Heat exchange fin, heat exchanger and gas water heater

Abstract

The present application relates to the technical field of water heaters, and particularly relates to a heat exchange sheet, a heat exchanger and a gas water heater. The heat exchange sheet is provided with a plurality of groups of heat exchange pipe holes in the direction of flue gas flow at intervals, and the circumferential direction of at least the heat exchange pipe hole at the rear end of the flue gas flow direction is provided with an annular structure. In the two adjacent heat exchange sheets, the top end of the annular structure of one heat exchange sheet corresponds to and abuts against the bottom end of the annular structure of the other heat exchange sheet one by one, so as to form an isolated cavity in the outer periphery of the corresponding heat exchange pipe hole. The heat exchanger and the gas water heater comprise the above heat exchange sheet, the isolated cavity separates the high-temperature flue gas between the heat exchange sheets from the heat exchange pipe hole, so that the high-temperature flue gas does not come into contact with the heat exchange pipe installed in the heat exchange pipe hole, thereby making the high-temperature flue gas and the heat exchange pipe have a temperature gradient, avoiding the high-temperature flue gas from condensing into condensed water on the surface of the heat exchange pipe, avoiding the heat exchange sheet and the heat exchange pipe from being corroded by the condensed water to cause the heat exchanger to leak, and improving the service life and safety of the heat exchanger and the gas water heater.

Description

Technical Field

[0001] The present invention relates to the technical field of water heaters, and in particular to a heat exchange plate, a heat exchanger and a gas water heater. Background Art

[0002] Conventional gas water heaters usually include components such as a burner, a combustion chamber, and a heat exchanger. The burner burns gas in the combustion chamber to heat water flowing through the heat exchanger, and the flue gas is discharged to the outside through a fan.

[0003] The heat exchanger of a gas water heater consists of heat exchange fins and heat exchange tubes mounted on them. The fins are provided with heat exchange tube holes and flue gas vents. Heat exchange tubes are installed within these holes, allowing high-temperature flue gas to pass through the flue gas vents and into the spaces between adjacent fins for heat exchange with the tubes. As the high-temperature flue gas passes upward through the fins, its temperature gradually decreases. When the inlet water temperature in the tubes is low, the high-temperature flue gas condenses on the tube surfaces, forming condensate. Because condensate is acidic, it can corrode the fins and tubes, leading to leaks and reducing the heat exchanger's lifespan and safety. Summary of the Invention

[0004] One of the technical problems solved by the present invention is to provide a heat exchange plate, which can effectively solve the technical problem of condensed water easily generated on the heat exchange tube in the prior art.

[0005] The second technical problem solved by the present invention is to provide a heat exchanger that can effectively solve the technical problem in the prior art that condensed water is easily generated on the heat exchange tubes, causing the heat exchanger to leak.

[0006] The third technical problem solved by the present invention is to provide a gas water heater that can effectively solve the technical problem in the prior art that condensation water is easily generated on the heat exchange tubes, causing the heat exchanger to leak.

[0007] The first technical problem mentioned above is solved by the following technical solution:

[0008] A heat exchange plate, wherein the heat exchange plate is provided with a plurality of groups of heat exchange tube holes at intervals along the direction of flue gas flow, and at least the heat exchange tube holes located at the rear end in the direction of flue gas flow are circumferentially surrounded by an annular structure;

[0009] In two adjacent heat exchange fins, the top end of the annular structure of one heat exchange fin abuts against the bottom end of the annular structure of the other heat exchange fin in a one-to-one correspondence, so as to form an isolation cavity around the outer periphery of the corresponding heat exchange tube hole.

[0010] Compared with the background art, the heat exchange plate of the present invention has the following beneficial effects:

[0011] In the heat exchange fins, an annular structure is provided around the circumference of at least the heat exchange tube holes at the rear end of the flue gas flow direction, forming an isolation cavity around the outer periphery of the heat exchange tube holes. This isolation cavity isolates the high-temperature flue gas between the fins from the heat exchange tube holes, preventing the high-temperature flue gas from coming into contact with the heat exchange tubes installed in the heat exchange tube holes. This creates a temperature gradient between the high-temperature flue gas and the heat exchange tubes, preventing the high-temperature flue gas from condensing into condensed water on the heat exchange tube surfaces. This prevents corrosion of the fins and heat exchange tubes by condensed water, which could cause leakage in the heat exchanger, thereby improving the service life and safety of the heat exchanger.

[0012] In one embodiment, the annular structure includes an outer wall, a top wall and an inner wall connected in sequence at an angle; in the two abutting annular structures, the top end of the outer wall of one annular structure abuts the bottom end of the outer wall of the other annular structure; or, the top end of the inner wall of one annular structure abuts the bottom end of the inner wall of the other annular structure.

[0013] In one embodiment, when the outer walls of the two annular structures abut against each other, the angle between the outer wall and the top wall is smaller than the angle between the inner wall and the top wall; or, when the inner walls of the two annular structures abut against each other, the angle between the outer wall and the top wall is larger than the angle between the inner wall and the top wall.

[0014] In one embodiment, the annular structure includes an outer wall, a top wall and an inner wall connected in sequence at an angle; in the two abutting annular structures, the top end of the outer wall of one annular structure abuts the bottom end of the outer wall of the other annular structure, and the top end of the inner wall of one annular structure abuts the bottom end of the inner wall of the other annular structure.

[0015] In one embodiment, the included angle between the outer side wall and the inner side wall is α, and α≤8°.

[0016] In one embodiment, the top wall has equal included angles with the outer side wall and the inner side wall.

[0017] In one embodiment, the radial distance between the inner side wall of the annular structure and the heat exchange tube hole therein is 1 mm to 8 mm.

[0018] In one embodiment, the heat exchange plate protrudes on one side along the thickness direction to form the annular structure, and the protruding direction of the annular structure is the same as or opposite to the protruding direction of the heat exchange tube hole.

[0019] The second technical problem mentioned above is solved by the following technical solution:

[0020] The heat exchanger comprises a heat exchange tube and a plurality of the above-mentioned heat exchange fins, wherein the plurality of the heat exchange fins are stacked and arranged, and the heat exchange tube is passed through the heat exchange tube holes of the plurality of the heat exchange fins.

[0021] Compared with the background technology, the heat exchanger of the present invention has the following beneficial effects:

[0022] By providing an annular structure around the heat exchange tube holes at the rear end of the flue gas flow direction, an isolation cavity is formed around the outer periphery of the heat exchange tube holes. This isolation cavity isolates the high-temperature flue gas between the heat exchange fins from the heat exchange tube holes, preventing the high-temperature flue gas from coming into contact with the heat exchange tubes installed in the heat exchange tube holes. This creates a temperature gradient between the high-temperature flue gas and the heat exchange tubes, preventing the high-temperature flue gas from condensing into condensed water on the heat exchange tube surfaces. This prevents corrosion of the heat exchange fins and heat exchange tubes by condensed water, which could lead to leakage in the heat exchanger, thereby improving the service life and safety of the heat exchanger.

[0023] The third technical problem mentioned above is solved by the following technical solution:

[0024] A gas water heater comprises the above-mentioned heat exchanger.

[0025] Compared with the background technology, the gas water heater of the present invention has the following beneficial effects:

[0026] By providing an annular structure around the heat exchange tube holes at the rear end of the flue gas flow direction, an isolation cavity is formed around the outer periphery of the heat exchange tube holes. This isolation cavity isolates the high-temperature flue gas between the heat exchange fins from the heat exchange tube holes, preventing the high-temperature flue gas from coming into contact with the heat exchange tubes installed in the heat exchange tube holes. This creates a temperature gradient between the high-temperature flue gas and the heat exchange tubes, preventing the high-temperature flue gas from condensing into condensed water on the heat exchange tube surfaces. This prevents corrosion of the heat exchange fins and heat exchange tubes by condensed water, which could lead to leakage in the heat exchanger. This improves the service life and safety of the gas water heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a heat exchange plate provided in Example 1 of the present invention;

[0028] Figure 2 is a partial cross-sectional view of a heat exchanger provided in Example 1 of the present invention;

[0029] Figure 3 is a partial cross-sectional view of a heat exchanger provided in Example 2 of the present invention;

[0030] Figure 4 is a partial cross-sectional view of a heat exchanger provided in Example 3 of the present invention;

[0031] Figure 5 It is a structural schematic diagram of the heat exchange plate provided in Example 4 of the present invention.

[0032] The names and labels of the components in the figures are as follows:

[0033] 100, heat exchange pipe;

[0034] 1, main piece; 11, heat exchange pipe hole; 111, pressing piece; 12, smoke hole; 2, annular structure; 20, isolation cavity; 21, outer side wall; 22, top wall; 23, inner side wall. DETAILED DESCRIPTION

[0035] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects reached more clear, the technical solutions of the present application will be further described below in conjunction with the accompanying drawings and through specific embodiments. It can be understood that the specific embodiments described here are only used to explain the present application, but not limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all.

[0036] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] In the description of the present embodiment, the terms "upper", "lower", "right", "left" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0038] The technical solutions of the present application will be further described below in conjunction with the accompanying drawings and through specific embodiments.

[0039] Embodiment one

[0040] The present embodiment proposes a heat exchanger, which is mainly used in a gas water heater, and can also be used in other devices with heat exchange demand. The gas water heater includes a burner and a heat exchanger and other components. The burner burns gas in the combustion chamber to heat the water flowing through the heat exchanger to provide hot water to the water end.

[0041] As Figure 1 and Figure 2As shown, this embodiment also provides a heat exchanger comprising a heat exchange tube 100 and multiple heat exchange fins. The heat exchange fins include a main body 1, which is provided with heat exchange tube holes 11 and smoke holes 12. The multiple heat exchange fins are stacked, and the heat exchange tubes 100 are inserted into the heat exchange tube holes 11 of the multiple heat exchange fins. High-temperature flue gas enters the space between adjacent heat exchange fins through the smoke holes 12 to exchange heat with the heat exchange tubes 100.

[0042] As the high-temperature flue gas passes through the heat exchange fins from bottom to top, its temperature gradually decreases. When the inlet water temperature in the heat exchange tubes 100 is low, the high-temperature flue gas condenses on the surface of the heat exchange tubes 100 to form condensed water. Because condensed water is acidic, it can easily corrode the heat exchange fins and tubes 100, causing leaks in the heat exchanger and reducing its service life and safety.

[0043] To solve the above problems, Figures 1-3 As shown, the heat exchanger is along the flue gas flow direction ( Figure 1 Multiple groups of heat exchange tube holes 11 are spaced apart (from bottom to top), and an annular structure 2 is provided around the circumference of at least the heat exchange tube hole 11 located at the rear end in the direction of flue gas flow. For two adjacent heat exchange fins, the top end of the annular structure 2 of one heat exchange fin abuts against the bottom end of the annular structure 2 of the other heat exchange fin, forming an isolation cavity 20 around the outer periphery of the corresponding heat exchange tube hole 11. The isolation cavity 20 isolates the high-temperature flue gas between the heat exchange fins from the heat exchange tube holes 11, preventing the high-temperature flue gas from coming into contact with the heat exchange tubes 100 installed in the heat exchange tube holes 11. This creates a temperature gradient between the high-temperature flue gas and the heat exchange tubes 100, preventing the high-temperature flue gas from condensing into condensed water on the surface of the heat exchange tubes 100. This prevents corrosion of the heat exchange fins and heat exchange tubes 100 by condensed water, which could cause leakage in the heat exchanger, thereby improving the service life and safety of the heat exchanger.

[0044] like Figure 1 As shown, high-temperature flue gas flows upward through the heat exchange fins and enters the space between any two adjacent heat exchange fins through the flue gas holes 12. Due to the high initial temperature of the high-temperature flue gas, condensation rarely forms on the heat exchange tubes 100 at the front end of the flue gas flow (the lower end of the heat exchange fins). As the heat exchange process progresses, the temperature of the high-temperature flue gas gradually decreases, making condensation more likely to form on the heat exchange tubes 100 at the rear end of the flue gas flow (the upper end of the heat exchange fins). This can cause corrosion and leakage in the heat exchange tubes 100 and heat exchange tube holes 11 at the rear end of the flue gas flow. Therefore, an annular structure 2 must be provided around at least the rear end of the heat exchange tube holes 11. In other embodiments, if operating conditions permit, an annular structure 2 can be provided around the circumference of all heat exchange tube holes 11.

[0045] It should be noted that the annular structure 2 can be a circular ring-shaped blocking ring, a ring table, etc. When the annular structure 2 is a blocking ring, the blocking ring is welded or threadedly connected to the main sheet body 1. When the annular structure 2 is a ring table, the heat exchange sheet protrudes along the thickness direction (by stamping or the like) and forms the annular structure 2, so that the main sheet body 1 is integrally formed with the ring table, improving the processing efficiency of the heat exchange sheet. The following will be described in detail with the annular structure 2 as a ring table.

[0046] Specifically, as shown in Figure 1 , the protruding direction of the annular structure 2 is the same as the protruding direction of the heat exchange pipe hole 11, so that the annular structure 2 and the heat exchange pipe hole 11 are formed by one-time stamping in the same direction, simplifying the stamping operation of the heat exchange sheet and improving the processing efficiency of the heat exchange sheet.

[0047] As shown in Figure 1 and Figure 2 , the annular structure 2 includes an outer side wall 21, a top wall 22 and an inner side wall 23 connected in sequence at an included angle. In the two annular structures 2 abutting each other, the top end of the outer side wall 21 of one annular structure 2 abuts the bottom end of the outer side wall 21 of the other annular structure 2, and the top end of the inner side wall 23 of one annular structure 2 abuts the bottom end of the inner side wall 23 of the other annular structure 2. Specifically, the radial cross section of the annular structure 2 is substantially U-shaped structure, in any two adjacent heat exchange sheets, the main sheet body 1 of one heat exchange sheet, the protruding wall of the heat exchange pipe hole 11, the inner side wall 23 of the annular structure 2 located outside the periphery of the heat exchange pipe hole 11 and the main sheet body 1 of the other heat exchange sheet together enclose a closed isolation cavity 20 to ensure the isolation effect of the high-temperature flue gas and the heat exchange pipe hole 11. At the same time, in the two annular structures 2 abutting each other of any two adjacent heat exchange sheets, the top wall 22 of one annular structure 2 blocks the U-shaped opening of the other annular structure 2, so that another closed space adjacent to the isolation cavity 20 is formed inside the annular structure 2, further increasing the isolation effect of the high-temperature flue gas and the heat exchange pipe hole 11 and improving the protection of the heat exchange pipe hole 11 and the heat exchange pipe 100.

[0048] As shown in Figure 2 , when the plurality of heat exchange sheets are stacked and assembled, the coaxial annular structures 2 are stacked together in the stacking direction of the heat exchange sheets, so that the plurality of coaxial annular structures 2 are connected in sequence end to end. In order to ensure the stable contact of the two adjacent and coaxial annular structures 2, the included angle between the outer side wall 21 and the inner side wall 23 of the present embodiment is α, and α≤8°. When the included angle α between the outer side wall 21 and the inner side wall 23 is greater than 8°, the inclination angle of the outer side wall 21 and the inner side wall 23 relative to the top wall 22 is too large, so that the inner and outer side walls of one annular structure 2 cannot abut the corresponding inner and outer side walls of the corresponding other annular structure 2 when the plurality of heat exchange sheets are stacked and assembled, resulting in that the high-temperature flue gas can enter the isolation cavity 20, which destroys the isolation effect of the isolation cavity 20.

[0049] Further, the top wall 22 is equal in angle to the outer side wall 21 and the inner side wall 23, i.e. the outer side wall 21 and the inner side wall 23 are equal in angle of inclination relative to the top wall 22, which reduces the difficulty in processing the annular structure 2 and reduces the cost of the heat exchange sheet.

[0050] As shown in Figure 1 and Figure 2 The circumferential interval of the convex wall of the heat exchange pipe hole 11 is provided with a plurality of inclined pressing pieces 111, and when a plurality of heat exchange sheets are stacked and assembled, the pressing piece 111 on one of the two adjacent heat exchange sheets elastically abuts against the main sheet body 1 of the other heat exchange sheet, so as to improve the stability of the assembled structure of the heat exchange sheet.

[0051] It should be noted that the radial distance between the inner side wall 23 of the annular structure 2 and the heat exchange pipe hole 11 inside it is 1mm-8mm. The radial distance between the inner side wall 23 of the annular structure 2 of the present embodiment and the heat exchange pipe hole 11 inside it can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm or 8mm, etc. The above distance makes the annular structure 2 have enough accommodation space, so that the heat exchange pipe hole 11 and the annular structure 2 do not interfere with each other during processing, ensuring the processing quality of the heat exchange sheet. When the radial distance between the inner side wall 23 of the annular structure 2 and the heat exchange pipe hole 11 inside it is too small, the heat exchange pipe hole 11 is prone to deformation or damage when the annular structure 2 is punched, which reduces the product yield of the heat exchange sheet. When the radial distance between the inner side wall 23 of the annular structure 2 and the heat exchange pipe hole 11 inside it is too large, the occupied area of the annular structure 2 is increased, which not only affects the reasonable arrangement of structures such as the smoke hole 12 on the heat exchange sheet, but also reduces the heat exchange efficiency between the high-temperature flue gas and the heat exchange pipe 100.

[0052] The present embodiment also provides a gas water heater, which comprises the heat exchanger described above. The isolation cavity 20 separates the high-temperature flue gas between the heat exchange sheets from the heat exchange pipe hole 11, avoiding the condensation of the high-temperature flue gas into condensed water on the surface of the heat exchange pipe 100, thereby avoiding the corrosion of the heat exchange sheet and the heat exchange pipe 100 by the condensed water, resulting in water leakage of the heat exchanger, improving the service life and safety of the gas water heater.

[0053] Embodiment Two

[0054] As shown in Figure 3As shown, this embodiment proposes a heat exchange plate, which has a structure basically the same as that of the heat exchange plate in Example 1, with the main difference being that the annular structure 2 includes an outer wall 21, a top wall 22, and an inner wall 23, which are connected in sequence at an angle. In the two abutting annular structures 2, the top end of the outer wall 21 of one annular structure 2 abuts the bottom end of the outer wall 21 of the other annular structure 2. Specifically, the radial cross-section of the annular structure 2 is roughly U-shaped. In any two adjacent heat exchange plates, the main plate body 1 of one heat exchange plate, the convex wall of the heat exchange tube hole 11, the annular structure 2 located on the outer periphery of the heat exchange tube hole 11, the annular structure 2 of the other heat exchange plate, and the main plate body 1 together form a Z-shaped isolation cavity 20 to ensure the isolation effect between the high-temperature flue gas and the heat exchange tube hole 11.

[0055] Furthermore, when the outer walls 21 of the two annular structures 2 abut, the angle between the outer walls 21 and the top wall 22 is smaller than the angle between the inner wall 23 and the top wall 22, resulting in a larger inclination angle of the inner wall 23 relative to the top wall 22, thereby creating a gap between the inner walls 23 of the two adjacent annular structures 2. The inclination angles of the inner wall 23 relative to the top wall 22 and the outer wall 21 relative to the top wall 22 need to be adaptively adjusted based on the specific structure of the heat exchange fin and are not specifically limited here.

[0056] Example 3

[0057] like Figure 4 As shown, this embodiment proposes a heat exchange plate, which has a structure basically the same as that of the heat exchange plate in Example 1, with the main difference being that the annular structure 2 includes an outer wall 21, a top wall 22, and an inner wall 23, which are connected in sequence at an angle. In the two abutting annular structures 2, the top end of the inner wall 23 of one annular structure 2 abuts the bottom end of the inner wall 23 of the other annular structure 2. Specifically, the radial cross-section of the annular structure 2 is roughly U-shaped. In any two adjacent heat exchange plates, the main plate body 1 of one heat exchange plate, the convex wall of the heat exchange tube hole 11, the inner wall 23 of the annular structure 2 located on the outer periphery of the heat exchange tube hole 11, and the main plate body 1 of the other heat exchange plate together form a rectangular isolation cavity 20 to ensure the isolation effect between the high-temperature flue gas and the heat exchange tube hole 11.

[0058] When the inner sidewalls 23 of the two annular structures 2 abut, the angle between the outer sidewall 21 and the top wall 22 is greater than the angle between the inner sidewall 23 and the top wall 22, resulting in a larger inclination angle of the outer sidewall 21 relative to the top wall 22, thereby creating a gap between the outer sidewalls 21 of the two adjacent annular structures 2. The inclination angles of the inner sidewall 23 and the outer sidewall 21 relative to the top wall 22 need to be adaptively adjusted based on the specific structure of the heat exchange fin and are not specifically limited here.

[0059] Example 4

[0060] As Figure 5 shown in the figure, the heat exchange sheet of the embodiment is basically the same as the heat exchange sheet of the first embodiment, and the main difference is that the protruding direction of the annular structure 2 of the embodiment is opposite to the protruding direction of the heat exchange pipe hole 11. The side of the heat exchange sheet in the thickness direction protrudes the annular structure 2, and the side of the heat exchange sheet in the thickness direction protrudes the convex wall of the heat exchange pipe hole 11, so that both sides of the heat exchange sheet in the thickness direction have protruding structures, so that the heat exchange sheet is not easy to deform or bend, and the structural strength of the heat exchange sheet is improved, thereby improving the structural strength and stability of the heat exchanger.

[0061] The above embodiments only illustrate the basic principles and characteristics of the present application, and the present application is not limited to the above embodiments. Without departing from the spirit and scope of the present application, various changes and modifications can be made to the present application, and these changes and modifications all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. Heat exchanger, characterized in that: The heat exchange plate is provided with a plurality of groups of heat exchange tube holes (11) at intervals along the flue gas flow direction, and at least the heat exchange tube holes (11) located at the rear end in the flue gas flow direction are circumferentially surrounded by an annular structure (2); In two adjacent heat exchange fins, the top end of the annular structure (2) of one heat exchange fin abuts against the bottom end of the annular structure (2) of the other heat exchange fin in a one-to-one correspondence, so as to form an isolation cavity (20) on the periphery of the corresponding heat exchange tube hole (11), the annular structure (2) being a ring platform, the heat exchange fin comprising a main plate body (1), and the ring platform and the main plate body (1) being integrally formed.

2. The heat exchange plate according to claim 1, characterized in that: The annular structure (2) comprises an outer wall (21), a top wall (22) and an inner wall (23) connected in sequence at an angle; in the two abutting annular structures (2), the top end of the outer wall (21) of one annular structure (2) abuts the bottom end of the outer wall (21) of the other annular structure (2); or, the top end of the inner wall (23) of one annular structure (2) abuts the bottom end of the inner wall (23) of the other annular structure (2).

3. The heat exchange fin according to claim 2, characterized in that: When the outer side walls (21) of the two annular structures (2) abut against each other, the included angle between the outer side walls (21) and the top wall (22) is smaller than the included angle between the inner side walls (23) and the top wall (22); or, when the inner side walls (23) of the two annular structures (2) abut against each other, the included angle between the outer side walls (21) and the top wall (22) is larger than the included angle between the inner side walls (23) and the top wall (22).

4. The heat exchange fin according to claim 1, characterized in that: The annular structure (2) comprises an outer wall (21), a top wall (22) and an inner wall (23) which are connected in sequence at an angle; in the two abutting annular structures (2), the top end of the outer wall (21) of one annular structure (2) abuts the bottom end of the outer wall (21) of the other annular structure (2), and the top end of the inner wall (23) of one annular structure (2) abuts the bottom end of the inner wall (23) of the other annular structure (2).

5. The heat exchange fin according to claim 4, characterized in that: The included angle between the outer side wall (21) and the inner side wall (23) is α, and α is ≤ 8°.

6. The heat exchange fin according to claim 5, characterized in that: The top wall (22) has equal included angles with the outer side wall (21) and the inner side wall (23).

7. The heat exchange fin according to claim 2 or 4, characterized in that: The radial distance between the inner side wall (23) of the annular structure (2) and the heat exchange tube hole (11) therein is 1 mm to 8 mm.

8. The heat exchange fin according to any one of claims 1 to 6, characterized in that: One side of the heat exchange plate protrudes along the thickness direction to form the annular structure (2), and the protruding direction of the annular structure (2) is the same as or opposite to the protruding direction of the heat exchange tube hole (11).

9. A heat exchanger, characterized in that It comprises a heat exchange tube and a plurality of heat exchange fins according to any one of claims 1 to 8, wherein the plurality of heat exchange fins are stacked, and the heat exchange tube is passed through the heat exchange tube holes (11) of the plurality of heat exchange fins.

10. Gas water heater, characterized in that Comprising the heat exchanger according to claim 9.

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