An ignition device

Abstract

The present invention discloses an ignition device, which has a combustion part and an ignition flame-stabilizing component. The combustion part has an injection port. The ignition flame-stabilizing component is at least partially located in the combustion part. The ignition flame-stabilizing component includes a flame-stabilizing device, an ignition device, an ion flame detection device and a signal enhancement device. The flame-stabilizing device has a disc-shaped flame-stabilizing body, which faces the injection port and has a first through hole. The ignition device extends into the first through hole. The ion flame detection device extends to the outside of the combustion part through the injection port. The signal enhancement device is grounded and extends to the outside of the combustion part, and the signal enhancement device is arranged close to the ion flame detection device and separated from it to enhance the detected electrical signal. According to the ignition device of the present invention, the flame can be stabilized when the gas flow rate in the device is very fast, and the flameout phenomenon can be avoided. A fan-shaped arc is formed during ignition, which is conducive to the successful ignition of the high-speed airflow; the flame signal intensity of the high-speed airflow can be stably detected, thereby realizing high-power operation.

Description

Technical Field

[0001] The invention relates to the field of mechanical technology, and in particular to an ignition device. Background Art

[0002] Current ignition guns, such as those used in incinerators and gasifiers, have many problems, such as low power, incomplete combustion, unstable flames, and poor flame detection signals. When existing ignition guns are used in scenarios that require high-power combustion, increasing the gas pressure or flow rate will cause flameout.

[0003] Therefore, an ignition device is needed to at least partially solve the above problems. Summary of the invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] In order to at least partially solve the above problems, the present invention provides an ignition device, the ignition device having a combustion part for burning and injecting a flame and an ignition and flame-stabilizing component, the combustion part having an injection port, the ignition and flame-stabilizing component being at least partially disposed in the combustion part to ignite the fuel gas in the combustion part to generate a flame, the ignition and flame-stabilizing component comprising:

[0006] A flame stabilizing device, wherein the flame stabilizing device has a disc-shaped flame stabilizing body, the flame stabilizing body is arranged facing the injection port, and a first through hole is arranged on the flame stabilizing body;

[0007] an ignition device, the ignition device extending into the first through hole;

[0008] an ion flame detection device extending through the injection port to the outside of the combustion portion; and

[0009] A signal enhancement device, wherein the signal enhancement device is configured for grounding and extends to the outside of the combustion portion. The signal enhancement device is disposed close to the ion flame detection device and is separated from the ion flame detection device so that an electrical circuit can be formed between the signal enhancement device and the ion flame detection device via ions generated by combustion, thereby enhancing the electrical signal detected by the ion flame detection device.

[0010] According to the ignition device of the present invention, a flame stabilizing device is arranged in the combustion part, which can stabilize the flame when the gas flow rate in the device is very fast, and avoid the occurrence of flameout; the ignition device extends into the first through hole on the flame stabilizing device to form a fan-shaped arc during ignition, which is conducive to the successful ignition of the high-speed airflow; the cooperation of the ion flame detection device and the signal enhancement device can stably detect the combustion of the high-speed airflow; thereby, efficient ignition and stable combustion can be achieved under conditions of very high gas pressure and / or flow rate, and thus high-power operation of the ignition device can be achieved.

[0011] Furthermore, the signal enhancement device comprises a main body, an end of the main body is provided with a first bending portion, and the first bending portion is bent toward the first side of the ion flame detection device, thereby facilitating the formation of a detection loop.

[0012] Furthermore, the signal enhancement device also has a second bent portion, the second bent portion is separated from the first bent portion, the second bent portion is bent from the main body toward the second side of the ion flame detection device, and the second side is opposite to the first side. According to this solution, the ion concentration near the ion flame detection device can be further increased, thereby improving the detection signal.

[0013] Furthermore, an included angle between projections of the first bent portion and the second bent portion on a radial cross section of the combustion portion is 80 to 100 degrees.

[0014] Furthermore, the ignition device further comprises:

[0015] a premixing section, wherein the premixing section is connected to the fuel gas channel and the combustion-supporting gas channel so that the fuel gas and the combustion-supporting gas can be premixed; and

[0016] an extension portion connected between the premixing portion and the combustion portion;

[0017] The ignition and flame stabilization assembly further includes a honeycomb portion, the honeycomb portion is provided with a plurality of through holes, the honeycomb portion is arranged on the extension portion, and the outer circumference of the honeycomb portion abuts against the inner circumference of the extension portion. According to this solution, the honeycomb portion can accelerate the mixed gas before entering the combustion portion, and is conducive to the formation of a reflow zone.

[0018] Further,

[0019] The flame stabilizing device further includes a connecting portion, which extends along the axial direction of the combustion portion and is connected between the middle portion of the honeycomb portion and the middle portion of the flame stabilizing body;

[0020] The signal enhancement device is connected to the flame stabilizing body;

[0021] The ignition device and the ion flame detection device extend through the honeycomb portion and are electrically connected to the control device; and / or

[0022] At most two through holes are arranged on the flame stabilizing body. According to the above arrangement, the flame stabilizing body is basically a solid structure, which can effectively reduce the speed of the airflow and facilitate the formation of the reflow zone.

[0023] Furthermore, a graded swirl device is provided in the premixing section, and the graded swirl device includes at least two swirl disks, so that the fuel gas and the combustion-supporting gas can be fully mixed, and the at least two swirl disks are arranged at intervals along the axial direction of the premixing section, and the outer periphery of the swirl disk abuts against the inner periphery of the premixing section, and the swirl disk is provided with a plurality of openings inclined along the axial direction of the swirl disk and extending approximately along the radial direction of the swirl disk. According to this solution, the fuel gas and the combustion-supporting gas can be fully mixed, thereby improving the combustion efficiency.

[0024] Furthermore, the graded swirl device includes a primary swirl disk and a secondary swirl disk, the secondary swirl disk is closer to the extension portion than the primary swirl disk, the premixing portion also has a fuel gas nozzle connected to the fuel gas channel, the end of the fuel gas nozzle close to the extension portion is configured as a closed end, the closed end extends through the primary swirl disk and is located between the primary swirl disk and the secondary swirl disk, and the side wall of the tube body close to the closed end is circumferentially provided with a plurality of nozzles, the plurality of nozzles are directed toward the inner wall of the premixing portion along the radial direction of the premixing portion. According to this solution, the intersection of the flow directions of the fuel gas and the combustion-supporting gas can be utilized to achieve uniform and sufficient mixing.

[0025] Furthermore, the number of the openings on the at least two swirl disks of the graded swirl device increases step by step in a direction away from the extension portion, thereby further facilitating gas mixing.

[0026] Further, a radial dimension of the extension portion is smaller than a radial dimension of the premixing portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following drawings of the present invention are used to understand the present invention as part of the present invention. The embodiments of the present invention are shown in the drawings and the description thereof is used to explain the principle of the present invention.

[0028] In the attached figure:

[0029] Figure 1 A schematic side view of the structure of an ignition device according to a preferred embodiment of the present invention;

[0030] Figure 2 A partial structural schematic diagram of a premixing unit of an ignition device according to a preferred embodiment of the present invention;

[0031] Figure 3 for Figure 2 A magnified schematic diagram of part A;

[0032] Figure 4 It is a partial structural schematic diagram of the ignition and flame stabilization structure of the ignition device according to the preferred embodiment of the present invention;

[0033] Figure 5 for Figure 4 A magnified schematic diagram of part B;

[0034] Figure 6 for Figure 1 A schematic diagram of the structure of the ignition device from another side view;

[0035] Figure 7 Bit Figure 6 The enlargement of the middle C part is to try;

[0036] Figure 8 It is a structural schematic diagram of a flame stabilizing device of an ignition device according to a preferred embodiment of the present invention;

[0037] Fig. 9 A schematic diagram of the structure of a signal strengthening device for an ignition device according to a preferred embodiment of the present invention; and

[0038] Fig.10 for Fig. 9 Schematic diagram of the signal enhancement device from another perspective.

[0039] Description of reference numerals:

[0040] 100: Ignition device 110: Combustion unit 111: Injection port

[0041] 120: flame stabilizing device 121: flame stabilizing body 122: first through hole

[0042] 123: Connecting portion 124: Second through hole 130: Ignition device

[0043] 140: Ion flame detection device 150: Signal enhancement device 151: Main body

[0044] 152: first bending portion 153: second bending portion 160: premixing portion

[0045] 161: fuel gas channel 162: combustion gas channel 163: fuel gas nozzle

[0046] 164: closed end 165: nozzle 170: extension

[0047] 180: Honeycomb 181: Perforation 190: Classification cyclone device

[0048] 191: First-stage swirl disc 192: Second-stage swirl disc 193: Opening

[0049] 166: Mounting flange DETAILED DESCRIPTION

[0050] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0051] In order to fully understand the present invention, a detailed description will be provided in the following description. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. Obviously, the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0052] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0053] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifications and do not have any other meanings, such as a specific order, etc. Moreover, for example, the term "first component" itself does not imply the existence of the "second component", and the term "second component" itself does not imply the existence of the "first component".

[0054] It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside" and similar expressions used in this document are for illustrative purposes only and are not limiting.

[0055] Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings.

[0056] refer to Figure 1 , Figure 2 and Figure 4. The ignition equipment of the present invention can be used in various types of incinerators, gasifiers and other equipment. The ignition equipment 100 of the present invention includes a premixing section 160, an extension section 170 and a combustion section 110, and the extension section 170 is connected between the premixing section 160 and the combustion section 110. The premixing section 160 is used for premixing fuel gas and combustion-supporting gas, and is connected to a fuel gas channel 161 and a combustion-supporting gas channel 162. The premixing section 160 can be arranged outside an incinerator, a gasifier and other equipment. In addition, a graded cyclone device 190 is also provided in the premixing section 160 to mix the fuel gas and the combustion-supporting gas evenly.

[0057] The extension portion 170 is used to extend into the above-mentioned incinerator, gasifier and other equipment to play the role of transition and mixing gas. A mounting flange 166 is provided at the connection between the extension portion 170 and the premixing portion 160. The ignition device 100 can be fixed to the above-mentioned incinerator, gasifier and other equipment through the mounting flange 166. The combustion portion 110 has an injection port 111, which is used for the combustion and injection of flames. The ignition device 100 also includes an ignition and flame stabilization assembly, which is at least partially located in the combustion portion 110. In other words, the ignition and flame stabilization assembly is partially arranged in the extension portion 170, partially arranged in the combustion portion 110, and the other part extends from the injection port 111. The radial dimension of the extension portion 170 is preferably smaller than the radial dimension of the premixing portion 160.

[0058] When the equipment is running, the fuel gas and the combustion-supporting gas enter the premixing section 160, are evenly mixed under the action of the graded swirl device 190, enter the combustion section 110 through the extension section 170, and are ignited to form a stable flame under the action of the ignition and flame stabilization assembly.

[0059] Please refer to the following Figure 1 , Figure 4 , Figure 5 and Figure 6 . The ignition and flame stabilization assembly includes a flame stabilization device 120, an ignition device 130, an ion flame detection device 140, a signal enhancement device 150 and a honeycomb portion 180. Among them, the honeycomb portion 180 is arranged in the extension portion 170, and its outer peripheral surface abuts against the inner peripheral surface of the extension portion 170. Specifically, the honeycomb portion 180 is stuck in the extension portion 170 perpendicular to the circumference of the extension portion 170. A plurality of through holes 181 are provided on the honeycomb portion 180. Among them, two large through holes are arranged in the radial direction of the honeycomb portion 180 for the passage of the ignition device 130 and the ion flame detection device 140. Other small through holes (i.e., the above-mentioned through holes 181) are distributed on both sides of the above-mentioned two large through holes. As a result, the mixed gas can be accelerated in the honeycomb portion 180, and the arrangement of the through holes 181 is conducive to the formation of a reflow zone at the flame during combustion.

[0060] For the specific structure of the flame stabilizing device 120, please refer to Figure 4 , Figure 5 , Figure 7and Figure 8 . It includes a disc-shaped flame-stabilizing body 121 and a connecting portion 123. One end of the connecting portion 123 is connected to the middle of the honeycomb portion 180, and the other end is connected to the middle of the flame-stabilizing body 121, and the flame-stabilizing body 121 is arranged facing the injection port 111. The circumferential cross-section of the flame-stabilizing device 120 along the combustion portion 110 is roughly formed into a "T" shape. Thus, the flame-stabilizing device 120 can be fixed on the honeycomb portion 180. Preferably, the flame-stabilizing body 121 can be coaxially arranged with the combustion portion 110. It is easy to understand that the area of ​​the flame-stabilizing body 121 is obviously smaller than the radial cross-sectional area of ​​the combustion portion 110. For example, the area of ​​the flame-stabilizing body 121 can be 10% to 90% of the radial cross-sectional area of ​​the combustion portion 110, preferably 30% to 70%, and more preferably 40% to 60%.

[0061] refer to Figure 4 , Figure 5 and Figure 7 , a first through hole 122 and a second through hole 124 are provided on the flame stabilizing body 121. It is easy to understand that a third hole (e.g., a threaded blind hole, not a through hole) can also be provided on the flame stabilizing body 121 to install the connecting portion 123. Preferably, the flame stabilizing body 121 and the connecting portion 123 are constructed as an integral piece, that is, the two are integrally formed, and only two through holes are provided on the flame stabilizing body 121, namely, the first through hole 122 and the second through hole 124 mentioned above.

[0062] Among them, one end of the ignition device 130 extends into the first through hole 122 and is located at the first through hole 122, and the other end passes through the large through hole on the honeycomb part 180 and is electrically connected to the control device. The ignition device 130 can be constructed as an ignition electrode, which can discharge to the flame stabilizing body 121. Due to the presence of the first through hole 122, the discharge arc will be fan-shaped. In this way, the mixed gas can be ignited more easily, especially when the flow rate of the mixed gas is extremely fast. One end of the ion flame detection device 140 extends to the outside of the combustion part 110 through the injection port 111, and the other end passes through another large through hole on the honeycomb part 180 and is electrically connected to the control device.

[0063] The ion flame detection device 140 is used to detect the electrical signal when the flame is burning, so as to judge the flame state according to the strength and fluctuation of the electrical signal. Specifically, ions are generated when the flame is burning, which have a unidirectional conductive property. When a potential is applied to the end of the ion flame detection device 140, a loop can be formed through the flame and the grounded device housing to generate a weak current, thereby obtaining an electrical signal.

[0064] Furthermore, the above-mentioned flame stabilizing body 121 is arranged to be approximately a solid plate, which can decelerate and redirect the high-speed mixed airflow to a certain extent, so that the mixed airflow is more likely to form two rotating vortices on the side of the flame stabilizing body 121 facing the injection port 111 to form a recirculation zone, and no flameout will occur during high-power operation. Utilizing the flame stabilization principle of the recirculation zone, the high-temperature flue gas generated by the combustion of the mixed gas flows back to the recirculation zone at the flame stabilizing disk under the recirculation effect of the rotating vortex. The recirculation of the high-temperature flue gas makes the gas in this area have a very high temperature, and the stable high-temperature zone can continue to ignite the flame after the flame is formed, so that the flame can burn stably.

[0065] However, since the ignition device 100 of the present invention can be operated at high power, the flow rate of the internal mixed gas is very fast, the ion concentration at the end of the ion flame detection device 140 will be reduced, and the contact between the flame and the outer shell of the combustion part 110 will be weakened, which may easily cause signal attenuation and poor stability. For this reason, a signal enhancement device 150 is provided. For details, please refer to Figure 4 , Figure 6 , Figure 7 , Fig. 9 and Fig.10 The structure is a grounding probe. One end of the signal enhancement device 150 is connected to the flame stabilizing body 121, and the other end extends out of the injection port 111. The signal enhancement device 150 is arranged close to the ion flame detection device 140 and separated from the ion flame detection device 140. In addition, the portion of the signal enhancement device 150 outside the injection port 111 preferably has a fork.

[0066] For example, the signal enhancement device 150 may include a main body 151, a first bending portion 152, and a second bending portion 153. The first bending portion 152 is located at the end of the main body 151 outside the injection port 111, and is bent toward the first side of the ion flame detection device 140. The second bending portion 153 is spaced apart from the first bending portion 152, or is arranged with a span. That is, the second bending portion 153 is closer to the injection port 111 than the first bending portion 152.

[0067] The second bent portion 153 is bent from the main body 151 toward the second side opposite to the first side of the ion flame detection device 140. Thus, the included angle between the projections of the first bent portion 152 and the second bent portion 153 on the radial cross section of the combustion portion 110 is 80-100°. For example, Figure 7 and Fig.10 The angle α between the first bending portion 152 and the second bending portion 153 shown in FIG. 1 is 90°. It is easy to understand that more bending portions can be provided according to the needs of signal strength, which will not be described in detail here.

[0068] As a result, an electrical circuit can be formed between the signal enhancement device 150 and the ion flame detection device 140 via the ions generated by combustion, thereby enhancing the electrical signal detected by the ion flame detection device 140 and forming a stable signal supplement when the speed of the mixed gas is too fast.

[0069] Please refer to the following Figure 1 , Figure 2 and Figure 3 As described above, the graded swirl device 190 in the premixing section 160 can fully mix the fuel gas and the combustion-supporting gas. The graded swirl device 190 includes at least two swirl disks, such as 2, 3, 4, 5 or more. At least two swirl disks are arranged at intervals along the axial direction of the premixing section 160, and the outer periphery of the swirl disk abuts against the inner periphery of the premixing section 160. That is, the swirl disk is arranged perpendicular to the axial direction of the premixing section 160.

[0070] The swirl disk is provided with a plurality of openings 193 which are inclined along the axial direction of the swirl disk and extend roughly along the radial direction of the swirl disk. Thus, the gas can turn when passing through the above-mentioned openings 193 to form a rotating flow trajectory. Preferably, the number of openings 193 on at least two swirl disks increases step by step in the direction away from the extension portion 170. That is, reducing the degree of swirl along the direction of travel of the gas is more conducive to uniform mixing without causing excessive loss to the gas velocity. Among them, the larger the inclination angle of the opening 193, the better the mixing effect.

[0071] Specifically, in this embodiment, two swirl discs are provided, namely, a primary swirl disc 191 and a secondary swirl disc 192. The primary swirl disc 191 is further away from the extension portion 170 than the secondary swirl disc 192. That is, the gas first passes through the primary swirl disc 191 and then passes through the secondary swirl disc 192.

[0072] The connection point between the combustion-supporting gas channel 162 and the premixing section 160 is located on the side of the primary swirl disk 191 away from the extension portion 170. The combustion-supporting gas channel is connected to the fuel gas nozzle 163 disposed in the premixing section 160, and the nozzle of the fuel gas nozzle 163 is located between the primary swirl disk 191 and the secondary swirl disk 192.

[0073] Specifically, the end of the fuel gas nozzle 163 near the extension portion 170 is configured as a closed end 164, and the closed end 164 extends through the primary swirl disk 191. A plurality of nozzles 165 are circumferentially arranged on the side wall of the tube body near the closed end 164, and the plurality of nozzles 165 face the inner wall of the premixing portion 160 along the radial direction of the premixing portion 160. Thus, the combustion-supporting gas can first swirl, and then violently mix with the fuel gas injected in the radial direction and then undergo a secondary swirl, which can greatly improve the uniformity of the mixing. Especially when the equipment is running at high power, this method can evenly mix the fuel gas and the combustion-supporting gas at an extremely fast flow rate.

[0074] According to the ignition device 100 of the present invention, a flame stabilizing device 120 is arranged in the combustion part 110, which can stabilize the flame when the gas flow rate in the device is very fast, and avoid the occurrence of flameout; the ignition device 130 extends into the first through hole 122 on the flame stabilizing device 120, which can form a fan-shaped arc during ignition, which is conducive to the successful ignition of the high-speed airflow; the cooperation of the ion flame detection device 140 and the signal enhancement device 150 can stably detect the combustion of the high-speed airflow; and the graded swirl device 190 can still make the airflow evenly mixed under the high flow rate state. Therefore, stable ignition and combustion can be achieved under the conditions of high gas pressure and / or flow rate, and then stable combustion can be achieved under the high-power operation state of the ignition device 100.

[0075] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present invention. The features described herein in one embodiment may be applied to another embodiment individually or in combination with other features, unless the feature is not applicable or otherwise specified in the other embodiment.

[0076] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. An ignition device, characterized in that: The ignition device comprises a combustion part for burning and spraying a flame and an ignition and flame-stabilizing component, wherein the combustion part comprises a spray port, and the ignition and flame-stabilizing component is at least partially arranged in the combustion part to ignite the fuel gas in the combustion part to generate a flame, and the ignition and flame-stabilizing component comprises: A flame stabilizing device, wherein the flame stabilizing device has a disc-shaped flame stabilizing body, the flame stabilizing body is arranged facing the injection port, and a first through hole is arranged on the flame stabilizing body; an ignition device, the ignition device extending into the first through hole; an ion flame detection device extending through the injection port to the outside of the combustion portion; and A signal strengthening device, wherein the signal strengthening device is configured for grounding and extends to the outside of the combustion portion, and the signal strengthening device is arranged close to the ion flame detection device and separated from the ion flame detection device, so that an electrical circuit can be formed between the signal strengthening device and the ion flame detection device via ions generated by combustion, thereby strengthening the electrical signal detected by the ion flame detection device. The signal enhancement device comprises a main body, an end of the main body is provided with a first bending portion, the first bending portion is bent toward a first side of the ion flame detection device, The ignition device also includes: a premixing section, wherein the premixing section is connected to the fuel gas channel and the combustion-supporting gas channel so that the fuel gas and the combustion-supporting gas can be premixed; and an extension portion connected between the premixing portion and the combustion portion; The ignition and flame stabilization assembly further includes a honeycomb portion, the honeycomb portion is provided with a plurality of through holes, the honeycomb portion is arranged on the extension portion, and the outer circumference of the honeycomb portion abuts against the inner circumference of the extension portion. The flame stabilizing device further includes a connecting portion, which extends along the axial direction of the combustion portion and is connected between the middle portion of the honeycomb portion and the middle portion of the flame stabilizing body; The signal enhancement device is connected to the flame stabilizing body; The ignition device and the ion flame detection device extend through the honeycomb portion and are electrically connected to the control device; and At most two through holes are arranged on the flame stabilizing body.

2. The ignition device according to claim 1, characterized in that The signal enhancement device further comprises a second bending portion, the second bending portion is separated from the first bending portion, and the second bending portion is bent from the main body toward a second side of the ion flame detection device, and the second side is opposite to the first side.

3. The ignition device according to claim 2, characterized in that The included angle of the projections of the first bending portion and the second bending portion on the radial cross section of the combustion portion is 80-100°.

4. The ignition device according to claim 1, characterized in that A graded swirl device is arranged in the premixing section, and the graded swirl device includes at least two swirl disks so that the fuel gas and the combustion-supporting gas can be fully mixed. The at least two swirl disks are arranged at intervals along the axial direction of the premixing section, and the outer periphery of the swirl disk abuts against the inner periphery of the premixing section. The swirl disk is provided with a plurality of openings which are inclined along the axial direction of the swirl disk and extend approximately along the radial direction of the swirl disk.

5. The ignition device according to claim 4, characterized in that The graded swirl device includes a primary swirl disk and a secondary swirl disk, the secondary swirl disk is closer to the extension portion than the primary swirl disk, the premixing portion also includes a fuel gas nozzle connected to the fuel gas channel, the end of the fuel gas nozzle close to the extension portion is configured as a closed end, the closed end extends through the primary swirl disk and is located between the primary swirl disk and the secondary swirl disk, and a side wall of the tube body close to the closed end is circumferentially provided with a plurality of nozzles, and the plurality of nozzles are directed toward the inner wall of the premixing portion along the radial direction of the premixing portion.

6. The ignition device according to claim 4, characterized in that The numbers of the openings on the at least two swirl disks of the graded swirl device are gradually increased in a direction away from the extension portion.

7. The ignition device according to claim 1, characterized in that The radial dimension of the extending portion is smaller than the radial dimension of the premixing portion.

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