A diffusion type gas burner

Abstract

The present invention provides a diffusion-type gas burner, which relates to the technical field of gas burners. The diffusion-type gas burner comprises a base, the front end of which is open and an air duct for combustion-supporting air to enter is arranged therein; a cylinder, which is a hollow structure with openings at both ends and is arranged at the front end opening position of the base; a rectifying plate is arranged at the front end opening of the cylinder, a main annular gap is formed between the rectifying plate and a baffle ring, and the diameter of the rectifying plate is larger than the diameter of the baffle ring. When the mixed combustion-supporting air and gas are released from the front end of the cylinder, they diffuse toward the surroundings along the radial direction of the flame stabilizing disk under the rectifying effect of the rectifying plate, and when ignited, high-temperature flue gas is formed; the effect of the flat plate rectification makes the radial velocity of the airflow direction of the central flame much higher than the axial velocity, so that the efficiency of eliciting the central flue gas is higher, and more central flue gas reflux will be generated. At the same time, since the radial direction directly points to the peripheral main flame, the stability is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of gas burners, in particular to a diffusion type gas burner. Background Art

[0002] There are many traditional flame stabilization methods, including the perforated plate bluff-body flame stabilization disk and the swirl disk commonly used in diffusion burners. The principle of the flame stabilizer is to form a sufficient amount of central recirculation of high-temperature flue gas on the axis of the flame stabilization disk to serve as a stable ignition source. With the increase in burner power and the requirement for low nitrogen emissions, how to reduce central nitrogen oxide emissions while ensuring flame stabilization has become an important issue.

[0003] The traditional orifice flame stabilizing disk has the weakest support for the main flame and the weakest flame stabilizing ability because the recirculating flue gas has no radial velocity. The swirl disk allows the recirculating flue gas to have a certain radial velocity, which improves the flame stabilizing performance to a certain extent. For example, CN 111059535B discloses a swirl disk of this structure. Another example is CN211040961U, which also discloses the use of a swirl disk to generate an airflow with a tangential velocity. The specific rotating airflow enhances the turbulent mixing of the fuel and the air, and at the same time, a large amount of flue gas is refluxed in the central recirculation zone of the swirl to generate a vortex. The appropriate vortex intensity will produce sufficient radial and axial gradients in the airflow, which will cause the airflow to reverse and produce an annular recirculation area in the center of the flame. The high-temperature gas in the central recirculation area will return to the burner throat, which ensures the ignition of the cold unburned gas, while reducing NOX generation by lowering the flame temperature and reducing the oxygen partial pressure.

[0004] Both of the above flame stabilizing disks cannot effectively reduce the temperature of the center reflow flue gas and the thermal nitrogen oxides of the center flame. The traditional center gas release also basically adopts centralized release, which overlaps with the mixing area of ​​the combustion-supporting air and the combustion area, and is prone to produce transient nitrogen oxides. Summary of the Invention

[0005] The purpose of the present invention is to provide a diffusion gas burner, aiming to solve the problems of insufficient central recirculation flue gas reflow, low radial flow velocity and high central nitrogen oxide emissions in traditional burners.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a diffusion-type gas burner, comprising a base, the front end of which is open and an air duct for combustion-supporting air is provided therein; a barrel, which is a hollow structure with openings at both ends and is provided at the front end opening of the base; a core assembly, which is provided at the axial center of the barrel, the core assembly comprising a central gas pipe, a flame stabilizer and a central air ejector, the central gas pipe comprising an axial central gas pipe, the flame stabilizer comprising a flame stabilizing disk sealed at the front end opening of the barrel and a retaining ring provided at the center of the flame stabilizing disk, and the axial central gas The front end of the tube is located in the baffle ring, so that when the combustion-supporting air from the air duct enters the baffle ring through the rear end opening of the cylinder, it is mixed with the gas released from the front end of the central gas pipe in the baffle ring, and the central wind ejector is used to axially eject the central jet wind at the front end of the cylinder; the rectifying plate is arranged at the front end opening of the cylinder, and a main annular gap is formed between the rectifying plate and the baffle ring, and the diameter of the rectifying plate is larger than the diameter of the baffle ring. When the mixed combustion-supporting air and gas are released from the front end of the cylinder, under the rectifying action of the rectifying plate, they diffuse toward the surroundings along the radial direction of the flame stabilizing disk, and when ignited, high-temperature flue gas is formed.

[0007] A further technical solution of the present invention is that the central gas pipe also includes a radial central gas pipe, which is basically perpendicular to the axial central gas pipe. The radial central gas pipe is connected to the base, thereby providing rear end support for the core head assembly, and the flame stabilizer provides front end support for the core assembly.

[0008] A further technical solution of the present invention is that the core assembly also includes a central wind ejector, which includes a central jet air duct, a rectifier plate installed at the front end of the central jet air duct, and a gas annular gap baffle installed adjacent to the front end of the central jet air duct.

[0009] A further technical solution of the present invention is that the diameter of the central jet air duct is smaller than the diameter of the axial central gas pipe, and both ends of the central jet air duct are arranged to penetrate the axial position of the axial central gas pipe, so that a central gas channel is formed between the central jet air duct and the axial central gas pipe, and the gas annular gap baffle is located at a front end opening position adjacent to the axial central gas pipe, and a gas annular gap is formed between the gas annular gap baffle and the front end surface of the axial central gas pipe, and the gas annular gap is located inside the baffle ring, so that the gas entering the central gas channel is released from the gas annular gap into the baffle ring.

[0010] A further technical solution of the present invention is that a conical inclined surface is provided on the front end surface of the axial central gas pipe and / or the side of the gas annular gap baffle facing the axial central gas pipe, thereby providing a velocity component toward the rectifier plate to the gas released from the gas annular gap.

[0011] A further technical solution of the present invention is that the central air ejector is slidably positioned on the axial central gas pipe. By axially moving the central air ejector relative to the axial central gas pipe, the distance between the gas annular gap baffle and the front end surface of the axial central gas pipe can be increased or decreased, thereby adjusting the size of the gas annular gap.

[0012] A further technical solution of the present invention is that a first screw is provided on the central wind ejector and the central gas pipe, and the central wind ejector is driven to slide relative to the axial axis of the central gas pipe by rotating the first screw.

[0013] A further technical solution of the present invention is that a pipe seat is fixedly connected to the central gas pipe, a valve plate is fixedly connected to the central wind ejector, the first screw rod is rotatably connected to the pipe seat, and the first screw rod is threadedly connected to the valve plate.

[0014] A further technical solution of the present invention is that the flame stabilizer is slidably connected to the axial center gas pipe, and the size of the main annular gap is adjusted by sliding the flame stabilizer along the axial direction of the axial center gas pipe.

[0015] A further technical solution of the present invention is that the flame stabilizer also includes a connecting sleeve sleeved on the outside of the axial center gas pipe, and the connecting sleeve is slidably matched with the axial center gas pipe; the connecting sleeve is connected to the flame stabilizing disk through reinforcing ribs.

[0016] A further technical solution of the present invention is that a second screw is installed on the flame stabilizer and the central gas pipe to drive the flame stabilizer to slide axially relative to the axial central gas pipe.

[0017] A further technical solution of the present invention is that a fixing seat is provided on the axial center gas pipe, an adjusting wire seat is provided on the flame stabilizer, the second screw rod is rotatably connected to the fixing seat, and the second screw rod is threadedly connected to the adjusting wire seat.

[0018] A further technical solution of the present invention is that a jet air duct is arranged in the axial direction of the central jet air duct, and an air duct opening connected to the jet air duct is opened near the rear end of the central jet air duct, and also includes a regulating valve for adjusting the air intake volume entering the jet air duct from the air duct opening.

[0019] The beneficial effects of the present invention are:

[0020] 1. The flat plate rectification makes the radial velocity of the central flame much higher than the axial velocity, which makes the efficiency of the central flue gas more efficient and generates more central flue gas reflux. At the same time, since the radial direction directly points to the peripheral main flame, the stability is higher.

[0021] 2. The center jet wind can cool the temperature of the center return flue gas, so that when the center flue gas participates in the center flame combustion, it can reduce the thermal nitrogen oxides of the center flame;

[0022] 3. Due to the low recirculation speed of the center recirculation flue gas, the early mixing of the center fuel gas released from the main annular gap and the center combustion-supporting air can reduce the instantaneous nitrogen oxides of the center flame. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a three-dimensional diagram of a diffusion burner;

[0024] Figure 2 yes Figure 1 A partial enlarged view of the middle part;

[0025] Figure 3 It is a side view of a diffusion burner;

[0026] Figure 4A yes Figure 3 The cross-section along AA is shown, with the reinforcement ribs omitted.

[0027] Figure 4B It is a schematic diagram of the burner installed in the furnace, showing the direction of the flue gas circulation;

[0028] Figure 5 yes Figure 4A Cross-sectional view of the middle front barrel;

[0029] Figure 6 yes Figure 4A Cross-sectional view of the inner and outer cylinders;

[0030] Figure 7 It is a three-dimensional diagram of the core assembly;

[0031] Figure 8 It is a three-dimensional diagram of the core assembly from another perspective;

[0032] Figure 9 It is a three-dimensional diagram of the central wind ejector;

[0033] Figure 10 This is an exploded view of the center air ejector and valve;

[0034] Figure 11 It is an exploded view of the regulating valve;

[0035] Figure 12 yes Figure 7 A partial enlarged view of point B in the middle;

[0036] Figure 13 It is a side view of the center gas pipe;

[0037] Figure 14 is a cross-sectional view of the core assembly;

[0038] Figure 15 yes Figure 14 A partial enlarged view of point C in the middle;

[0039] Figure 16 yes Figure 15 A modified embodiment of

[0040] Figure 17 It is a three-dimensional diagram of the flame stabilizer;

[0041] Figure 18 It is a side view of the flame stabilizer.

[0042] In the picture:

[0043] 1. Base; 11. Air duct; 12. Induced draft fan;

[0044] 2. Outer cylinder; 21. Gas ring cavity; 22. Outer annular seam; 23. Rectifier cavity; 24. Ring cavity tube; 25. Outer annular seam gas pipe; 26. Connector;

[0045] 3. Front cylinder; 31. Cylinder body; 32. Rectifying cone; 32a. Conical surface;

[0046] 4. Central air ejector; 41. Central jet air duct; 41a. Front end of central jet air duct; 41b. Rear end of central jet air duct; 42. Rectifier plate; 43. Gas annular baffle; 44. Rib plate; 45. Jet air duct; 451. Air duct opening;

[0047] 46. ​​Control valve; 461. Valve seat; 4611. Valve seat opening; 4612. Mounting hole; 462. Valve core; 4622. Valve core opening; 4621. Retaining wall; 463. Adjusting shaft; 464. Valve plate; 4641. Bayonet; 465. Annular mounting groove; 466. Fastening assembly; 4661. Bolt; 4662. Nut.

[0048] 5. Central gas pipe; 51. Axial central gas pipe; 511. Inclined surface; 52. Radial central gas pipe; 53. Central gas channel; 54. Gas annular gap; 55. Pipe seat; 56. Fixing seat;

[0049] 6. Flame stabilizer; 61. Connecting sleeve; 62. Reinforcement rib; 63. Flame stabilizer plate; 631. Ventilation hole; 64. Retaining ring; 65. Adjustment wire seat; 66. Main ring seam;

[0050] 7. First screw rod; 71. Annular limiting groove;

[0051] 8. Second screw rod;

[0052] 9. Gas supply device; 91. Annular cavity gas inlet pipe; 92. Center gas inlet pipe; 93. Valve group;

[0053] 10. Furnace; DETAILED DESCRIPTION

[0054] First of all, the main flame area of ​​the traditional diffusion burner is still mixing and burning. During operation, the burner is divided into a combustion area and a mixing area. The two areas may overlap or not. Since the mixing of gas and combustion air requires a process, there must be a gas concentration gradient in the mixing area. The closer the area is to the gas release port, the higher the gas concentration. When the mixing area and the combustion area overlap, when the area with excessive gas concentration is in the overlapping area, a large amount of transient nitrogen oxides will be produced. For this reason, the diffusion burner we provide aims to reduce the amount of transient nitrogen oxides by effectively isolating the mixing area and the combustion area to ensure that the fuel concentration in the combustion area is low enough and evenly distributed under the premise that the fuel concentration can be ignited.

[0055] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0056] refer to Figures 1 to 6 , a diffusion burner includes a base 1, an air duct 11 is provided in the base 1, and external air is introduced into the air duct 11 through the induced draft fan 12; an outer cylinder 2 is mounted on the front end opening of the base 1, and the outer circumferential wall of the outer cylinder 2 partially surrounds the outer circumference of the front end of the base 1, wherein the outer cylinder 2 is a hollow structure with two ends open, the rear end diameter of the outer cylinder 2 is larger than the diameter of the front end of the base 1, and the front end of the outer cylinder 2 extends from the front end opening of the base 1 along the axial direction of the outer cylinder 2, and a gas ring cavity 21 is formed after the outer cylinder 2 and the base 1 are assembled (Figure 4). Specifically, one side wall constituting the gas ring cavity 21 is the outer wall of the base 1. Of course, the gas ring cavity 21 can also be separately provided at the rear end of the outer cylinder 2; it needs to be explained that: in this embodiment, the end of the outer cylinder 2 connected to the base 1 is the rear end, and the other end is the front end;

[0057] refer to Figure 4A and Figure 5 The front cylinder 3 is inserted into the front end of the outer cylinder 2. The front cylinder 3 is also a hollow structure with openings at both ends, including a cylinder body 31 with an annular cross section and a rectifying cone cylinder 32 that is integral with or welded to the cylinder body 31. The rectifying cone cylinder 32 is located inside the outer cylinder 2, wherein part of the outer periphery of the cylinder body 31 and the outer periphery of the front part of the outer cylinder 2 form an outer annular gap 22, and the conical surface 32a of the rectifying cone cylinder 32 and the outer cylinder 2 form a rectifying cavity 23. Part of the air entering the air duct 11 enters the interior of the cylinder body 31, and part of the air enters the rectifying cavity 23 and is discharged from the outer annular gap 22. It is particularly noted that the distance between the conical surface 32a and the outer circumferential wall of the outer cylinder 2 gradually decreases from the air inlet direction, so as to allow as much air from the air duct 11 as possible to enter the outer annular gap 22.

[0058] refer to Figure 1 、 Figure 4A and Figure 6 , the gas ring cavity 21 is connected to a ring cavity tube 24 for gas to enter the inside of the ring cavity tube 24, and a plurality of outer ring seam gas pipes 25 are arranged in an array on the inner circumference of the outer ring seam 22, and one end of the plurality of outer ring seam gas pipes 25 are all connected to the gas ring cavity 21, so that the gas and air passing through the outer ring seam 22 are finally mixed and ignited; preferably, one end of the outer ring seam gas pipe 25 extends outside the outer ring seam. In other words, one end of the outer ring seam gas pipe 25 extends a distance from the outer ring seam 22, and the outer ring seam gas pipe 25 almost contacts the outer circumferential wall of the cylinder 31, that is, the outer ring seam gas pipe 25 is arranged at an inner side position close to the outer ring seam 22, and the outer ring seam gas pipe The distance between the axis of 25 and the inner surface of the outer cylinder 2 is smaller than the distance between the axis of the outer annular seam gas pipe 25 and the outer circumferential surface of the cylinder 31. Therefore, after the gas with a certain speed is discharged through the outer annular seam gas pipe 25, it will be released axially forward close to the outer circumferential wall of the cylinder 31. The gas concentration is highest when it is released near the outer annular seam 22. As the gas is released toward the front cylinder 3, the gas concentration gradually decreases. The gas can be ignited at a position near the front cylinder 3, effectively reducing the content of nitrogen oxides produced. It is worth noting that one end of the outer annular seam gas pipe 25 may not extend out of the outer annular seam 22, which can be adjusted according to the actual situation of the burner and boiler.

[0059] refer to Figure 2 and Figure 6 In order to connect the outer tube 2 and the front tube 3 together, a plurality of connecting members 26 can be provided in the outer annular gap 22 to fix the outer tube 2 and the front tube 3 together.

[0060] refer to Figure 4A 、 Figure 7 and Figure 8 The diffusion burner also includes a core assembly, which is arranged at the axial position of the outer tube 2 and the front tube 3. The core assembly includes a central air ejector 4, a central gas pipe 5 and a flame stabilizer 6. By arranging the core assembly, a main flame can be generated at the front end of the front tube 3. The following will describe in detail how to generate the main flame.

[0061] refer to Figure 9 The central wind ejector 4 includes a central jet air duct 41, a rectifier plate 42 is installed at the front end 41a of the central jet air duct 41, and a gas annular baffle 43 is installed near the front end 41a of the central jet air duct 41. In order to improve the connection strength between the central jet air duct 41 and the rectifier plate 42, one or more ribs 44 are welded and fixed between the front end 41a of the central jet air duct 41 and the rectifier plate 42. The central jet air duct 41 has a jet air duct 45 in the axial direction, so that part of the air in the air duct 11 enters the jet air duct 45 to form a jet wind, which is ejected axially from the front end of the diffusion burner; wherein the shape of the rectifier plate 42 is preferably disc-shaped, and can also be square or elliptical.

[0062] The central jet wind can reduce the temperature of the central return flue gas and increase the oxygen content of the central return flue gas. When the mixed central return flue gas participates in the combustion of the central fuel gas, it reduces the central flame temperature and reduces the thermal nitrogen oxides of the central flame. At the same time, due to the advance premixing of the central fuel gas, the generation of instantaneous nitrogen oxides of the central flame is avoided, and the overall emission of the central flame is achieved.

[0063] The function of the center jet wind is to cool the center return flue gas temperature. If the air volume is small, the effect is not obvious. If the air volume is large, the stability of the center flame may deteriorate.

[0064] refer to Figure 10 In order to adjust the amount of air entering the jet air duct 45 from the air duct 11, a regulating valve 46 is installed at the rear end 41b of the central jet air duct 41. Two opposing air duct openings 451 are opened on the outer peripheral wall of the jet air duct 45 near the rear end. The air intake into the air duct openings 451 is adjusted by the regulating valve 46.

[0065] refer to Figure 11 Exemplarily, the regulating valve 46 includes a valve seat 461, a valve core 462, and an adjusting shaft 463. The valve seat 461 is a hollow structure with openings at both ends and has opposing valve seat openings 4611. One end of the valve core 462 is open to facilitate the accommodation of the rear end 41b of the central jet air duct 41 within the valve core 462. The other end of the valve core 462 has a retaining wall 4621 to facilitate blocking the rear end surface of the central jet air duct 41. The valve core 462 also has two opposing valve core openings 4622. The outer diameter of the valve core 462 is slightly smaller than the inner diameter of the valve seat 461 to facilitate the rotation of the valve core 462 relative to the valve seat 461.

[0066] As a variation, the valve core 462 can also move axially relative to the valve seat 461 , so that the positions of the valve core opening 4622 and the valve seat opening 4611 correspond to or are staggered, which can also help regulate the amount of air entering the air duct opening 451 .

[0067] When the regulating valve 46 is opened, the two opposing air duct openings 451 of the jet air duct 45, the two opposing valve core openings 4622 of the valve core 462, and the two opposing valve seat openings 4611 of the valve seat 461 are completely aligned. At this time, the valve core 462 can be rotated by adjusting the shaft 463 to change the overlapping area of ​​the valve core opening 4622 and the valve seat opening 461, thereby adjusting the air intake from the air duct 11 into the jet air duct 45. When the positions of the valve core opening 4622 and the valve seat opening 4611 are completely staggered, the regulating valve 46 is closed. It should be emphasized that: the air duct opening 451, the valve core opening 4622, and the valve seat opening 4611 can also be respectively provided with only one, three, or more. By rotating the valve core 462, the overlapping area of ​​the valve core opening 4622 and the valve seat opening 4611 can be changed, or the valve core opening 4622 and the valve seat opening 4611 can be completely staggered.

[0068] Continue to refer Figure 11 A valve plate 464 is welded to the valve seat 461 of the regulating valve 46 , and the valve plate 464 is fixed to the core assembly.

[0069] refer to Figure 7 、 Figure 10 and Figure 12 In order to facilitate the rapid assembly of the valve seat 461, the valve core 462 and the adjusting shaft 463, the diameter of the adjusting shaft 463 is smaller than the diameter of the retaining wall 4621 of the valve core 462, and the axial length of the valve seat 461 is greater than the axial length of the valve core 462, which means that when the valve core 462 is rotated and assembled inside the valve seat 461, and the positions of the valve core port 4622 and the valve seat port 4611 correspond to each other, the end of the valve seat 461 close to the adjusting shaft 463 has a portion extending out of the retaining wall 4621, and an annular mounting groove 465 is formed between the protruding portion, the retaining wall 4621 and the adjusting shaft 463. The fastening assembly 466 is arranged on the protruding portion, the retaining wall 4621 and the adjusting shaft 463, so that the valve seat 461, the valve core 462 and the adjusting shaft 463 are assembled together;

[0070] refer to Figure 11 and Figure 12 The valve seat 461 has one or more mounting holes 4612 on the portion extending out of the retaining wall 4621. The fastening assembly 466 includes a bolt 4661 installed inside the mounting hole 4612 and a nut 4662 provided inside the annular mounting groove 465 and threadedly engaged with the bolt 4661. When tightened, the nut 4662 contacts the inner circumferential surface of the annular mounting groove 465, and one end of the bolt 4661 contacts the outer circumferential surface of the adjusting shaft 463.

[0071] refer to Figure 13 and Figure 14 The central gas pipe 5 includes an axial central gas pipe 51 and a radial central gas pipe 52. The axial central gas pipe 51 is arranged at the axial position of the diffusion burner. Its inner diameter is larger than the outer diameter of the central jet air pipe 41. The two are coaxially arranged to form a central gas channel 53 between the axial central gas pipe 51 and the central jet air pipe 41.

[0072] The radial central gas pipe 52 is connected to the rear end of the axial central gas pipe 51 and extends radially along the air duct 11. The lower end of the radial central gas pipe 52 is connected to the outer wall of the base 1 through a flange, thereby supporting the rear end of the entire core assembly.

[0073] refer to Figure 15The front end surface of the radial center gas pipe 52 and the gas annular gap baffle 43 on the above-mentioned center air ejector 4 form a gas annular gap 54, wherein the diameter of the gas annular gap baffle 43 is substantially the same as the diameter of the axial center gas pipe 51. After the gas passes through the radial center gas pipe 52 and enters the central gas channel 53 formed by the axial center gas pipe 51 and the center jet air pipe 41, the gas at a certain speed flows through the central gas channel 53 and is released from the gas annular gap 54. It is particularly noted that: in order to ensure that the gas released from the gas annular gap 54 has an axial forward velocity component, the front end surface of the axial center gas pipe 51 has an inclined surface 511. When the gas at a certain speed is released from the gas annular gap 54, due to the guidance of the inclined surface 511, the released gas has radial and axial velocity components.

[0074] refer to Figure 16 As a variation, the inclined surface 511 may be provided only on the outer edge of the gas annular gap baffle 43, or the inclined surface 511 may be provided on both the front end surface of the axial center gas pipe 51 and the outer edge of the gas annular gap baffle 43. When gas with a certain velocity is released from the gas annular gap 54, the released gas has radial and axial velocity components due to the guidance of the inclined surface 511.

[0075] refer to Figure 14 、 Figure 17 and Figure 18 The flame stabilizer 6 includes a connecting sleeve 61 that is sleeved on the front end of the axial center gas pipe 51. The connecting sleeve 61 is fixedly connected to a flame stabilizing disc 63 through a reinforcing rib 62. A retaining ring 64 is installed in the center of the flame stabilizing disc 63, wherein the flame stabilizing disc 63 is sealed at the front end opening position of the front tube 3. The gas annular gap baffle 43 and the front end of the axial center gas pipe 51 are both arranged in the retaining ring 64. In other words, the gas annular gap 54 is located inside the retaining ring 64. As mentioned above, the gas released from the gas annular gap 54 has radial and axial velocity components. The inner circumferential surface of the retaining ring 64 can limit The range of gas release, that is, the gas released from the gas annular gap 54, will be blocked in the radial direction by the inner circumferential surface of the retaining ring 64. The combustion-supporting air entering the interior of the front tube 3 through the air duct 11 will also enter the interior of the retaining ring 64 and mix with the gas released from the gas annular gap 54. Preferably, the flame stabilizing disk 63 is provided with a plurality of ventilation holes 631. The air entering the front tube 3 can be discharged from the ventilation holes 631, which has a cooling effect on the flame stabilizing disk 63, effectively avoiding the problem of long-term heat deformation of the flame stabilizing disk 63, and improving the service life of the flame stabilizing disk 63.

[0076] In order to increase the recirculation velocity of the center recirculation flue gas and reduce the thermal nitrogen oxides of the main flame;

[0077] refer to Figure 14A main annular gap 66 is formed between the rectifying plate 42 on the central air ejector 4 and the retaining ring 64 on the flame stabilizer 6. The gas and combustion-supporting air mixed together inside the retaining ring 64 are ejected from the main annular gap 66 in the radial direction of the rectifying plate 42 toward the surroundings. At this time, the mixed gas and combustion-supporting air are ignited by a spark plug (not shown in the figure) to form a main flame. Unlike traditional burners, in this embodiment, the main flame formed is diffused in the radial direction of the rectifying plate 42 toward the surroundings, and the mixture of gas and combustion-supporting air released through the outer annular gap is ignited by the high-temperature flue gas formed by the main flame. When the burner of this embodiment is installed on the boiler, parts of the outer tube 2 and the front tube 3 extend into the furnace 10 of the boiler.

[0078] refer to Figure 4B During combustion, according to the principles of gas dynamics, the high-speed jet of combustion-supporting air released through the outer annular gap 22 generates momentum exchange with the high-temperature flue gas in the furnace 10, forming an entrainment effect. The area near the outer annular gap 22 inside the furnace 10 generates a similar annular recirculation area. The high-temperature flue gas in the recirculation area will return to the position adjacent to the outer annular gap 22, ensuring the ignition of the cold unburned mixture. At the same time, the flame hot spot temperature and the oxygen content of the combustion-supporting air are reduced, thereby reducing the formation of thermal nitrogen oxides.

[0079] Continue to refer Figure 4B According to the principles of gas dynamics, the high-speed jet of combustion-supporting air released through the main annular gap 66 produces momentum exchange with the high-temperature flue gas in the furnace 10, and also forms a suction effect, generating a ring-like recirculation area in front of the front tube 3. The high-temperature flue gas in the recirculation area will return to a position adjacent to the front tube 3.

[0080] It is worth mentioning that the diameter of the rectifying plate 42 is larger than the diameter of the retaining ring 64. The function of the rectifying plate 42 is that in the airflow direction of the main flame, the radial velocity of the main flame is much higher than its axial velocity, which makes the efficiency of the induced central flue gas higher and generates more central flue gas reflux. At the same time, since the radial direction of the main flame directly points to the peripheral main flame, the stability is higher; at the same time, the early mixing of the central fuel gas and the central combustion-supporting air can reduce the instantaneous nitrogen oxides of the central flame.

[0081] refer to Figure 7 and Figure 14 Since the oxygen content in the combustion-supporting air varies in different regions and at different temperatures, the size of the gas annular gap 54 is adjustable in order to control the mixing ratio of the gas and the combustion-supporting air released from the main annular gap 66. For example, a first screw 7 is mounted on the core assembly, and the first screw 7 is used to drive the central air ejector 4 to move axially relative to the central gas pipe 5.

[0082] refer to Figure 13 and Figure 14The rear end of the central gas pipe 5 is connected to the pipe seat 55. The length direction of the first screw rod 7 is parallel to the axial direction of the central gas pipe 51. One end of the first screw rod 7 is threadedly connected to the pipe seat 55, and the other end extends to the outside of the base 1. The first screw rod 7 is rotatably connected to the valve plate 464. The first screw rod 7 can be connected to the valve plate 464 through a bearing, or it can be connected as shown. Figure 11 and Figure 12 As shown, one side of the valve plate 464 has a bayonet 4641, and the first screw rod 7 is provided with an annular limiting groove 71, which enters the bayonet 4641 and is rotatably connected to the valve plate 464. In other embodiments, the first screw rod 7 can also be threadedly connected to the base 1, and the front end near the first screw rod 7 is rotatably connected to the valve plate 464, which can also drive the central air ejector 4 to move axially.

[0083] When adjusting the mixing ratio of gas and combustion-supporting air, the first screw 7 is rotated. Since the central gas pipe 5 is fixed to the base 1, when the first screw 7 moves axially, it drives the central air ejector 4 to move forward and backward in the axial direction, thereby increasing or decreasing the distance between the gas annular gap baffle 43 and the axial central gas pipe 51. Ultimately, by adjusting the size of the gas annular gap 54, the amount of gas released from the gas annular gap 54 is adjusted. At the same time, the rectifying plate 42 also moves forward and backward in the axial direction, causing the distance between the rectifying plate 42 and the end face of the retaining ring 64 to increase or decrease, thereby correspondingly increasing or decreasing the main annular gap 66.

[0084] refer to Figure 8 In order to better control the amount of combustion mixture released from the main annular gap 66, the flame stabilizer 6 is individually adjustable, that is, the flame stabilizer 6 can be moved axially forward and backward relative to the central wind ejector 4; exemplarily, the flame stabilizer 6 also includes an adjusting wire seat 65 fixedly mounted on the rear end of the connecting sleeve 61, a fixing seat 56 is fixedly provided on the central gas pipe 5, and the second screw rod 8 is threadedly connected to the adjusting wire seat 65. The second screw rod 8 and the fixing seat 56 can be rotatably connected through a bearing, and one end of the second screw rod 8 passes through the outside of the base 1, so that when the second screw rod 8 is rotated, the connecting sleeve 61 slides axially at the front end of the axial central gas pipe 51, and finally adjusts the size of the main annular gap 66.

[0085] refer to Figure 14 , the diffusion burner further includes a gas supply device 9 for delivering gas to the outer annular gap 22 and the central gas pipe 5, wherein the gas supply device 9 includes a gas source (not shown in the figure) and a gas input pipe connected to the gas source. In this embodiment, the gas input pipe includes an annular gas input pipe 91 and a central gas input pipe 92, which are connected to the same gas source and, in combination with the existing valve group 93, control the opening and closing of the annular gas input pipe 91 and the central gas input pipe 92; wherein the annular gas input pipe 91 is connected to the annular pipe 24 via a flange, and the central gas pipe 5 is connected to the central gas input pipe 92, thereby releasing the gas into the outer annular gap 22 and the main annular gap 66.

[0086] The working principle of the burner is as follows: the induced draft fan 12 introduces the combustion-supporting air into the air duct 11, a part of the combustion-supporting air enters from the rear end opening of the front tube 3 and is discharged from the front end opening of the front tube 3; the other part of the combustion-supporting air enters from the rectifying cavity 23 and is discharged from the outer annular gap 22, and at the same time, part of the fuel gas enters the fuel gas ring cavity 21 through the annular cavity tube 24, and is released from the front of the outer annular gap 22 through the outer annular gap gas pipe 25. The fuel gas released from the front of the outer annular gap 22 is mixed with the combustion-supporting air discharged from the outer annular gap 22. Due to the existence of the outer annular gap 22, the fuel gas released in an annular shape ensures that the mixing area and the combustion area of ​​the burner are effectively isolated, so that the high-gas concentration mixing area will not overlap with the combustion area, and the position of the gas nozzle is close to the inner side of the outer annular gap, so that the high-temperature side fuel gas concentration of the mixed gas is very low, lean gas combustion is achieved, and nitrogen oxide emissions are very low;

[0087] On the other hand, when the combustion-supporting air entering the front tube 3 is released from the baffle ring 64, it is mixed with the gas released from the gas annular gap 54 and released in an annular manner along the radial direction of the rectifier plate 42 from the main annular gap 66. After being ignited by an ignition device (such as a spark plug), high-temperature flue gas with a certain speed is formed. The high-temperature flue gas can ignite the mixture of gas and combustion-supporting air released from the outer annular gap 22, thereby realizing diffused ultra-low nitrogen combustion.

[0088] This document describes in detail exemplary implementations of the present invention with reference to preferred embodiments. However, it will be understood by those skilled in the art that, without departing from the spirit of the present invention, various modifications and variations may be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the present invention may be combined in various ways without exceeding the scope of protection of the present invention, which is determined by the appended claims.

Claims

1. A diffusion gas burner, characterized in that: include: A base body (1), wherein the front end of the base body (1) is open and an air duct (11) for combustion-supporting air to enter is provided therein; The cylinder is a hollow structure with openings at both ends, and is arranged at the front opening of the base (1); A core assembly is arranged at the axial center position of the cylinder, the core assembly includes a central gas pipe (5), a flame stabilizer (6) and a central wind ejector (4), the central gas pipe (5) includes an axial central gas pipe (51), the flame stabilizer (6) includes a flame stabilizer disk (63) blocking the front end opening of the cylinder and a retaining ring (64) arranged at the center of the flame stabilizer disk (63), and the front end of the axial central gas pipe (51) is located in the retaining ring (64), so that when the combustion-supporting wind from the air duct (11) enters the retaining ring (64) through the rear end opening of the cylinder, it is mixed with the gas released from the front end of the central gas pipe (5) in the retaining ring (64), and the central wind ejector (4) is used to eject the central jet wind axially at the front end of the cylinder; A rectifying plate (42) is provided at the front end opening of the cylinder. A main annular gap (66) is formed between the rectifying plate (42) and the retaining ring (64). The diameter of the rectifying plate (42) is larger than the diameter of the retaining ring (64). When the mixed combustion-supporting air and fuel gas are released from the front end of the cylinder, they diffuse in all directions along the radial direction of the flame stabilizing disk (63) under the rectifying effect of the rectifying plate (42). When ignited, high-temperature flue gas is formed.

2. The diffusion type gas burner according to claim 1, characterized in that: The central gas pipe (5) further comprises a radial central gas pipe (52), wherein the radial central gas pipe (52) is substantially perpendicular to the axial central gas pipe (51), and the radial central gas pipe (52) is connected to the base (1), thereby providing rear end support for the core head assembly, and the flame stabilizer (6) provides front end support for the core assembly.

3. The diffusion type gas burner according to claim 1, characterized in that: The core assembly further comprises a central wind ejector (4), the central wind ejector (4) comprising a central jet air duct (41), a rectifying plate (42) mounted at the front end of the central jet air duct (41), and a gas annular gap baffle (43) mounted adjacent to the front end of the central jet air duct (41).

4. The diffusion type gas burner according to claim 3, characterized in that: The diameter of the central jet air duct (41) is smaller than the diameter of the axial central gas pipe (51), and both ends of the central jet air duct (41) are arranged to penetrate the axial position of the axial central gas pipe (51), so that a central gas channel (53) is formed between the central jet air duct (41) and the axial central gas pipe (51), the gas annular gap baffle (43) is located at a front end opening position adjacent to the axial central gas pipe (51), and a gas annular gap (54) is formed between the gas annular gap baffle (43) and the front end surface of the axial central gas pipe (51), and the gas annular gap (54) is located inside the baffle ring (64), so that the gas entering the central gas channel (53) is released from the gas annular gap (54) into the baffle ring (64).

5. The diffusion type gas burner according to claim 4, characterized in that: A conical inclined surface (511) is provided on the front end surface of the axial central gas pipe (51) and / or the side of the gas annular gap baffle (43) facing the axial central gas pipe (51), thereby providing a velocity component in a direction toward the rectifying plate (42) to the gas released from the gas annular gap (54).

6. The diffusion type gas burner according to claim 4, characterized in that: The central air ejector (4) is slidably positioned on the axial central gas pipe (51). By axially moving the central air ejector (4) relative to the axial central gas pipe (51), the distance between the gas annular gap baffle (43) and the front end surface of the axial central gas pipe (51) can be increased or decreased, thereby adjusting the size of the gas annular gap (54).

7. The diffusion type gas burner according to claim 6, characterized in that: A first screw is provided on the central air ejector (4) and the central gas pipe (5), and the central air ejector (4) is driven to slide relative to the axis of the axial central gas pipe (51) by rotating the first screw.

8. The diffusion type gas burner according to claim 7, characterized in that: The central gas pipe (5) is fixedly connected to a pipe seat (55), the central air ejector (4) is fixedly connected to a valve plate (464), the first screw rod is rotatably connected to the pipe seat (55), and the first screw rod is threadedly connected to the valve plate (464).

9. The diffusion type gas burner according to claim 8, characterized in that: The flame stabilizer (6) is slidably connected to the axial center gas pipe (51), and the size of the main annular gap (66) is adjusted by sliding the flame stabilizer (6) along the axial direction of the axial center gas pipe (51).

10. The diffusion type gas burner according to claim 9, characterized in that: The flame stabilizer (6) further comprises a connecting sleeve (61) sleeved on the outside of the axial center gas pipe (51), wherein the connecting sleeve (61) is in sliding engagement with the axial center gas pipe (51); the connecting sleeve (61) is connected to the flame stabilizing disk (63) via a reinforcing rib (62).

11. The diffusion type gas burner according to claim 10, characterized in that: A second screw (8) is mounted on the flame stabilizer (6) and the central gas pipe (5) to drive the flame stabilizer (6) to slide axially relative to the axial central gas pipe (51).

12. The diffusion type gas burner according to claim 11, characterized in that: A fixing seat (56) is provided on the axial center gas pipe (51), an adjusting thread seat (65) is provided on the flame stabilizer (6), the second screw rod (8) is rotatably connected to the fixing seat (56), and the second screw rod (8) is threadedly connected to the adjusting thread seat (65).

13. The diffusion type gas burner according to any one of claims 3 to 12, characterized in that: A jet air duct is provided in the axial direction of the central jet air duct (41), and an air duct opening (451) communicating with the jet air duct is provided adjacent to the rear end of the central jet air duct (41). A regulating valve is also provided for regulating the amount of air entering the jet air duct from the air duct opening (451).

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