Heat exchanger and gas water heater

Abstract

The utility model discloses a heat exchanger and gas water heater, the heat exchanger includes at least one layer heat exchange layer along the flue gas flowing direction arrangement, in the at least one layer heat exchange layer, the downstream of the downstream end heat exchange layer is equipped with the baffle, the baffle with the end heat exchange layer is connected through the temperature -sensing spare, the temperature -sensing spare is configured as with the flue gas temperature rises, its elongation amount is small, to change the interval between the baffle and the end heat exchange layer. Through this scheme, compared with the design without the baffle, can improve the heat exchange efficiency, and the heat exchange efficiency can be changed through the temperature -sensing spare changes the baffle and the end heat exchange layer interval mode, thereby avoids appearing the condensed water.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange, and in particular to a heat exchanger and a gas water heater. Background Technology

[0002] In stainless steel gas water heaters, the heat exchanger is the core component. The commonly used stainless steel heat exchangers in the industry consist of heat exchange tubes with fins inserted on the outside for indirect heat exchange, thereby achieving the heating of water by high-temperature flue gas.

[0003] Current technology suffers from condensation issues. When high-temperature flue gas exchanges heat with the fins, the flue gas temperature gradually decreases. If the temperature is too low, condensation may occur. Therefore, heat exchanger design must ensure sufficient efficiency while avoiding excessively high efficiency that could lead to excessively low flue gas temperatures and condensation. Some of the condensate adheres to the wall surface, corroding the metal; some condenses and drips downwards. If it drips onto the fin surface, it will not only corrode the fins but also block the airflow channels. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the defect of heat exchangers in the prior art that are prone to producing condensate, and to provide a heat exchanger and a gas water heater.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] A heat exchanger includes at least one heat exchange layer arranged along the flue gas flow direction; in the at least one heat exchange layer, a baffle is provided downstream of the most downstream end heat exchange layer, and the baffle is connected to the end heat exchange layer via a temperature sensing element.

[0007] The temperature sensing element is configured to elongate less as the flue gas temperature increases, thereby changing the distance between the baffle and the end heat exchange layer.

[0008] In this design, a baffle is installed downstream of the heat exchange layer at the end of the heat exchanger. The baffle obstructs the flow of flue gas, allowing it to remain within the heat exchange layer for a longer period, thus improving heat exchange efficiency. The baffle and the end heat exchange layer are connected by a temperature-sensing element. The extension of this element decreases as the flue gas temperature increases. At higher flue gas temperatures, the element contracts, reducing the distance between the baffle and the end heat exchange layer to increase heat exchange efficiency; conversely, at lower flue gas temperatures, the element extends, increasing the distance between the baffle and the end heat exchange layer to decrease heat exchange efficiency. During this process, excessively high heat exchange efficiency leads to lower flue gas temperatures, which are prone to condensation. By adjusting the distance between the baffle and the end heat exchange layer using the temperature-sensing element, the heat exchange efficiency can be adjusted according to the flue gas temperature, thereby preventing condensation. Therefore, this design improves heat exchange efficiency compared to a design without a baffle; furthermore, the heat exchange efficiency can be altered by changing the distance between the baffle and the end heat exchange layer using the temperature-sensing element, thus preventing condensation.

[0009] Preferably, the temperature sensing element includes any one of the following: a temperature-sensing spring, a metal sheet with a high coefficient of thermal expansion, a thermosensitive polymer hydrogel, a porous metal, and paraffin wax.

[0010] Preferably, the temperature-sensing spring is a shape memory alloy spring.

[0011] Preferably, each heat exchange layer includes multiple heat exchange tubes arranged sequentially along a direction perpendicular to the flue gas flow direction; the temperature sensing element is connected between the heat exchange tubes and the baffle.

[0012] Preferably, the baffle covers the downstream side of the end heat exchange layer, and two temperature sensing elements are provided between the two heat exchange tubes at both ends of the end heat exchange layer and the baffle, with the two temperature sensing elements located on both sides of the heat exchange tube.

[0013] In this scheme, through the above structural configuration, temperature sensing elements can be connected to the corresponding heat exchange tubes at the four corners of the baffle, thereby improving the connection balance between the baffle and the end heat exchange layer, which is beneficial for the temperature sensing elements to move the baffle relative to the end heat exchange layer.

[0014] Preferably, the temperature sensing element is a temperature sensing spring, one end of which is connected to the baffle via a first connector, and the other end of which is connected to the heat exchange tube via a second connector.

[0015] Preferably, the first connecting member is a first protrusion disposed on the surface of the baffle facing the heat exchange layer, and one end of the temperature sensing spring is sleeved on the first protrusion.

[0016] In this design, the temperature-sensing spring is sleeved on the first protrusion to connect with the baffle. This method is simple in structure and easy to implement.

[0017] Preferably, the second connector includes a pipe connection portion and a second protrusion, the pipe connection portion being connected to the heat exchange pipe, the second protrusion being connected to the top of the pipe connection portion, and the other end of the temperature sensing spring being sleeved on the second protrusion.

[0018] In this design, the temperature-sensing spring is sleeved on the second protrusion, and the tube connection part can be connected to the heat exchange tube, thereby realizing the connection between the temperature-sensing spring and the heat exchange tube. This method has a simple structure and is easy to implement.

[0019] Preferably, the tube connection portion is an arc-shaped ring, which is sleeved on the heat exchange tube.

[0020] In this design, the arc-shaped ring can be adapted to the shape of the heat exchange tube, thus connecting with the heat exchange tube.

[0021] Preferably, the baffle is a flat plate with openings, the positions of which correspond to the positions of the heat exchange tubes.

[0022] In this design, the openings on the plate allow flue gas to flow out. By configuring the total area of ​​the openings on the plate, the flue gas resistance can be adjusted. This allows the plate to be configured to increase heat exchange efficiency while maintaining flue gas resistance that meets exhaust requirements, based on actual conditions. Furthermore, the position of the openings corresponds to the position of the heat exchange tubes, allowing adjustment of the flue gas flow path so that the flue gas flows evenly around the tube walls before being discharged.

[0023] Preferably, the total area of ​​the openings on the plate is not less than the minimum cross-sectional area of ​​the exhaust channel of the heat exchanger.

[0024] In this solution, by configuring the total area of ​​the openings to be no less than the minimum cross-sectional area of ​​the smoke exhaust channel, it is possible to avoid additional smoke exhaust resistance caused by the baffle.

[0025] Preferably, along the axial direction of the heat exchange tube, the baffle is provided with a plurality of openings at intervals at positions corresponding to the heat exchange tube.

[0026] Preferably, the opening is at least one of a circular hole or an elongated hole.

[0027] Preferably, the heat exchange layer includes at least one of a finned heat exchange layer and a tube heat exchange layer, wherein the finned heat exchange layer is formed by multiple finned heat exchange tubes, and the tube heat exchange layer includes at least one of a corrugated heat exchange tube and a smooth tube heat exchange tube.

[0028] Preferably, the end heat exchange layer is a tube heat exchange layer.

[0029] In this scheme, the heat exchange efficiency of the tube heat exchange layer is low compared to the finned heat exchange layer. By setting a baffle downstream of the tube heat exchange layer, the heat exchange efficiency of the tube heat exchange layer can be improved.

[0030] A gas water heater, the gas water heater comprising a heat exchanger as described above.

[0031] The significant advantages of this invention are as follows: A baffle is installed downstream of the end heat exchange layer of the heat exchanger. This baffle obstructs the flow of flue gas, allowing it to remain within the heat exchange layer for a longer period, thus improving heat exchange efficiency. The baffle and the end heat exchange layer are connected by a temperature-sensing element. The elongation of this element decreases as the flue gas temperature increases. At higher flue gas temperatures, the element contracts, reducing the distance between the baffle and the end heat exchange layer to increase heat exchange efficiency; conversely, at lower flue gas temperatures, the element elongates, increasing the distance between the baffle and the end heat exchange layer to decrease heat exchange efficiency. During this process, excessively high heat exchange efficiency leads to lower flue gas temperatures, which are prone to condensation. By adjusting the distance using the temperature-sensing element, the heat exchange efficiency can be adjusted according to the flue gas temperature, thereby preventing condensation. Therefore, this design improves heat exchange efficiency compared to a design without a baffle; furthermore, the heat exchange efficiency can be altered by changing the distance between the baffle and the end heat exchange layer using the temperature-sensing element, thus preventing condensation. Attached Figure Description

[0032] Figure 1 A schematic diagram of the structure of a heat exchanger provided in an embodiment of this utility model;

[0033] Figure 2 This is a schematic diagram of a heat exchanger provided for an embodiment of the present utility model, wherein the baffle, temperature sensing element and connecting parts are hidden;

[0034] Figure 3 A cross-sectional schematic diagram of a heat exchanger provided for an embodiment of this utility model;

[0035] Figure 4 A partial schematic diagram of a heat exchanger at the temperature sensing element provided for an embodiment of this utility model;

[0036] Figure 5 A schematic diagram of the structure of a baffle, a temperature sensing element, and a connecting component provided in an embodiment of this utility model;

[0037] Figure 6 This is a schematic diagram of the structure of a baffle provided in an embodiment of the present utility model;

[0038] Figure 7 This is a schematic diagram of another baffle provided in an embodiment of the present utility model.

[0039] Explanation of reference numerals in the attached figures:

[0040] Heat exchanger 1, heat exchange layer 100, end heat exchange layer 101, finned heat exchange layer 102, tube heat exchange layer 103, heat exchange tube 110, finned heat exchange tube 111, corrugated heat exchange tube 112, bare tube heat exchange tube 113, baffle 200, opening 210, temperature sensing element 300, temperature sensing spring 301, first connector 410, first protrusion 411, second connector 420, tube connection 421, second protrusion 422, flue gas flow direction F. Detailed Implementation

[0041] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0042] This embodiment provides a heat exchanger 1, such as Figures 1-3 As shown, the heat exchanger 1 includes at least one heat exchange layer 100 arranged along the flue gas flow direction F; in the at least one heat exchange layer 100, a baffle 200 is provided downstream of the downstream end heat exchange layer 101, and the baffle 200 is connected to the end heat exchange layer 101 by a temperature sensing element 300. The temperature sensing element 300 is configured to elongate less as the flue gas temperature increases, so as to change the distance between the baffle 200 and the end heat exchange layer 101.

[0043] A baffle 200 is installed downstream of the terminal heat exchange layer 101 of the heat exchanger 1. The baffle 200 can block the flow of flue gas, thereby allowing the flue gas to stay in the heat exchange layer 101 for a longer time and improving the heat exchange efficiency. The baffle 200 and the terminal heat exchange layer 101 are connected by a temperature sensing element 300. The elongation of the temperature sensing element 300 decreases as the flue gas temperature increases. Thus, when the flue gas temperature is high, the temperature sensing element 300 contracts, reducing the distance between the baffle 200 and the terminal heat exchange layer 101 to increase the heat exchange efficiency; when the flue gas temperature is low, the temperature sensing element 300 elongates, increasing the distance between the baffle 200 and the terminal heat exchange layer 101 to reduce the heat exchange efficiency. In this process, when the heat exchange efficiency is too high, the flue gas temperature will be low, and the lower flue gas temperature is prone to condensation. By adjusting the distance of the temperature sensing element 300, the heat exchange efficiency can be adjusted according to the flue gas temperature, thereby avoiding the generation of condensation. Therefore, this solution can improve heat exchange efficiency compared to a design without baffles 200; and the heat exchange efficiency can be changed by altering the distance between baffles 200 and the end heat exchange layer 101 through the temperature sensing element 300, thereby avoiding condensation.

[0044] In a gas water heater, the heat exchanger 1 is typically arranged horizontally, while the flue gas flows from bottom to top in a generally vertical direction. The heat exchanger 1 usually comprises two or more heat exchange layers 100, such as... Figure 1-3The heat exchanger 1 shown includes two heat exchange layers 100, which are arranged layer by layer along the vertical direction. The heat exchange layer 100 located at the downstream end in the flue gas flow direction F is... Figure 1-3 The heat exchange layer 100 located at the top is the terminal heat exchange layer 101. The baffle 200 is located above the terminal heat exchange layer 101 and is connected via the temperature sensing element 300. The baffle 200 is a component that can control the flow speed and path of the flue gas, and its specific structural form is not limited to the structure provided in this embodiment.

[0045] In practical implementation, the temperature sensing element 300 can be implemented in various ways. In the following embodiments, such as... Figure 3 , Figure 4 and Figure 5 As shown, the temperature sensing element 300 is provided by means of a temperature sensing spring 301, which is arranged vertically between the baffle 200 and the end heat exchange layer 101. The temperature sensing spring 301 can come into contact with the flue gas and deform under the influence of the flue gas temperature. The elastic force can be applied between the baffle 200 and the end heat exchange layer 101.

[0046] As a more specific implementation, the temperature-sensing spring 301 is a shape memory alloy temperature-sensing spring 301.

[0047] In other embodiments, the temperature sensing element also includes any one of the following: a high coefficient of expansion metal sheet, a temperature-sensitive polymer hydrogel, a porous metal, and paraffin wax. The high coefficient of expansion metal sheet can deform with temperature, such as by bending, thereby achieving the same expansion and contraction process as the temperature-sensing spring 301; porous metals, such as aluminum foam, change in porosity with temperature, causing volume changes, and can also adjust the distance between the baffle 200 and the end heat exchange layer 101 under the influence of temperature.

[0048] like Figure 2 and Figure 3 As shown, each heat exchange layer 100 includes multiple heat exchange tubes 110, which are arranged sequentially along a direction perpendicular to the flue gas flow direction F; a temperature sensing element 300 is connected between the heat exchange tubes 110 and the baffle 200. In a specific implementation, the temperature sensing element 300 can be connected to a suitable position in the heat exchanger 1, thereby being arranged between the baffle 200 and the end heat exchange layer 101. In this embodiment, as shown... Figure 3 and Figure 4 As shown, the two ends of the temperature-sensing spring 301 are connected to the heat exchange tube 110 and the baffle 200, respectively.

[0049] like Figure 1 ,like Figure 3 , Figure 4 and Figure 5As shown, the baffle 200 covers the downstream side of the end heat exchange layer 101. Two temperature sensing elements 300 are provided between each of the two heat exchange tubes 110 located at both ends of the end heat exchange layer 101 and the baffle 200. The two temperature sensing elements 300 are located on both sides of the heat exchange tubes 110. The baffle 200 covering the end heat exchange layer 101 means that the projection of the end heat exchange layer 101 onto the baffle 200 falls within the range of the baffle 200. Through this structural configuration, temperature sensing elements 300 can be connected to the corresponding heat exchange tubes 110 at the four corners of the baffle 200, thereby improving the connection balance between the baffle 200 and the end heat exchange layer 101 and facilitating the movement of the baffle 200 relative to the end heat exchange layer 101 by the temperature sensing elements 300. In other embodiments, more or fewer temperature sensing elements 300 may be used, arranged at appropriate positions on the heat exchange tubes 110 and the baffle 200.

[0050] In specific implementation, the temperature sensing spring 301 can be connected to the baffle 200 and the heat exchange tube 110 in various ways. Specifically, one end of the temperature sensing spring 301 is connected to the baffle 200 through the first connector 410, and the other end of the temperature sensing spring 301 is connected to the heat exchange tube 110 through the second connector 420.

[0051] like Figure 4 As shown, the first connecting member 410 is a first protrusion 411 disposed on the surface of the baffle 200 facing the heat exchange layer 100, and one end of the temperature sensing spring 301 is sleeved on the first protrusion 411. The temperature sensing spring 301 is sleeved on the first protrusion 411 to achieve connection with the baffle 200. This method has a simple structure and is easy to implement.

[0052] like Figure 4 As shown, the second connector 420 includes a pipe connection portion 421 and a second protrusion 422. The pipe connection portion 421 is connected to the heat exchange tube 110, and the second protrusion 422 is connected to the top of the pipe connection portion 421. The other end of the temperature-sensing spring 301 is sleeved on the second protrusion 422. The temperature-sensing spring 301 is sleeved on the second protrusion 422, and the pipe connection portion 421 can be connected to the heat exchange tube 110, thereby realizing the connection between the temperature-sensing spring 301 and the heat exchange tube 110. This method has a simple structure and is easy to implement.

[0053] like Figure 4 and Figure 5 As shown, the pipe connection part 421 is an arc-shaped ring, which is fitted onto the heat exchange tube 110. The arc-shaped ring can adapt to the shape of the heat exchange tube 110, thereby connecting with the heat exchange tube 110. Specifically, the central angle of the arc-shaped ring is preferably greater than 180°, so as to form a reliable connection with the heat exchange tube 110.

[0054] like Figure 1 , Figures 3-7As shown, the baffle 200 is a flat plate with openings 210, the positions of which correspond to the positions of the heat exchange tubes 110. In the gas water heater, flue gas flows layer by layer into each heat exchange layer 100 to exchange heat with the heat exchange layer 100, and flows out of the heat exchanger 1 through the openings 210 on the flat plate and flows towards the gas collection hood. Furthermore, by configuring the total area of ​​the openings 210 on the flat plate, the exhaust resistance of the flat plate can be adjusted. Thus, the flat plate can be configured to increase heat exchange efficiency while meeting exhaust resistance requirements according to actual conditions. In addition, the position of the openings 210 corresponding to the position of the heat exchange tubes 110 can also adjust the flow path of the flue gas, so that the flue gas can flow evenly around the tube wall of the heat exchange tubes 110 before being discharged.

[0055] The total area of ​​the openings 210 on the flat plate is not less than the minimum cross-sectional area of ​​the exhaust channel of the heat exchanger 1. It is understandable that a smaller total area of ​​the openings 210 results in more heat exchange time and increased heat exchange efficiency, but as the area of ​​the openings 210 decreases, the exhaust resistance increases, and the flue gas quality deteriorates. By configuring the total area of ​​the openings 210 to be not less than the minimum cross-sectional area of ​​the exhaust channel, additional exhaust resistance caused by the baffle 200 can be avoided. The exhaust channel refers to the flue gas passage from the heat exchanger to the gas collector hood of the gas water heater, and then to the end of the exhaust pipe. The minimum cross-sectional area of ​​the exhaust channel is the minimum flow cross-section from the heat exchanger to the end of the exhaust pipe. The location of the minimum flow cross-section varies for different systems; for example, it may be at the fin position or at the connection between the gas collector hood and the exhaust pipe.

[0056] like Figure 1 As shown, along the axial direction of the heat exchange tube 110, the baffle 200 has multiple openings 210 spaced apart at positions corresponding to the heat exchange tube 110. Figure 3 As shown, an opening 210 is provided directly above each heat exchange tube 110.

[0057] The shape, size, and density of the openings 210 on the plate can be adjusted according to requirements, and the shapes of the openings 210 on the plate can be the same or different. Specifically, the openings 210 are at least one of circular holes and elongated holes. Figure 6 As shown, a schematic diagram illustrates the structure of the baffle 200, which has uniformly distributed circular holes. Figure 7 The diagram shows a schematic representation of a baffle 200 with uniformly spaced elongated holes. In other embodiments, the openings 210 may be configured in other suitable shapes.

[0058] The baffle 200 and temperature sensing element 300 mentioned above can be applied to existing heat exchangers 1. For example, for heat exchangers 1 with heat exchange efficiency that is not as expected, the heat exchange efficiency can be improved and the heat exchange efficiency can be automatically adjusted by configuring the baffle 200 and temperature sensing element 300 mentioned above.

[0059] In a specific implementation, the heat exchange layer 100 includes at least one of a finned heat exchange layer 102 and a tube heat exchange layer 103, wherein the finned heat exchange layer 102 is formed by multiple finned heat exchange tubes 111, and the tube heat exchange layer 103 includes at least one of a corrugated heat exchange tube 112 and a smooth tube heat exchange tube 113.

[0060] like Figure 2 As shown, taking the application of baffle 200 and temperature sensing element 300 to the end heat exchange layer 101 as the tube heat exchange layer 103, and the other heat exchange layers 100 as the finned heat exchange layer 102 as an example, the heat exchange efficiency of the tube heat exchange layer 103 is lower than that of the finned heat exchange layer 102. By setting baffle 200 downstream of the tube heat exchange layer 103, the heat exchange efficiency of the tube heat exchange layer 103 can be improved. Specifically, without baffle 200, the flue gas will be quickly discharged after passing through the tube heat exchange layer 103, especially the upper half of the heat exchange tube 110 has poor heat exchange capacity, resulting in insufficient heat exchange in the tube heat exchange layer 103. With the addition of baffle 200, the flue gas will flow around the tube wall of the corrugated heat exchange tube 112 and / or the smooth tube heat exchange tube 113, and the entire tube wall can better exchange heat with the flue gas, thus improving efficiency.

[0061] This embodiment also provides a gas water heater, which includes the heat exchanger 1 as described above. The gas water heater using any of the heat exchangers 1 described above can improve heat exchange efficiency compared to a design without baffles 200. Furthermore, the heat exchange efficiency can be changed by altering the distance between the baffles 200 and the end heat exchange layer 101 using the temperature sensing element 300, thereby preventing condensation and thus avoiding corrosion of the water heater's metal parts due to condensation. It also prevents the fins of the finned heat exchange layer 102 from becoming clogged due to corrosion by condensation.

[0062] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A heat exchanger, characterized in that, The heat exchanger includes at least one heat exchange layer arranged along the flue gas flow direction; in the at least one heat exchange layer, a baffle is provided downstream of the most downstream end heat exchange layer, and the baffle is connected to the end heat exchange layer via a temperature sensing element. The temperature sensing element is configured to elongate less as the flue gas temperature increases, thereby changing the distance between the baffle and the end heat exchange layer.

2. The heat exchanger as claimed in claim 1, characterized in that, The temperature sensing element includes any one of the following: a temperature-sensing spring, a metal sheet with a high coefficient of expansion, a thermosensitive polymer hydrogel, a porous metal, and paraffin wax.

3. The heat exchanger as described in claim 2, characterized in that, The temperature-sensing spring is a shape memory alloy spring.

4. The heat exchanger according to any one of claims 1-3, characterized in that, Each heat exchange layer includes multiple heat exchange tubes, which are arranged sequentially along a direction perpendicular to the flue gas flow direction; the temperature sensing element is connected between the heat exchange tubes and the baffle.

5. The heat exchanger as described in claim 4, characterized in that, The baffle covers the downstream side of the end heat exchange layer. Two temperature sensing elements are provided between the two heat exchange tubes at both ends of the end heat exchange layer and the baffle. The two temperature sensing elements are located on both sides of the heat exchange tube.

6. The heat exchanger as claimed in claim 4, characterized in that, The temperature sensing element is a temperature sensing spring. One end of the temperature sensing spring is connected to the baffle through a first connector, and the other end of the temperature sensing spring is connected to the heat exchange tube through a second connector.

7. The heat exchanger as claimed in claim 6, characterized in that, The first connecting member is a first protrusion disposed on the surface of the baffle facing the heat exchange layer, and one end of the temperature sensing spring is sleeved on the first protrusion.

8. The heat exchanger as claimed in claim 6, characterized in that, The second connector includes a pipe connection portion and a second protrusion. The pipe connection portion is connected to the heat exchange pipe, and the second protrusion is connected to the top of the pipe connection portion. The other end of the temperature sensing spring is sleeved on the second protrusion.

9. The heat exchanger as claimed in claim 8, characterized in that, The tube connection part is an arc-shaped ring, which is sleeved on the heat exchange tube.

10. The heat exchanger as claimed in claim 4, characterized in that, The baffle is a flat plate with openings, and the position of the openings corresponds to the position of the heat exchange tube.

11. The heat exchanger as claimed in claim 10, characterized in that, The total area of ​​the openings on the plate is not less than the minimum cross-sectional area of ​​the exhaust channel of the heat exchanger.

12. The heat exchanger as claimed in claim 10, characterized in that, Along the axial direction of the heat exchange tube, the baffle is provided with a plurality of openings at intervals at positions corresponding to the heat exchange tube; And / or, the opening is at least one of a circular hole or an elongated hole.

13. The heat exchanger as claimed in claim 1, characterized in that, The heat exchange layer includes at least one of a finned heat exchange layer and a tube heat exchange layer, wherein the finned heat exchange layer is formed by multiple finned heat exchange tubes, and the tube heat exchange layer includes at least one of a corrugated heat exchange tube and a smooth tube heat exchange tube.

14. The heat exchanger as claimed in claim 13, characterized in that, The end heat exchange layer is the tube body heat exchange layer.

15. A gas-fired water heater, characterized in that, The gas water heater includes a heat exchanger as described in any one of claims 1-14.

Images