CN210601607U - Mixer and combustor using same - Google Patents

Abstract

The utility model relates to a blender for combustor, it includes: a mixing tube; a gas distributor configured to have a cylindrical shape with inner and outer layers, which is located at a central position of the mixing tube, and a plurality of fins provided on an outer cylinder thereof, which are configured to mount the gas distributor; the gas distributor has the distribution function of combustible gas or fuel and the function of distributing and adjusting air flow, and the secondary air pipe penetrates through the center positions of the gas distributor and the mixing pipe. The utility model discloses still relate to a combustor including above-mentioned blender. The utility model discloses a combustor that blender and used it enables combustible gas or fuel and air mixing more even to multiple combustion method has been coupled, thereby has reduced because combustible gas or fuel and air mixing are inhomogeneous, the single incomplete combustion and the local high temperature that brings of combustion method, and reduce the emission of pollutant correspondingly.

Description

Mixer and combustor using same

Technical Field

The present invention relates to the field of industrial burner structures and combustion modes thereof, and more particularly to a mixer for mixing fuel and air prior to combustion and having fuel distribution and air distribution conditioning functions. The utility model discloses still relate to a combustor including above-mentioned blender, it has coupled multiple combustion method simultaneously.

Background

As is known, industrial burners are commonly used to provide heat, such as mixing combustible gas or fuel with air for combustion, for heating specific workpieces or equipment.

However, existing combustors often have undesirably high emissions of pollutants such as carbon monoxide and nitrogen oxides. With the increasing environmental standards, the emission requirements of the burners are also higher and higher by the skilled person. Accordingly, there is a continuing need for improvements to existing combustors.

It is therefore desirable to provide an improved mixer and burner incorporating the same such that the combustible gas or fuel is more uniformly mixed with air and the burner is coupled to multiple combustion modes so that less polluting gases are produced.

Disclosure of Invention

An object of the utility model is to provide a mixer, it can make combustible gas or fuel and air mix more evenly to this mixer has combustible gas or the distribution function and the air distribution regulatory function of fuel. Another object of the present invention is to provide a burner including the above mixer, which is coupled with a plurality of combustion modes.

The utility model aims at realizing through the following technical scheme:

a mixer, comprising:

a mixing tube; a gas distributor configured to be composed of a combination of an inner cylinder and an outer cylinder, which is located at a central position of the mixing pipe; and

a plurality of fins disposed on the outer cylinder and configured to secure the gas distributor; and

the outer layer cylinder is provided with a combustible gas or fuel injection hole in the circumferential direction and a combustible gas or fuel inlet; and

the inner cylinder is provided with combustible gas or fuel injection holes in the circumferential direction.

Optionally, the inner cylinder is configured in a waist drum shape with a middle diameter smaller than the diameters of the two ends, the length of the outer cylinder is larger than that of the inner cylinder, the outer diameter of the inner cylinder is the same as the inner diameter of the outer cylinder, and the inner cylinder is just inserted into the outer cylinder; the front end of the outer cylinder is cut into a plurality of uniform strip-shaped structures.

Alternatively, the positions of the combustible gas or fuel injection hole of the outer layer cylinder and the combustible gas or fuel injection hole of the inner layer cylinder are provided with a tubular structure, and the tubular structure is symmetrically provided with a plurality of holes on two sides or provided with a plurality of holes on one side.

A burner to which the mixer as described above is applied, comprising:

an air input section comprising an air inlet;

a mixing tube; a gas distributor located downstream of the air input section, an

A mixing tube, comprising:

a first mixing tube and a second mixing tube; and

the gas distributor is positioned in the center of the middle part of the first mixing pipe; and

the first mixing tube includes a first combustion face downstream thereof; and

a second mixing tube located downstream of the combustible gas or fuel injection orifice of the inner cylinder, the second mixing tube including a second combustion face downstream thereof; the injection hole of the combustion surface is a circular or square hole, and the combustion surface is composed of a plurality of injection holes; and

one or more layers of high-temperature-resistant stainless steel nets are arranged on the outer surfaces and the inner surfaces of the first mixing pipe and the second mixing pipe; and

overgrate air tuber pipe, it includes:

the air pipe is provided with a plurality of fins at the front end, air injection holes for secondary air are circumferentially arranged at the rear end, and the air pipe penetrates through the central positions of the air distributor, the first mixing pipe and the second mixing pipe; the position of the air injection hole of the secondary air is positioned at the downstream of the second mixing pipe; the fins are used for fixing the air pipe; and

the front end of the air pipe is cut into a plurality of uniform strip-shaped structures, and the opening of each strip-shaped structure is adjusted to be used for controlling the air flow of secondary air; and

one or more layers of high-temperature resistant stainless steel nets are arranged on the outer surface of the air pipe.

Optionally, the inward or outward opening of the elongated structure at the front end of the outer cylinder is adjusted to adjust the flow rate of air flowing to the first mixing tube, so that the first combustion surface is in a lean or rich combustion state, and the second combustion surface is also in a rich or lean combustion state.

Optionally, the high-temperature resistant stainless steel nets disposed on the outer surfaces of the first mixing pipe, the second mixing pipe and the air pipe are woven nets, sintered nets or metal fiber woven nets, and the high-temperature resistant stainless steel nets are fixed on the outer surfaces of the first mixing pipe, the second mixing pipe and the air pipe in a spot welding manner.

Optionally, the refractory stainless steel meshes of the inner surfaces of the first combustion face and the second combustion face are woven meshes with the pore size larger than 80 meshes.

Alternatively, the apertures of the refractory stainless steel nets of the outer surfaces of the first and second mixing pipes are the positions of the injection holes of the first and second combustion surfaces, and the size and shape of the apertures are the same as the injection holes.

Optionally, the injection hole of the first combustion surface, the injection hole of the second combustion surface and the air injection hole of the secondary air duct are provided with tubular structures, and the inside of the outlet of the tubular structures is provided with swirl vanes, and the tubular structures are straight pipes and bent pipes.

Alternatively, the burner is adapted for use in confined spaces where the inner walls are provided with one or more layers of high temperature resistant stainless steel mesh.

The mixer and the burner using the mixer have the advantages that the combustible gas or the fuel is mixed with the air more uniformly, and the mixer can be set to a fuel shade combustion mode during combustion, so that the mixer has the atmosphere of reducing nitrogen oxides and a secondary air burnout technology; the high-temperature flue gas internal circulation and external circulation technology reduces the emission of pollution gas.

Drawings

The present invention will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of illustrating the preferred embodiments and therefore should not be taken as limiting the scope of the present invention. Furthermore, unless specifically stated otherwise, the drawings are intended to be conceptual in nature or in construction of the objects depicted and may contain exaggerated displays and are not necessarily drawn to scale.

Fig. 1 is a schematic side cross-sectional view of an embodiment of a mixer and a burner using the same according to the present invention.

Figure 2 is a side schematic view of one embodiment of the inner cylinder of the gas distributor of the present invention.

Fig. 3 is a side schematic view of an embodiment of the gas distributor of the present invention and a second mixing tube downstream thereof.

Fig. 4 is a schematic side view of an embodiment of the overfire air duct of the present invention.

Fig. 5 is a side schematic view of an embodiment of the bilaterally symmetrically apertured tubular structure of the present invention.

Fig. 6 is a side schematic view of one embodiment of a single-sided apertured tubular structure of the present invention.

Fig. 7 is a side schematic view of an embodiment of the spinning disk of the present invention.

Fig. 8 is a schematic side view of an embodiment of a straight pipe according to the present invention.

Fig. 9 is a side schematic view of an embodiment of an elbow of the present invention.

Fig. 10 is a schematic side cross-sectional view of another embodiment of a mixer and a burner using the same according to the present invention.

Fig. 11 is a schematic side cross-sectional view of a further embodiment of a mixer and burner using the same of the present invention.

Fig. 12 is a schematic side cross-sectional view of another embodiment of a mixer and a burner using the same according to the present invention.

Fig. 13 is a schematic side cross-sectional view of a further embodiment of a mixer and burner using the same of the present invention.

Fig. 14 is a schematic side cross-sectional view of another embodiment of a mixer and burner using the same of the present invention.

It is to be noted that the hatched portion of the mesh shape in the illustration is a high temperature resistant stainless steel mesh provided for the purpose.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that the description is illustrative only, and is not to be construed as limiting the scope of the invention.

First, it should be noted that the terms of orientation of center, middle, front, rear, upstream, downstream, etc., referred to herein, are defined relative to the orientation in the drawings, they are relative terms, and thus can vary according to the different positions and different practical conditions in which they are located. These and other directional terms should not be construed as limiting terms.

Furthermore, it should be pointed out that any single technical feature described or implied in the embodiments herein, or any single technical feature shown or implied in the figures, can still be combined continuously between these technical features (or their equivalents) to obtain other embodiments of the present invention not directly mentioned herein.

It should be noted that in different drawings, the same reference numerals indicate the same or substantially the same components.

Fig. 1 is a schematic side cross-sectional view of an embodiment of a mixer and a burner using the same according to the present invention. Wherein, combustor 100 includes: an air input section 110 comprising an air inlet 111; a mixing tube 112; a gas distributor 200 located downstream of the air input section 110, configured by a combination of an inner cylinder and an outer cylinder, located at a central position in the middle of the mixing tube 112, and a plurality of fins 216 provided on the outer cylinder, configured for fixing the gas distributor 200; the outer layer cylinder 217 is provided with a combustible gas or fuel injection hole 210 in the circumferential direction, and the outer layer cylinder 217 is provided with a combustible gas or fuel inlet 212; the front end of the outer cylinder 217 is cut into a plurality of uniform strip-shaped structures 211; and a combustible gas or fuel injection hole provided circumferentially of the inner cylinder (for ease of reference, the inner cylinder is not shown in fig. 1); a mixing tube, comprising: a first mixing pipe 112 and a second mixing pipe 215; the first mixing tube 112 includes a first combustion face 115 downstream thereof; a second mixing tube 215 is located downstream of the injection hole of the combustible gas or fuel of the inner cylinder, the second mixing tube 215 including a second combustion face 213 downstream thereof; in the illustration, the injection holes of the combustion surface are circular, but in practical application, the injection holes can also be arranged in a square shape, and the combustion surface is formed by a plurality of injection holes; and the outer and inner surfaces of the first mixing pipe 112 and the second mixing pipe 215 are both provided with one or more layers of high temperature resistant stainless steel mesh; overgrate air tuber pipe, it includes: an air duct 500 configured such that a front end thereof is provided with a plurality of fins (for ease of reference, the fins are not shown in fig. 1), a rear end thereof is circumferentially provided with air injection holes 510 for secondary air, the air duct 500 penetrates through the central positions of the gas distributor 200, the first mixing pipe 112 and the second mixing pipe 215, the air injection holes 510 for the secondary air duct are located downstream of the second mixing pipe 215, and the fins are used to fix the air duct 500; and a plurality of uniform strip-shaped structures 530 cut at the front end of the air duct 500, and the opening of the strip-shaped structures 530 is adjusted to control the air flow of the secondary air; and a high temperature-resistant stainless steel net 540 provided on an outer surface of the air duct 500.

Figure 2 is a side schematic view of one embodiment of the inner cylinder of the gas distributor of the present invention. Wherein the inner cylinder 400 is constructed in a drum shape having a middle diameter smaller than both ends, and the inner cylinder 400 is circumferentially provided with gas or fuel injection holes 410.

Fig. 3 is a side schematic view of the gas distributor of the present invention and a second mixing tube downstream thereof. Wherein, the gas distributor 200 includes: an outer cylinder 217 with a front elongated structure 211; an injection hole 210 for combustible gas or fuel; an inlet 212 for combustible gas or fuel; a fin 216; the diameter changing member 218. Wherein the second mixing pipe 215 includes: a second combustion face 213, and a high temperature resistant stainless steel mesh 214 disposed on an outer surface thereof.

Fig. 4 is a schematic side view of an embodiment of the secondary air duct of the present invention, wherein the air duct 500 includes: an elongated structure 530; a fin 520; air injection holes 510; and a high temperature-resistant stainless steel net 540 provided on an outer surface thereof.

Alternatively, the inward or outward opening of the elongated structure 211 at the front end of the outer cylinder 217 is adjusted to adjust the amount of air flow to the first mixing tube 112 such that the first combustion surface 115 is in a lean or rich condition and the second combustion surface 213 is in a rich or lean condition.

Optionally, the length of the outer cylinder 217 is greater than the length of the inner cylinder 400, and the outer diameter of the inner cylinder 400 is the same as the inner diameter of the outer cylinder 217, so that the inner cylinder 400 is just inserted into the outer cylinder 217 and fixed; the gas distributor 200 is connected with the second mixing pipe 215 by the reducing member 218; and the high temperature resistant stainless steel net 214 is fixed to the outer surface of the second mixing pipe 215 by spot welding, and the high temperature resistant stainless steel net 116 of the outer surface of the first mixing pipe 112 and the high temperature resistant stainless steel net 540 of the outer surface of the air duct 500 are fixed in the same manner.

Optionally, the high temperature resistant stainless steel mesh disposed on the inner surface of the first combustion surface 115 of the first mixing tube 112 and the second combustion surface 213 of the second mixing tube 215 is a woven mesh with a pore size greater than 80 mesh. And the arranged high-temperature resistant stainless steel mesh grid is one or more layers.

Alternatively, the apertures of the high temperature resistant stainless steel mesh 116 of the outer surface of the first mixing pipe 112 and the high mixing resistant stainless steel mesh 214 of the outer surface of the second mixing pipe 215 are the positions of the injection holes of the first combustion face 115 and the second combustion face 213, and the size and shape of the apertures are the same as the injection holes.

Alternatively, the high temperature resistant stainless steel net provided to the outer surfaces of the first mixing pipe 112, the second mixing pipe 215, and the wind pipe 500 is one or more layers. The high-temperature resistant stainless steel net is a woven net, a sintered net or a metal fiber woven net.

Optionally, the air input section 110 includes a viewing port 113 thereon.

Optionally, a mounting flange 114 is provided around the outer circumference of the first mixing tube 112.

In use, air is delivered from the air inlet 111 to the air input section 110 and through the air distributor 200, and delivered by the air distributor 200 to the air injection holes 510 of the first mixing tube 112, the second mixing tube 215, and the overfire air duct, respectively, and a combustible gas or fuel is delivered into the air distributor 200 from the inlet 212 of the combustible gas or fuel, and is mixed with the air delivered to the first mixing tube 112 and the second mixing tube 215 through the injection holes 210 of the combustible gas or fuel of the outer cylinder 217 and the injection holes 410 of the combustible gas or fuel of the inner cylinder 400, respectively, and is then output through the injection holes of the first combustion face 115 and the injection holes of the second combustion face 213 and combusted.

In order to improve combustion efficiency and reduce the generation of pollutant gases, it is desirable to mix combustible gas or fuel and air uniformly before combustion, it is more desirable that the combustible gas mixture is further mixed well in combustion and has an atmosphere in which the pollutant gases are reduced in combustion, and the burner is coupled with a plurality of combustion modes to reduce the generation of pollutant gases.

Fig. 5 is a side schematic view of an embodiment of the bilaterally symmetrically apertured tubular structure of the present invention. Wherein the tubular structure 600 comprises: and an injection hole 610 for combustible gas or fuel.

Fig. 6 is a side schematic view of one embodiment of a single-sided apertured tubular structure of the present invention. Wherein the tubular structure 700 comprises: an injection hole 710 for combustible gas or fuel.

Alternatively, the tubular structure 600 and the tubular structure 700 are suitably used to position the injection holes 210 and 410 of the fuel gas or fuel in the gas distributor of the large or medium burner so that the air and the fuel gas or fuel are mixed more uniformly.

Fig. 7 is a side schematic view of an embodiment of the spinning disk of the present invention. The manufacturing method of the spinning disk 800 comprises the following steps: one of the ends is fixed with a rectangular stainless steel flat plate and the other end is rotated so that it forms a twist shape.

Fig. 8 is a schematic side view of an embodiment of a straight pipe according to the present invention. Wherein, one end of the straight pipe 900 is provided with the spinning disk 800, and the spinning disk 800 is just inserted into the straight pipe 900 and then fixed.

Fig. 9 is a side schematic view of an embodiment of an elbow of the present invention. Wherein, one end of the elbow 1000 is provided with the spinning disk 800, and the spinning disk 800 is just inserted into the elbow 1000 and then fixed.

Alternatively, the straight tube 900 and the bent tube 1000 are disposed at the injection hole of the first combustion surface 115, the injection hole of the second combustion surface 213, and the air injection hole 510 of the overgrate air duct 500, and the straight tube 900 and the bent tube 1000 are disposed at intervals. For convenience of reference, the straight pipe 900 and the bent pipe 1000 are not shown in the illustration of the mixer and the burner using the mixer of the present invention.

Fig. 10 is a schematic side cross-sectional view of another embodiment of a mixer and a burner using the same according to the present invention. Wherein, the secondary air duct 500 is connected to the air distributor 200, the first mixing pipe 112 and the second mixing pipe 215. Air and combustible gas or fuel are delivered to the gas distributor 200 for mixing and then to the downstream collection of the first mixing tube 112, to the second mixing tube 215, and out of the injection holes of the combustion face and combusted. The second mixing pipe 215 is provided with two or more combustion surfaces, which are constituted by a plurality of injection holes.

Fig. 11 is a schematic side cross-sectional view of a further embodiment of a mixer and burner using the same of the present invention. Wherein, the secondary air duct 500 is connected to the air distributor 200, the first mixing pipe 112 and the second mixing pipe 215. The inner wall of the precombustion chamber 2000 is provided with a high-temperature resistant stainless steel mesh, and the periphery of the precombustion chamber can also be provided with a high-temperature resistant stainless steel mesh. The second mixing tube 215 is provided with one or more combustion surfaces, which are formed by a plurality of injection holes. It is suitable for central back-burning boiler or kiln.

Fig. 12 is a schematic side cross-sectional view of another embodiment of the mixer and the burner using the same according to the present invention, wherein the second mixing tube 215 is partially perforated, the combustion surface 213 is axially elongated, the area of the combustion surface is 10% -70% of the surface area of the second mixing tube 215, and the combustion surface is composed of a plurality of injection holes. Which is suitable for use in an upward fume extractor, a downward fume extractor or a lateral fume extractor, the unapertured portion of the second mixing tube 215 faces in the direction of the fume hole.

Fig. 13 is a schematic side cross-sectional view of a mixer and a burner using the same according to another embodiment of the present invention. Wherein, the combustion surface is a circular cone formed by a high-temperature resistant stainless steel plate or a polyhedral cone formed by a plurality of trapezoidal high-temperature resistant stainless steel plates. The overfire air duct 500 runs through the air distributor 200 and the cone, and the outer or inner cylinder of the air distributor 200 extends to about the middle of the cone. One or more layers of high-temperature-resistant stainless steel woven meshes are arranged on the inner surface of the combustion surface of the cone. The combustion surface is formed by a plurality of injection holes.

Fig. 14 is a schematic side cross-sectional view of another embodiment of a mixer and burner using the same of the present invention. Wherein, the secondary air duct 500 passes through the air input section 110, the air distributor 200, the first mixing duct 112 and the second mixing duct 215. The secondary air duct 500 is used for conveying high-temperature flue gas, the high-temperature flue gas is not mixed with air, and the high-temperature flue gas is kept in a state of not generating condensed water. The high-temperature flue gas is provided by a high-temperature resistant fan. It is suitable for boiler and other equipment.

Alternatively, the mixer and the burner using the same are suitable for being applied to a limited space, and one or more layers of high-temperature-resistant stainless steel nets are arranged on the inner wall of the limited space.

In practical application, the utility model discloses a blender and use its combustor is like this work: the air supplied by the fan is input from the air inlet 111 to the air input section 110 and delivered downstream, then passes through the gas distributor 200 while being uniformly mixed with the combustible gas or fuel injected from the injection holes 210 and 410 of the combustible gas or fuel of the gas distributor 200, and then is delivered to the injection holes of the downstream combustion face to be output and combusted. The utility model discloses a combustion mode of blender and use its combustor includes: the small fire or the start is a premixed surface combustion mode; the medium fire or the big fire is a premixed flameless combustion mode in a fire-off state; a premixing stage combustion mode, a premixing rich-lean combustion mode, a premixing segmentation flame combustion mode, a mixing promotion combustion mode and a premixing pre-combustion mode; and a high-temperature resistant stainless steel mesh heat preservation and infrared radiation technology, a secondary air burnout technology and a high-temperature flue gas recirculation technology.

Through adopting the utility model discloses a mixer and use its combustor can improve the effect that air and combustible gas or fuel mix effectively to coupled multiple technical scheme, used fuel still less when the burning, and produced less polluted gas, accomplished real energy saving and emission reduction.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and selecting appropriate materials and using any incorporated methods. The scope of the present invention is defined by the claims and encompasses other examples that occur to those skilled in the art. Such other examples are to be considered within the scope of protection defined by the claims, provided that they include structural elements that do not differ from the literal language of the claims, or that such other substantially different equivalent structural elements.

Claims (10)

1. A mixer, characterized in that it comprises:

a mixing tube; a gas distributor configured to be composed of a combination of an inner cylinder and an outer cylinder, which is located at a central position of the mixing pipe; and

a plurality of fins disposed on the outer cylinder and configured to secure the gas distributor; and

the outer layer cylinder is provided with a combustible gas or fuel injection hole in the circumferential direction, and an inlet of the combustible gas or fuel arranged on the outer layer cylinder;

and the inner-layer cylinder is circumferentially provided with combustible gas or fuel injection holes.

2. The mixer according to claim 1, wherein the inner cylinder is constructed in a drum shape having a middle diameter smaller than both ends, the outer cylinder has a length greater than that of the inner cylinder, an outer diameter of the inner cylinder is the same as an inner diameter of the outer cylinder, and the inner cylinder is just inserted into the outer cylinder; the front end of the outer layer cylinder is cut into a plurality of uniform strip-shaped structures.

3. The mixer of claim 1, wherein the location of the combustible gas or fuel injection holes of the outer cylinder and the location of the combustible gas or fuel injection holes of the inner cylinder are tubular structures, and the tubular structures are bilaterally symmetrical or unilateral.

4. A burner to which the mixer according to any one of claims 1 to 3 is applied, characterized in that it comprises:

an air input section comprising an air inlet;

a mixing tube; a gas distributor located downstream of the air input section, an

A mixing tube, comprising:

a first mixing tube and a second mixing tube; and

the gas distributor is positioned at the center of the middle part of the first mixing pipe; and

the first mixing tube includes a first combustion face downstream thereof; and

said second mixing tube being located downstream of said inner cylinder's combustible gas or fuel injection orifice, said second mixing tube including a second combustion face downstream thereof; the injection hole of the combustion surface is round and square, and the combustion surface is formed by a plurality of injection holes; and

one or more layers of high-temperature-resistant stainless steel nets are arranged on the outer surfaces and the inner surfaces of the first mixing pipe and the second mixing pipe;

overgrate air tuber pipe, it includes:

the air pipe is provided with a plurality of fins at the front end and a plurality of air injection holes for secondary air at the rear end in the circumferential direction, and penetrates through the central positions of the air distributor, the first mixing pipe and the second mixing pipe; the position of the air injection hole of the secondary air is positioned at the downstream of the second mixing pipe; the fins are used for fixing the air pipe; and

the front end of the air pipe is cut into a plurality of uniform strip-shaped structures, and the opening of each strip-shaped structure is adjusted to control the air flow of the secondary air; and

and one or more layers of high-temperature-resistant stainless steel nets are arranged on the outer surface of the air pipe.

5. The burner of claim 4, wherein the inward or outward opening of the elongated structure at the forward end of the outer cylinder is adjusted to adjust the amount of air flow to the first mixing tube such that the first combustion surface is in a lean or rich condition and the second combustion surface is in a rich or lean condition.

6. The burner as claimed in claim 4, wherein the high temperature resistant stainless steel net provided on the outer surfaces of the first mixing pipe, the second mixing pipe and the blast pipe is a woven net, a sintered net or a woven metal fiber net, and the high temperature resistant stainless steel net is fixed to the outer surfaces of the first mixing pipe, the second mixing pipe and the blast pipe by spot welding.

7. The burner of claim 4, wherein the refractory stainless steel mesh of the inner surfaces of the first and second combustion faces is a woven mesh having a mesh size greater than 80 mesh.

8. The burner of claim 4, wherein the apertures of the refractory stainless steel mesh of the outer surface of the first and second mixing tubes are the locations of the injection holes of the first and second combustion faces, and the apertures are the same size and shape as the injection holes.

9. The burner of claim 4, wherein the injection holes of the first combustion surface, the second combustion surface and the air injection holes of the overfire air duct are provided with tubular structures, and wherein swirl vanes are provided inside the outlet of the tubular structures, the tubular structures being straight and curved.

10. A burner as claimed in claim 4, 6, 7, 8 or 9, wherein the burner is adapted for application in a confined space, the inner wall of which is provided with one or more layers of the high temperature resistant stainless steel mesh.

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