Self-preheating burner with self-cooling shell

Abstract

The utility model discloses a self-preheating burner with a self-cooling shell, which belongs to the technical field of burners and comprises an air conduit, a fixed shell and a combustion chamber are respectively arranged at two ends of the air conduit, the fixed shell is provided with a fuel gas conduit and an ignition electrode which extend into the combustion chamber, and a heat exchanger is sleeved outside the air conduit. A connecting flange is arranged at the end, close to the fixed shell, of the heat exchanger, the heat exchanger is sleeved with a cooling shell, a cooling guide pipe and two air partition plates are arranged in the cooling shell, and the cooling guide pipe and the air partition plates divide the interior of the cooling shell into four air channels guiding combustion-supporting air to flow in sequence. Combustion-supporting air exchanges heat with the flue gas twice in the flowing process in the cooling shell, and then exchanges heat for the third time in the heat exchanger, so that the recycling rate of heat in the flue gas can be increased, the combustion efficiency can be improved, and the temperature of flame during combustion can be reduced so as to reduce the generation of thermal NOx.

Description

Technical Field

[0001] The utility model relates to the technical field of burners, in particular to a self-preheating burner with a self-cooling shell. Background Art

[0002] Industrial production activities are an important cause of energy and environmental problems. Industrial heating equipment in thermal industries such as industrial furnaces and kilns has a relatively large impact on air pollution. As one of the main structures of industrial furnaces, burners will emit a large amount of thermal NOx during their application. With the strengthening of environmental awareness and stricter environmental standards, how to reduce NOx emissions in the thermal industry, especially NOx emissions in the field of high-temperature combustion, has become a top priority. On the other hand, the energy crisis also requires us to achieve energy saving and energy recovery as much as possible on industrial heating equipment. The combustion efficiency of the burner directly determines the energy consumption and pollutant emissions of industrial heating equipment. At present, the self-preheating burner has the characteristics of recovering flue gas heat and has good application prospects. However, the flue gas still carries a large amount of heat after the self-preheating burner recovers the heat, and the heat is transferred to the outer shell of the burner during the flow of the flue gas, making the outer shell of the burner hot and dissipating a large amount of heat. The heat lost through the outer shell is difficult to recycle, which reduces the energy utilization efficiency of the burner.

[0003] A Chinese patent with publication number CN220556173U discloses a low NOx self-preheating burner, comprising a shell, a flue gas duct, an air duct, an end cover, a heat exchanger, a gas duct, a combustion chamber and a burner core, wherein a flue gas duct flange is provided at one end of the flue gas duct, an air duct flange is provided at one end of the air duct, the flue gas duct flange and the air duct flange are respectively arranged at two ends of the shell, the end cover is arranged on the air duct flange, one end of the gas duct is arranged on the end cover, the other end of the gas duct is arranged on the burner core, the burner core is arranged in the combustion chamber, the gas duct and the combustion chamber are both arranged in the air duct, the air duct is arranged in the heat exchanger, the heat exchanger is arranged in the flue gas duct, and a flue gas channel is formed between the outer wall of the heat exchanger and the inner wall of the flue gas duct, an air channel is formed between the inner wall of the heat exchanger and the outer wall of the air duct, and heat exchange fins are provided on the inner wall and the outer wall of the heat exchanger.

[0004] The self-preheating burner disclosed in the above patent provides combustion air multiple times and fuel gas twice in stages, thereby reducing the oxygen concentration in the combustion chamber, prolonging the combustion time, and reducing the combustion intensity in the combustion chamber. The forced reflux dilution of the combustion products further reduces the flame temperature to achieve low NOx emissions. However, the flue gas and the combustion air only undergo heat exchange once, and the heat in the flue gas will be conducted along the flue gas duct to the shell and dissipated, thereby losing a large amount of heat in the flue gas. The burner has a low efficiency in utilizing the heat in the flue gas, so there is still room for improvement. Utility Model Content

[0005] In view of the technical defects existing in the background technology, the utility model proposes a self-preheating burner with a self-cooling shell, which solves the above technical problems and meets the actual needs. The specific technical solution is as follows:

[0006] A self-preheating burner with a self-cooling shell, comprising an air duct, a fixed shell and a combustion chamber are respectively provided at both ends of the air duct, and the fixed shell is provided with a gas duct and an ignition electrode both extending into the combustion chamber;

[0007] The air duct is provided with a heat exchanger outside the casing, an air heat exchange channel is formed between the heat exchanger and the air duct, a connecting flange is provided at one end of the heat exchanger close to the fixed shell, a cooling shell is provided outside the heat exchanger, one end of the cooling shell is fixedly connected to the fixed shell and the other end extends toward the combustion chamber, a smoke channel is formed between the cooling shell and the heat exchanger, a smoke inlet is provided at one end of the smoke channel close to the combustion chamber and a smoke outlet is provided at the other end;

[0008] The cooling shell is hollow inside to form a cooling cavity and is provided with an air inlet connected to the cooling cavity. The connecting flange divides the cooling cavity into a hot air chamber close to the fixed shell side and connected to the air heat exchange channel and a cooling space close to the combustion chamber side. The connecting flange is provided with a flange notch that connects the hot air chamber with the cooling space.

[0009] A cooling duct fixedly connected to the connecting flange is provided in the cooling space, and the cooling duct divides the cooling space into an inner cooling chamber and an outer cooling chamber. A duct gap is provided at one end of the cooling duct close to the combustion chamber for connecting the inner cooling chamber with the outer cooling chamber. Two air baffles are provided in the cooling space, both of which penetrate from the inner cooling chamber to the outer cooling chamber. The two air baffles divide the outer cooling chamber into a first air channel and a second air channel and divide the inner cooling chamber into a third air channel and a fourth air channel. An end of the air baffle close to the connecting flange is provided with a baffle gap for connecting the third air channel with the fourth air channel. The first air channel is connected to the third air channel through the duct gap, and the second air channel is connected to the fourth air channel through the duct gap.

[0010] As a further technical solution of the utility model, the air duct is hollow inside to form a primary air channel, and a surface of the air duct is provided with a plurality of primary air holes connecting the primary air channel with the hot air chamber.

[0011] As a further technical solution of the utility model, the gas conduit and the ignition electrode are both located in the air conduit, the gas conduit is provided with a gas inlet at one end close to the fixed shell and a gas outlet at the other end, and the ignition electrode is provided with an ignition end at one end close to the combustion chamber.

[0012] As a further technical solution of the utility model, a combustion mixing hood is provided in the combustion chamber, and a gas nozzle extending to the outside of the combustion mixing hood is provided at one end of the gas conduit close to the gas outlet.

[0013] As a further technical solution of the utility model, the heat exchanger is provided with a plurality of heat exchange fins penetrating from the air heat exchange channel to the smoke channel.

[0014] As a further technical solution of the utility model, the air inlet is located close to one side of the fixed shell and is connected to the first air channel, and the second air channel is connected to the hot air chamber through the flange notch.

[0015] As a further technical solution of the utility model, the smoke channel is provided with a smoke pipe extending outside the cooling shell, the smoke pipe is sleeved outside the air inlet, and the smoke outlet is located at one end of the smoke pipe away from the smoke channel.

[0016] As a further technical solution of the utility model, an air disk is provided at one end of the air heat exchange channel close to the combustion chamber, and a plurality of hot air holes penetrate the air disk.

[0017] As a further technical solution of the utility model, a mounting flange is provided outside the cooling shell.

[0018] The beneficial effects of the utility model are:

[0019] The interior of the cooling shell of the utility model is separated by air ducts and air partitions to form four air channels for guiding the combustion air to circulate in sequence. During the flow of the combustion air in the cooling shell, the combustion air absorbs heat in the cooling shell to reduce its temperature and exchanges heat with the flue gas in the flue gas channel twice, thereby improving the recovery rate of heat in the flue gas. The combustion air that has completed two heat exchanges is divided into primary air and secondary air through the air duct in the hot air chamber. The primary air is mixed with the fuel gas and ignited as the basis for burner combustion. The secondary air exchanges heat with the flue gas for the third time through the heat exchanger, thereby further improving the recovery rate of heat in the flue gas. The combustion air with increased temperature after heat exchange can also improve the combustion efficiency. Moreover, the secondary air and the primary air are burned separately to realize the staged combustion of the combustion air, which can reduce the temperature of the flame during combustion to reduce the generation of thermal NOx. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The schematic diagram is a structural diagram of a self-preheating burner with a self-cooling shell.

[0021] Figure 2 yes Figure 1 Sectional view of AA.

[0022] Figure 3 yes Figure 1 Cross-sectional view of BB.

[0023] Figure 4 A schematic diagram of the combustion air flow path of a self-preheating burner with a self-cooling shell.

[0024] Figure 5 yes Figure 1 Partial schematic diagram of C in the figure.

[0025] Figure 6 The present invention is a schematic structural diagram of a second embodiment of a self-preheating burner having a self-cooling shell.

[0026] Figure 7 The present invention is a schematic structural diagram of a third embodiment of a self-preheating burner having a self-cooling shell.

[0027] Figure 8 yes Figure 7 Middle DD section view.

[0028] Among them: air duct 1, combustion chamber 11, primary air channel 12, primary air hole 13, combustion mixing hood 14, wind disk 15, fixed shell 2, gas duct 3, gas inlet 31, gas outlet 32, gas nozzle 33, ignition electrode 4, ignition end 41, heat exchanger 5, air heat exchange channel 51, smoke channel 52, smoke inlet 53, smoke outlet 54, heat exchange fins 55, smoke pipe 56, connecting flange 6, flange notch 61, cooling shell 7, air inlet 71, hot air chamber 72, cooling duct 73, duct notch 731, air baffle 74, baffle notch 741, first air channel 75, second air channel 76, third air channel 77, fourth air channel 78, mounting flange 8. DETAILED DESCRIPTION

[0029] The implementation methods of the present invention are described below in conjunction with the accompanying drawings and relevant embodiments. The implementation methods of the present invention are not limited to the following embodiments, and the present invention involves relevant necessary components in this technical field, which should be regarded as common knowledge in this technical field and can be known and mastered by technical personnel in this technical field.

[0030] like Figure 1-4As shown, a self-preheating burner with a self-cooling shell comprises an air duct 1, wherein a fixed shell 2 and a combustion chamber 11 are respectively arranged at both ends of the air duct 1, and the fixed shell 2 is provided with a gas duct 3 and an ignition electrode 4 both extending into the combustion chamber 11; a heat exchanger 5 is arranged outside the air duct 1, and an air heat exchange channel 51 is formed between the heat exchanger 5 and the air duct 1, and a connecting flange 6 is arranged at one end of the heat exchanger 5 close to the fixed shell 2, and a cooling shell 7 is arranged outside the heat exchanger 5, and one end of the cooling shell 7 is fixedly connected to the fixed shell 2 and the other end extends toward the combustion chamber 11, and a smoke channel 52 is formed between the cooling shell 7 and the heat exchanger 5, and a smoke inlet 53 is arranged at one end of the smoke channel 52 close to the combustion chamber 11 and a smoke outlet 54 is arranged at the other end; the cooling shell 7 is hollow inside to form a cooling cavity and is provided with an air inlet 71 connected to the cooling cavity, and the connecting flange 6 divides the cooling cavity into a hot air chamber 72 close to one side of the fixed shell 2 and connected to the air heat exchange channel 51, and a hot air chamber 72 close to the combustion chamber A flange notch 61 is provided on the cooling space on one side of the combustion chamber 11, and the connecting flange 6 is provided with a cooling duct 73 fixedly connected to the connecting flange 6, and the cooling duct 73 divides the cooling space into an inner cooling chamber and an outer cooling chamber. The cooling duct 73 is provided with a duct notch 731 at one end thereof close to the combustion chamber 11, and two air baffles 74 are provided in the cooling space, both of which penetrate from the inner cooling chamber to the outer cooling chamber. The two air baffles 74 divide the outer cooling chamber into a first air channel 75 and a second air channel 76, and divide the inner cooling chamber into a third air channel 77 and a fourth air channel 78. The air baffle 74 is provided with a baffle notch 741 at one end thereof close to the connecting flange 6, and the third air channel 77 is connected with the fourth air channel 78. The first air channel 75 is connected with the third air channel 77 through the duct notch 731, and the second air channel 76 is connected with the fourth air channel 78 through the duct notch 731.

[0031] The self-preheating burner of the utility model is used to be installed in industrial heating equipment such as industrial furnaces, and is heated by the flame generated by combustion, wherein the fixed shell 2 is a structure for connecting and fixing most components in the burner, and fixes structures such as the air duct 1, the gas duct 3, the ignition electrode 4, and the cooling shell 7 to form the burner structure of the utility model; the working principle of the burner is as follows: the air duct 1 guides the combustion air into the combustion chamber 11, and the gas duct 3 guides the gas into the combustion chamber 11, and the combustion air and the gas are mixed and ignited by the ignition electrode 4 to generate a flame, and the flame is ejected from the combustion chamber 11 to heat the product in the industrial heating equipment such as industrial furnaces.

[0032] After adopting the above structure, it needs to be further explained that, referring to Figure 5The air duct 1 is hollow inside to form a primary air channel 12, and a plurality of primary air holes 13 are provided on the surface of the air duct 1 to connect the primary air channel 12 with the hot air chamber 72; the combustion air enters the cooling shell 7 from the air inlet 71, flows through a specific path, and is divided at the primary air holes 13: a part of the combustion air enters the primary air channel 12 from the primary air holes 13 to form the primary air for burner combustion, the primary air flows along the primary air channel 12 to the combustion chamber 11, mixes with the fuel gas, and is ignited by the ignition electrode 4 as the basis for burner combustion, and the smoke generated by the flame combustion in the industrial heating equipment will enter from the smoke inlet 53 The flue gas passage 52 contains a part of the combustion air; the other part of the combustion air enters the air heat exchange passage 51 and exchanges heat with the flue gas in the flue gas passage 52 through the heat exchanger 5, thereby recovering the heat carried in the flue gas and increasing the temperature of the combustion air, thereby improving energy utilization efficiency and combustion efficiency. The flue gas after heat exchange is discharged from the flue gas outlet 54, and the combustion air after heat exchange will be ejected from the end of the air heat exchange passage 51 close to the combustion chamber 11 as secondary air to contact the flame and participate in combustion. By realizing staged combustion through primary air and secondary air, the combustion reaction zone can be expanded, which plays a role in reducing the temperature of the flame during combustion, thereby reducing the amount of thermal NOx generated.

[0033] The outer side of the connecting flange 6 of the utility model is fixedly connected to the inner wall of the cooling shell 7 and divides the cooling cavity into a hot air chamber 72 and a cooling space. The cooling space is a circular space formed between the cooling shell 7 and the heat exchanger 5. The cooling duct 73 divides the cooling space into an inner cooling chamber and an outer cooling chamber that are coaxial and both are circular. The inner cooling chamber and the outer cooling chamber are connected to each other through the duct notch 731. The two air baffles 74 divide the outer cooling chamber into a first air channel 75 and a second air channel 76 that are both semi-circular in shape, and the air baffle 74 divides the duct notch 731 into two unconnected ends so that the first air channel 75 and the second air channel 76 are not connected at the duct notch 731. At the same time, the two air baffles 74 separate the inner cooling chamber The third air channel 77 and the fourth air channel 78 are separated into semicircular shapes, and the air baffle 74 separates the duct notch 731 so that the third air channel 77 and the fourth air channel 78 are not connected at the duct notch 731. In addition, the air inlet 71 is located close to the side of the fixed shell 2 and is connected to the first air channel 75, and the second air channel 76 is connected to the hot air chamber 72 through the flange notch 61. Therefore, after the combustion air enters the cooling shell 7 from the air inlet 71, it will flow along the first air channel 75, the duct notch 731, the third air channel 77, the baffle notch 741, the fourth air channel 78, the other end of the duct notch 731, the second air channel 76, the flange notch 61, and the hot air chamber 72 in sequence.

[0034] After adopting the above structure, it needs to be further explained that, referring to Figure 4Schematic diagram of the combustion air flow path indicated by the middle arrow, the combustion air enters the first air channel 75 from the air inlet 71, flows to the duct notch 731, enters the third air channel 77, then flows in the third air channel 77 to the partition notch 741 to enter the fourth air channel 78, then flows in the fourth air channel 78 to the other end of the duct notch 731 to enter the second air channel 76, and finally flows in the second air channel 76 to the flange notch 61 to enter the hot air chamber 72; the cooling shell 7 serves as the shell of the outer surface of the burner, and the first air channel 75 and the second air channel 76 are located on the side close to the outer surface of the cooling shell 7. During the flow of the combustion air in the first air channel 75 and the second air channel 76, it can absorb the heat conducted to the cooling shell 7 by the flue gas and industrial heating equipment. Thereby, the temperature of the surface of the cooling shell 7 is reduced and the combustion air is preheated, thereby improving the energy utilization efficiency and the combustion efficiency; when the combustion air flows in the third air channel 77 and the fourth air channel 78, it can pass through the inner side of the cooling shell 7 to perform the first stage heat exchange and the second stage heat exchange with the flue gas in the flue gas channel 52, respectively, to recover the heat in the flue gas and preheat the combustion air, thereby further improving the energy utilization efficiency and the combustion efficiency; the combustion air in the hot air chamber 72 enters the primary air channel 12 from the primary air hole 13 to form the primary air and enters the air heat exchange channel 51 to form the secondary air, and the secondary air performs the third stage heat exchange with the flue gas through the heat exchanger 5 in the air heat exchange channel 51, and further recovers the heat in the flue gas and preheats the combustion air, thereby further improving the energy utilization efficiency and the combustion efficiency.

[0035] The interior of the cooling shell 7 of the utility model is separated by the air duct 1 and the air baffle 74 to form four air channels for guiding the combustion air to circulate in sequence. During the flow of the combustion air in the cooling shell 7, the combustion air absorbs the heat in the cooling shell 7 to reduce its temperature and performs two heat exchanges with the flue gas in the flue gas channel 52, thereby improving the heat recovery rate in the flue gas. The combustion air that has completed two heat exchanges is divided into primary air and secondary air through the air duct 1 in the hot air chamber 72. The primary air is mixed with the fuel gas and ignited as the basis for burner combustion. The secondary air undergoes a third heat exchange with the flue gas through the heat exchanger 5, thereby further improving the heat recovery efficiency in the flue gas. The combustion air with increased temperature after heat exchange can also improve the combustion efficiency. Moreover, the secondary air and the primary air are burned separately to realize the staged combustion of the combustion air, which can reduce the temperature of the flame during combustion to reduce the generation of thermal NOx.

[0036] like Figure 1 As shown, as one of the preferred embodiments of the utility model, the gas conduit 3 and the ignition electrode 4 are both located in the air conduit 1, the gas conduit 3 is provided with a gas inlet 31 at one end close to the fixed shell 2 and a gas outlet 32 ​​at the other end, and the ignition electrode 4 is provided with an ignition end 41 at one end close to the combustion chamber 11.

[0037] The gas conduit 3 and the ignition electrode 4 of the utility model are both fixedly connected to the fixed shell 2 and extend into the combustion chamber 11. The end of the gas conduit 3 close to the gas inlet 31 is connected to a pipeline or equipment for supplying gas. After the gas enters the gas conduit 3 from the gas inlet 31, it is ejected from the gas outlet 32 ​​into the combustion chamber 11 to mix with the combustion-supporting air. The ignition electrode 4 generates high-temperature sparks through the flow of current at the ignition end 41 to ignite the mixture of the gas and the combustion-supporting air, thereby causing the burner to generate flames in the combustion chamber 11.

[0038] like Figure 1 , 2 As shown, as one of the preferred embodiments of the utility model, a combustion mixing hood 14 is provided in the combustion chamber 11 , and a gas nozzle 33 extending to the outside of the combustion mixing hood 14 is provided at one end of the gas conduit 3 close to the gas outlet 32 ​​.

[0039] The combustion mixing hood 14 of the utility model is used to provide a space for mixing the fuel gas and the combustion-supporting air. After the fuel gas and the combustion-supporting air are ignited in the combustion mixing hood 14 to form a flame, the flame is ejected from the flame outlet at the end of the combustion mixing hood 14 away from the fixed shell 2. The shape of the flame outlet in the combustion mixing hood 14 can be adjusted to adjust the shape of the flame; the gas nozzle 33 extends outside the flame outlet, and after the fuel gas flows to the gas outlet 32, a part of the fuel gas will enter the gas nozzle 33 and be ejected near the end of the flame outlet. These gases will contact the flame and participate in combustion, realizing staged combustion of the fuel gas, which can expand the combustion reaction zone and play a role in reducing the temperature of the flame during combustion, thereby reducing the amount of thermal NOx generated.

[0040] like Figure 6 As shown, as one of the preferred embodiments of the present utility model, the heat exchanger 5 is provided with a plurality of heat exchange fins 55 penetrating from the air heat exchange channel 51 to the smoke channel 52 .

[0041] The heat exchanger 5 of the utility model increases the heat exchange area and heat exchange efficiency between the flue gas and the combustion air through a plurality of heat exchange fins 55, and can efficiently transfer the heat in the flue gas to the combustion air, thereby efficiently preheating the combustion air and improving the utilization efficiency of the heat in the flue gas; in addition, the heat exchange fins 55 can extend through the inner side of the cooling shell 7 into the cooling space, so that the heat in the flue gas can be transferred to the combustion air in the cooling space through the heat exchange fins 55, further improving the preheating efficiency of the combustion air and the utilization efficiency of the heat in the flue gas.

[0042] like Figure 7 , 8 As shown, as one of the preferred embodiments of the utility model, the smoke channel 52 is provided with a smoke pipe 56 extending to the outside of the cooling shell 7, the smoke pipe 56 is sleeved outside the air inlet 71, and the smoke outlet 54 is located at one end of the smoke pipe 56 away from the smoke channel 52.

[0043] In the present invention, the smoke pipe 56 is sleeved outside the air inlet 71 , and the smoke will further exchange heat with the combustion-supporting air entering from the air inlet 71 before being discharged from the smoke outlet 54 of the smoke pipe 56 , thereby reducing the temperature of the discharged smoke.

[0044] like Figure 1 , 2 As shown, as one of the preferred embodiments of the present utility model, an air heat exchange channel 51 is provided with an air disk 15 at one end close to the combustion chamber 11, and the air disk 15 is penetrated by a plurality of hot air holes.

[0045] The wind disk 15 of the utility model is used to guide the secondary air to mix with the flame. The size of the hot air hole can be adjusted to change the speed of the secondary air ejection, or the direction of the hot air hole can be adjusted to make the secondary air mix with the flame at a specific angle, thereby changing the way the secondary air and the flame are mixed, and adapting to the combustion intensity of different fuel gases in a specific mixing method. The best way to mix different fuel gases with combustion-supporting air is common knowledge and will not be elaborated here.

[0046] like Figure 1 , 2 As shown, as one of the preferred embodiments of the present utility model, a mounting flange 8 is provided outside the cooling shell 7 .

[0047] The mounting flange 8 of the utility model is used to install the burner on industrial heating equipment such as industrial furnaces. The position of the mounting flange 8 can be adjusted to match the thickness of the furnace wall of the industrial furnace, so that the flame outlet of the burner is closely aligned with the inner side of the furnace wall, so that the burner can heat more efficiently.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A self-preheating burner with a self-cooling housing, comprising an air duct (1), characterized in that: A fixed shell (2) and a combustion chamber (11) are respectively provided at both ends of the air duct (1); the fixed shell (2) is provided with a gas duct (3) and an ignition electrode (4) both extending into the combustion chamber (11); A heat exchanger (5) is disposed on the outer casing of the air duct (1), an air heat exchange channel (51) is formed between the heat exchanger (5) and the air duct (1), a connecting flange (6) is disposed on one end of the heat exchanger (5) close to the fixed shell (2), a cooling shell (7) is disposed on the outer casing of the heat exchanger (5), one end of the cooling shell (7) is fixedly connected to the fixed shell (2) and the other end extends toward the combustion chamber (11), a smoke channel (52) is formed between the cooling shell (7) and the heat exchanger (5), and a smoke inlet (53) is disposed on one end of the smoke channel (52) close to the combustion chamber (11) and a smoke outlet (54) is disposed on the other end; The cooling shell (7) is hollow inside to form a cooling cavity and is provided with an air inlet (71) connected to the cooling cavity; the connecting flange (6) divides the cooling cavity into a hot air chamber (72) close to the fixed shell (2) and connected to the air heat exchange channel (51) and a cooling space close to the combustion chamber (11); the connecting flange (6) is provided with a flange notch (61) that connects the hot air chamber (72) with the cooling space; A cooling duct (73) fixedly connected to the connecting flange (6) is provided in the cooling space, the cooling duct (73) divides the cooling space into an inner cooling chamber and an outer cooling chamber, a duct notch (731) for connecting the inner cooling chamber with the outer cooling chamber is provided at one end of the cooling duct (73) close to the combustion chamber (11), two air baffles (74) are provided in the cooling space, both of which extend from the inner cooling chamber to the outer cooling chamber, the two air baffles (74) divide the outer cooling chamber into a first air channel (75) and a second air channel (76) and divide the inner cooling chamber into a third air channel (77) and a fourth air channel (78), a baffle notch (741) for connecting the third air channel (77) with the fourth air channel (78) is provided at one end of the air baffle (74) close to the connecting flange (6), the first air channel (75) is connected to the third air channel (77) through the duct notch (731), and the second air channel (76) is connected to the fourth air channel (78) through the duct notch (731).

2. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: The air duct (1) is hollow inside to form a primary air channel (12), and a surface of the air duct (1) is provided with a plurality of primary air holes (13) that connect the primary air channel (12) with the hot air chamber (72).

3. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: The gas conduit (3) and the ignition electrode (4) are both located in the air conduit (1); the gas conduit (3) is provided with a gas inlet (31) at one end close to the fixed shell (2) and a gas outlet (32) at the other end; the ignition electrode (4) is provided with an ignition end (41) at one end close to the combustion chamber (11).

4. The self-preheating burner with a self-cooling shell according to claim 3, characterized in that: A combustion mixing hood (14) is provided in the combustion chamber (11), and a gas nozzle (33) extending to the outside of the combustion mixing hood (14) is provided at one end of the gas conduit (3) close to the gas outlet (32).

5. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: The heat exchanger (5) is provided with a plurality of heat exchange fins (55) extending from the air heat exchange channel (51) to the smoke channel (52).

6. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: The air inlet (71) is located close to a side of the fixed housing (2) and is in communication with the first air channel (75); the second air channel (76) is in communication with the hot air chamber (72) via the flange notch (61).

7. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: The smoke passage (52) is provided with a smoke pipe (56) extending to the outside of the cooling shell (7); the smoke pipe (56) is sleeved outside the air inlet (71); and the smoke outlet (54) is located at an end of the smoke pipe (56) away from the smoke passage (52).

8. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: An air disk (15) is provided at one end of the air heat exchange channel (51) close to the combustion chamber (11), and a plurality of hot air holes are penetrated through the air disk (15).

9. The self-preheating burner with a self-cooling shell according to claim 1, characterized in that: The cooling shell (7) is provided with a mounting flange (8) outside.

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