Improved upper air inlet burner

Abstract

The utility model discloses an improved upper air inlet burner which comprises a base and a support arranged on the base, a primary air inlet space is formed between the base and the support, and a first air inlet nozzle and a second air inlet nozzle are arranged on the base. A first injection pipe corresponding to the first air inlet nozzle and a second injection pipe corresponding to the second air inlet nozzle are arranged on the support, and the first injection pipe comprises a first injection pipe downward-concave part integrally formed on the support and a first injection pipe cover matched with the first injection pipe downward-concave part. The second injection pipe comprises a second injection pipe downward-concave part integrally formed on the support and a second injection pipe cover matched with the second injection pipe downward-concave part, and the inner-layer annular groove is arranged in a slope mode, wherein the end, close to the center injection pipe, of the inner-layer annular groove is low, and the end, away from the center injection pipe, of the inner-layer annular groove is high. Due to the fact that the first injection pipe cover and the second injection pipe cover are detachably arranged, the combustor is simple in structure and convenient to manufacture and assemble. Through the arrangement of the slope, the injection performance of the inner-layer annular groove of the combustor and the heat efficiency of the whole machine are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of stoves, in particular to an improved upper air inlet burner. Background Art

[0002] At present, many gas stoves have begun to use fully top-inlet burners. Since the primary and secondary air required for combustion in the fully top-inlet burners come from the upper part of the stove panel, the chassis of the gas stove can be fully sealed. Compared with the traditional bottom-inlet burner, the fully top-inlet burner is not only safer to use, but also can effectively solve the problem of the stove being shut down due to opening and closing the cabinet door.

[0003] The working principle of the upper air inlet burner is: the gas flows out of the nozzle at a certain pressure and a certain flow rate, enters the ejector tube, and relies on the ejection effect of the gas's own energy to attract a certain amount of surrounding air, which is called "primary air". The primary air and gas are mixed in the ejector tube and the burner mixing chamber, and then flow out through the fire hole to burn. During the combustion process, air is attracted from around the flame to assist combustion, and this part of air is called "secondary air".

[0004] A top air inlet burner disclosed in a Chinese utility model patent (publication number: CN205245173U) includes a base, a burner base and an annular upper cover, the base is fixedly connected to the burner base and an installation space is provided between the base and the burner base, the upper end of the burner base is provided with an annular groove matched with the upper cover, and the annular groove is provided with two lower parts of ejector tubes formed by downward depression; the two lower parts of the ejector tubes are centrally symmetrically arranged, the lower end surface of the upper cover is connected with the upper part of the ejector tube, when the upper cover is fixed to the burner base, the lower part of the ejector tube and the upper part of the ejector tube are combined to form an ejector tube, the axis of the ejector tube is spiral, the lower end of the ejector tube extends out of the burner base into the installation space, the base is provided with a gas channel, the outlet end of the combustion channel is arranged opposite to the inlet of the ejector tube, and the upper cover is provided with a gas hole. It adopts a combined ejector tube, and the ejector tube is directly connected to the annular groove, so that the ejector tube structure is reasonable and the gas ejection effect is good.

[0005] However, the upper air inlet burner disclosed in the above prior art has the following disadvantages:

[0006] ① The structure is relatively complex, the manufacturing and assembly are inconvenient, and it cannot meet the actual use needs well;

[0007] ② The gas and air in the inner ring fire are not mixed sufficiently, and the combustion efficiency is low, which in turn affects the combustion effect of the burner.

[0008] Therefore, it is necessary to improve the existing technology. Utility Model Content

[0009] The utility model aims to provide an improved upper air inlet burner in view of the defects and shortcomings of the prior art. The utility model has a first ejector tube cover and a second ejector tube cover which are detachably mounted, so that the burner has a simple structure and is easy to manufacture and assemble. The utility model guides the gas coming in from the central ejector tube to flow upward in a rotation along the left and right sides of the inner annular groove through the slope setting of the inner annular groove. The gas flows smoothly and can be well mixed with the air during the rotation and upward process, thereby effectively improving the mixing ratio of the gas and air, and improving the ejection performance of the inner annular groove of the burner and the thermal efficiency of the whole machine.

[0010] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0011] A modified upper air inlet burner comprises a base and a bracket arranged on the base, a primary air inlet space is formed between the base and the bracket, a first air inlet nozzle and a second air inlet nozzle are arranged on the base, a first ejector tube corresponding to the first air inlet nozzle and a second ejector tube corresponding to the second air inlet nozzle are arranged on the bracket, an outer annular groove, an intermediate annular groove and an inner annular groove are arranged on the bracket from the outer edge to the center, the outer annular groove is connected to the first air inlet nozzle through the first ejector tube, the outer annular groove is connected to the second air inlet nozzle through the second ejector tube, the first ejector tube comprises a first ejector tube lower concave portion integrally formed on the bracket and a first ejector tube cover matched with the first ejector tube lower concave portion, the first ejector tube The two ejector tubes include a second ejector tube recess integrally formed on the bracket and a second ejector tube cover matched with the second ejector tube recess, step surfaces are provided along the upper edges of the inner walls of the first ejector tube recess and the second ejector tube recess, the first ejector tube cover and the second ejector tube cover are provided with abutment surfaces abutting against the step surfaces, the bracket is also provided with a central air inlet nozzle, the base is also provided with a central ejector tube corresponding to the central air inlet nozzle, the inner annular groove is connected with the central air inlet nozzle through the central ejector tube, and the inner annular groove is provided with a slope which is lower at one end close to the central ejector tube and higher at one end away from the central ejector tube.

[0012] Furthermore, the inner wall of the first ejector tube cover and the inner wall of the first ejector tube recess cooperate to form a first air inlet channel with a smooth inner wall, and the inner wall of the second ejector tube cover and the inner wall of the second ejector tube recess cooperate to form a second air inlet channel with a smooth inner wall.

[0013] Furthermore, the ends of the first ejector tube recess and the second ejector tube recess are both provided with vertical step surfaces, and the ends of the first ejector tube cover and the second ejector tube cover are both provided with vertical abutting surfaces abutting against the vertical step surfaces.

[0014] Furthermore, a plurality of positioning columns and support ear grooves are provided at the bottom end of the bracket.

[0015] Furthermore, the first ejector tube cover and the second ejector tube cover are both provided with a plurality of mounting holes and connecting ears corresponding to the positioning columns and the ear grooves.

[0016] Furthermore, the upper end surfaces of the first ejector tube cover and the second ejector tube cover are in the same plane as the upper end surface of the bracket.

[0017] Furthermore, the outer annular groove is provided with a first flow guiding inclined surface corresponding to the first ejector tube and a second flow guiding inclined surface corresponding to the second ejector tube.

[0018] Furthermore, a secondary air inlet is arranged at the center of the bracket.

[0019] Furthermore, the central axes of the first ejector tube and the second ejector tube are both spiral.

[0020] After adopting the above structure, the utility model has the following beneficial effects:

[0021] ① The utility model describes an improved upper air intake burner, wherein the first ejector tube includes a first ejector tube recess integrally formed on the bracket and a first ejector tube cover matched with the first ejector tube recess, and the second ejector tube includes a second ejector tube recess integrally formed on the bracket and a second ejector tube cover matched with the second ejector tube recess. The first ejector tube cover is matched with the first ejector tube recess to form a first air intake channel, and the second ejector tube cover is matched with the second ejector tube recess to form a second air intake channel. During processing, the first ejector tube cover, the second ejector tube cover, the first recess and the second recess can be processed separately, and then the first ejector tube and the second ejector tube are formed by pressing and other processes, so that the burner has a simple structure and is easy to manufacture and assemble.

[0022] ② The utility model discloses an improved upper air inlet burner, wherein the bracket is also provided with a central air inlet nozzle, and the base is also provided with a central ejector tube corresponding to the central air inlet nozzle. The inner annular groove is connected with the central air inlet nozzle through the central ejector tube, and the inner annular groove is set in a slope with a lower end close to the central ejector tube and a higher end away from the central ejector tube. The inner annular groove is set in a slope to guide the gas coming from the central ejector tube to flow upward along the left and right sides of the inner annular groove. The gas flows smoothly and can be well mixed with the air during the process of rotating and rising, thereby effectively improving the mixing ratio of the gas and air, and improving the ejection performance of the inner annular groove of the burner and the thermal efficiency of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present utility model, the drawings required for use in the description of the specific implementation methods will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is an exploded view of the overall structure of the utility model;

[0025] Figure 2 It is a three-dimensional structural schematic diagram of the base of the utility model;

[0026] Figure 3 It is a three-dimensional structural schematic diagram of the bracket of the utility model;

[0027] Figure 4 It is a three-dimensional schematic diagram of the first ejector tube cover of the utility model;

[0028] Figure 5 It is a bottom view of the bracket of the utility model;

[0029] Figure 6 The utility model Figure 5 A cross-sectional view at AA;

[0030] Figure 7 It is a top view of the bracket of the utility model;

[0031] Figure 8 The utility model Figure 7 Cross-sectional view at BB;

[0032] Fig. 9 The utility model Figure 8 A schematic diagram of the structure at A;

[0033] Figures 1 to 9 The bid number is:

[0034] 1. Base; 11. First air inlet nozzle; 12. Second air inlet nozzle; 13. Center air inlet nozzle; 2. Bracket; 21. First ejector tube; 211. Bell mouth section; 212. Gradient section; 2121. Straight tube section; 2122. Cone tube section with enlarged inner diameter; 213. Bend tube section with enlarged inner diameter; 214. Lower concave portion of first ejector tube; 2141. Step surface; 2142. Vertical step surface; 2143. Positioning column; 2144. Support ear groove; 215. First ejector tube cover; 2151. Abutment surface; 2152. Vertical abutment surface Joint; 2153, mounting hole; 2154, connecting ear; 216, first air inlet channel; 22, second ejector tube; 221, second ejector tube recess; 222, second ejector tube cover; 223, second air inlet channel; 23, outer annular groove; 231, first guide slope; 232, second guide slope; 233, first slope; 234, second slope; 24, middle annular groove; 25, inner annular groove; 251, slope; 26, center ejector tube; 27, secondary air inlet; 3, reinforcing ribs. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0036] In the description of the present invention, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly defined and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0039] In the present utility model, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this utility model are only for illustrative purposes and do not represent the only implementation method.

[0041] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] like Figures 1 to 9As shown, an improved upper air inlet burner comprises a base 1 and a bracket 2 arranged on the base 1, a primary air inlet space is formed between the base 1 and the bracket 2, a first air inlet nozzle 11 and a second air inlet nozzle 12 are arranged on the base 1, a first ejector tube 21 corresponding to the first air inlet nozzle 11 and a second ejector tube 22 corresponding to the second air inlet nozzle 12 are arranged on the bracket 2, an outer annular groove 23, an intermediate annular groove 24 and an inner annular groove 25 are arranged on the bracket 2 from the outer edge to the center, the outer annular groove 23 is connected to the first air inlet nozzle 11 through the first ejector tube 21, the outer annular groove 23 is connected to the second air inlet nozzle 12 through the second ejector tube 22, the first ejector tube 21 comprises a first ejector tube lower concave portion 214 integrally formed on the bracket 2 and a first ejector tube cover 2 matched with the first ejector tube lower concave portion 214 15. The second ejector tube 22 includes a second ejector tube recess 221 integrally formed on the bracket 2 and a second ejector tube cover 222 matched with the second ejector tube recess 221. A step surface 2141 is provided along the upper edge of the inner wall of the first ejector tube recess 214 and the second ejector tube recess 221. The first ejector tube cover 215 and the second ejector tube cover 222 are both provided with abutting surfaces 2151 abutting with the step surface 2141. The inner wall of the first ejector tube cover 215 and the inner wall of the first ejector tube recess 214 cooperate to form a first air inlet channel 216 with a smooth inner wall. The inner wall of the second ejector tube cover 222 and the inner wall of the second ejector tube recess 221 cooperate to form a second air inlet channel 223 with a smooth inner wall. The ends of the first ejector tube lower recess 214 and the second ejector tube lower recess 221 are both provided with a vertical step surface 2142, and the ends of the first ejector tube cover 215 and the second ejector tube cover 222 are both provided with a vertical abutment surface 2152 that abuts with the vertical step surface 2142. The bottom end of the bracket 2 is provided with a plurality of positioning posts 2143 and support ear grooves 2144. The first ejector tube cover 215 and the second ejector tube cover 222 are both provided with a plurality of mounting holes 2153 and connecting ears 2154 that correspond to the positioning posts 2143 and the support ear grooves 2144. The upper end surfaces of the first ejector tube cover 215 and the second ejector tube cover 222 are in the same plane as the upper end surface of the bracket 2. The bracket 2 is also provided with a central air inlet nozzle 13, and the base 1 is also provided with a central ejection pipe 26 corresponding to the central air inlet nozzle 13. The inner annular groove 25 is connected to the central air inlet nozzle 13 through the central ejection pipe 26. The inner annular groove 25 is provided with a slope 251 with a lower end close to the central ejection pipe 26 and a higher end away from the central ejection pipe 26. A secondary air inlet 27 is provided at the center of the bracket 2.

[0043] Based on the above embodiments, the utility model aims to provide an improved upper air intake burner, wherein the first ejector tube cover 215 cooperates with the first ejector tube lower recess 214 to form the first air intake channel 216, and the second ejector tube cover 222 cooperates with the second ejector tube lower recess 221 to form the second air intake channel 223. During processing, the first ejector tube cover 215, the second ejector tube cover 222, the first ejector tube lower recess 214, and the second ejector tube lower recess 221 can be processed separately, and then the first ejector tube 21 and the second ejector tube 22 are formed by pressing and other processes. Under the premise of ensuring the pipeline contours of the first air intake channel 216 and the second air intake channel 223, the burner structure is simple and easy to manufacture and assemble. The abutting surface 2151 and the step surface 2141 are matched and fitted, and the vertical abutting surface 2152 and the vertical step surface 2142 are matched and fitted, so that after the first ejector tube cover 215 and the first ejector tube lower recess 214 are assembled, an effectively sealed first air inlet channel 216 with a smooth inner wall is obtained, and after the second ejector tube cover 222 and the second ejector tube lower recess 221 are assembled, an effectively sealed second air inlet channel 223 with a smooth inner wall is obtained. The bottom end of the bracket 2 is provided with a plurality of positioning columns 2143 and support ear grooves 2144. The first ejector tube cover 215 and the second ejector tube cover 222 are both provided with a plurality of mounting holes 2153 and connecting ears 2154 that correspond to the positioning columns 2143 and the support ear grooves 2144. The first ejector tube cover 215 and the second ejector tube cover 222 are quickly positioned during installation by the cooperation of the positioning column 2143 and the mounting hole 2153, and the connecting lug 2154 and the lug groove 2144, thereby improving the installation efficiency and making the first ejector tube cover 215 and the second ejector tube cover 222 more secure and not easy to fall off after installation. The upper end faces of the first ejector tube cover 215 and the second ejector tube cover 222 are in the same plane as the upper end face of the bracket 2. The upper end faces of the first ejector tube cover 215 and the second ejector tube cover 222 are in the same plane as the upper end face of the bracket 2 after installation, making the burner beautiful as a whole, and the sealing of the first air inlet channel 216 and the second air inlet channel 223 will not be affected by the collision of the protrusions of the upper end faces of the first ejector tube cover 215 and the second ejector tube cover 222. The bracket 2 is also provided with a central air inlet nozzle 13, and the base 1 is also provided with a central ejection pipe 26 corresponding to the central air inlet nozzle 13. The inner annular groove 25 is connected to the central air inlet nozzle 13 through the central ejection pipe 26. The inner annular groove 25 is provided with a slope 251 with a lower end close to the central ejection pipe 26 and a higher end away from the central ejection pipe 26. A secondary air inlet 27 is provided at the center of the bracket 2. Figure 1 , Figure 2 , Figure 5 , Figure 6As shown, when in use, the gas is ejected from the first air inlet nozzle 11 and the second air inlet nozzle 12 respectively, and enters the outer annular groove 23 through the first ejector tube 21 and the second ejector tube 22. Therefore, the gas ejected from the first ejector tube 21 and the second ejector tube 22 will flow along the circumference of the outer annular groove 23, accelerating the mixing speed of the gas and air. The mixed gas burns in the outer annular groove 23 to form an outer ring fire; at the same time, the gas is ejected from the central air inlet nozzle 13, enters the inner annular groove 25 through the central ejector tube 26 to burn, forming an inner ring fire. Finally, a double-ring fire combustion effect is formed to improve the combustion efficiency of the burner. A secondary air inlet 27 is arranged at the center of the bracket 2. The secondary air inlet 27 increases the air intake, ensures that the secondary air is sufficient, and the burner burns fully. The slope 251 is provided to guide the gas coming in from the central ejector tube 26 to flow upward in a rotation along the left and right sides of the inner annular groove 25. The gas flows smoothly in the process of rotation and can be well mixed with the air, thereby effectively improving the mixing ratio of the gas and air, and improving the ejection performance of the inner annular groove 25 of the burner and the thermal efficiency of the whole machine.

[0044] As another preferred embodiment of the present invention, the outer annular groove 23 is provided with a first guide slope 231 corresponding to the first ejector tube 21 and a second guide slope 232 corresponding to the second ejector tube 22. The outer annular groove 23 is also provided with a first slope 233 corresponding to the first guide slope 231 and a second slope 234 corresponding to the second guide slope 232. Figure 5 , Figure 8 As shown, the arrangement of the first guide slope 231 and the second guide slope 232 reduces the impact force of the gas when it enters the outer annular groove 23, and the first guide slope 231 and the second guide slope 232 reduce the resistance of the gas and air when they are mixed in a rotating flow, ensuring that the gas and air can be evenly mixed in the outer annular groove 23. In this embodiment, preferably, the outer annular groove 23 is further provided with a first slope 233 corresponding to the first guide slope 231 and a second slope 234 corresponding to the second guide slope 232. The arrangement of the first slope 233 and the second slope 234 further reduces the resistance of the gas and air when they are mixed in a rotating flow, and better ensures that the gas and air can be evenly mixed in the outer annular groove 23.

[0045] As another preferred embodiment of the present invention, the central axes of the first ejector tube 21 and the second ejector tube 22 are both spiral. Preferably, the first ejector tube 21 and the second ejector tube 22 both include a bell-mouth section 211, a gradient section 212 and an inner diameter enlarged curved tube section 213, the inner diameters of the bell-mouth section 211 and the inner diameter enlarged curved tube section 213 are both larger than the inner diameter of the gradient section 212, the gradient section 212 includes a straight tube section 2121 and an inner diameter enlarged conical tube section 2122, and the bell-mouth sections 211 of the first ejector tube 21 and the second ejector tube 22 are arranged in opposite directions. In this embodiment, as Figure 5 As shown, by setting the bell mouth section 211, the gradient section 212 and the inner diameter enlarged curved pipe section 213, a first air inlet channel 216 and a second air inlet channel 223 with an inner diameter changing from "coarse" to "fine" and then to "coarse" are formed in the first ejector tube 21 and the second ejector tube 22, realizing the process of first contraction and acceleration, then mixing, and finally deceleration and pressurization, thereby improving the primary air ejection capacity and mixing capacity, and meeting the combustion performance of the burner. In this embodiment, preferably, the gradient section 212 is provided with a straight section 2121, and the setting of the straight section 2121 further improves the ejection capacity. When in use, the gas is ejected from the first air inlet nozzle 11 and the second air inlet nozzle 12 respectively, and the gas flows in through the bell mouth section 211. Since the inner diameter of the gradient section 212 is smaller than the inner diameter of the bell mouth section 211, when the gas flows through the gradient section 212, the flow velocity increases. Low pressure will be generated near the high-speed flowing gas, thereby generating an adsorption effect, adsorbing the surrounding air, ensuring the primary air injection capacity, and increasing the mixing degree of gas and air. At the same time, since the first ejector tube 21 and the second ejector tube 22 are double-helical and arranged in opposite directions, when the mixed gas of gas and air enters the outer annular groove 23 from the first ejector tube 21 and the second ejector tube 22, a 360° rotating flow type secondary mixing can be performed in the outer annular groove 23, and the mixing is more sufficient and uniform, so that the burner has high combustion efficiency. In this embodiment, preferably, a raised, integrally formed reinforcing rib 3 is provided along the junction of the outer wall of the first ejector tube 21 and the second ejector tube 22 and the bracket 2. By setting the reinforcing rib 3, the strength of the first ejector tube 21 and the second ejector tube 22 is enhanced, and the problem of the first ejector tube 21 and the second ejector tube 22 being easy to deform or even crack due to the large difference between the thickness of the first ejector tube 21 and the second ejector tube 22 and the overall thickness of the bracket 2 and the large difference in expansion ratio when heated is reduced. This ensures the smoothness and sealing of the inner walls of the first air inlet channel 216 and the second air inlet channel 223, increases the flow rate of the gas, thereby improving the combustion effect of the burner and also increasing the service life of the burner.

[0046] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present utility model.

Claims

1. An improved upper air intake burner, comprising a base (1) and a bracket (2) arranged on the base (1), a primary air intake space being formed between the base (1) and the bracket (2), a first air intake nozzle (11) and a second air intake nozzle (12) being arranged on the base (1), a first ejector tube (21) corresponding to the first air intake nozzle (11) and a second ejector tube (22) corresponding to the second air intake nozzle (12) being arranged on the bracket (2), an outer annular groove (23), an intermediate annular groove (24) and an inner annular groove (25) being arranged on the bracket (2) from the outer edge to the center, the outer annular groove (23) being connected to the first air intake nozzle (11) through the first ejector tube (21), and the outer annular groove (23) being connected to the second air intake nozzle (12) through the second ejector tube (22), characterized in that: The first ejector tube (21) comprises a first ejector tube lower recess (214) integrally formed on the bracket (2) and a first ejector tube cover (215) cooperating with the first ejector tube lower recess (214); the second ejector tube (22) comprises a second ejector tube lower recess (221) integrally formed on the bracket (2) and a second ejector tube cover (222) cooperating with the second ejector tube lower recess (221); step surfaces (2141) are provided along the upper edges of the inner walls of the first ejector tube lower recess (214) and the second ejector tube lower recess (221); the first ejector tube The tube cover (215) and the second ejector tube cover (222) are both provided with an abutting surface (2151) that abuts against the step surface (2141). The bracket (2) is also provided with a central air inlet nozzle (13). The base (1) is also provided with a central ejector tube (26) corresponding to the central air inlet nozzle (13). The inner annular groove (25) is connected to the central air inlet nozzle (13) through the central ejector tube (26). The inner annular groove (25) is provided with a slope (251) with a lower end close to the central ejector tube (26) and a higher end away from the central ejector tube (26).

2. The improved upper air inlet burner according to claim 1, characterized in that: The inner wall of the first ejector tube cover (215) and the inner wall of the first ejector tube recess (214) cooperate to form a first air inlet channel (216) with a smooth inner wall, and the inner wall of the second ejector tube cover (222) and the inner wall of the second ejector tube recess (221) cooperate to form a second air inlet channel (223) with a smooth inner wall.

3. The improved upper air inlet burner according to claim 2 is characterized in that: The ends of the first ejector tube recess (214) and the second ejector tube recess (221) are both provided with vertical step surfaces (2142), and the ends of the first ejector tube cover (215) and the second ejector tube cover (222) are both provided with vertical abutting surfaces (2152) that abut against the vertical step surfaces (2142).

4. The improved upper air inlet burner according to claim 3 is characterized in that: A plurality of positioning columns (2143) and support ear grooves (2144) are provided at the bottom end of the bracket (2).

5. The improved upper air inlet burner according to claim 4, characterized in that: The first ejector tube cover (215) and the second ejector tube cover (222) are both provided with a plurality of mounting holes (2153) and connecting ears (2154) corresponding to the positioning columns (2143) and the ear grooves (2144).

6. The improved upper air inlet burner according to claim 5, characterized in that: The upper end surfaces of the first ejector tube cover (215) and the second ejector tube cover (222) are located in the same plane as the upper end surface of the bracket (2).

7. The improved upper air inlet burner according to claim 1, characterized in that: The outer annular groove (23) is provided with a first flow guiding inclined surface (231) corresponding to the first ejector tube (21) and a second flow guiding inclined surface (232) corresponding to the second ejector tube (22).

8. The improved upper air inlet burner according to claim 1, characterized in that: A secondary air inlet (27) is provided at the center of the bracket (2).

9. The improved upper air inlet burner according to claim 1, characterized in that: The central axes of the first ejector tube (21) and the second ejector tube (22) are both spiral.

Images