 may narrow stepwise. The width of the detection unit 20 may include a mixture of parts where the width narrows continuously and parts where the width narrows stepwise. The width of the detection unit 20 may narrow overall from one side to the other. In this specification, such shapes are generally referred to as "shapes where the width narrows from one side to the other."

[0018] As shown in FIGS. 1 and 2(c), the surface (first side surface 26) of the detection unit 20 facing the flame ejection portion 18 is inclined from one side to the other in a direction away from the flame ejection portion 18. In this embodiment, the first side surface 26 of the flame detector 6 is continuously inclined from the support portion 22 side of the detection unit 20 toward the tip side, downward in FIG. 2(c). The first side surface 26 does not have to be continuously inclined. For example, the first side surface 26 may be inclined in a stepped manner away from the flame ejection portion 18. The first side surface 26 may have a mixture of a continuously inclined portion and a stepped portion inclined away from the flame ejection portion 18. It is sufficient that the first side surface 26 as a whole is inclined away from the flame ejection portion 18 from one side to the other. In this specification, such a shape is generally referred to as "inclined from one side to the other in a direction away from the flame ejection portion 18."

[0019] The support part 22 is attached to the body part 10 of the combustion chamber 4. One end of the support part 22 protrudes into the combustion chamber 4, and the other end protrudes outside the combustion chamber 4. The support part 22 penetrates the body part 10. The part of the support part 22 that comes into contact with the body part 10 is insulating. The support part 22 and the body part 10 are insulated from each other. Although not shown, a conductor penetrates the inside of the support part 22. This electrically connects the detection part 20 located inside the body part 10 and the detection circuit 24 located outside the body part 10.

[0020] The detection circuit 24 is electrically connected to the detection unit 20 via the support unit 22. As shown in FIG. 1 , in this embodiment, the detection circuit 24 includes an AC power supply 30, a voltage transformer 32, a resistor 34, a capacitor 36, and a rectifier circuit 38. The same voltage (the voltage at the position indicated by the symbol P) is applied from the AC power supply 30 to the detection unit 20 and the rectifier circuit 38. The output of the rectifier circuit 38 is connected to the determiner 8.

[0021] As mentioned above, the ceiling 12 that forms the flame ejection section 18 is grounded. When a voltage is applied to the detection section 20, a voltage difference occurs between the flame ejection section 18 and the detection section 20. Because a gap exists between the flame ejection section 18 and the detection section 20, when there is no flame 16 from the flame ejection section 18, or when there is a flame 16 but it has not reached the detection section 20, no current flows between the flame ejection section 18 and the detection section 20. When the flame 16 from the flame ejection section 18 reaches the detection section 20, ions generated by the flame 16 flow as an ion current between the flame ejection section 18 and the detection section 20. The current flowing at this time is indicated by an arrow in FIG. 1. When the ion current flows, the voltage at the position indicated by symbol P fluctuates, and the fluctuated voltage is input to the rectifier circuit 38. The rectifier circuit 38 rectifies this signal and outputs it to the determiner 8. The output voltage from the rectifier circuit 38 fluctuates in accordance with the amount of ionic current that has flowed. That is, the detection circuit 24 detects the amount of ionic current that has flowed and transmits it to the determiner 8.

[0022] 3(a)-(c) are schematic diagrams showing the state of contact between the flame 16 and the detection unit 20 when the flame 16 is of different sizes. In each of FIGS. 3(a)-(c), the upper side is a side view and the lower side is a plan view. In each plan view, the dotted line represents the outer edge 40 of the flame 16 at the position of the first side surface 26 of the detection unit 20. The size of the flame 16 decreases in the order of FIGS. 3(a), (b), and (c).

[0023] In the example of FIG. 3( a), the flame 16 extends beyond the detection unit 20. As shown in the plan view of FIG. 3( a), a portion of the outer edge 40 of the flame 16 extends beyond the detection unit 20. In the example of FIG. 3( b), the flame 16 does not extend beyond the detection unit 20. As shown in the plan view of FIG. 3( b), the entire outer edge 40 of the flame 16 is in contact with the first side surface 26 of the detection unit 20. Therefore, the length of the outer edge 40 in contact with the first side surface 26 is longer than in the example of FIG. 3( a). In the example of FIG. 3( c), the flame 16 does not extend beyond the detection unit 20, and the entire outer edge 40 of the flame 16 is in contact with the first side surface 26 of the detection unit 20. However, because the flame 16 is smaller than in FIG. 3( b), the length of the outer edge 40 in contact with the first side surface 26 is shorter than in the example of FIG. 3( b).

[0024] 3( a)-(c), in this detection unit 20, as the flame 16 shrinks from the state in which it protrudes from the first side surface 26, the length of the portion of the outer edge 40 of the flame 16 in contact with the first side surface 26 increases. After the entire outer edge 40 of the flame 16 comes into contact with the first side surface 26, the length of the portion of the outer edge 40 of the flame 16 in contact with the first side surface 26 decreases as the flame 16 shrinks. The amount of ionic current flowing between the flame ejection portion 18 and the detection unit 20 is substantially proportional to the length of the contact portion between the outer edge 40 of the flame 16 and the first side surface 26. Therefore, when this detection unit 20 is used, the ionic current increases as the flame 16 shrinks from the state in which it protrudes from the first side surface 26, and after the entire outer edge 40 of the flame 16 comes into contact with the first side surface 26, the ionic current decreases as the flame 16 shrinks.

[0025] FIG. 4 is a graph showing the relationship between the size of the flame 16 and the magnitude of the ion current (detected ion amount) in this embodiment. The size of the flame 16 varies depending on the velocity and equivalence ratio of the gaseous fuel 14. In FIG. 4, the flow velocity of the fuel 14 is set to a predetermined value, and the size of the flame 16 is changed by changing the equivalence ratio. Therefore, this graph shows the relationship between the equivalence ratio and the magnitude of the ion current. As the equivalence ratio decreases (the fuel 14 is leaner), the combustion speed decreases and the flame 16 spreads, resulting in a larger outline of the flame 16. As the equivalence ratio increases (the fuel 14 is richer), the combustion speed increases and the flame 16 becomes shorter, resulting in a smaller outline of the flame 16. In other words, as the equivalence ratio changes from the lean side to the rich side, the size of the flame 16 gradually decreases. For the reasons explained using FIG. 3, as the equivalence ratio changes from the lean side to the rich side, the detected ion amount first gradually increases and then decreases.

[0026] The determiner 8 determines the combustion state from the output of the detection circuit 24. For example, the determiner 8 makes the following determination. (i) The determiner 8 determines whether or not an ion current is flowing from the output of the detection circuit 24, thereby determining whether or not a flame 16 of a predetermined size or larger is occurring. (ii) The determiner 8 stores a characteristic graph shown in Fig. 4, which is measured in advance, for a predetermined flow velocity of the fuel 14. The determiner 8 determines the equivalence ratio of the fuel 14 at the predetermined flow velocity by determining the amount of ion current from the output of the detection circuit 24 and referring to this characteristic graph. Similarly, the determiner 8 determines whether the fuel 14 is in a stoichiometric state, a state leaner than stoichiometric, or a state richer than stoichiometric. (iii) The determiner 8 stores a characteristic graph (not shown) of the relationship between the flow velocity of the fuel 14 at a predetermined equivalence ratio and the ion current, which has been measured in advance. The determiner 8 determines the flow velocity of the fuel 14 at the predetermined equivalence ratio by determining the amount of ion current from the output of the detection circuit 24 and referring to this characteristic graph. Similarly, the determiner 8 determines whether the flow velocity of the fuel 14 is the expected flow velocity, or whether the flow velocity is faster or slower than the expected flow velocity.

[0027] In this embodiment, the determiner 8 includes a controller and a memory. The controller is typically a CPU. The memory is typically a semiconductor memory or a hard disk. The determiner 8 may be configured with a dedicated circuit.

[0028] In the following, in order to facilitate understanding of the effects of this embodiment, which will be described later, a typical conventional flame detector will first be described with reference to FIGS.

[0029] Figures 5(a)-(c) are schematic diagrams showing contact between the detection unit 100 of a conventional flame detector and a flame 102. In each of Figures 5(a)-(c), the upper side is a side view and the lower side is a plan view. In each plan view, a dotted line represents the outer edge 104 of the flame 102 at the surface of the detection unit 100. The size of the flame 102 decreases in the order of Figures 5(a), (b), and (c).

[0030] Conventional flame detectors use a cylindrical detection unit 100 called a flame rod 100. As shown in Figures 5(a)-(c), in the conventional flame rod 100, even if the size of the flame 102 changes, the length of the outer edge 104 of the flame 102 that contacts the surface of the flame rod 100 changes very little. In other words, in the conventional flame rod 100, even if the size of the flame 102 changes, the ion current changes very little.

[0031] FIG. 6 is a graph showing the relationship between the size of the flame 102 and the magnitude of the ion current (detected ion amount) in a flame detector using a conventional flame rod 100. In this example, as in the case of FIG. 4, the size of the flame 102 is changed by changing the equivalence ratio of the gaseous fuel. As explained using FIG. 5, even if the size of the flame 102 changes, the length of the outer edge 104 of the flame 102 that contacts the surface of the flame rod 100 hardly changes. Therefore, even if the equivalence ratio changes from the lean side to the rich side, the detected ion amount remains almost constant. This shows that it is difficult for this flame detector to determine the equivalence ratio from the ion current. If the equivalence ratio further increases and the flame 102 becomes too small to reach the flame rod 100 or if an extinguishment occurs, the ion current becomes zero. It can be seen that the conventional detector can only determine whether an ion current is flowing, i.e., whether the flame 102 is larger than a predetermined size.

[0032] The effects of this embodiment will be described below.

[0033] In the combustion device 2 of this embodiment, the detection section 20 of the flame detector 6 has a shape that narrows from one side to the other when viewed from the flame ejection section 18 side. Unlike the conventional flame rod 100, in this detection section 20, the length of the portion where the outer edge 40 of the flame 16 contacts the first side surface 26 varies depending on the size of the flame 16, and therefore the ion current varies depending on the size of the flame 16. By processing the output from the flame detector 6 in the determiner 8, it is possible not only to determine whether the flame 16 is larger than a predetermined size, but also to determine the combustion state, such as the equivalence ratio of the fuel 14 and the flow velocity of the fuel 14, which were difficult to determine with the conventional flame rod 100.

[0034] In this embodiment, the surface (first side surface 26) of the detection unit 20 facing the flame ejection portion 18 is inclined from the support portion 22 side toward the tip side, in a direction away from the flame ejection portion 18. By doing so, as shown in FIG. 3 , the outline of the outer edge 40 of the flame 16 at the position of the first side surface 26 becomes elliptical. Compared to when the first side surface 26 is not inclined with respect to the flame ejection portion 18, the length of the outer edge 40 in contact with the first side surface 26 can be made longer. This makes it possible to increase the amount of ion current to be detected, which contributes to improving the accuracy of detecting the combustion state.

[0035] In this embodiment, the shape of the detection unit 20 is a quadrangular pyramid. By making the detection unit 20 quadrangular pyramid, the combustion state can be detected with high accuracy. Furthermore, since this detection unit 20 has a simple shape, it is easy to manufacture.

[0036] In this embodiment, the determiner 8 determines the equivalence ratio of the fuel 14 at a predetermined flow rate. The determiner 8 also determines the flow rate of the fuel 14 at the predetermined equivalence ratio. This allows the operator to know whether the combustion device 2 is in a desired combustion state. This contributes to improving the safety of the combustion device 2.

[0037] 7 is a graph showing the relationship between the equivalence ratio and the magnitude of the ion current (detected ion amount) at a predetermined flow velocity in another embodiment. In this embodiment, unlike the embodiment shown in FIG. 4, the ion current is maximized in the stoichiometric state, and the distance between the flame ejection part 18 and the detection part 20 is adjusted so that the ion current can be detected over a wide range on the lean side. In this embodiment, the equivalence ratio can be determined accurately mainly when the fuel 14 is burned on the lean side.

[0038] FIG. 8(a) is a perspective view showing a detection unit 50 of a combustion device according to another embodiment. This combustion device is the same as the combustion device 2 of FIG. 1 except for the shape of the detection unit 50. As shown in FIG. 8(a), this detection unit 50 has a triangular pyramid shape. Although not shown, one of the side surfaces of this detection unit 50 (first side surface 52) faces the flame ejection portion. The first side surface 52 is inclined from the support portion side toward the tip, in a direction away from the flame ejection portion.

[0039] In the combustion apparatus of this embodiment, the detection unit 50 of the flame detector has a triangular shape that narrows from one side to the other when viewed from the flame ejection portion side. In this detection unit 50, the length of the portion where the outer edge of the flame contacts the first side surface 52 varies depending on the size of the flame, and therefore the ion current varies depending on the size of the flame. By processing the output from the flame detector with a determiner, it is possible to determine not only whether the flame is larger than a predetermined size, but also the combustion state, such as the fuel equivalence ratio and fuel flow rate. The combustion apparatus of this embodiment is capable of detecting the combustion state.

[0040] FIG. 8(b) is a perspective view showing a detection unit 60 of a combustion device according to yet another embodiment. This combustion device is the same as the combustion device shown in FIG. 1 except for the shape of the detection unit 60. As shown in FIG. 8(b), this detection unit 60 has a plate shape with a triangular maximum surface 62. Although not shown, the maximum surface 62 of this detection unit 60 faces the flame ejection portion. This maximum surface 62 is inclined from the support portion side toward the tip, moving away from the flame ejection portion.

[0041] In the combustion apparatus of this embodiment, the detection unit 60 of the flame detector has a triangular shape that narrows from one side to the other when viewed from the flame ejection side. In this detection unit 60, the length of the portion where the outer edge of the flame contacts the maximum surface 62 varies depending on the size of the flame, and therefore the ion current varies depending on the size of the flame. By processing the output from the flame detector with a determiner, it is possible to determine not only whether the flame is larger than a predetermined size, but also the combustion state, such as the fuel equivalence ratio and fuel flow rate. The combustion apparatus of this embodiment is capable of detecting the combustion state.

[0042] The shape of the detection unit is not limited to the shapes shown in Figures 2 and 8. The detection unit may have another polygonal pyramid shape, such as a hexagonal pyramid. The detection unit may also have a conical shape. When viewed from the flame ejection part side, the detection unit should have a shape that narrows from one side to the other. In this case, it is preferable that the surface of the detection unit facing the flame ejection part is inclined from one side to the other in a direction away from the flame ejection part.

[0043] 9 is a schematic diagram showing a portion of a combustion device 70 according to yet another embodiment. This combustion device 70 is the same as the combustion device 2 of FIG. 1 except for a detection circuit 72. This detection circuit 72 includes a DC power supply 74, a resistor 76, and an amplifier circuit 78. A voltage is applied from the DC power supply 74 to the detection unit 20 via the resistor 76. The voltage across the resistor 76 is applied to the amplifier circuit 78, and the output of the amplifier circuit 78 is connected to the determiner 8.

[0044] When a voltage is applied to the detection unit 20, a voltage difference occurs between the flame ejection unit 18 and the detection unit 20. When a flame from the flame ejection unit 18 reaches the detection unit 20, ions generated by the flame flow as an ion current between the flame ejection unit 18 and the detection unit 20. The current at this time is indicated by an arrow in Figure 9. When a current flows, a potential difference occurs across the two ends of the resistor 76, which is input to the amplifier circuit 78. The amplifier circuit 78 amplifies this potential difference and outputs it to the determiner 8. The voltage from the amplifier circuit 78 is proportional to the amount of ion current that has flowed. The detection circuit 72 detects the amount of ion current that has flowed and transmits it to the determiner 8.

[0045] FIG. 10 is a schematic diagram showing a portion of a combustion device 80 according to yet another embodiment. This combustion device 80 is the same as the combustion device 2 of FIG. 1 except for a detection circuit 82. This detection circuit 82 includes a DC power supply 84, a resistor 86, and an amplifier circuit 88. This embodiment differs from the embodiment of FIG. 9 in the position where the resistor 86 is inserted. In this embodiment, the resistor 86 of the detection circuit 82 is inserted between the combustion chamber 4 and ground. The voltage across the resistor 86 is applied to the amplifier circuit 88. The output of the amplifier circuit 88 is connected to the determiner 8.

[0046] When a voltage is applied to the detection unit 20 from the DC power supply 84, a voltage difference occurs between the flame ejection unit 18 and the detection unit 20. When a flame from the flame ejection unit 18 reaches the detection unit 20, ions generated by the flame flow as an ion current between the flame ejection unit 18 and the detection unit 20. The current at this time is indicated by an arrow in Figure 10. When a current flows, a potential difference occurs across the resistor 86, and this potential difference is input to the amplifier circuit 88. The amplifier circuit 88 amplifies this potential difference and outputs it to the determiner 8. The output voltage from the amplifier circuit 88 is proportional to the amount of ion current that has flowed. The detection circuit 82 detects the amount of ion current that has flowed and transmits it to the determiner 8.

[0047] The configuration of the detection circuit is not limited to the circuits shown in Figures 1, 9, and 10. The detection circuit only needs to be able to output to the determiner a signal corresponding to the amount of ion current flowing between the flame ejection part and the detection part.

[0048] As described above, according to this embodiment, it is possible to provide a combustion apparatus equipped with a flame detector capable of detecting the combustion state. From this, the superiority of this embodiment is clear.

[0049] [Disclosure items] The following items are disclosures of preferred embodiments.

[0050] [Item 1] a flame detector having a flame ejection section, a detection section positioned in the direction in which the flame ejection section ejects a flame, and a determiner for determining a combustion state from the output of the flame detector, A combustion device in which, when the detection section is viewed from the flame ejection section side, the detection section has a shape that narrows from one side to the other.

[0051] [Item 2] Item 2. The combustion device according to item 1, wherein a surface of the detection unit facing the flame ejection portion is inclined in a direction away from the flame ejection portion from the one side to the other side.

[0052] [Item 3] 3. The combustion device according to item 1 or 2, wherein the detection unit has a pyramidal shape, and one of the side surfaces of the detection unit faces the flame ejection unit.

[0053] [Item 4] Item 4. The combustion device according to item 3, wherein the detection unit has a triangular pyramid shape or a square pyramid shape.

[0054] [Item 5] 3. The combustion device according to item 1 or 2, wherein the detection unit is plate-shaped, and the largest surface of the detection unit faces the flame ejection unit.

[0055] [Item 6] 6. The combustion device according to any one of items 1 to 5, wherein the determiner determines an equivalence ratio of fuel as the combustion state.

[0056] [Item 7] 7. The combustion device according to any one of items 1 to 6, wherein the determiner determines a fuel flow rate as the combustion state.

[0057] [Item 8] a detection unit disposed in a direction in which a flame ejection unit of the combustion device ejects a flame, and a detection circuit that detects a current flowing in the detection unit; A flame detector in which the detection portion has a shape that narrows from one side to the other. [Industrial Applicability]

[0058] The combustion devices described above can be used to combust a variety of fuels. [Explanation of symbols]

[0059] 2, 70, 80... Combustion equipment 4. Combustion chamber 6. Detector 8...Judgment device 10. Torso 12. Ceiling 14...Fuel 16, 102... Flame 18...Flame spout part 20, 50, 60...Detection unit 22...Support part 24, 72, 82... Detection circuit 26, 52...first side 28...Second side 30...AC power supply 32. Voltage transformer 34, 76, 86... Resistor 36. Capacitor 38... Rectifier circuit 40, 104....Outer edge of flame 62...Inner wall of hole 74, 84...DC power supply 78, 88... Amplifier circuit 100···Detection unit (frame rod)

Claims

1. a flame detector having a flame ejection section, a detection section positioned in the direction in which the flame ejection section ejects a flame, and a determiner for determining a combustion state from the output of the flame detector, A combustion device in which, when the detection section is viewed from the flame ejection section side, the detection section has a shape that narrows from one side to the other.

2. The combustion device according to claim 1 , wherein a surface of the detection unit facing the flame ejection portion is inclined in a direction away from the flame ejection portion from the one side to the other side.

3. 3. The combustion apparatus according to claim 1, wherein the detection section is pyramidal, and one of the side surfaces of the detection section faces the flame ejection section.

4. The combustion device according to claim 3 , wherein the detection portion has a triangular pyramid shape or a quadrangular pyramid shape.

5. 3. The combustion apparatus according to claim 1, wherein the detection section is plate-shaped, and the largest surface of the detection section faces the flame ejection section.

6. The combustion device according to claim 1 or 2, wherein the determiner determines an equivalence ratio of fuel as the combustion state.

7. The combustion device according to claim 1 or 2, wherein the determiner determines a flow velocity of fuel as the combustion state.

8. a detection unit disposed in a direction in which a flame ejection unit of the combustion device ejects a flame, and a detection circuit that detects a current flowing in the detection unit; A flame detector in which the detection portion has a shape that narrows from one side to the other.

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