Gas water heater

Abstract

The present invention provides a gas water heater, which includes a housing, a catalytic burner and a first heat exchanger. Among them, a combustion chamber is formed inside the housing; the catalytic combustion chamber is installed in the combustion chamber; the first heat exchanger is located above the catalytic burner, and a part of the first heat exchanger is installed in the first combustion chamber, and the other part is installed outside the first combustion chamber. The part of the heat exchanger located inside the combustion chamber has a relatively high temperature rise of the stopped water due to contact with high-temperature flue gas; while the part of the heat exchanger located outside the combustion chamber absorbs less heat due to non-contact with high-temperature flue gas, and the temperature rise of the stopped water is relatively low. After the high-temperature and low-temperature water in the first heat exchanger is neutralized, the final temperature rise of the stopped water can be effectively reduced, reducing the risk of scalding users.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a gas water heater. Background Art

[0002] A gas water heater is a device that heats cold water by burning gas. Most gas water heaters use flame combustion as the main combustion method, which easily emits a large amount of harmful gases during the combustion process, which not only endangers personal safety but also pollutes the environment. In order to achieve low emissions of pollutants from gas water heaters, the existing technology uses a catalytic burner to heat the heat exchanger. Catalytic combustion is flameless combustion, close to complete combustion, and can significantly reduce carbon monoxide (CO) and nitrogen oxides (NO x ) emissions. However, the prior art still has the following problems: the catalytic burner dissipates heat slowly, causing the water flow in the heat exchanger to stop and the temperature rises too high. The high-temperature hot water will scare and annoy the user, and may even scald the user. Summary of the invention

[0003] The main purpose of the present invention is to provide a gas water heater, aiming to solve at least one of the above problems.

[0004] To achieve the above object, the present invention provides a gas water heater, which comprises:

[0005] a housing, wherein the interior of the housing forms a combustion chamber;

[0006] A catalytic burner, wherein the catalytic combustion chamber is installed in the combustion chamber;

[0007] A first heat exchanger, wherein the first heat exchanger is located above the catalytic burner, wherein a portion of the first heat exchanger is installed in the combustion chamber, and another portion of the first heat exchanger is installed outside the combustion chamber.

[0008] In one embodiment, the catalytic burner divides the combustion chamber into a first combustion chamber and a second combustion chamber arranged from top to bottom, and the first heat exchanger is partially installed in the first combustion chamber.

[0009] In one embodiment, the first heat exchanger includes fins, a plurality of heat exchange inner tubes and a plurality of heat exchange outer tubes, the plurality of heat exchange inner tubes are interspersed on the fins, the fins and the heat exchange inner tubes are installed in the first combustion chamber, and the plurality of heat exchange outer tubes are installed on the shell and located outside the first combustion chamber.

[0010] In one embodiment, the shell includes two oppositely arranged partitions and two first end plates connecting the two partitions, the two partitions and the two first end plates enclose the first combustion chamber, the heat exchange inner tube is located on the inner side of the partition, and the heat exchange outer tube is located on the outer side of the partition.

[0011] In one embodiment, 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 multiple heat exchange inner tubes are arranged in multiple layers between the two partition plates; the heat exchange outer tubes are arranged side by side in the vertical direction and are attached to the outer sides of the upper parts of the partition plates.

[0012] In one embodiment, the first heat exchanger has a first water inlet and a first water outlet, and the first water inlet, the heat exchange inner tubes, the heat exchange outer tubes and the first water outlet are communicated.

[0013] In one embodiment, the gas water heater further includes a preheating burner and a second heat exchanger. The preheating burner and the second heat exchanger are installed in the second combustion chamber. The preheating burner is arranged below the catalytic burner and is used to heat the catalytic burner, and the catalytic burner is clamped between the first heat exchanger and the second heat exchanger.

[0014] In one embodiment, the second heat exchanger includes multiple heat exchange sub-tubes, and the heat exchange sub-tubes are attached and supported to the bottom of the catalytic burner.

[0015] In one embodiment, the housing further includes two oppositely arranged side plates and two second end plates connecting the two side plates. The two side plates and the two second end plates enclose the second combustion chamber. The second heat exchanger further includes multiple first heat exchange sub-tubes, and the first heat exchange sub-tubes are clamped between the catalytic burner and the side plates.

[0016] In one embodiment, the second heat exchanger further includes multiple second heat exchange sub-tubes, and the second heat exchange sub-tubes are clamped between the preheating burner and the side plates.

[0017] In one embodiment, the second heat exchanger further includes multiple third heat exchange sub-tubes, and the third heat exchange sub-tubes are attached to the inner side of the side plates and are located between the first heat exchange sub-tubes and the second heat exchange sub-tubes.

[0018] In one embodiment, the second heat exchanger has a second water inlet and a second water outlet, and the second water inlet, the heat exchange sub-tubes, the first heat exchange sub-tubes, the second heat exchange sub-tubes, the third heat exchange sub-tubes and the second water outlet are communicated.

[0019] In one embodiment, the gas water heater further includes a blower and a gas mixing device. The gas mixing device is arranged between the blower and the preheating burner. The gas mixing device has a gas mixing chamber, and the gas mixing chamber, the second combustion chamber and the first combustion chamber are communicated in sequence. The blower is used to drive air and gas into the gas mixing chamber.

[0020] In the technical solution of the present invention, part of the first heat exchanger is arranged inside the combustion chamber, and the other part is arranged outside the combustion chamber. During the use by the user, when the water is turned off and then turned on midway, there will be a stop water temperature rise. The part of the heat exchanger located inside the combustion chamber has a relatively high stop water temperature rise because it is in contact with the high-temperature flue gas; while the part of the heat exchanger located outside the combustion chamber has a relatively low stop water temperature rise because it is not in contact with the high-temperature flue gas and absorbs less heat. After the high-temperature and low-temperature water in the first heat exchanger are neutralized, the final stop water temperature rise can be effectively reduced, reducing the risk of scalding the user. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0022] Figure 1 External structure schematic diagram of an embodiment of the gas burner of the present invention;

[0023] Figure 2 is Figure 1 Internal structure schematic diagram of the shown gas burner;

[0024] Figure 3 is Figure 1 Front view of the shown gas burner;

[0025] Figure 4 is Figure 1 Structure schematic diagram of the first combustion chamber and the first heat exchanger in ;

[0026] Figure 5 is Figure 1 Explosion diagram of the shown first combustion chamber and the first heat exchanger;

[0027] Figure 6 is Figure 1 Structure schematic diagram of the second combustion chamber and the second heat exchanger shown in ;

[0028] Figure 7 is Figure 1 Explosion diagram of the shown second combustion chamber and the second heat exchanger.

[0029] Explanation of the reference numerals in the drawings:

[0030]

[0031]

[0032] The realization, functional features, and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0037] An embodiment of the present invention provides a gas water heater. The following will be combined with Figures 1 to 7 to specifically describe the mobile air conditioner according to the embodiment of the present invention.

[0038] In an embodiment of the present invention, the gas water heater includes:

[0039] A housing, the interior of which forms a combustion chamber;

[0040] A catalytic burner 10, which is installed in the combustion chamber;

[0041] The first heat exchanger 30 is located above the catalytic burner 10 , wherein a portion of the first heat exchanger 30 is installed in the combustion chamber, and another portion of the first heat exchanger 30 is installed outside the combustion chamber.

[0042] Specifically, part of the heat exchange tubes of the first heat exchanger 30 are located in the combustion chamber, and can come into contact with the high-temperature flue gas generated by the catalytic burner 10, so that the water-stop temperature rise of this part of the heat exchange tubes is higher; in addition, part of the heat exchange tubes in the first heat exchanger 30 are located inside the burner, so that the water-stop temperature rise of this part of the heat exchange tubes is lower. The above two parts of the heat exchange tubes in the first heat exchanger 30 are connected, and after the high and low temperature water from the two parts of the heat exchange tubes is neutralized, the final water-stop temperature rise can be effectively reduced, reducing the risk of users being scalded. It should be noted that the part of the heat exchange tubes in the first heat exchanger 30 located outside the combustion chamber does not refer to the connecting tubes used to connect the various heat exchange tubes.

[0043] Specifically, a preheating burner 20 is installed in the shell, and the preheating burner 20 is a porous honeycomb structure. Optionally, the preheating burner 20 is made of ceramic material; the catalytic burner 10 includes a catalyst carrier and a catalyst coated on the catalyst carrier. Optionally, the catalyst carrier is made of silicon carbide. It can be understood that the preheating burner 20 heats the catalytic burner 10 by flame combustion. When the catalytic burner 10 is heated to its catalytic ignition temperature, the gas and air flowing through it will be flamelessly burned under the action of the catalyst to release heat, and the heat will be transferred to the heat exchanger through the flue gas and air in the combustion chamber.

[0044] Specifically, if Figure 1 and Figure 2 As shown, the gas water heater also includes a fan 50 and a gas mixing device 60. The gas mixing device 60 is arranged between the fan 50 and the preheating burner 20. The gas mixing device 60 has a gas mixing chamber 61. The fan 50 is used to drive air and gas into the gas mixing chamber 61. The gas mixing chamber 61 is connected to the combustion chamber. An ignition needle and a flame sensing needle are also installed in the combustion chamber. The flame sensing needle is used to detect whether the ignition needle is successfully ignited. When the gas water heater is working, the fan 50 drives the air and gas into the gas mixing chamber 61 for full mixing, and then the gas mixing device 60 disperses them to each through hole of the preheating burner 20, and the ignition needle discharges and ignites and burns to preheat the catalytic burner 10. When the catalytic burner 10 is heated to a certain temperature, the air and gas mixture is transferred from the preheating burner 20 to the catalytic burner 10 for catalytic combustion and releases heat. The mid-flow water in the heat exchanger absorbs the heat and heats up to the user-specified temperature. The water heater outputs hot water for the user to use.

[0045] It should be noted that existing gas water heaters have the following problems: the catalytic burner dissipates heat slowly, causing the water flow in the heat exchanger to stop and the temperature to rise too high. The high-temperature hot water will scare and trouble the users, and may even scald the users; under the long-term high-temperature heating of the catalytic burner, the shell is prone to discoloration or deformation due to the high heat temperature, affecting the service life of the heat exchanger.

[0046] The technical solution of the present invention sets part of the first heat exchanger 30 inside the combustion chamber and the other part outside the combustion chamber. When the user turns off the water and then turns it on again during use, the water temperature rise will occur. The heat exchanger part inside the combustion chamber is in contact with the high-temperature flue gas, so the water temperature rise is higher; while the heat exchanger part outside the combustion chamber is not in contact with the high-temperature flue gas, so it absorbs less heat and has a lower water temperature rise. After the high and low temperature water in the first heat exchanger 30 is neutralized, the final water outlet temperature rise can be effectively reduced, reducing the risk of scalding the user.

[0047] Furthermore, if Figure 1 and Figure 2 As shown, the catalytic burner 10 divides the combustion chamber into a first combustion chamber 100 and a second combustion chamber 200 arranged from top to bottom, the first heat exchanger 30 is installed in the first combustion chamber 100, and the preheating burner 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 part of the first heat exchanger 30 located in the first combustion chamber 100.

[0048] Furthermore, if Figure 2 , Figure 4 and Figure 5 As shown, the first heat exchanger 30 includes fins 31, multiple heat exchange inner tubes 32 and multiple heat exchange outer tubes 33. The multiple heat exchange inner tubes 32 are interspersed on the fins 31. The fins 31 and the heat exchange inner tubes 32 are installed in the first combustion chamber 100. The multiple heat exchange outer tubes 33 are installed on the shell and are located outside the first combustion chamber 100. It can be understood that in the combustion chamber, the heat transfer can be enhanced by installing fins 31 on the heat exchange inner tubes 32, so that the water temperature can reach the user's needs as soon as possible; and the heat exchange outer tubes 33 are also provided outside the combustion chamber without fins 31, in order to prevent the temperature of the heat exchange outer tubes 33 from continuing to rise when the user stops the water supply midway, so as to keep the water temperature of the heat exchange outer tubes 33 lower than the water temperature of the heat exchange inner tubes 32. After the high and low temperature water in the inner and outer tubes are neutralized, the final outlet water temperature rise can be effectively reduced.

[0049] Further, the housing includes 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 tube 32 is located inside the partition plate 101, and the heat exchange outer tube 33 is located outside the partition plate 101. It can be understood that the partition plate 101 can isolate the heat exchange outer tube 33 from the high-temperature flue gas, avoiding the temperature of the heat exchange outer tube 33 from still rising after the user stops water supply midway.

[0050] In one embodiment, as Figure 2 shown, the distance between the upper parts of the two partition plates 101 is smaller than the distance between the lower parts of the two partition plates 101. Multiple heat exchange inner tubes 32 are arranged in multiple layers and stacked between the two partition plates 101; the heat exchange outer tubes 33 are arranged side by side in the vertical direction and are attached to the outer sides of the upper parts of the partition plates 101. It can be understood that the water temperature of the heat exchange inner tubes 32 closer to the catalytic combustor 10 will be higher. If the first combustion chamber 100 is set in a "convex" structure, making its upper space smaller than the lower space, it is beneficial to make the heat more dispersed in the lower space and more concentrated in the upper space, thereby facilitating the temperature uniformity in the first combustion chamber 100 and the water temperature uniformity of the multiple layers of heat exchange inner tubes 32. In addition, an avoidance space will be formed on the outer side of the upper part of the partition plate 101 for installing the heat exchange outer tubes 33, making the overall structure of the first heat exchanger 30 more compact and smaller in volume.

[0051] Specifically, as Figure 3 and Figure 5 shown, the first heat exchanger 30 has a first water inlet 34 and a first water outlet 35. The first water inlet 34, the heat exchange inner tube 32, the heat exchange outer tube 33, and the first water outlet 35 are connected. In this embodiment, multiple first through holes are provided in both first end plates 102. Both ends of the heat exchange inner tube 32 and both ends of the heat exchange outer tube 33 are connected to the first through holes. The housing further includes two first peripheral plates 103 located outside the first end plates 102. The first peripheral plates 103 partially protrude outward to form multiple first convex protrusions 1031. The multiple first convex protrusions 1031 and the first end plates 102 enclose multiple first pipelines, and the first pipelines are connected to the first through holes to establish connections between the heat exchange inner tubes 32, between the heat exchange inner tube 32 and the heat exchange outer tube 33, and between the heat exchange outer tubes 33.

[0052] The gas water heater further includes a second heat exchanger 40. The second heat exchanger 40 is installed in the second combustion chamber 200, and at least a part of the second heat exchanger 40 is disposed at the bottom of the catalytic burner 10. In the technical solution of this embodiment, at least a part of the second heat exchanger 40 is disposed at the bottom of the catalytic burner 10 to support the catalytic burner 10 and timely absorb and carry away the high-temperature heat released during the combustion of the catalytic burner 10, so as to prevent the housing from discoloring or deforming due to excessive heat. In addition, by arranging heat exchangers above and below the catalytic burner 10, it is beneficial to make full use of the heat released by the catalytic burner 10 and improve the energy utilization rate.

[0053] Further, as Figure 2 shown, the catalytic burner 10 is installed in the second combustion chamber 200, and the catalytic burner 10 is clamped between the first heat exchanger 30 and the second heat exchanger 40. It can be understood that the catalytic burner 10 is installed in the second combustion chamber 200 to facilitate the preheating burner 20 to heat it. And the catalytic burner 10 is clamped between the first heat exchanger 30 and the second heat exchanger 40, which is beneficial for the two heat exchangers to fully absorb the heat of the catalytic burner 10 and improve the energy utilization rate.

[0054] Specifically, as Figure 2 shown, the second heat exchanger 40 includes a plurality of heat exchange sub-tubes 41, and the heat exchange sub-tubes 41 are attached to and supported at the bottom of the catalytic burner 10. It can be understood that using the heat exchange sub-tubes 41 through which water flows to replace the housing to heat the catalytic burner 10 can timely carry away the heat released by the catalytic burner 10 and utilize it, so as to prevent the high-temperature heat generated by the catalytic burner 10 from causing the housing to discolor or deform.

[0055] As Figure 6 and Figure 7 shown, the housing further includes two oppositely arranged side plates 201 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 sub-tubes 42, and the first heat exchange sub-tubes 42 are clamped between the catalytic burner 10 and the side plate 201. The first heat exchange sub-tubes 42 are used to absorb and carry away the high-temperature heat released during the combustion of the catalytic burner 10, so as to prevent the side plate 201 from deforming due to excessive heat.

[0056] The second heat exchanger 40 further includes a plurality of second heat exchange sub-tubes 43, and the second heat exchange sub-tubes 43 are clamped between the preheating burner 20 and the side plate 201. Although the preheating burner 20 will gradually go out after igniting the catalytic burner 10, a large amount of heat will still be released before the preheating burner 20 goes out. The second heat exchange sub-tubes 43 can absorb and carry away the heat of the preheating burner 20 and utilize it.

[0057] The second heat exchanger 40 further includes a plurality of third heat exchange sub-tubes 44, which are attached to the inner side of the side plate 201 and are located between the first heat exchange sub-tube 42 and the second heat exchange sub-tube 43. By providing the third heat exchange sub-tubes 44, the heat exchange space of the second combustion chamber 200 can be fully utilized to timely absorb and carry away the heat generated by the two burners, and help the side plate 201 dissipate heat to prevent it from deforming due to high temperature.

[0058] Specifically, as Figure 3 and Figure 7 shown, the second heat exchanger 40 has a second water inlet 45 and a second water outlet 46, and the second water inlet 45, the heat exchange sub-tube 41, the first heat exchange sub-tube 42, the second heat exchange sub-tube 43, the third heat exchange sub-tube 44 and the second water outlet 46 are communicated. In this embodiment, a plurality of second through holes are provided in both second end plates 202, and both ends of the inner heat exchange tube 32 and both ends of the outer heat exchange tube 33 are connected to the second through holes. The housing further includes two second outer plates 203 located outside the second end plates 202. The second outer plates 203 are partially convex outward to form a plurality of second convex bumps 2031. The plurality of second convex bumps 2031 and the second end plates 202 enclose a plurality of second pipelines, and the second pipelines are communicated with the second through holes to establish communication between the heat exchange sub-tube 41, the first heat exchange sub-tube 42, the second heat exchange sub-tube 43 and the third heat exchange sub-tube 44. It should be noted that the first heat exchanger 30 and the second heat exchanger 40 respectively have independent flow paths. After cold water enters the gas water heater, it is split. Part of the cold water enters the first heat exchanger 30 for heating, and part of the cold water enters the second heat exchanger 40 for heating. Finally, the hot water flowing out of the two heat exchangers will be aggregated and then flow out of the gas water heater for the user to use.

[0059] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A gas water heater, characterized in that, The gas water heater comprises: a housing, wherein the interior of the housing forms a combustion chamber; A catalytic burner, the catalytic burner is installed in the combustion chamber; A first heat exchanger, wherein the first heat exchanger is located above the catalytic burner, wherein a portion of the first heat exchanger is installed in the combustion chamber, and another portion of the first heat exchanger is installed outside the combustion chamber; The first heat exchanger includes a plurality of inner heat exchange tubes and a plurality of outer heat exchange tubes, the shell includes two oppositely arranged partitions, the inner heat exchange tubes are located on the inner side of the partitions, the outer heat exchange tubes are located on the outer side of the partitions, the spacing between the upper parts of the two partitions is smaller than the spacing between the lower parts of the two partitions, and the plurality of inner heat exchange tubes are stacked in multiple layers between the two partitions; the outer heat exchange tubes are arranged side by side in a vertical direction and attached to the outer side of the upper part of the partitions, and the partitions isolate the outer heat exchange tubes from high-temperature flue gas to prevent the temperature of the outer heat exchange tubes from still rising after the user stops using water.

2. The gas water heater according to claim 1, characterized in that, The catalytic burner divides the combustion chamber into a first combustion chamber and a second combustion chamber arranged from top to bottom, and the first heat exchanger is partially installed in the first combustion chamber.

3. The gas water heater according to claim 2, characterized in that The first heat exchanger includes fins, and a plurality of heat exchange inner tubes are interspersed on the fins. The fins and the heat exchange inner tubes are installed in the first combustion chamber. A plurality of heat exchange outer tubes are installed on the shell and are located outside the first combustion chamber.

4. The gas water heater according to claim 3, wherein The shell includes two first end plates connecting the two partitions, and the two partitions and the two first end plates enclose the first combustion chamber; the gas water heater also includes a preheating burner and a second heat exchanger, and the second heat exchanger includes a plurality of heat exchange sub-pipes, and the heat exchange sub-pipes are supported on the bottom of the catalytic burner.

5. The gas water heater according to claim 4, characterized in that The preheating burner and the second heat exchanger are installed in the second combustion chamber, the preheating burner is arranged below the catalytic burner, the preheating burner is used to heat the catalytic burner, and the catalytic burner is sandwiched between the first heat exchanger and the second heat exchanger.

6. The gas water heater according to claim 5, characterized in that, The shell also includes two oppositely arranged side plates and two second end plates connecting the two side plates, the two side plates and the two second end plates enclose the second combustion chamber, and the second heat exchanger also includes a plurality of first heat exchange secondary tubes, which are clamped between the catalytic burner and the side plates.

7. The gas water heater according to claim 6, characterized in that, The second heat exchanger further includes a plurality of second heat exchange secondary tubes, and the second heat exchange secondary tubes are sandwiched between the preheating burner and the side plate.

8. The gas water heater according to claim 7, characterized in that The second heat exchanger further includes a plurality of third heat exchange secondary tubes, wherein the third heat exchange secondary tubes are attached to the inner side of the side plate and are located between the first heat exchange secondary tubes and the second heat exchange secondary tubes.

9. The gas water heater according to claim 8, characterized in that, The second heat exchanger has a second water inlet and a second water outlet, and the second water inlet, the heat exchange auxiliary pipe, the first heat exchange secondary pipe, the second heat exchange secondary pipe, the third heat exchange secondary pipe and the second water outlet are in communication.

10. The gas water heater according to any one of claims 4 to 9, characterized in that, The gas water heater further includes a blower and a gas mixing device. The gas mixing device is arranged between the blower and the preheating burner. The gas mixing device has a gas mixing chamber. The gas mixing chamber, the second combustion chamber, and the first combustion chamber are communicated in sequence. The blower is used to drive air and gas into the gas mixing chamber.

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