Low nitrogen oxide burner structure

Abstract

The invention discloses a low-nitrogen oxide burner structure which comprises an air inlet barrel, an air barrel, a fire gathering cover, a flame stabilizing barrel, a gas main pipe and a gas ejector with an ejection pipe. The air inlet barrel, the air barrel, the fire gathering cover and the flame stabilizing barrel are sequentially in butt joint and communicated to be used for conveying air, the gas main pipe is arranged in the air barrel, and the gas main pipe is branched into a plurality of gas branch pipes. A center air pipe is arranged in the center of the flame stabilizing barrel, a plurality of blades are arranged in the flame stabilizing barrel around the center air pipe, and gaps between the adjacent blades form outer air through grooves. The gas branch pipes extend into inlets of the injection pipes in a one-to-one correspondence mode with gaps, and the injection pipes are arranged around the flame stabilizing barrel by a circle. A two-stage air conveying channel is formed by the central air pipe and the outer air through groove, and a fuel gas input channel is formed by the injection pipe. The mixing uniformity of air and fuel gas is enhanced, graded conveying of the fuel gas and the air is achieved, combustion flames are stable, flue gas can flow back for combustion, and meanwhile generation of nitric oxide is reduced.

Description

Technical Field

[0001] The invention relates to a gas burner, and in particular to a burner structure capable of producing low nitrogen oxides. Background Art

[0002] For this reason, the country's environmental protection requirements are becoming increasingly stringent. The latest atmospheric emission standards have reduced the emission of pollutants such as smoke concentration, NOx (nitrogen oxides), and CO. Therefore, whether it is to respond to the strict requirements of national policies on emissions, or the environmental protection needs of energy conservation and emissions caused by the large-scale use of various fuel gases, the development of burners with low NOx emissions will become a key factor in resolving these contradictions. Thermal NOx is nitrogen oxides generated by the oxidation of N2 (nitrogen) in the combustion air at high temperatures. The amount of thermal NOx generated is related to the flame temperature, oxygen concentration and residence time in the high temperature zone, and is not affected by the fuel composition. The higher the combustion temperature, the more NOx is generated. In actual combustion, the temperature distribution in the furnace is not uniform. Even if the average temperature of the flame is not high, a large amount of NOx is still generated at the local high temperature, which plays a decisive role. Most of the existing burners use diffusion combustion. In order to ensure sufficient combustion, the burner generally adopts a design method with better mixing of fuel and air. This type of combustion has a high flame temperature and a large area of ​​high temperature zone, which is easy to produce a large amount of NOx.

[0003] In order to solve the technical problem of excessively high temperature in the combustion high temperature zone generating a large amount of NOx. The prior art has proposed a variety of solutions, such as the Chinese patent with the patent publication number "CN101089467A" which discloses a low nitrogen oxide gas burner, in which the fuel is ejected through a plurality of inclined branch pipes, and the air flows through the inclined groove of the swirl disk. After the two are mixed, an airflow rotating toward the periphery is formed and burned. At the same time, the front part of the combustion tube with a large inclination angle is used to form a secondary reflux air to reduce the flame temperature. This form is conducive to reducing the generation of nitrogen oxides. However, this technology is prone to flameout due to the serious deviation of the flame area from the center area of ​​the combustion tube, and the flame is also easy to burn the inner wall of the furnace; in addition, the single mixing method of the branch pipe and the air also makes the mixing uneven, resulting in incomplete combustion.

[0004] Therefore, there is an urgent need for a low-nitrogen oxide burner structure with a stable combustion flame and flue gas that can reflux and burn, thereby reducing the generation of nitrogen oxides. Summary of the invention

[0005] The object of the present invention is to provide a low-nitrogen oxide burner structure capable of reducing the generation of nitrogen oxides, wherein the low-nitrogen oxide burner structure has a stable combustion flame and the smoke can be refluxed for combustion.

[0006] To achieve the above object, the present invention provides a low nitrogen oxide burner structure, which includes:

[0007] Air inlet;

[0008] A wind tube, the rear end of which is connected to the front end of the air inlet tube in a sealed butt connection, and the front end of which contracts inwardly to form a contraction wind tube;

[0009] A fire hood, wherein the fire hood is a cylindrical structure, and the rear end of the fire hood is connected to the front end of the contraction air cylinder;

[0010] A flame stabilizing cylinder, the flame stabilizing cylinder is embedded and fixed in the port at the front end of the fire hood, a central air pipe is arranged at the center of the flame stabilizing cylinder, a plurality of blades are arranged around the central air pipe in the flame stabilizing cylinder, and the gaps between adjacent blades form external air passages;

[0011] A gas main pipe, the front end of which extends into the air inlet cylinder and branches into a plurality of gas branch pipes, the gas branch pipes being arranged around the gas main pipe;

[0012] A gas ejector, the gas ejector comprising an ejector pipe, the gas branch pipes correspondingly extend into the inlet of the ejector pipe with a gap, the ejector pipe is laid along the axial direction of the cage fire cover and the outlet exceeds the flame stabilizing tube, and the ejector pipe is arranged around the flame stabilizing tube;

[0013] The front ends of the air inlet duct, wind duct, contraction wind duct, fire hood, gas main pipe and the central axis of the central air pipe are all located on the same straight line; the air inlet duct, wind duct, contraction wind duct, fire hood and central air pipe are connected in sequence by airflow to form a central air outlet channel; the air inlet duct, wind duct, contraction wind duct, fire hood and external air groove are connected in sequence by airflow to form an external air outlet channel; the external air outlet channel is arranged around the central air outlet channel; the gas main pipe, gas branch pipe and ejector pipe are connected in sequence by airflow to form a gas direct injection channel, and the gas direct injection channel is arranged around the external air inlet channel.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention forms a contraction wind tube with a smaller diameter by contracting the front end of the wind tube inward, and combines the configuration of the central air outlet channel and the external air outlet channel of the present invention. The air passing through the contraction wind tube is pressurized and the flow rate is accelerated; the flow rate of the air blown out from the central air outlet channel and the air blown out from the external air outlet channel is accelerated and the injection force is strengthened, thereby increasing the air coverage area entering the combustion zone of the present invention, and at the same time increasing the oxygen supply per unit time in the combustion zone; the increase in the air coverage area entering the combustion zone effectively improves the mixing uniformity of the gas entering the combustion zone and expands the combustion zone; strengthens the mixing uniformity of air and gas and increases the area of ​​the combustion zone; not only can the gas in the combustion zone be burned more fully, but also the area of ​​the high-temperature zone in the combustion zone is greatly reduced. As a result, the present invention reduces the generation of CO while also reducing the generation of nitrogen oxides, and also improves the combustion efficiency and increases the heating efficiency. (2) In the present invention, the air and gas entering the combustion zone are transported through independent channels, wherein the air is ejected through two channels, the air center outlet channel and the air exterior outlet channel, and the gas is ejected through the gas direct injection channel. At the same time, the outlet of the air outlet channel of the present invention is arranged around the outlet of the air center outlet channel, and the outlet of the gas direct injection channel is arranged around the outlet of the air center outlet channel; the two-level classification of air and the classification layout of air and gas are effectively realized, so that an approximately coaxial three-level annular combustion zone is formed in the combustion area, that is, the first-level annular combustion zone where the air and gas are mixed and burned by the air center outlet channel located in the center, the second-level annular combustion zone where the air and gas are mixed and burned by the air outlet channel located in the middle, and the third-level annular combustion zone where the gas and air are mixed by the gas direct injection channel located in the outermost part; the above-mentioned three-level annular combustion zones are distributed in an approximately coaxial annular manner to form the main combustion zone, and the cross-section of the combustion zone is stacked in a distribution shape, forming a multi-level stacked flame, forming a stable combustion flame, effectively avoiding the occurrence of flameout, and also expanding the combustion area, so that the area of ​​the high-temperature area in the combustion area is greatly reduced, the flame temperature of the flame in the high-temperature area is reduced, the generation of nitrogen oxides is reduced, and the heating efficiency is increased. (3) The gas branch pipes of the present invention extend into the inlet of the ejector pipe with a gap in a one-to-one correspondence, so that the gap between the two forms a reflux inlet for the smoke generated by combustion to reflux. The high temperature in the combustion area increases the air pressure, and combined with the injection effect of the gas and air, the smoke generated by combustion in the combustion area moves toward the wind tube. When the smoke moves to the reflux inlet, the inlet of the ejector pipe is inserted into the gas branch pipe that transports the gas at a positive pressure. According to the Bernoulli principle, it can be known that a negative pressure will be formed outside the open reflux inlet.Therefore, the flue gas moved to the reflux inlet will be sucked into the ejector pipe from the reflux inlet in a reflux manner and ejected together with the fuel gas; the present invention forms a flue gas internal circulation system, greatly reducing the generation and emission of nitrogen oxides, so that the burner structure of the present invention can adapt to different working conditions, has a wide range of applications, and has a significant effect in reducing the generation and emission of nitrogen oxides.

[0015] Preferably, in the low nitrogen oxide burner structure of the present invention, the blades are arranged obliquely, so that the outer air passages of the present invention are uniformly distributed in a rotating manner in a clockwise or counterclockwise direction with the central air pipe as the center, so that the present invention realizes flame transition, rotation and diffusion from the inside to the outside, thereby forming a stable swirl flame field in the combustion zone. The swirl flame field serves as a duty fire to stabilize the flame of the entire flow field, providing a stable combustion flame for the present invention, and effectively avoiding the occurrence of flameout and flashback.

[0016] Preferably, in the low nitrogen oxide burner structure of the present invention, the ejector tube branches out an ejector tube branch toward the central air tube, the ejector tube branch is distributed around the central air tube, and the outlet end of the ejector tube branch is located on the extension line of the flame stabilizing tube. The present invention forms a gas branch channel outside the air outlet channel and inside the gas direct injection channel, further strengthening the stacked combustion distribution shape of the combustion zone cross section and the stability of the flame; further forming a stable combustion flame, effectively avoiding the occurrence of flameout, while also reducing the flame temperature of the flame in the high-temperature area, reducing the generation of nitrogen oxides, and increasing the heating efficiency.

[0017] Preferably, in the low nitrogen oxide burner structure of the present invention, the ejector pipe branch is synchronously inclined in the direction in which the blades are inclined, and the outlet end of the ejector pipe branch is facing the airflow direction of the external air slot. The gas branch channel of the present invention is synchronously distributed in a rotating manner around the external air slot as the center. The gas ejected from the gas branch channel is synchronously rotated and ejected at an inclined angle around the air ejected from the external air slot as the center; the rotating air ejected from the external air slot is mixed with the synchronously rotating gas transported from the gas branch pipe channel and burned to form a secondary rotating flame; the secondary rotating flame cooperates with the main rotating flame to make the swirl flame field in the central area of ​​the combustion zone more stable, which strengthens the important role of the swirl flame field as a duty fire to stabilize the flame of the entire flow field, further improves the stability of the combustion flame of the present invention, and effectively avoids the occurrence of flameout and flashback.

[0018] Preferably, in the low nitrogen oxide burner structure of the present invention, the fire hood is expanded outward to form an extension hood, a hollow structure is formed between the fire hood and the extension hood, the hollow structure forms a flame stabilizing buffer cavity, and the ejector tube passes through the extension hood horizontally. The present invention effectively solves the flashback problem by setting the extension hood and the flame stabilizing buffer cavity, and also achieves the purpose of enhancing the flame stability of the entire flow field in the central area.

[0019] Preferably, in the low nitrogen oxide burner structure of the present invention, the inlet of the ejector tube expands outward and extends to form a backflow hood, and the backflow hood is a trumpet-shaped structure. By virtue of the characteristics of the trumpet-shaped structure with a large opening and a small inlet, on the one hand, the speed of the smoke entering the backflow inlet is enhanced, and on the other hand, it plays a guiding role in the smoke entering the backflow inlet.

[0020] Preferably, in the low nitrogen oxide burner structure of the present invention, the connection between the expansion hood and the fire hood is an inclined structure, and the backflow hood is provided with a notch for it to be closely connected with the contraction air cylinder and to make the ejector tube closely connected with the fire hood. Through the notch provided by the backflow hood, the ejector tube can be closely connected with the fire hood, which simplifies the installation process of the ejector tube and makes the structure reasonable and compact.

[0021] Preferably, in the low nitrogen oxide burner structure of the present invention, the expansion cover has a contraction portion that bends and extends into the flame stabilizing buffer chamber, and a notch is correspondingly provided on the contraction portion for the ejector tube to pass through. The contraction portion and the notch can effectively locate and limit the ejector tube, ensuring that it does not tilt in position and angle in a high temperature environment, thereby inducing flame stability of the entire flow field in the combustion area.

[0022] Preferably, in the low nitrogen oxide burner structure of the present invention, the rear end of the gas main pipe is bent and extended to form an external pipe, and the external pipe passes through the air inlet cylinder in a sealed manner.

[0023] Preferably, the low nitrogen oxide burner structure of the present invention further includes a fan connecting flange and a heating furnace connecting flange, wherein the fan connecting flange is sleeved and fixed at the inlet of the air inlet duct; and the heating furnace connecting flange is sleeved and fixed on the air duct. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the low nitrogen oxide burner structure of the present invention.

[0025] Figure 2 It is a partial cross-sectional structural schematic diagram of the present invention.

[0026] Figure 3 yes Figure 1 Schematic diagram of the top view structure. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application are clearly and completely described below in conjunction with specific implementation examples and the accompanying drawings, and the technical solutions of the present invention are explained. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. The specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are explained to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below. Embodiments of the present invention are now described with reference to the accompanying drawings, and similar element numbers in the accompanying drawings represent similar elements.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] like Figure 1 - Figure 3 As shown, the low nitrogen oxide burner structure of the present invention includes an air inlet tube 1, an air tube 2, a fire hood 3, a flame stabilizing tube 4, a gas main pipe 5, and a gas ejector with an ejector tube 6.

[0030] like Figure 1 - Figure 3 As shown, the outside air enters through the air inlet 1 of the present invention, thereby providing oxygen for the present invention; specifically, in order to improve the combustion efficiency of the burner structure of the present invention, the present invention preferably performs pressurized blowing into the air inlet 1 to enhance the flow rate of air entering the air inlet 1, thereby increasing the oxygen supply per unit time. Specifically, a fan connecting flange 12 is fixedly mounted at the inlet 11 of the air inlet 1, and a fan 7 for blowing (i.e., blowing) into the air inlet 1 is installed on the fan connecting flange 12, so that the air outlet of the fan 7 is sealed and connected to the inlet 11 of the air inlet 1.

[0031] like Figure 1 - Figure 3As shown, the present invention further provides a heating furnace connecting flange 8 for facilitating and stably connecting to the heating furnace. The heating furnace connecting flange 8 is sleeved and fixed on the wind tube 2, so that the heating furnace connecting flange 8 is connected and fixed to the present invention, and is detachably connected to an external heating furnace through the mounting hole 81 on the heating furnace connecting flange 8; it can be seen that the present invention can be quickly and conveniently installed on an external heating furnace through the heating furnace connecting flange 8, and at the same time, the area of ​​the front end of the present invention used for combustion extends into the furnace cavity of the heating furnace, thereby providing a heat source for the furnace cavity during operation.

[0032] like Figure 1 - Figure 3 As shown, the present invention is used to deliver air to the combustion zone as follows: the rear end 21 of the air duct 2 of the present invention is connected to the front end of the air inlet duct 1 in a sealed docking connection, so that the air entering from the air inlet duct 1 can smoothly enter the air duct 2; the front end 22 of the air duct 2 of the present invention is contracted inward to form a contraction air duct 23. The fire hood 3 of the present invention is a cylindrical structure, and the rear end 31 of the fire hood 3 is connected to the front end 231 of the contraction air duct 23; so that the air entering from the air inlet duct 1 passes through the air duct 2 and then passes through the contraction contraction air duct 23 to enter the fire hood 3 of the cylindrical structure. The flame stabilizing tube 4 of the present invention is embedded and fixed in the port 32 at the front end of the fire hood 3. A central air pipe 41 is provided at the center of the flame stabilizing tube 4. A plurality of blades 42 are provided around the central air pipe 41 in the flame stabilizing tube 4, and the gaps between adjacent blades form external air grooves 43; thereby, the air entering the fire hood 3 is ejected from the flame stabilizing tube 4 in two stages, one stage is ejected through the central air pipe 41, and the other stage is ejected through the external air grooves 43.

[0033] like Figure 1 - Figure 3As shown, the present invention is used to transport gas to the combustion zone as follows: the gas main pipe 5 of the present invention is used to transport gas from the outside to the combustion zone; specifically, the rear end of the gas main pipe 5 is bent and extended to form an external pipe 5a that can be directly connected to the external gas tank or gas pipeline, and the external pipe 5a passes through the air inlet 1 in a sealed manner. The front end of the gas main pipe 5 extends into the air inlet 1 and branches out a plurality of gas branch pipes 51, and the gas branch pipes 51 are arranged around the gas main pipe 5. The gas branch pipes 51 of the present invention correspond to each other and extend into the inlet 61 of the ejector pipe 6 with a gap. The ejector pipe 6 is laid along the axial direction of the cage fire cover 3 and the outlet 62 exceeds the flame stabilizing tube 4, so as to avoid the gas ejected from the outlet 62 from rushing toward the inside of the flame stabilizing tube 4, causing air and gas to rush from the flame stabilizing tube 4 into the return air tube 2, causing safety accidents such as backfire and flameout. The gas entering the gas main pipe 5 is diverted by the gas branch pipe 51 and enters the gas branch pipe 51. The gas entering the gas branch pipe 51 is ejected into the combustion zone through the corresponding ejector pipes 6. The ejector pipes 6 of the present invention are arranged around the flame stabilizing tube; specifically, the gas branch pipes 51 are evenly distributed around the gas branch pipe 51. Figure 1 - Figure 3 In the illustrated embodiment, the number of the gas branch pipes 51 is eight. Of course, the number of the gas branch pipes 51 may also be three, four, five, six, seven, nine, ten, etc. Those skilled in the art may select the number of the gas branch pipes 51 according to actual needs without any creative labor.

[0034] Continue to combine Figure 1 - Figure 3 As shown, the front ends of the air inlet duct 1, the air duct 2, the contraction air duct 23, the fire hood 3, the gas main pipe 5 and the central axis of the central air pipe 41 of the present invention are all located on the same straight line, that is, the above-mentioned components are coaxially arranged with the central axis of the central air pipe 41 as the center. The air inlet duct 1, the air duct 2, the contraction air duct 23, the fire hood 3 and the central air pipe 41 of the present invention are connected by airflow in sequence to form an air central air outlet channel. The air inlet duct 1, the air duct 2, the contraction air duct 23, the fire hood 3 and the external air groove 43 of the present invention are connected by airflow in sequence to form an air external air outlet channel. The air external air outlet channel of the present invention is arranged around the air central air outlet channel. The gas main pipe 5, the gas branch pipe 51 and the ejector pipe 6 of the present invention are connected by airflow in sequence to form a gas direct injection channel, and the gas direct injection channel is arranged around the external air inlet channel.

[0035] Continue to combine Figure 1 - Figure 3As shown, it can be seen that: (1) The present application forms a contraction wind tube 23 with a smaller diameter by contracting the front end of the wind tube 2 inward, and combines the setting of the central air outlet channel and the external air outlet channel of the present invention. The air passing through the contraction wind tube 23 is pressurized and the flow rate is accelerated; the flow rate of the air blown out from the central air outlet channel and the air blown out from the external air outlet channel is accelerated and the injection force is strengthened, thereby increasing the air coverage area entering the combustion zone (i.e., the furnace cavity) of the present invention, and at the same time increasing the oxygen supply per unit time in the combustion zone; the increase in the air coverage area entering the combustion zone effectively improves the mixing uniformity of the gas entering the combustion zone and expands the combustion zone; strengthens the mixing uniformity of air and gas and increases the area of ​​the combustion zone; not only can the gas in the combustion zone be burned more fully, but also greatly reduces the area of ​​the high-temperature zone in the combustion zone. As a result, the present invention reduces the generation of CO while also reducing the generation of nitrogen oxides, and also improves the combustion efficiency and increases the heating efficiency. (2) In the present invention, the air and gas entering the combustion zone are transported through independent channels, wherein the air is ejected through two channels, the air center outlet channel and the air exterior outlet channel, and the gas is ejected through the gas direct injection channel. At the same time, the outlet of the air outlet channel of the present invention is arranged around the outlet of the air center outlet channel, and the outlet of the gas direct injection channel is arranged around the outlet of the air center outlet channel; the two-level classification of air and the classification layout of air and gas are effectively realized, so that an approximately coaxial three-level annular combustion zone is formed in the combustion area, that is, the first-level annular combustion zone where the air and gas are mixed and burned by the air center outlet channel located in the center, the second-level annular combustion zone where the air and gas are mixed and burned by the air outlet channel located in the middle, and the third-level annular combustion zone where the gas and air are mixed by the gas direct injection channel located in the outermost part; the above-mentioned three-level annular combustion zones are distributed in an approximately coaxial annular manner to form the main combustion zone, and the cross-section of the combustion zone is stacked in a distribution shape, forming a multi-level stacked flame, forming a stable combustion flame, effectively avoiding the occurrence of flameout, and also expanding the combustion area, so that the area of ​​the high-temperature area in the combustion area is greatly reduced, the flame temperature of the flame in the high-temperature area is reduced, the generation of nitrogen oxides is reduced, and the heating efficiency is increased. (3) The gas branch pipes 51 of the present invention extend into the inlet 61 of the ejector pipe 6 with a gap, so that the gap between the two forms a reflux inlet 6a for the smoke generated by combustion to reflux. The high temperature in the combustion area increases the air pressure, and combined with the injection of gas and air, the smoke generated by combustion in the combustion area moves toward the wind tube 2. When the smoke moves to the reflux inlet 6a, the inlet 61 of the ejector pipe 6 is inserted into the gas branch pipe 51 that transports gas at a positive pressure. According to the Bernoulli principle, it can be known that a negative pressure will be formed outside the open reflux inlet 6a.Therefore, the flue gas moved to the reflux inlet 6a will be sucked into the ejector pipe 6 from the reflux inlet 6a in a reflux manner and ejected together with the fuel gas; so that the present invention forms a flue gas internal circulation system, greatly reducing the generation and emission of nitrogen oxides, so that the burner structure of the present invention can adapt to different working conditions, has a wide range of applications, and has a significant effect on reducing the generation and emission of nitrogen oxides. In order to improve the reflux effect of the reflux inlet 6a on the flue gas, the aperture of the end of the gas branch pipe 51 corresponding to the inlet 61 of the ejector pipe 6 is reduced, so that the gas velocity injected into the ejector pipe 6 by the gas branch pipe 51 can be increased, thereby improving the reflux effect of the reflux inlet 6a on the flue gas.

[0036] like Figure 2 and Figure 3 As shown, the blades 42 in the flame stabilizing tube 4 of the present invention are arranged in an inclined manner. The inclined blades 42 make the outer air passages 43 of the present invention uniformly distributed in a rotating manner in a clockwise or counterclockwise direction with the central air tube 41 as the center ( Figure 3 In the embodiment shown, from Figure 3 The angle of view shown is counterclockwise rotation distribution). The inclined blades 42 also make the air ejected by the outer air slot 43 rotate around the air ejected by the central air channel corresponding to the central air pipe 41 at an inclined angle; the rotating air ejected by the outer air slot 43 is mixed with the gas and burned to form a main rotating flame, that is, the second-level annular combustion partition of the present invention forms a main rotating flame, the second-level annular combustion partition is located between the central first-level annular combustion partition and the outermost third-level annular combustion partition, the flame of the first-level annular combustion partition diffuses outward to the second-level annular combustion partition under the inward rotation of the main rotating flame of the second-level annular combustion partition, and the main rotating flame of the second-level annular combustion partition expands to the third-level annular combustion partition under its own outward rotation, so that the present invention realizes flame transition, rotation and diffusion from the inside to the outside, thereby forming a stable swirl flame field in the combustion zone, the swirl flame field as a duty fire stabilizes the flame of the entire flow field, provides a stable combustion flame for the present invention, and effectively avoids the occurrence of flameout and flashback.

[0037] like Figure 1 - Figure 3As shown, the ejector tube 6 of the present invention branches out an ejector tube branch 63 toward the central air tube 41, and the ejector tube branch 63 is distributed around the central air tube 41, and the outlet end 631 of the ejector tube branch 63 is located on the extension line of the flame stabilizing tube 4. The present invention forms a gas branch channel outside the air outlet gas outlet channel and inside the gas direct injection channel by setting the ejector tube branch 63 branched out from each ejector tube 6, and the outlet end 631 of the ejector tube branch 63 is located on the extension line of the flame stabilizing tube 4; the present invention effectively realizes the two-stage classification of gas and the two-stage layout of air by setting the ejector tube branch 63 branched out from each ejector tube 6, and the outlet end 631 of the ejector tube branch 63 is located on the extension line of the flame stabilizing tube 4; thereby, the present invention forms a gas branch channel outside the air outlet gas outlet channel and inside the gas direct injection channel, and the outlet of the gas branch channel is centered on the outlet of the air central outlet gas outlet channel and is arranged around the outlet of the air outlet gas outlet channel; The gas ejected from the gas branch channel of the present invention mixes with air to form a fourth-level annular combustion zone, thereby allowing the present invention to form approximately coaxial four-level annular combustion zones within the combustion area, further enhancing the stacked combustion distribution shape of the combustion zone cross section and the stability of the flame; further forming a stable combustion flame, effectively avoiding the occurrence of flameout, and also expanding the combustion area, greatly reducing the area of ​​the high-temperature zone within the combustion area, reducing the flame temperature of the flame in the high-temperature zone, reducing the generation of nitrogen oxides, and increasing the heating efficiency.

[0038] Continue to combine Figure 1 - Figure 3 As shown, specifically, the ejector branch pipe 63 of the present invention is synchronously inclined in the direction in which the blade 42 is inclined, and the outlet end 631 of the ejector branch pipe 63 is directly in the airflow direction of the external air slot 43. The gas branch channel of the present invention is synchronously distributed in a rotating manner around the external air slot as the center. The gas ejected from the gas branch channel is synchronously and rotatingly ejected at an inclined angle around the air ejected from the external air slot 43 as the center; the rotating air ejected from the external air slot 43 is mixed with the synchronously rotating gas transported from the gas branch pipe channel and burned to form a secondary rotating flame; since the gas branch channel is a branch channel branched from the gas main pipe 5, its caliber is small and inclined to the center, so the combustion area of ​​the secondary rotating flame burns in the central area of ​​the entire combustion area, and the secondary rotating flame cooperates with the main rotating flame in the central area of ​​the combustion area. The swirl flame field in the central area of ​​the combustion area is more stable, which strengthens the important role of the swirl flame field as a duty fire to stabilize the flame of the entire flow field, further improves the stability of the combustion flame of the present invention, and effectively avoids the occurrence of flameout and flashback.

[0039] like Figure 1 - Figure 3As shown, the fire hood 3 of the present invention is expanded outward to form an extension hood 33, and a hollow structure is formed between the fire hood 3 and the extension hood 33, and the hollow structure forms a flame stabilizing buffer chamber 34, and the ejector tube 6 passes through the extension hood 33 horizontally. When the burner is working in the furnace chamber, due to the limited space in the combustion area, the burning flame will have a flashback phenomenon of flashback toward the air inlet duct; when the fire in the combustion area flashes back toward the air inlet duct 1, the flashback will enter the flame stabilizing buffer chamber 34 and be blocked and continue to radiate heat to the central area of ​​the combustion area in the form of thermal radiation. It can be seen that the present invention effectively solves the flashback problem by setting the extension hood 33 and the flame stabilizing buffer chamber 34, and at the same time achieves the purpose of enhancing the flame stability of the entire flow field in the central area.

[0040] like Figure 1 and Figure 2 As shown, the inlet 61 of the ejector tube 6 of the present invention expands outward and extends to form a return hood 64, which is a trumpet-shaped structure. The trumpet-shaped structure has the characteristics of a large opening and a small inlet, which, on the one hand, increases the speed of the smoke entering the return inlet 6a, and on the other hand, plays a guiding role in the smoke entering the return inlet 6a; so that the internal smoke circulation system formed by the present invention has an enhanced ability to process the smoke circulation, and further reduces the generation and emission of nitrogen oxides.

[0041] like Figure 1 and Figure 2 As shown, the connection between the expansion cover 33 and the fire-collecting cover 3 of the present invention is an inclined structure 35, and the return cover 64 is provided with a notch 641, which allows the return cover 64 to be closely connected with the contraction air cylinder 23 and allows the ejector tube 6 to be closely installed with the fire-collecting cover 3. The notch 641 provided in the return cover 64 allows the ejector tube 6 to be closely installed with the fire-collecting cover 3, avoiding the situation where the ejector tube 6 is suspended due to the protrusion of the return cover 64 from the ejector tube 6, simplifying the installation process of the ejector tube 6, and making the structure reasonable and compact.

[0042] like Figure 2 and Figure 3 As shown, the expansion cover 33 of the present invention has a contraction portion 331 that is bent and extended into the flame stabilizing buffer chamber 34, and a notch 332 is correspondingly provided on the contraction portion 331 for the ejector tube 6 to pass through. The contraction portion 331 and the notch 332 can effectively locate and limit the position of the ejector tube 6, ensuring that the ejector tube 6 does not tilt in position and angle in a high temperature environment, thereby inducing flame stability of the entire flow field in the combustion area.

[0043] like Figure 1As shown, in order to further improve the outstanding effects of the present invention in terms of combustion efficiency, energy saving and emission reduction, and safety performance, the present invention has also made the following improvements. The present invention is provided with a damper 71 at the air inlet of the fan 7, and an air regulator 72 for controlling the opening and closing of the damper 71 is provided on the inlet side of the damper 71. A wind pressure switch 9 is also provided on the outer shell of the fan 7, and the wind pressure switch 9 has a positive pressure detection port and a negative pressure detection port, and the opening and closing of the damper 71 are controlled by the positive pressure detection port and the negative pressure detection port; specifically, when working, under normal circumstances, the fan 7 works to blow air into the air inlet tube 1, and then the positive pressure detection port is positive pressure, and the damper 71 is controlled to open by the wind pressure switch 9, and the air regulator 72 controls the opening and closing of the damper 71 according to the actual demand for the amount of air required; when the fan 7 stops working or a serious backfire phenomenon occurs, the negative pressure detection port detects that the state is negative pressure and controls the damper 71 to close by the wind pressure switch 9 to avoid accidents. Furthermore, the present invention is also provided with a flame detector 10 on the side of the air inlet 1 for detecting whether there is backfire entering the air inlet 1. When the flame detector 10 detects a flame, it will issue a corresponding warning message and the system will automatically start emergency stop measures to ensure safety. More specifically, in order to improve the controllability and convenience of gas delivery, the present invention is also provided with an air inlet pipe 5b that can be quickly and conveniently connected to an external gas delivery pipeline or gas tank. The air inlet pipe 5b is connected to the gas main pipe 5. A gas regulating valve 5c is provided on the air inlet pipe 5b. The gas regulating valve 5c is electrically connected to the gas regulating actuator 5d. The gas regulating actuator 5d controls the amount of gas delivered to the gas main pipe 5 by controlling the opening and closing size of the gas regulating valve 5c according to the actual gas demand.

[0044] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. At the same time, what is disclosed above is only the preferred embodiment of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A low nitrogen oxide burner structure, characterized in that: include: Air inlet; A wind tube, the rear end of which is connected to the front end of the air inlet tube in a sealed butt connection, and the front end of which contracts inwardly to form a contraction wind tube; A fire hood, wherein the fire hood is a cylindrical structure, and the rear end of the fire hood is connected to the front end of the contraction air cylinder; A flame stabilizing cylinder, the flame stabilizing cylinder is embedded and fixed in the port at the front end of the fire hood, a central air pipe is arranged at the center of the flame stabilizing cylinder, a plurality of blades are arranged around the central air pipe in the flame stabilizing cylinder, and the gaps between adjacent blades form external air passages; A gas main pipe, the front end of which extends into the air inlet cylinder and branches into a plurality of gas branch pipes, the gas branch pipes being arranged around the gas main pipe; A gas ejector, the gas ejector comprising an ejector pipe, the gas branch pipes correspondingly extend into the inlet of the ejector pipe with a gap, the ejector pipe is laid along the axial direction of the cage fire cover and the outlet exceeds the flame stabilizing tube, and the ejector pipe is arranged around the flame stabilizing tube; The front ends of the air inlet duct, wind duct, contraction wind duct, fire hood, gas main pipe and the central axis of the central air pipe are all located on the same straight line; the air inlet duct, wind duct, contraction wind duct, fire hood and central air pipe are connected in sequence by airflow to form a central air outlet channel; the air inlet duct, wind duct, contraction wind duct, fire hood and external air groove are connected in sequence by airflow to form an external air outlet channel; the external air outlet channel is arranged around the central air outlet channel; the gas main pipe, gas branch pipe and ejector pipe are connected in sequence by airflow to form a gas direct injection channel, and the gas direct injection channel is arranged around the external air inlet channel.

2. The low nitrogen oxide burner structure according to claim 1, characterized in that: The blades are arranged in an inclined manner.

3. The low nitrogen oxide burner structure according to claim 2, characterized in that: The ejector tube branches out ejector tube branches toward the central air tube, the ejector tube branches are distributed around the central air tube, and the outlet ends of the ejector tube branches are located on the extension line of the flame stabilizing tube.

4. The low nitrogen oxide burner structure according to claim 3, characterized in that: The ejector pipe branch is tilted synchronously with the tilting direction of the blades, and the outlet end of the ejector pipe branch faces the airflow direction of the external air passage.

5. The low nitrogen oxide burner structure according to claim 1, characterized in that: The fire-collecting hood is expanded outward to form an extension hood, a hollow structure is formed between the fire-collecting hood and the extension hood, the hollow structure forms a flame-stabilizing buffer cavity, and the ejector tube passes through the extension hood in a horizontal manner.

6. The low nitrogen oxide burner structure according to claim 5, characterized in that: The inlet of the ejector tube expands outward and extends to form a backflow cover, and the backflow cover is a trumpet-shaped structure.

7. The low nitrogen oxide burner structure according to claim 6, characterized in that: The connection between the expansion hood and the fire hood is in an inclined structure, and the return hood is provided with a notch for it to be closely connected with the contraction air cylinder and to make the ejection tube closely connected with the fire hood.

8. The low nitrogen oxide burner structure according to claim 5, characterized in that: The expansion cover has a contraction portion that is bent and extended into the flame stabilizing buffer cavity, and a cutout for the ejector tube to pass through is correspondingly opened on the contraction portion.

9. The low nitrogen oxide burner structure according to claim 1, characterized in that: The rear end of the gas main pipe is bent and extended to form an external pipe, and the external pipe passes through the air inlet cylinder in a sealed manner.

10. The low nitrogen oxide burner structure according to claim 1, characterized in that: It also includes a fan connecting flange and a heating furnace connecting flange. The fan connecting flange is sleeved and fixed at the inlet of the air inlet duct; the heating furnace connecting flange is sleeved and fixed on the air duct.

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