Low-nitrogen burner and gas water heater

Abstract

The utility model discloses a low-nitrogen burner which comprises a shell, and the shell is provided with a plurality of fire hole groups communicated with an airflow channel at the other end of the airflow channel; the fire hole group comprises a first fire hole and a second fire hole; according to the low-nitrogen combustor, single-area combustion is formed in each fire hole set, multiple single-area combustion is formed in the multiple fire hole sets, and combustion is more stable; in each fire hole group, fuel gas passes through the gas inlet and the gas flow channel to form a low-speed flow area at the position of the first fire hole, the fuel gas passes through the gas inlet and the gas flow channel to form a high-speed flow area at the position of the second fire hole, the fuel gas realizes rich combustion in the low-speed flow area, and the fuel gas realizes lean combustion in the high-speed flow area, so that the formation of NOx is reduced; and the low-nitrogen combustor is of an integral combustion structure and is good in sealing performance, simple in structure and low in cost. The utility model discloses a gas water heater which comprises the low-nitrogen burner, reduces NOx formation, and is simple in structure and low in cost.

Description

Technical Field

[0001] This utility model relates to the field of combustion equipment technology, and in particular to a low-NOx burner and a gas water heater. Background Technology

[0002] In related technologies, low-NOx combustion in gas water heaters generally uses methods such as rich-lean combustion or fully premixed combustion. The above-mentioned atmospheric combustion methods generally control nitrogen oxide emissions by reducing power.

[0003] The rich-lean combustion method typically requires the use of rich-lean combustion equipment, which includes both rich combustion channels and lean combustion channels. The rich combustion channel has a rich combustion inlet and a rich combustion burner, while the lean combustion channel has a lean combustion inlet and a lean combustion burner. The rich gas is burned through the rich combustion inlet and channel at the rich combustion burner, and the lean gas is burned through the lean combustion inlet and channel at the lean combustion burner. This method requires two sets of combustion structures to achieve rich-lean combustion, resulting in a complex overall design and high cost.

[0004] The fully premixed combustion method refers to the complete and uniform mixing of gas and air before combustion to form a mixed fuel gas with the optimal air-fuel ratio, which is then sent to the burner for combustion. This combustion method requires the installation of a mixer such as a fan and the assembly of the burner body. The connection between the mixer and the burner body is prone to not being sealed, resulting in a lack of coordination between air and gas. Utility Model Content

[0005] To overcome the shortcomings of existing technologies, one of the objectives of this utility model is to provide a low-NOx burner in which each burner group forms a single-zone combustion, and multiple burner groups form multiple single-zone combustion, resulting in more stable combustion. In each burner group, fuel gas forms a low-speed flow zone at the first burner position through the air inlet and airflow channel, and forms a high-speed flow zone at the second burner position through the air inlet and airflow channel. The fuel gas achieves fuel-rich combustion in the low-speed flow zone and fuel-lean combustion in the high-speed flow zone, thereby reducing NOx formation. Furthermore, this low-NOx burner has an integral combustion structure, good sealing performance, simple structure, and low cost.

[0006] The second objective of this utility model is to provide a gas water heater that uses the aforementioned low-NOx burner to reduce NOx formation, and has a simple structure and low cost.

[0007] One of the objectives of this utility model is achieved through the following technical solution:

[0008] A low-NOx burner, comprising:

[0009] The shell has an internal cavity that forms an airflow channel. At one end of the airflow channel, the shell has an air inlet that communicates with the airflow channel. At the other end of the airflow channel, the shell has multiple sets of burner groups that communicate with the airflow channel. Each set of burner groups forms a single-zone combustion.

[0010] The breech assembly includes a first breech and a second breech, with the first breech located in the middle of the breech assembly and the second breech located on the periphery of the breech assembly.

[0011] The fuel gas forms a low-speed flow zone at the first ignition point by passing through the air inlet and airflow channel, and a high-speed flow zone at the second ignition point by passing through the air inlet and airflow channel.

[0012] As an optional implementation, the diameter of the first burner is larger than the diameter of the second burner.

[0013] As an optional implementation, in a group of burners, both the first burner and the second burner emit gas toward the combustion center of their respective areas.

[0014] The first burner outlet emits gas in the longitudinal direction, and the outlet of the second burner outlet is equipped with a baffle to allow the second burner outlet to emit gas in the transverse direction.

[0015] As an optional implementation, the breech assembly also includes a third breech, the diameter of which is larger than that of the second breech, and the third breech is located in the middle of the breech assembly.

[0016] In a group of flare heads, the third flare head emits gas toward the combustion center of the area it belongs to, and the third flare head emits gas in the longitudinal direction.

[0017] As an optional implementation, the breech assembly further includes a fourth breech, the diameter of which is smaller than that of the first breech and the diameter of which is smaller than that of the third breech, and the fourth breech is located on the periphery of the breech assembly.

[0018] In a group of flare heads, the fourth flare head emits gas toward the combustion center of its assigned area, and the fourth flare head emits gas along the longitudinal direction.

[0019] As an optional implementation, a fire transfer port is provided between two adjacent fire ports.

[0020] As an optional implementation, the airflow channel includes a first channel segment, a second channel segment, and a third channel segment that are interconnected. The first channel segment is arranged in the transverse direction, the second channel segment is arranged in the longitudinal direction, and the third channel segment is arranged in the transverse direction.

[0021] The air intake is located in the first channel section, and the ignition group is located in the third channel section.

[0022] As an optional implementation, a first flow-blocking protrusion is provided on the first channel segment to form a first flow-blocking area;

[0023] And / or, a second flow-blocking protrusion is provided on the second channel segment to form a second flow-blocking area;

[0024] And / or, a third flow-blocking protrusion is provided on the third channel segment to form a third flow-blocking zone.

[0025] As an optional implementation, the third channel segment has a larger end and a smaller end, with the larger end of the third channel segment closer to the ignition group and the smaller end of the third channel segment closer to the second channel segment.

[0026] The second objective of this utility model is achieved by the following technical solution:

[0027] A gas water heater includes the aforementioned low-NOx burner.

[0028] In summary, this utility model has the following technical effects:

[0029] 1. In the low-NOx burner of this utility model, each burner group forms a single-zone combustion, and multiple burner groups form multiple single-zone combustion, resulting in more stable combustion. In each burner group, the fuel gas forms a low-speed flow zone at the first burner position through the air inlet and airflow channel, and a high-speed flow zone at the second burner position through the air inlet and airflow channel. The fuel gas achieves fuel-rich combustion in the low-speed flow zone and fuel-lean combustion in the high-speed flow zone, thereby reducing NOx formation. Furthermore, this low-NOx burner has an integral combustion structure, good sealing performance, simple structure, and low cost.

[0030] 2. The gas water heater in this utility model uses the above-mentioned low-NOx burner, which reduces NOx formation and has a simple structure and low cost. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the external structure of the low-NOx burner in Embodiment 1 of this utility model from a first-view perspective;

[0032] Figure 2 This is the low-NOx burner of Embodiment 1 of the present invention. Figure 1 A partial structural diagram;

[0033] Figure 3 This is a schematic diagram of the external structure of the low-NOx burner in Embodiment 1 of this utility model from a second perspective;

[0034] Figure 4 This is a schematic diagram of the external structure of the low-NOx burner in Embodiment 1 of this utility model from a third-view perspective;

[0035] Figure 5This is a schematic diagram of the external structure of the low-NOx burner in Embodiment 1 of this utility model from a fourth perspective;

[0036] Figure 6 This is a combustion diagram of the low-NOx burner in Embodiment 1 of this utility model;

[0037] Figure 7 This is a schematic diagram of the gas outlet of the burner assembly of the low-NOx burner in Embodiment 1 of this utility model.

[0038] The meanings of the reference numerals in the attached figures are as follows:

[0039] 10. Shell; 20. Airflow channel; 201. First channel section; 202. Second channel section; 203. Third channel section; 30. Air inlet; 40. Burner assembly; 401. First burner; 402. Second burner; 403. Third burner; 404. Fourth burner; 50. Baffle; 60. Ignition port; 70. First flow-blocking protrusion; 80. Second flow-blocking protrusion; 90. Third flow-blocking protrusion; a. Low-speed flow zone; b. High-speed flow zone; c. Ignition zone. Detailed Implementation

[0040] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0041] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0043] Example 1

[0044] See Figures 1-7This utility model discloses a low-NOx burner, comprising: a shell 10, the interior of which has a cavity forming an airflow channel 20; an air inlet 30 communicating with the airflow channel 20 is provided at one end of the shell 10; and multiple sets of burner groups 40 communicating with the airflow channel 20 are provided at the other end of the shell 10, each set of burner groups 40 forming a single-zone combustion; the burner group 40 includes a first burner 401 and a second burner 402, the first burner 401 being located in the middle of the burner group 40, and the second burner 402 being located on the periphery of the burner group 40; fuel gas forms a low-speed flow zone at the first burner 401 through the air inlet 30 and the airflow channel 20, and forms a high-speed flow zone at the second burner 402 through the air inlet 30 and the airflow channel 20.

[0045] It should be noted that multiple sets of burner groups 40 are spaced apart on the burner face of the low-NOx burner; the aforementioned multiple sets of burner groups 40 refers to having two sets of burner groups 40 or more sets of burner groups 40, such as having two sets of burner groups 40, three sets of burner groups 40, four sets of burner groups 40, etc.

[0046] Specifically, NOx refers to nitrogen oxides, fuel-rich combustion refers to the combustion of excess fuel in a combustible mixture with a stoichiometric ratio greater than 1, and fuel-lean combustion refers to the combustion of excess oxygen in a combustible mixture with a stoichiometric ratio less than 1.

[0047] Because the fuel gas flows slowly in the low-speed zone, it is a slow diffusion combustion rather than forced convection, resulting in a slow and insufficient mixing rate between the fuel gas and air at this location. This easily leads to a high fuel concentration at this location, resulting in fuel enrichment and rich combustion. Conversely, because the fuel gas flows quickly in the high-speed zone, the fuel gas mixes fully with air in a shorter time, avoiding fuel enrichment. This easily leads to an excess of oxygen at this location, resulting in lean combustion.

[0048] In lean combustion sites, the combustion temperature is lower, which can effectively suppress the formation of high-temperature NOx (thermal NOx is the result of the reaction between nitrogen and oxygen at high temperatures).

[0049] In the fuel-rich combustion position, insufficient oxygen reduces the formation of nitrogen oxides, while some unburned fuel can act as a reducing agent to reduce the generated NOx into nitrogen (N2).

[0050] By alternating between lean and rich combustion, NOx emissions from the overall combustion process can be reduced by 30%-50% compared to traditional homogeneous combustion.

[0051] In the low-NOx burner of this invention, each burner group 40 forms a single-zone combustion, and multiple burner groups 40 form multiple single-zone combustion, resulting in more stable combustion. In each burner group 40, fuel gas forms a low-speed flow zone at the first burner 401 through the air inlet 30 and the airflow channel 20, and forms a high-speed flow zone at the second burner 402 through the air inlet 30 and the airflow channel 20. The fuel gas achieves fuel-rich combustion in the low-speed flow zone and fuel-lean combustion in the high-speed flow zone, thereby reducing NOx formation. Furthermore, this low-NOx burner has an integral combustion structure, good sealing performance, simple structure, and low cost.

[0052] In this embodiment of the invention, the diameter of the first burner 401 is larger than the diameter of the second burner 402; thus, the gas flow rate of the fuel gas is controlled by controlling the diameter of the first burner 401 and the diameter of the second burner 402.

[0053] It should be noted that the diameter of the first burner 401 refers to the dimension of the first burner 401 in the direction of its minor axis, and the diameter of the first burner 401 is set as D1; ​​the diameter of the second burner 402 refers to the dimension of the second burner 402 in the direction of its minor axis, and the diameter of the second burner 402 is set as D2; thus, D1 > D2.

[0054] In this embodiment of the present invention, in a group of vents 40, the first vent 401 and the second vent 402 both emit gas toward the combustion center of their respective areas; the first vent 401 emits gas in the longitudinal direction, and the outlet position of the second vent 402 is provided with a baffle 50 so that the second vent 402 emits gas in the transverse direction.

[0055] See Figure 7 Each second burner 402 is unidirectional, so that multiple second burners 402 in each burner group 40 are all directed toward the combustion center of their respective area; for adjacent burner groups 40, the second burners 402 in different burner groups 40 are all directed toward their respective combustion centers.

[0056] In this embodiment of the present invention, the vent group 40 further includes a third vent 403, the diameter of which is larger than that of the second vent 402, and the third vent 403 is located in the middle of the vent group 40; in a vent group 40, the third vent 403 emits gas toward the combustion center of the area to which it belongs, and the third vent 403 emits gas along the longitudinal direction.

[0057] In this embodiment of the present invention, the vent group 40 further includes a fourth vent 404, the diameter of which is smaller than that of the first vent 401 and smaller than that of the third vent 403. The fourth vent 404 is disposed on the periphery of the vent group 40. In a vent group 40, the fourth vent 404 exhausts gas toward the combustion center of the area to which it belongs, and the fourth vent 404 exhausts gas along the longitudinal direction.

[0058] It should be noted that the diameter of the third burner 403 refers to the dimension of the third burner 403 in the direction of its minor axis, and the diameter of the third burner 403 is set as D3; the diameter of the fourth burner 404 refers to the dimension of the fourth burner 404 in the direction of its minor axis, and the diameter of the fourth burner 404 is set as D4; thus D3 > D2, D1 > D4, and D3 > D4.

[0059] The fuel gas forms a low-speed flow zone at the third burner 403 through the air inlet 30 and the airflow channel 20, and forms a high-speed flow zone at the fourth burner 404 through the air inlet 30 and the airflow channel 20.

[0060] Specifically, multiple first burners 401, second burners 402, third burners 403, and fourth burners 404 can be set, and the specific number of burners can be determined according to the actual application scenario and is not limited.

[0061] In this embodiment of the invention, a fire transfer port 60 is provided between two adjacent fire port groups 40.

[0062] Because multiple sets of ignition assemblies 40 form multiple single-zone combustion, and the ignition assemblies 40 are separated from each other to form stable combustion, and the ignition port 60 is used to enable multiple single-zone combustion to ignite each other and avoid flameout, compared with the whole ignition assembly 40, the flame combustion formed by first forming single-zone combustion and then connecting multiple ignition assemblies 40 through the ignition port 60 is more stable.

[0063] Furthermore, since each group of ignition 40 has a second ignition 402 and a fourth ignition 404 on its periphery, and a first ignition 401 and a third ignition 403 in the middle, the periphery of the ignition group 40 forms a high-speed flow zone, and the middle of the ignition group 40 forms a low-speed flow zone. Consequently, the periphery of the ignition group 40 forms a lean combustion zone, and the middle of the ignition group 40 forms a rich combustion zone. Since the flame in the lean combustion zone is unstable and easily extinguished, a flame transfer port 60 needs to be set between adjacent ignition groups 40 to prevent flameout.

[0064] In this embodiment of the invention, multiple sets of flare groups 40 are arranged to extend along the length of the low-NOx burner.

[0065] In this embodiment of the utility model, the airflow channel 20 includes a first channel section 201, a second channel section 202, and a third channel section 203 that are interconnected. The first channel section 201 is arranged in the transverse direction, the second channel section 202 is arranged in the longitudinal direction, and the third channel section 203 is arranged in the transverse direction. The air inlet 30 is arranged in the first channel section 201, and the burner assembly 40 is arranged in the third channel section 203.

[0066] In this embodiment of the present invention, a first flow-blocking protrusion 70 is provided on the first channel segment 201 to form a first flow-blocking area.

[0067] In this embodiment of the invention, a second flow-blocking protrusion 80 is provided on the second channel segment 202 to form a second flow-blocking area.

[0068] In this embodiment of the present invention, a third flow-blocking protrusion 90 is provided on the third channel segment 203 to form a third flow-blocking area.

[0069] In this embodiment of the utility model, one end of the third channel segment 203 is larger than the other end, the larger end of the third channel segment 203 is closer to the ignition group 40, and the smaller end of the third channel segment 203 is closer to the second channel segment 202.

[0070] The aforementioned airflow channel 20 is U-shaped. The second channel section 202 is located on the side close to the third channel section 203. A second flow-blocking protrusion 80 is provided so that the fuel body faces the other side of the third channel section 203, thereby avoiding uneven fuel gas distribution on both sides of the third channel section 203.

[0071] The first obstruction zone of the first channel section 201 forms a Venturi effect, creating a natural ejection and drawing in an appropriate amount of air. The gradually expanding section of the first obstruction zone along the airflow can reduce the airflow velocity and prevent the flame from backflashing.

[0072] Because the cross-section of the third channel section 203 is reduced at the position of the third flow-blocking protrusion 90, the gas velocity increases when the fuel gas passes through the position of the third flow-blocking protrusion 90, which is beneficial to the transportation of fuel gas.

[0073] Specifically, see Figure 3 From a side view of this low-NOx burner, the larger end of the third channel section 203 is close to the ignition group 40, and the smaller end of the third channel section 203 is close to the second channel section 202, forming a larger combustion surface; see reference Figure 5 From the main viewing angle of this low-NOx burner, the large end of the third channel section 203 is close to the ignition group 40, and the small end of the third channel section 203 is close to the second channel section 202, forming a larger combustion surface.

[0074] Specifically, the shell 10 can be formed by two separate parts that snap together, see reference. Figure 3When viewed from the side, the two parts of the low-NOx burner form an angle at the position of the third channel section 203, and the angle is α, where 30° < α < 60°.

[0075] Example 2

[0076] See Figures 1-7 This utility model discloses a gas water heater, including the aforementioned low-NOx burner.

[0077] This utility model gas water heater uses the aforementioned low-NOx burner, which reduces NOx formation and has a simple structure and low cost.

[0078] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A low-NOx burner, characterized in that, include: The housing has an internal cavity forming an airflow channel. At one end of the airflow channel, the housing has an air inlet communicating with the airflow channel. At the other end of the airflow channel, the housing has multiple sets of burner groups communicating with the airflow channel. Each set of burner groups forms a single-zone combustion. The breech assembly includes a first breech and a second breech, with the first breech located in the middle of the breech assembly and the second breech located on the periphery of the breech assembly. The fuel gas forms a low-speed flow zone at the first ignition point by passing through the air inlet and the airflow channel, and forms a high-speed flow zone at the second ignition point by passing through the air inlet and the airflow channel.

2. The low-NOx burner according to claim 1, characterized in that: The diameter of the first burner is larger than the diameter of the second burner.

3. The low-NOx burner according to claim 1, characterized in that: In one group of the aforementioned flare groups, both the first flare and the second flare emit gas toward the combustion center of their respective burning areas; The first burner outlet emits gas in the longitudinal direction, and the outlet of the second burner outlet is equipped with a baffle to allow the second burner outlet to emit gas in the transverse direction.

4. The low-NOx burner according to claim 2, characterized in that: The breech assembly also includes a third breech, the diameter of which is larger than that of the second breech, and the third breech is located in the middle of the breech assembly. In one group of the burner groups, the third burner outlets gas towards the combustion center of the area to which it belongs, and the third burner outlets gas along the longitudinal direction.

5. The low-NOx burner according to claim 4, characterized in that: The breech assembly further includes a fourth breech, the diameter of which is smaller than that of the first breech and smaller than that of the third breech, and the fourth breech is located on the periphery of the breech assembly. In one group of the burner groups, the fourth burner outlets gas towards the combustion center of the area to which it belongs, and the fourth burner outlets gas along the longitudinal direction.

6. The low-NOx burner according to any one of claims 1-5, characterized in that: A fire transfer port is provided between two adjacent fire vent groups.

7. The low-NOx burner according to any one of claims 1-5, characterized in that: The airflow channel includes a first channel segment, a second channel segment, and a third channel segment that are interconnected. The first channel segment is arranged in the transverse direction, the second channel segment is arranged in the longitudinal direction, and the third channel segment is arranged in the transverse direction. The air inlet is located in the first channel section, and the ignition group is located in the third channel section.

8. The low-NOx burner according to claim 7, characterized in that: The first channel segment is provided with a first flow-blocking protrusion to form a first flow-blocking area; And / or, a second flow-blocking protrusion is provided on the second channel segment to form a second flow-blocking area; And / or, the third channel segment is provided with a third flow-blocking protrusion to form a third flow-blocking zone.

9. The low-NOx burner according to claim 7, characterized in that: The third channel segment is larger at one end and smaller at the other end. The larger end of the third channel segment is closer to the ignition group, and the smaller end of the third channel segment is closer to the second channel segment.

10. A gas water heater, characterized in that: Including the low-NOx burner as described in claim 1.

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