CN113137755A

CN113137755A - Gas water heater

Info

Publication number: CN113137755A
Application number: CN202010073803.5A
Authority: CN
Inventors: 李茂照; 黄官贤; 梁国荣
Original assignee: Wuhu Midea Kitchen and Bath Appliances Manufacturing Co Ltd
Current assignee: Wuhu Midea Kitchen and Bath Appliances Manufacturing Co Ltd
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2021-07-20

Abstract

The invention provides a gas water heater, which comprises a shell, a catalytic combustor and a first heat exchanger. Wherein the interior of the housing forms a combustion chamber; the catalytic combustion chamber is arranged in the combustion chamber; the first heat exchanger is positioned above the catalytic combustor, and part of the first heat exchanger is arranged in the first combustion chamber, and the other part of the first heat exchanger is arranged outside the first combustion chamber. The heat exchanger part in the combustion chamber is contacted with high-temperature flue gas, so that the water cut-off temperature rise is higher; and the heat exchanger part outside the combustion chamber absorbs less heat and has lower water cut-off temperature rise because of not contacting with high-temperature flue gas. After the high-temperature water and the low-temperature water in the first heat exchanger are neutralized, the final water cut-off temperature rise can be effectively reduced, and the risk of scalding users is reduced.

Description

Gas water heater

Technical Field

The invention relates to the technical field of household appliances, in particular to a gas water heater.

Background

A gas water heater isAn apparatus for heating cold water by burning gas. The main combustion mode adopted by most of gas water heaters is flame combustion, a large amount of harmful gas is easily discharged in the combustion process, the personal safety is harmed, and the environment is polluted. In order to realize low emission of pollutants of a gas water heater, a catalytic combustor is adopted to heat a heat exchanger in the prior art, the catalytic combustion is flameless combustion and is nearly complete combustion, and carbon monoxide (CO) and Nitric Oxide (NO) can be remarkably reduced_x) The amount of discharge of (c). However, the prior art also has the following problems: the catalytic combustor has slow heat dissipation, so that water flow in the heat exchanger is stopped and the temperature is raised too high, and high-temperature hot water can cause frightening and puzzling to users and even can scald the users.

Disclosure of Invention

The main object of the present invention is to propose a gas water heater, aiming at solving at least one of the above problems.

In order to achieve the above object, the present invention provides a gas water heater, comprising:

a housing, an interior of which forms a combustion chamber;

a catalytic combustor mounted within the combustion chamber;

the first heat exchanger is positioned above the catalytic combustor, and part of the first heat exchanger is arranged in the combustion chamber, and the other part of the first heat exchanger is arranged outside the combustion chamber.

In one embodiment, the catalytic combustor divides the combustion chamber into a first combustion chamber and a second combustion chamber arranged from top to bottom, the first heat exchanger portion being mounted within the first combustion chamber.

In an embodiment, the first heat exchanger includes fins, a plurality of inner heat exchange tubes and a plurality of outer heat exchange tubes, the plurality of inner heat exchange tubes are inserted into the fins, the fins and the inner heat exchange tubes are installed in the first combustion chamber, and the plurality of outer heat exchange tubes are installed on the housing and located outside the first combustion chamber.

In an embodiment, the casing includes two opposite partition plates and two first end plates connecting the two partition plates, the two partition plates and the two first end plates enclose the first combustion chamber, the heat exchange inner tube is located inside the partition plates, and the heat exchange outer tube is located outside the partition plates.

In one embodiment, the distance between the upper parts of the two separators is smaller than the distance between the lower parts of the two separators, and the plurality of heat exchange inner tubes are arranged between the two separators in a multilayer stacking manner; the heat exchange outer pipes are arranged side by side in the vertical direction and attached to the outer side of the upper portion of the partition plate.

In an embodiment, the first heat exchanger has a first water inlet and a first water outlet, and the first water inlet, the inner heat exchange tube, the outer heat exchange tube and the first water outlet are communicated.

In an embodiment, the gas water heater still includes preheating combustor and second heat exchanger, preheating combustor with the second heat exchanger install in the second combustion chamber, preheating combustor set up in the below of catalytic combustor, preheating combustor is used for heating the catalytic combustor, just the catalytic combustor presss from both sides and locates first heat exchanger with between the second heat exchanger.

In one embodiment, the second heat exchanger comprises a plurality of secondary heat exchange tubes, and the secondary heat exchange tubes are attached to and supported at the bottom of the catalytic combustor.

In an embodiment, the casing further includes two side plates disposed opposite to each other and two second end plates connecting the two side plates, the two side plates and the two second end plates surround the second combustion chamber, the second heat exchanger further includes a plurality of first heat exchange secondary pipes, and the first heat exchange secondary pipes are sandwiched between the catalytic combustor and the side plates.

In an embodiment, the second heat exchanger further comprises a plurality of second heat exchange secondary pipes, and the second heat exchange secondary pipes are clamped between the preheating burner and the side plates.

In an embodiment, the second heat exchanger further includes a plurality of third secondary heat exchange tubes, and the third secondary heat exchange tubes are attached to the inner sides of the side plates and located between the first secondary heat exchange tubes and the second secondary heat exchange tubes.

In an embodiment, the second heat exchanger has a second water inlet and a second water outlet, and the second water inlet, the heat exchange secondary pipe, the first secondary heat exchange pipe, the second secondary heat exchange pipe, the third secondary heat exchange pipe and the second water outlet are communicated.

In an embodiment, the gas water heater further comprises a fan and a gas mixing device, the gas mixing device is arranged between the fan and the preheating burner, the gas mixing device is provided with a gas mixing cavity, the second combustion chamber and the first combustion chamber are sequentially communicated, and the fan is used for driving air and gas to enter the gas mixing cavity.

According to the technical scheme, one part of the first heat exchanger is arranged in the combustion chamber, the other part of the first heat exchanger is arranged outside the combustion chamber, water cut-off and temperature rise can occur when a user turns off water and then boils water in the midway in the using process, and the heat exchanger part in the combustion chamber is contacted with high-temperature smoke gas, so that the water cut-off and temperature rise is high; and the heat exchanger part outside the combustion chamber absorbs less heat and has lower water cut-off temperature rise because of not contacting with high-temperature flue gas. After the high-temperature water and the low-temperature water in the first heat exchanger are neutralized, the final water cut-off temperature rise can be effectively reduced, and the risk of scalding users is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic external view of a gas burner according to an embodiment of the present invention;

FIG. 2 is a schematic view of the internal structure of the gas burner shown in FIG. 1;

FIG. 3 is a front view of the gas burner of FIG. 1;

FIG. 4 is a schematic view of the first combustion chamber and the first heat exchanger of FIG. 1;

FIG. 5 is an exploded view of the first combustion chamber and first heat exchanger shown in FIG. 1;

FIG. 6 is a schematic view of the second combustion chamber and the second heat exchanger shown in FIG. 1;

fig. 7 is an exploded view of the second combustion chamber and the second heat exchanger shown in fig. 1.

The reference numbers illustrate:

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

An embodiment of the present invention provides a gas water heater, and a mobile air conditioner according to an embodiment of the present invention is specifically described below with reference to fig. 1 to 7.

In one embodiment of the present invention, the gas water heater includes:

a housing, an interior of which forms a combustion chamber;

a catalytic combustor 10 mounted within the combustion chamber;

a first heat exchanger 30, said first heat exchanger 30 being located above the catalytic burner 10, a portion of said first heat exchanger 30 being mounted inside said combustion chamber and another portion being mounted outside said combustion chamber.

Specifically, a part of heat exchange tubes of the first heat exchanger 30 are located in the combustion chamber and can contact with high-temperature flue gas generated by the catalytic combustor 10, so that the water cut-off temperature rise of the part of heat exchange tubes is high; in addition, a part of heat exchange tubes in the first heat exchanger 30 are positioned in the combustor, so that the water cut-off temperature rise of the part of heat exchange tubes is lower, the two parts of heat exchange tubes in the first heat exchanger 30 are communicated, and after the high-temperature water and the low-temperature water of the two parts of heat exchange tubes are neutralized, the final water cut-off temperature rise can be effectively reduced, and the risk of scalding a user is reduced. It should be noted that, the portion of the heat exchange tubes located outside the combustion chamber in the first heat exchanger 30 is not a connecting tube for connecting the heat exchange tubes.

Specifically, a preheating burner 20 is further installed in the shell, the preheating burner 20 is of a porous honeycomb structure, and optionally, the preheating burner 20 is made of a ceramic material; the catalytic combustor 10 includes a catalyst carrier and a catalyst coated on the catalyst carrier, and optionally, the catalyst carrier is made of silicon carbide. It will be appreciated that the preheating burner 20 heats the catalytic burner 10 by way of flame combustion, and when the catalytic burner 10 is heated to its catalytic light-off temperature, the fuel gas and air flowing therethrough will undergo flameless combustion under the action of the catalyst to release heat, and will be conducted to the heat exchanger via the flue gas and air in the combustion chamber.

Specifically, as shown in fig. 1 and 2, the gas water heater further includes a fan 50 and a gas mixing device 60, the gas mixing device 60 is disposed between the fan 50 and the preheating burner 20, the gas mixing device 60 has a gas mixing cavity 61, the fan 50 is used to drive air and gas into the gas mixing cavity 61, and the gas mixing cavity 61 is communicated with the combustion chamber. An ignition needle and a flame induction needle are further installed in the combustion chamber, and the flame induction needle is used for detecting whether the ignition needle is ignited successfully or not. When the gas water heater works, air and gas are driven by the fan 50 to enter the gas mixing cavity 61 to be fully mixed, and then are dispersed to each through hole of the preheating burner 20 by the gas mixing device 60, and are discharged by the ignition needle to ignite and burn, so that the catalytic burner 10 is preheated. When the catalytic combustor 10 is heated to reach a certain temperature, the air and gas mixed gas is transferred from the preheating combustor 20 to the catalytic combustor 10 for catalytic combustion and heat release, the flowing water of the heat exchanger absorbs the heat and then is heated to a temperature specified by a user, and the water heater outputs hot water for the user to use.

It should be noted that, the existing gas water heater has the following problems: the catalytic combustor has slow heat dissipation, so that water flow in the heat exchanger is stopped and the temperature is raised too high, high-temperature hot water can cause frightening and puzzling to users, and even can scald the users; under the long-term high-temperature heating of the catalytic combustor, the shell is easy to change color or deform due to overhigh heating temperature, and the service life of the heat exchanger is influenced.

According to the technical scheme, one part of the first heat exchanger 30 is arranged in the combustion chamber, the other part of the first heat exchanger is arranged outside the combustion chamber, water cut-off and temperature rise can occur when a user turns off water and then boils water in the midway in the using process, and the water cut-off and temperature rise is higher due to the fact that the part of the heat exchanger located in the combustion chamber is contacted with high-temperature smoke; and the heat exchanger part outside the combustion chamber absorbs less heat and has lower water cut-off temperature rise because of not contacting with high-temperature flue gas. After the high-temperature water and the low-temperature water in the first heat exchanger 30 are neutralized, the final temperature rise of the outlet water can be effectively reduced, and the risk of scalding users is reduced.

Further, as shown in fig. 1 and 2, the catalytic combustor 10 divides the combustion chamber into a first combustion chamber 100 and a second combustion chamber 200 arranged from the top to the bottom, the first heat exchanger 30 is installed in the first combustion chamber 100, and the preheating combustor 20 is installed in the second combustion chamber 200. It can be understood that the high temperature flue gas generated by the combustion of the preheating burner 20 flows through the second combustion chamber 200 and reaches the inside of the catalytic burner 10 to heat the catalytic burner 10. The high-temperature flue gas generated by the flameless combustion of the catalytic burner 10 flows through the first combustion chamber 100 and heats the portion of the first heat exchanger 30 located in the first combustion chamber 100.

Further, as shown in fig. 2, 4 and 5, the first heat exchanger 30 includes fins 31, a plurality of inner heat exchange tubes 32 and a plurality of outer heat exchange tubes 33, the plurality of inner heat exchange tubes 32 are inserted into the fins 31, the fins 31 and the inner heat exchange tubes 32 are installed in the first combustion chamber 100, and the plurality of outer heat exchange tubes 33 are installed on the housing and located outside the first combustion chamber 100. It can be understood that in the combustion chamber, the heat transfer can be enhanced by additionally arranging the fins 31 on the heat exchange inner tube 32, so that the water temperature can meet the requirements of users as soon as possible; and still be provided with heat transfer outer tube 33 and do not install fin 31 outside the combustion chamber, the temperature continues to rise when aim at avoiding heat transfer outer tube 33 to user's midway cutting off water to keep the temperature of heat transfer outer tube 33 to be less than the temperature of heat transfer inner tube 32, high low warm water in the interior outer tube neutralizes the back, can effectively reduce final play water temperature rise.

Further, the casing comprises two oppositely-arranged partition plates 101 and two first end plates 102 connecting the two partition plates 101, the two partition plates 101 and the two first end plates 102 enclose the first combustion chamber 100, the heat exchange inner pipe 32 is located on the inner side of the partition plates 101, and the heat exchange outer pipe 33 is located on the outer side of the partition plates 101. It can be understood that the partition plate 101 can isolate the heat exchange outer tube 33 from the high-temperature flue gas, and the temperature of the heat exchange outer tube 33 is prevented from rising after the water supply is stopped midway by a user.

In an embodiment, as shown in fig. 2, the distance between the upper parts of the two separators 101 is smaller than the distance between the lower parts of the two separators 101, and the plurality of heat exchange inner tubes 32 are stacked between the two separators 101 in a plurality of layers; the heat exchange outer tubes 33 are arranged side by side in the vertical direction and attached to the outer side of the upper portion of the partition plate 101. It can be understood that the closer to the heat exchange inner tube 32 of the catalytic combustor 10, the higher the water temperature will be, if the first combustion chamber 100 is configured to have a "convex" structure, so that the upper space is smaller than the lower space, which is beneficial to make the heat more dispersed in the lower space and more concentrated in the upper space, which is beneficial to the temperature homogenization in the first combustion chamber 100 and the water temperature homogenization of the multi-layer heat exchange inner tube 32. In addition, a space for avoiding space is formed on the outer side of the upper part of the partition plate 101 for installing the heat exchange outer tube 33, so that the overall structure of the first heat exchanger 30 is more compact and smaller.

Specifically, as shown in fig. 3 and 5, the first heat exchanger 30 has a first water inlet 34 and a first water outlet 35, and the first water inlet 34, the heat exchange inner tube 32, the heat exchange outer tube 33, and the first water outlet 35 are communicated. In this embodiment, a plurality of first through holes are all opened to two first end plates 102, and both ends of heat exchange inner tube 32 and both ends of heat exchange outer tube 33 are all connected with first through holes. The shell further comprises two first peripheral plates 103 which are positioned on the outer sides of the first end plates 102, the first peripheral plates 103 are partially outwards protruded to form a plurality of first convex hulls 1031, the first convex hulls 1031 and the first end plates 102 are surrounded to form a plurality of first pipelines, and the first pipelines are communicated with the first through holes, so that communication is established between the heat exchange inner tube 32 and the heat exchange inner tube 32, between the heat exchange inner tube 32 and the heat exchange outer tube 33, and between the heat exchange outer tube 33 and the heat exchange outer tube 33.

The gas water heater further comprises a second heat exchanger 40, the second heat exchanger 40 is installed in the second combustion chamber 200, and at least part of the second heat exchanger 40 is arranged at the bottom of the catalytic burner 10. According to the technical scheme, at least part of the second heat exchanger 40 is arranged at the bottom of the catalytic combustor 10 to support the catalytic combustor 10, and high-temperature heat released during combustion of the catalytic combustor 10 is absorbed and taken away in time, so that the phenomenon that the shell is discolored or deformed due to overhigh heated temperature is avoided. In addition, the heat exchangers are arranged above and below the catalytic combustor 10, so that the heat released by the catalytic combustor 10 can be fully utilized, and the energy utilization rate is improved.

Further, as shown in fig. 2, the catalytic combustor 10 is installed in the second combustion chamber 200, and the catalytic combustor 10 is sandwiched between the first heat exchanger 30 and the second heat exchanger 40. It will be appreciated that the catalytic burner 10 is mounted within the second combustion chamber 200 so as to be heated by the preheat burner 20. The catalytic combustor 10 is clamped between the first heat exchanger 30 and the second heat exchanger 40, so that the two heat exchangers can fully absorb heat of the catalytic combustor 10, and the energy utilization rate is improved.

Specifically, as shown in fig. 2, the second heat exchanger 40 includes a plurality of heat exchange secondary pipes 41, and the heat exchange secondary pipes 41 are attached to and supported by the bottom of the catalytic combustor 10. It can be understood that the heat exchange secondary pipe 41 through which the flowing water flows is adopted to heat the catalytic combustor 10 instead of the shell, so that the heat released by the catalytic combustor 10 can be taken away in time and utilized, and the phenomenon that the shell is discolored or deformed due to the high-temperature heat generated by the catalytic combustor 10 can be avoided.

As shown in fig. 6 and 7, the housing further includes two side plates 201 disposed opposite to each other and two second end plates 202 of the two side plates 201, the two side plates 201 and the two second end plates 202 enclose the second combustion chamber 200, the second heat exchanger 40 further includes a plurality of first heat exchange secondary pipes 42, and the first heat exchange secondary pipes 42 are sandwiched between the catalytic combustor 10 and the side plates 201. The first heat exchange secondary pipe 42 is used for absorbing and taking away high-temperature heat released during combustion of the catalytic combustor 10, and the side plate 201 is prevented from being deformed due to overhigh heated temperature.

The second heat exchanger 40 further includes a plurality of second heat exchange secondary pipes 43, and the second heat exchange secondary pipes 43 are clamped between the preheating burner 20 and the side plate 201. Although the preheating burner 20 is gradually extinguished after the ignition of the catalytic burner 10, a large amount of heat is also released before the preheating burner 20 is extinguished, and the heat taken away from the preheating burner 20 can be absorbed and utilized by the second heat exchange secondary pipe 43.

The second heat exchanger 40 further includes a plurality of third secondary heat exchange tubes 44, and the third secondary heat exchange tubes 44 are attached to the inner side of the side plate 201 and located between the first secondary heat exchange tubes 42 and the second secondary heat exchange tubes 43. Through setting up third heat transfer secondary pipe 44 can make full use of second combustion chamber 200's heat transfer space, in time absorb and take away the heat that two combustors produced to help curb plate 201 heat dissipation avoid it to warp because of high temperature.

Specifically, as shown in fig. 3 and 7, the second heat exchanger 40 has a second water inlet 45 and a second water outlet 46, and the second water inlet 45, the secondary heat exchange pipe 41, the primary heat exchange secondary pipe 42, the secondary second heat exchange pipe 43, the secondary third heat exchange pipe 44 and the second water outlet 46 are communicated. In this embodiment, a plurality of second through holes have all been seted up to two second end plates 202, and the both ends of heat transfer inner tube 32 and the both ends of heat transfer outer tube 33 all are connected with the second through hole. The shell further comprises two second outer boards 203 which are positioned on the outer sides of the second end boards 202, wherein the second outer boards 203 are partially arranged outwards in a protruding mode to form a plurality of second convex hulls 2031, the second convex hulls 2031 and the second end boards 202 are arranged in a surrounding mode to form a plurality of second pipelines, and the second pipelines are communicated with the second through holes, so that the heat exchange auxiliary pipes 41, the first heat exchange secondary pipes 42, the second heat exchange secondary pipes 43 and the third heat exchange secondary pipes 44 are communicated with one another. It should be noted that the first heat exchanger 30 and the second heat exchanger 40 have independent flow paths, respectively, cold water is split after entering the gas water heater, part of the cold water enters the first heat exchanger 30 to be heated, part of the cold water enters the second heat exchanger 40 to be heated, and finally, hot water flowing out of the two heat exchangers is gathered and then flows out of the gas water heater for use by a user.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A gas water heater, comprising:

a housing, an interior of which forms a combustion chamber;

a catalytic burner mounted within the combustion chamber;

2. The gas water heater of claim 1, wherein said catalytic burner divides said combustion chamber into a first combustion chamber and a second combustion chamber arranged from top to bottom, said first heat exchanger portion being mounted within said first combustion chamber.

3. The gas water heater of claim 2, wherein the first heat exchanger includes fins, inner heat exchange tubes and outer heat exchange tubes, the inner heat exchange tubes are inserted into the fins, the fins and the inner heat exchange tubes are mounted in the first combustion chamber, and the outer heat exchange tubes are mounted on the housing and located outside the first combustion chamber.

4. The gas water heater of claim 3, wherein said housing includes two oppositely disposed partitions and two first end plates connecting said two partitions, said two partitions and said two first end plates enclosing said first combustion chamber, said heat exchange inner tube being located inside said partitions, and said heat exchange outer tube being located outside said partitions.

5. The gas water heater of claim 4, wherein the distance between the upper parts of the two partition plates is smaller than the distance between the lower parts of the two partition plates, and the heat exchange inner pipes are arranged between the two partition plates in a multilayer stacking manner; the heat exchange outer pipes are arranged side by side in the vertical direction and attached to the outer side of the upper portion of the partition plate.

6. The gas water heater of claim 3, wherein said first heat exchanger has a first water inlet and a first water outlet, said first water inlet, said inner heat exchange tube, said outer heat exchange tube and said first water outlet being in communication.

7. The gas water heater of claim 2, further comprising a preheating burner and a second heat exchanger, said preheating burner and said second heat exchanger being mounted within said second combustion chamber, said preheating burner being disposed below said catalytic burner, said preheating burner being configured to heat said catalytic burner, and said catalytic burner being sandwiched between said first heat exchanger and said second heat exchanger.

8. The gas water heater of claim 7, wherein said second heat exchanger includes a plurality of secondary heat exchange tubes, said secondary heat exchange tubes being conformingly supported to a bottom portion of said catalytic burner.

9. The gas water heater of claim 8, wherein said housing further includes two oppositely disposed side plates and two second end plates connecting said two side plates, said two side plates and said two second end plates enclosing said second combustion chamber, said second heat exchanger further including a plurality of first heat exchange secondary tubes interposed between said catalytic burner and said side plates.

10. The gas water heater of claim 9, wherein said second heat exchanger further comprises a plurality of second heat exchange secondary tubes sandwiched between said preheat burner and said side plates.

11. The gas water heater of claim 10, wherein said second heat exchanger further comprises a plurality of secondary third heat exchange tubes attached to the inside of said side plate and located between said secondary first heat exchange tubes and said secondary second heat exchange tubes.

12. The gas water heater of claim 11, wherein said second heat exchanger has a second water inlet and a second water outlet, said second water inlet, said secondary heat exchange tube, said secondary first heat exchange tube, secondary second heat exchange tube, secondary third heat exchange tube and said second water outlet being in communication.

13. The gas water heater of any one of claims 1 to 12, further comprising a fan and a gas mixing device, wherein the gas mixing device is disposed between the fan and the preheating burner, the gas mixing device has a gas mixing cavity, the second combustion chamber and the first combustion chamber are sequentially communicated, and the fan is used for driving air and gas into the gas mixing cavity.