A multi-stage cyclone burner

Abstract

This utility model discloses a multi-stage swirl burner, belonging to the field of burner technology. The device includes a combustion chamber, a fuel channel, an air duct, and a flue gas channel. Within the fuel channel, a vibration filter structure and a Laval nozzle are coaxially nested from the outside in. The vibration filter structure includes a first filter screen, a second filter screen, a third filter screen, and an ultrasonic generator. The pore sizes of the first, second, and third filter screens decrease sequentially from the outside in. The ultrasonic generator is fitted onto the outer wall of the fuel channel. The inlet end of the Laval nozzle is close to the third filter screen. By setting up a vibration filter structure composed of the first, second, and third filter screens and the ultrasonic generator, combined with a gradient filtration design with decreasing pore sizes and a high-frequency vibration self-cleaning function, the problem of nozzle clogging caused by solid particles and viscous impurities in the fuel is effectively solved, significantly extending the equipment maintenance cycle.

Description

Technical Field

[0001] This utility model relates to the field of burner technology, and in particular to a multi-stage swirl burner. Background Technology

[0002] In the field of industrial thermal energy conversion, the burner, as a core piece of equipment, directly affects energy utilization efficiency, pollutant emission levels, and production process stability. With the adjustment of the global energy structure and increasingly stringent environmental standards, traditional combustion technologies can no longer meet the modern industrial demand for efficient, low-emission, and intelligently controllable combustion. The burner releases heat through a chemical reaction by igniting a mixture of fuel and oxidant in a certain proportion.

[0003] Traditional burners typically only have a single-layer filter or a simple screening device, which makes it difficult to intercept large, medium, and small particles of impurities in a graded manner. This allows fine impurities to still enter the nozzle area. Furthermore, the lack of an active cleaning device makes it easy for viscous substances or chemical deposits in the fuel to adhere to the filter surface, causing filter pores to become clogged in a short time. Although increasing the filter pore size can prevent frequent clogging, it reduces the filtration accuracy, allowing large particles of impurities to enter the downstream pipeline, exacerbating nozzle wear and the risk of clogging. In addition, traditional straight-through nozzles rely solely on pressure difference to achieve fuel injection and do not adopt the scaling structure of Laval nozzles, which cannot accelerate the fuel to supersonic speeds, resulting in insufficient kinetic energy and coarse atomized particles.

[0004] In summary, existing burners suffer from problems such as insufficient impurity classification and interception capabilities and easy clogging of filter holes due to the use of a single-layer filter screen and the lack of active ash removal function, which requires sacrifice of filtration accuracy. In addition, their straight-through nozzles rely solely on pressure difference for injection and lack the Laval scaling structure, resulting in insufficient fuel acceleration and coarse atomized particles. Utility Model Content

[0005] The present invention provides a multi-stage swirl burner that can solve the problems of easy clogging and insufficient fuel injection in existing burners.

[0006] A multi-stage swirl burner includes a combustion chamber, a fuel passage, an air duct, and a flue gas passage. One side of the combustion chamber connects to the fuel passage and the air duct, which are coaxial. The flue gas passage is located directly above and communicates with the combustion chamber. The fuel passage is coaxially nested with a vibration filter structure and a Laval nozzle from the outside to the inside. The vibration filtering structure includes a first filter layer, a second filter layer, a third filter layer, and an ultrasonic generator. The pore sizes of the first, second, and third filter layers decrease sequentially from the outside to the inside. The ultrasonic generator is sleeved on the outer wall of the fuel passage, and the inlet end of the Laval nozzle is close to the third filter layer.

[0007] Preferably, the Laval nozzle is provided with a double-layer swirl vane assembly at the outlet end, and the double-layer swirl vane assembly is coaxial with the fuel passage.

[0008] Preferably, the double-layer swirl blade assembly includes an inner swirl blade and an outer swirl blade; The inner swirl blades are nested within the outer swirl blades; The outer swirl blades are nested on the inner wall of the fuel channel; The inner swirl blades rotate in the opposite direction to the outer swirl blades.

[0009] Preferably, the air duct is divided into a main air duct and a secondary air duct; The main air duct is fitted around the fuel passage. The auxiliary air duct has several parts that are evenly distributed around the outer periphery of the main air duct.

[0010] Preferably, the main air duct is connected to the outer swirl vane, the gap between the main air duct and the fuel passage is connected to the inner swirl vane, and the fuel passage is connected to the inner swirl vane.

[0011] Preferably, a venturi tube is provided in the flue gas passage, and the inlet end of the venturi tube is connected to the combustion chamber.

[0012] Preferably, the bottom of the combustion chamber is provided with a slag discharge port, and a slag discharge mechanism is provided at the slag discharge port.

[0013] Preferably, the slag discharge mechanism includes a slag discharge funnel and a sealing valve; The upper end of the slag discharge funnel is bolted to the bottom of the combustion chamber and located directly below the slag discharge port. The slag discharge funnel is connected to the interior of the combustion chamber. The sealing valve is fixedly installed at the lower end of the slag discharge funnel.

[0014] Preferably, the central axis of the throat of the venturi tube is in the same vertical plane as the central axis of the slag discharge port, and the valve core of the sealing valve moves in a direction perpendicular to the axial direction of the venturi tube.

[0015] Preferably, the combustion chamber is provided with an observation window on the opposite side of the fuel passage.

[0016] The beneficial effects of this invention are as follows: By setting up a vibration filtration structure consisting of a first layer filter, a second layer filter, a third layer filter, and an ultrasonic generator, combined with a gradient filtration design with decreasing pore size and a high-frequency vibration self-cleaning function, this invention effectively solves the problem of nozzle clogging caused by solid particles and viscous impurities in the fuel, significantly extending the equipment maintenance cycle. In addition, the use of a Laval nozzle to perform supersonic acceleration and scaling effect treatment on the fuel atomizes it to the micron level, greatly increasing the contact area between the fuel and the air. Furthermore, the double-layer swirling structure formed by the counter-rotating inner and outer swirling blades enhances the shear mixing of fuel and air while suppressing flame pulsation through a double vortex ring structure, thus balancing mixing intensity and flame stability. Attached Figure Description

[0017] Figure 1 This is a front view structural diagram of the present invention; Figure 2 This is a side view of the structure of this utility model; Figure 3 This is a schematic diagram of the internal structure of the fuel channel of this utility model; Figure 4 for Figure 3 Enlarged view at point A.

[0018] Explanation of reference numerals in the attached figures: 1. Combustion chamber; 2. Fuel passage; 3. Air duct; 31. Main air duct; 32. Auxiliary air duct; 4. Flue gas passage; 41. Venturi tube; 5. Vibration filter structure; 51. First layer filter screen; 52. Second layer filter screen; 53. Third layer filter screen; 54. Ultrasonic generator; 6. Laval nozzle; 7. Double-layer swirl vane assembly; 71. Inner layer swirl vane; 72. Outer layer swirl vane; 8. Ash discharge port; 9. Ash discharge mechanism; 91. Ash discharge funnel; 92. Sealing valve; 10. Observation window. Detailed Implementation

[0019] The specific embodiments of this utility model are described in detail below, but it should be understood that the protection scope of this utility model is not limited to the specific embodiments.

[0020] like Figures 1 to 4 As shown in the figure, a multi-stage swirl burner provided by this utility model includes a combustion chamber 1, a fuel channel 2, an air duct 3, and a flue gas channel 4. One side of the combustion chamber 1 is connected to the fuel channel 2 and the air duct 3. The fuel channel 2 and the air duct 3 are coaxial. The flue gas channel 4 is located directly above the combustion chamber 1 and is connected to it. The fuel channel 2 is coaxially nested with a vibration filter structure 5 and a Laval nozzle 6 from the outside to the inside. The vibration filtering structure 5 includes a first filter 51, a second filter 52, a third filter 53, and an ultrasonic generator 54. The pore sizes of the first filter 51, the second filter 52, and the third filter 53 decrease sequentially from the outside to the inside. The ultrasonic generator 54 is sleeved on the outer wall of the fuel channel 2, and the inlet end of the Laval nozzle 6 is close to the third filter 53.

[0021] Fuel itself contains physical solid particles or viscous soft impurities. When their size or shape exceeds the tolerance range of the extremely small orifice of the nozzle, coupled with the catalytic effect of high temperature accelerating the formation of chemical deposits, the nozzle orifice will eventually be partially or completely blocked, destroying the fuel flow and atomization. Therefore, a filter device is used to filter the fuel. However, the filter is essentially also intercepting impurities present in the fuel itself by using the orifice size. Similar to the nozzle, it is also prone to clogging. Therefore, a vibration filter structure 5 is designed. The first filter screen 51, the second filter screen 52 and the third filter screen 53 have decreasing pore sizes, intercepting large, medium and small particles of impurities step by step, extending the maintenance cycle. When the fuel passes through the filter screen, the high-frequency vibration emitted by the ultrasonic generator 54 will destroy the deposits left by the fuel when passing through the filter screen, realizing online self-cleaning. When the fuel reaches the Laval nozzle 6, due to the acceleration effect of the Laval nozzle 6, the fuel will be accelerated to the speed of sound, and a vacuum environment will be created by the scaling effect, which will enhance the fuel atomization effect.

[0022] After the fuel source is bolted to the fuel channel 2, the fuel passes through the first filter screen 51 to remove large particles, through the second filter screen 52 to filter medium particles, and through the third filter screen 53 to trap tiny impurities before entering the Laval nozzle 6. The nozzle's contraction section accelerates the fluid to the critical velocity, and a low-pressure zone is formed at the throat to adsorb more air. The diffusion section transforms the high-speed jet into violent turbulence, achieving micron-level atomization of the fuel.

[0023] The Laval nozzle 6 is provided with a double-layer swirl vane assembly 7 at the outlet end, and the double-layer swirl vane assembly 7 is coaxial with the fuel passage 2.

[0024] High swirling intensity promotes mixing but can disrupt flame stability. Efficient combustion requires rapid fuel-air mixing. When high swirling intensity generates strong centrifugal and shear forces, it creates intense turbulence, promoting fuel-air mixing. Simultaneously, the strong swirling creates a large-scale recirculation zone downstream of the nozzle, drawing high-temperature flue gas back to the flame root to provide a continuous ignition source. However, when the swirling is too strong, the recirculation zone becomes too large and its position shifts downwards, causing the flame root to be stretched. Furthermore, the high-temperature flue gas cannot be stably anchored near the nozzle, making the flame prone to flare-off or flickering, especially... It is easy to extinguish under low load or fuel fluctuation; although the relatively low swirl intensity is beneficial to stability, it weakens the mixing between fuel and air. The backflow zone formed by the weak swirl is close to the nozzle outlet, and the high temperature flue gas directly wraps the fuel jet, providing a stable ignition source and the flame is not easy to extinguish. However, the weak turbulence will cause the fuel and air to mix slowly, the combustion efficiency will decrease, and the local fuel-rich zone will be easily generated, resulting in incomplete combustion or increased pollutants. Therefore, a double-layer swirl blade assembly 7 is used. The weak swirl is used to maintain the stability of the flame root, and the strong swirl enhances the mixing between fuel and air.

[0025] The double-layer swirl blade assembly 7 includes an inner swirl blade 71 and an outer swirl blade 72; The inner swirl blade 71 is nested within the outer swirl blade 72; The outer swirl blade 72 is nested on the inner wall of the fuel channel 2; The inner swirl blade 71 rotates in the opposite direction to the outer swirl blade 72.

[0026] The inner swirl blade 71 and the outer swirl blade 72 rotate in opposite directions, forming a double vortex ring structure, which intensifies the shear mixing of fuel and air. The opposing swirls restrain each other and suppress flame pulsation caused by the shearing of local vortex clusters.

[0027] The air duct 3 is divided into a main air duct 31 and a secondary air duct 32; The main air duct 31 is fitted around the outer periphery of the fuel passage 2; The auxiliary air duct 32 has several parts that are evenly distributed around the outer periphery of the main air duct 31.

[0028] Existing burners often employ a single air passage. A single air passage cannot provide spatial concentration stratification. All air is injected from the same inlet and mixes rapidly with the fuel, failing to form a concentration gradient. In the main combustion zone, low-momentum air is required to avoid extinguishing the flame and maintain stable, rich combustion. In the burnout zone, high-momentum air is needed to penetrate the flue gas and enhance post-combustion mixing. Therefore, a multi-stage air passage design is adopted. The main air duct 31 surrounds the fuel passage 2, providing the primary air required for the core combustion zone. The secondary air ducts 32 are evenly distributed around the periphery, supplementing the flame periphery with secondary air and suppressing CO generation. The annular layout shortens the air delivery path and reduces pressure loss. The main path enters the space between the inner swirl vanes 71 and the outer swirl vanes 72 through the main air duct 31, participating in primary mixing. The secondary path is radially injected into the edge of the combustion chamber 1 through the secondary air duct 32, forming an air curtain surrounding the flame, which both aids combustion and cools the interior of the combustion chamber 1.

[0029] The main air duct 31 is connected to the outer swirl vane 72, the gap between the main air duct 31 and the fuel channel 2 is connected to the inner swirl vane 71, and the fuel channel 2 is connected to the inner swirl vane 71.

[0030] The high-speed fuel jet ejected from the Laval nozzle 6 impacts the inner swirl vanes 71, forcing the fuel to rotate along the vane curvature; the outer swirl vanes 72 receive the air flowing in from the main air duct 31 and apply a secondary swirl in the opposite direction. The two rotating airflows superimpose to form a three-dimensional spiral motion, tearing the fuel into tiny droplets and dispersing them evenly in the air.

[0031] The flue gas passage 4 is equipped with a venturi tube 41, and the inlet end of the venturi tube 41 is connected to the combustion chamber 1.

[0032] The contraction-expansion structure of the venturi tube 41 converts the kinetic energy of the flue gas into potential energy, thereby improving the suction capacity. The inlet end of the venturi tube 41 smoothly transitions with the combustion chamber 1, reducing eddy separation. Furthermore, its integral design avoids blockage during the conveying of ash.

[0033] When the high-temperature flue gas enters the contraction section of the Venturi tube 41, it will be accelerated under its structural characteristics. The static pressure drops sharply to create a negative pressure zone, which actively draws in the exhaust gas produced by combustion. When the flue gas reaches the maximum flow rate at the throat, it enters the expansion section, where kinetic energy is converted into pressure energy, which pushes the flue gas to overcome the system resistance and be discharged.

[0034] The bottom of the combustion chamber 1 is provided with a slag discharge port 8, and a slag discharge mechanism 9 is provided at the slag discharge port 8.

[0035] The slag discharge mechanism 9 includes a slag discharge funnel 91 and a sealing valve 92; The upper end of the slag discharge funnel 91 is bolted to the bottom of the combustion chamber 1 and is located directly below the slag discharge port 8. The slag discharge funnel 91 is connected to the interior of the combustion chamber 1. The sealing valve 92 is fixedly installed at the lower end of the slag discharge funnel 91.

[0036] The waste residue produced by combustion will fall into the slag discharge funnel 91 through the slag discharge port 8 under the action of gravity, and the waste residue will be temporarily blocked in the slag discharge funnel 91 by the sealing valve 92. After combustion is completed, the sealing valve 92 will be opened to collect the waste residue.

[0037] The central axis of the throat of the Venturi tube 41 is in the same vertical plane as the central axis of the slag discharge port 8, and the valve core of the sealing valve 92 moves in a direction perpendicular to the axial direction of the Venturi tube 41.

[0038] An observation window 10 is provided on the other side of the combustion chamber 1 opposite to the fuel passage 2.

[0039] In summary, the multi-stage swirl burner provided by this utility model embodiment allows for the following process: First, the fuel channel 2 is tightly connected to the external feeding system via flange bolts. The fuel is filtered through the first layer filter 51, the second layer filter 52, and the third layer filter 53 before entering the Laval nozzle 6. The ultrasonic generator 54 continuously vibrates to remove impurities from the filter screens. Simultaneously, the primary air delivered by the main air duct 31 forms a clockwise rotating airflow along the outer swirl blades 72. The fuel is accelerated in the Laval nozzle 6 and impacts the inner swirl blades 71 to form a counterclockwise jet. The two collide in the combustion chamber 1 to generate a stable three-dimensional vortex. Meanwhile, the auxiliary air duct 32 supplements the flame periphery with secondary air to enhance combustion. The high-temperature flue gas is discharged through the contraction-expansion structure of the venturi tube 41. The molten slag produced by combustion falls into the slag discharge funnel 91 through the slag discharge port 8 and is discharged under the control of the sealing valve 92. The entire combustion process can be monitored in real time through the observation window 10, achieving efficient fuel atomization, precise graded air distribution, and stable, low-pollution combustion.

[0040] The above-disclosed embodiments are only a few specific examples of the present utility model. However, the embodiments of the present utility model are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present utility model.

Claims

1. A multi-stage swirl burner, comprising a combustion chamber (1), a fuel passage (2), an air duct (3), and a flue gas passage (4), wherein one side of the combustion chamber (1) is connected to the fuel passage (2) and the air duct (3), the fuel passage (2) and the air duct (3) are coaxial, and the flue gas passage (4) is located directly above and connected to the combustion chamber (1), characterized in that: The fuel passage (2) is coaxially nested with a vibration filter structure (5) and a Laval nozzle (6) from the outside to the inside. The vibration filter structure (5) includes a first filter (51), a second filter (52), a third filter (53), and an ultrasonic generator (54). The pore sizes of the first filter (51), the second filter (52), and the third filter (53) decrease sequentially from the outside to the inside. The ultrasonic generator (54) is fitted on the outer wall of the fuel channel (2). The inlet end of the Laval nozzle (6) is close to the third filter (53).

2. The multi-stage swirl burner as described in claim 1, characterized in that: The Laval nozzle (6) is provided with a double-layer swirl vane assembly (7) at the outlet end, and the double-layer swirl vane assembly (7) is coaxial with the fuel passage (2).

3. A multi-stage swirl burner as described in claim 2, characterized in that: The double-layer swirl blade assembly (7) includes an inner swirl blade (71) and an outer swirl blade (72). The inner swirl blade (71) is nested within the outer swirl blade (72); The outer swirl blades (72) are nested on the inner wall of the fuel channel (2); The rotation direction of the inner swirl blade (71) is opposite to that of the outer swirl blade (72).

4. A multi-stage swirl burner as described in claim 1, characterized in that: The air duct (3) is divided into a main air duct (31) and a secondary air duct (32). The main air duct (31) is fitted around the outer periphery of the fuel passage (2); The auxiliary air duct (32) has several parts that are evenly distributed around the outer periphery of the main air duct (31).

5. A multi-stage swirl burner as described in claim 4, characterized in that: The main air duct (31) is connected to the outer swirl vane (72), the gap between the main air duct (31) and the fuel channel (2) is connected to the inner swirl vane (71), and the fuel channel (2) is connected to the inner swirl vane (71).

6. A multi-stage swirl burner as described in claim 1, characterized in that: The flue gas passage (4) is provided with a venturi tube (41), and the inlet end of the venturi tube (41) is connected to the combustion chamber (1).

7. A multi-stage swirl burner as described in claim 6, characterized in that: The bottom of the combustion chamber (1) is provided with a slag discharge port (8), and a slag discharge mechanism (9) is provided at the slag discharge port (8).

8. A multi-stage swirl burner as described in claim 7, characterized in that: The slag discharge mechanism (9) includes a slag discharge funnel (91) and a sealing valve (92). The upper end of the slag discharge funnel (91) is bolted to the bottom of the re-combustion chamber (1) and located directly below the slag discharge port (8). The slag discharge funnel (91) is connected to the interior of the combustion chamber (1). The sealing valve (92) is fixedly installed at the lower end of the slag discharge funnel (91).

9. A multi-stage swirl burner as described in claim 8, characterized in that: The central axis of the throat of the Venturi tube (41) is in the same vertical plane as the central axis of the slag discharge port (8), and the valve core of the sealing valve (92) moves in a direction perpendicular to the axial direction of the Venturi tube (41).

10. A multi-stage swirl burner as described in claim 1, characterized in that: The combustion chamber (1) is provided with an observation window (10) on the other side of the fuel passage (2).

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