Heat exchanger and gas water heater

Abstract

The utility model relates to the technical field of gas water heaters, in particular to a heat exchanger and a gas water heater. The heat exchanger comprises heat exchange pipes, connecting pipes, a water inlet pipe, a water outlet pipe, a bypass pipe and an inner pipe, the multiple heat exchange pipes are connected in series, and the ends of every two adjacent heat exchange pipes are connected through the corresponding connecting pipe. The first heat exchange pipe in the water flow direction is a first heat exchange pipe, the other heat exchange pipes are second heat exchange pipes, the water inlet pipe is connected with the first heat exchange pipe, and the water outlet pipe is connected with the last second heat exchange pipe in the water flow direction. One end of the bypass pipe is connected with the water inlet pipe, the other end of the bypass pipe is connected with the inner pipe, and the inner pipe extends into and communicates with one second heat exchange pipe. The gas water heater comprises the heat exchanger, part of cold water of the water inlet pipe passes through the bypass pipe and the inner pipe and then flows into the second heat exchange pipe, so that the cold water is fully mixed with high-temperature water in the second heat exchange pipe, the water temperature in the heat exchange pipe is reduced, and the undesirable phenomena of water gasification and gasification noise caused by too high water temperature in the heat exchange pipe are avoided.

Description

Technical Field

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

[0002] After the gas water heater is turned off and stops working, the internal residual heat will heat up the stored water in the heat exchange pipe. When it is restarted, the outlet water temperature is higher than that before the water valve is closed (i.e., the water temperature rise during shutdown), which will lead to a poor user experience and even scald the user. To solve the problem of water temperature rise during shutdown, a bypass pipe is usually connected between the inlet pipe and the outlet pipe. When the water valve is opened, part of the cold water flows from the inlet pipe through the bypass pipe and is diverted into the outlet pipe, and quickly mixes with the high-temperature water in the outlet pipe and cools down.

[0003] In the existing gas water heaters, part of the cold water in the inlet pipe is directly conveyed into the outlet pipe through the bypass pipe, resulting in less cold water entering the heat exchange pipe. Under the same load, the water temperature in the heat exchange pipe is relatively high, and water gasification and gasification noise are likely to occur in the heat exchange pipe of the heat exchanger due to the relatively high water temperature. Summary of the Utility Model

[0004] One of the technical problems to be solved by the utility model is to provide a heat exchanger, which can effectively solve the technical problem that water gasification and gasification noise occur in the heat exchange pipe due to the direct conveyance of the cold water in the inlet pipe to the outlet pipe by the bypass pipe in the prior art.

[0005] Another technical problem to be solved by the utility model is to provide a gas water heater, which can effectively solve the technical problem that water gasification and gasification noise occur in the heat exchange pipe due to the direct conveyance of the cold water in the inlet pipe to the outlet pipe by the bypass pipe in the prior art.

[0006] The above first technical problem is solved by the following technical solutions:

[0007] A heat exchanger, comprising heat exchange pipes, connecting pipes, an inlet pipe and an outlet pipe. A plurality of the heat exchange pipes are connected in series, and the ends of two adjacent heat exchange pipes are connected by the connecting pipes; the first heat exchange pipe in the water flow direction is the first heat exchange pipe, and the remaining heat exchange pipes are the second heat exchange pipes. The inlet pipe is connected to the first heat exchange pipe, and the outlet pipe is connected to the last second heat exchange pipe in the water flow direction;

[0008] The heat exchanger further comprises a bypass pipe and an inner pipe. One end of the bypass pipe is connected to the inlet pipe, the other end of the bypass pipe is connected to the inner pipe, and the inner pipe extends into and communicates with one of the second heat exchange pipes.

[0009] The heat exchanger of the utility model, compared with the background art, has the following beneficial effects:

[0010] In a heat exchanger, a water inlet pipe, a bypass pipe and an inner pipe are connected in sequence, and the inner pipe extends into and is connected to the inside of a second heat exchange pipe, so that part of the cold water in the water inlet pipe flows into the inside of the second heat exchange pipe after passing through the bypass pipe and the inner pipe, so that the cold water is fully mixed with the high-temperature water in the second heat exchange pipe, so as to reduce the water temperature in the heat exchange pipe and avoid the bad phenomena of water vaporization and vaporization noise caused by too high water temperature in the heat exchange pipe.

[0011] In one embodiment, the inner pipe is eccentrically arranged at the inner bottom of the second heat exchange pipe towards the second heat exchange pipe. In one embodiment, the inner pipe is provided with through holes in a penetrating manner, and the second heat exchange pipe into which the inner pipe extends is connected to the inner pipe through the through holes.

[0012] In one embodiment, the heat exchanger further includes a heat exchange plate group, and the heat exchange plate group is provided with pipe holes for the heat exchange pipes to pass through;

[0013] A plurality of the through holes are arranged at intervals along the axial direction of the inner pipe. The through holes located in the heat exchange plate group are first holes. Along the water flow direction in the second heat exchange pipe into which the inner pipe extends, the apertures of the plurality of first holes become larger and / or the distances between the plurality of first holes become smaller.

[0014] In one embodiment, at least part of the first holes are located at the bottom of the inner pipe to face the inner bottom of the corresponding second heat exchange pipe.

[0015] In one embodiment, the through holes located outside the heat exchange plate group are second holes, and there is a set distance between the second holes and the heat exchange plate group.

[0016] In one embodiment, at least two bypass pipes are provided. Both ends of one bypass pipe are respectively connected to the water inlet pipe and the inner pipe, and both ends of at least another bypass pipe are respectively connected to the water inlet pipe and the water outlet pipe.

[0017] In one embodiment, a transfer shell is connected and installed between the last second heat exchange pipe in the water flow direction and the water outlet pipe. The bypass pipe is installed on the transfer shell, and the inner pipe passes through the transfer shell and then extends into the corresponding second heat exchange pipe.

[0018] In one embodiment, at least two bypass pipes are provided. Both ends of one bypass pipe are respectively connected to the water inlet pipe and the inner pipe, and both ends of at least another bypass pipe are respectively connected to the water inlet pipe and the second heat exchange pipe without the inner pipe installed.

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

[0020] The gas water heater includes the heat exchanger described above.

[0021] Compared with the background art, the gas water heater of the present utility model has the following beneficial effects:

[0022] In the heat exchanger, the water inlet pipe, the bypass pipe and the inner pipe are connected in sequence, and the inner pipe extends into and is connected to the inside of a second heat exchange pipe, so that part of the cold water in the water inlet pipe flows into the inside of the second heat exchange pipe after passing through the bypass pipe and the inner pipe, so that the cold water is fully mixed with the high-temperature water in the second heat exchange pipe, so as to reduce the water temperature in the heat exchange pipe and avoid the adverse phenomena of water gasification and gasification noise caused by too high water temperature in the heat exchange pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural view of the heat exchanger provided by Embodiment 1 of the present utility model Figure 1 ;

[0024] Figure 2 is a cross-sectional view of the heat exchanger provided by Embodiment 1 of the present utility model;

[0025] Figure 3 is a schematic structural view of the heat exchanger provided by Embodiment 1 of the present utility model Figure 2 ;

[0026] Figure 4 is a schematic structural view of the heat exchanger provided by Embodiment 2 of the present utility model;

[0027] Figure 5 is a schematic structural view of the heat exchanger provided by Embodiment 3 of the present utility model.

[0028] The names and reference numerals of the components in the figure are as follows:

[0029] 1. Heat exchange pipe; 11. First heat exchange pipe; 12. Second heat exchange pipe; 2. Connecting pipe; 3. Water inlet pipe; 4. Water outlet pipe; 5. Bypass pipe; 6. Inner pipe; 61. First hole; 62. Second hole; 7. Heat exchange plate group; 71. Splint; 72. Heat exchange plate; 8. Adapter housing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present utility model clearer, the technical solutions of the present utility model will be further described below with reference to the drawings and through specific embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. In addition, it should be noted that only the parts related to the present utility model are shown in the drawings for the convenience of description, rather than all of them.

[0031] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0032] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0033] In the description of this embodiment, the orientation or positional relationship such as "above", "below", "right", and "left" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0034] The technical solution of the present utility model will be further described below with reference to the drawings and through specific embodiments.

[0035] Embodiment 1

[0036] This embodiment provides a gas water heater, which includes a combustion device, a heat exchanger, and a fan assembly. The combustion device includes a combustion chamber and a burner installed in the combustion chamber. The heat exchanger is installed at the upper end of the combustion chamber. The burner generates high-temperature flue gas by burning gas. The high-temperature flue gas passes through the heat exchange plate group 7 from bottom to top ( Figure 1 in the up-and-down direction) to heat and raise the temperature of the water in the heat exchange tube 1, and the flue gas after heat exchange is discharged from the gas water heater through the fan assembly.

[0037] Such as Figure 1 and Figure 2As shown in the figure, this embodiment also proposes a heat exchanger, which includes heat exchange tubes 1, connecting tubes 2, a water inlet pipe 3, a water outlet pipe 4, and a heat exchange plate group 7. Among them, there are multiple heat exchange tubes 1 and connecting tubes 2. The multiple heat exchange tubes 1 are connected in series, and the ends of two adjacent heat exchange tubes 1 are connected by a connecting tube 2, so that the multiple heat exchange tubes 1 and the multiple connecting tubes 2 form an S-shaped pipeline. The heat exchange plate group 7 includes two clamping plates 71 and multiple heat exchange plates 72 installed between the clamping plates 71. Pipe holes for the heat exchange tubes 1 to pass through are provided on both the clamping plates 71 and the heat exchange plates 72, so that the heat exchange tubes 1 are installed in the heat exchange plate group 7.

[0038] Specifically, the heat exchange tubes 1 are straight tubes, and the connecting tubes 2 are U-shaped bent tubes. The multiple heat exchange tubes 1 are installed in the pipe holes of the heat exchange plate group 7. The same ends of two adjacent heat exchange tubes 1 extend out of the clamping plates 71 and are connected by a connecting tube 2. The first heat exchange tube 1 along the water flow direction ( Figure 2 the direction indicated by the arrow in the figure) is the first heat exchange tube 11, and the remaining heat exchange tubes 1 are the second heat exchange tubes 12. The water inlet pipe 3 is connected to the first heat exchange tube 11, and the water outlet pipe 4 is connected to the last second heat exchange tube 12 along the water flow direction. The water inlet pipe 3 is connected to an external water supply pipeline to supply cold water (relative to the high-temperature water in the heat exchange tubes 1) to the water inlet pipe 3. The water outlet pipe 4 is connected to the water-using end to supply hot water to the water-using end (such as the kitchen or bathroom, etc.).

[0039] When the gas water heater stops working after closing the water valve, the internal residual heat will heat up the stored water in the heat exchange tubes 1. When restarted, there will be a stop water temperature rise, resulting in a poor user experience and even scalding the user. To solve the stop water temperature rise phenomenon, in existing gas water heaters, a bypass pipe is usually connected between the water inlet pipe and the water outlet pipe. When the water valve is opened, part of the cold water is diverted from the water inlet pipe through the bypass pipe into the water outlet pipe to quickly mix with and cool the high-temperature water in the water outlet pipe. However, directly delivering part of the cold water in the water inlet pipe to the water outlet pipe will result in less cold water entering the heat exchange tubes. Under the same load, the temperature at the water outlet position of the heat exchanger is relatively high, and water vaporization and vaporization noise are likely to occur in the heat exchange tubes of the heat exchanger due to the relatively high water temperature.

[0040] To solve the above problems, as Figure 2 shown in the figure, the heat exchanger of this embodiment further includes a bypass pipe 5 and an inner pipe 6. One end of the bypass pipe 5 is connected to the water inlet pipe 3, and the other end of the bypass pipe 5 is connected to the inner pipe 6. The inner pipe 6 extends into and communicates with a second heat exchange tube 12. It should be noted that the above inner pipe 6 and bypass pipe 5 can be an integrated pipe or a split pipe, and no specific limitation is made here.

[0041] In a heat exchanger, the water inlet pipe 3, the bypass pipe 5 and the inner pipe 6 are connected in sequence, and the inner pipe 6 extends into and is connected to a second heat exchange pipe 12, so that part of the cold water in the water inlet pipe 3 flows into the interior of the second heat exchange pipe 12 after passing through the bypass pipe 5 and the inner pipe 6, enabling the cold water to be fully mixed with the high-temperature water in the second heat exchange pipe 12, reducing the water temperature in the heat exchange pipe 1, and avoiding the adverse phenomena of water vaporization and vaporization noise caused by too high water temperature in the heat exchange pipe 1. At the same time, since the water temperature in the heat exchange pipe 1 gradually rises along the water flow direction, the water temperature in the subsequent heat exchange pipes 1 is higher than that in the previous heat exchange pipes 1, resulting in a smaller temperature difference between the high-temperature water in the subsequent heat exchange pipes 1 and the high-temperature flue gas, that is, the heat exchange temperature difference is reduced, and the heat exchange efficiency is lowered. Under the cooling effect of the inner pipe 6, the temperature difference between the water temperature in the second heat exchange pipe 12 where the inner pipe 6 is located and the high-temperature flue gas becomes larger, improving the heat exchange efficiency of the heat exchanger.

[0042] In this embodiment, since the high-temperature flue gas passes through the heat exchange plate group 7 from bottom to top, the water temperature at the inner bottom of the heat exchange pipe 1 is higher than the water temperature at the inner top of the heat exchange pipe 1. Therefore, the inner pipe 6 of this embodiment is eccentrically arranged in the second heat exchange pipe 12 towards the inner bottom of the second heat exchange pipe 12. Setting the inner pipe 6 to be biased towards the inner bottom of the second heat exchange pipe 12 enables the cold water flowing out of the inner pipe 6 to be fully mixed with the high-temperature water at the inner bottom of the heat exchange pipe 1, improving the cooling effect of the inner pipe 6. In other embodiments, the inner pipe 6 can also extend coaxially into the second heat exchange pipe 12.

[0043] Specifically, along the water flow direction, the water temperatures in the first heat exchange pipe 11 and the multiple second heat exchange pipes 12 gradually increase, and the water temperature in the first heat exchange pipe 11 is the lowest, and the water temperature in the last second heat exchange pipe 12 connected to the water outlet pipe 4 is the highest. As Figure 2 shown, the inner pipe 6 extends into the last second heat exchange pipe 12, enabling the cold water to be directly mixed with the highest-temperature high-temperature water, further improving the cooling effect of the inner pipe 6. In other embodiments, the inner pipe 6 can also extend into other second heat exchange pipes 12, as long as the cooling effect can be achieved to avoid water vaporization and vaporization noise in the heat exchange pipe 1.

[0044] As Figure 2 shown, the end of the inner pipe 6 extending into the second heat exchange pipe 12 has an opening to ensure that the cold water in the water inlet pipe 3 flows into the second heat exchange pipe 12 after passing through the bypass pipe 5 and the inner pipe 6 in sequence. At the same time, the inner pipe 6 is provided with through holes, and the second heat exchange pipe 12 into which the inner pipe 6 extends is connected to the inner pipe 6 through the through holes. The cold water in the inner pipe 6 can also flow into the second heat exchange pipe 12 through the through holes, not only increasing the flow rate of the cold water, but also achieving full mixing of the cold water with the high-temperature water in the second heat exchange pipe 12, ensuring a good cooling effect.

[0045] In this embodiment, the inner tube 6 is axially provided with a plurality of through holes at intervals. The through holes located within the heat exchange plate group 7 are the first holes 61. Along the water flow direction within the second heat exchange tube 12 extending into the inner tube 6, the apertures of the plurality of first holes 61 become larger and / or the spacing between the plurality of first holes 61 becomes smaller. It should be noted that the through holes are circular holes to facilitate machining on the inner tube 6.

[0046] As Figure 2 shown, the inner tube 6 extends into the last second heat exchange tube 12, and the water temperature gradually increases under the heat exchange effect of the high-temperature flue gas along the water flow direction indicated by the arrow in Figure 2 . The water temperature at the end of the last second heat exchange tube 12 connected to the water outlet pipe 4 is the highest. By gradually increasing the aperture of the plurality of first holes 61 on the inner tube 6 along the water flow direction within the second heat exchange tube 12, the apertures of the first holes 61 in the region with relatively higher water temperature are larger, and the apertures of the first holes 61 in the region with relatively lower water temperature are smaller, so that the cold water flow at different positions on the inner tube 6 is adaptively adjusted according to the water temperature within the second heat exchange tube 12, further improving the cooling effect of the inner tube 6. At the same time, the spacing between the plurality of first holes 61 can also be adjusted according to the water temperature within the second heat exchange tube 12, thereby adjusting the distribution density of the plurality of first holes 61 along the axial direction of the inner tube 6 (or the axial direction of the second heat exchange tube 12), such that the distribution density of the first holes 61 in the region with relatively higher water temperature is larger, and the distribution density of the first holes 61 in the region with relatively lower water temperature is smaller.

[0047] In one embodiment, at least part of the first holes 61 are located at the bottom of the inner tube 6 to face the inner bottom of the corresponding second heat exchange tube 12. Since at least part of the first holes 61 face the inner bottom of the second heat exchange tube 12, part of the cold water directly flows to the region with relatively higher water temperature at the inner bottom of the second heat exchange tube 12 to ensure the cooling effect of the inner tube 6. In this embodiment, a row of first holes 61 is axially provided at intervals at the bottom of the inner tube 6. In other embodiments, the number and distribution positions of the first holes 61 can be flexibly adjusted according to requirements and are not specifically limited herein.

[0048] As Figure 2 shown, the through holes located outside the heat exchange plate group 7 are the second holes 62, and there is a set spacing between the second holes 62 and the heat exchange plate group 7. Since the second holes 62 are located outside the clamping plate 71 of the heat exchange plate group 7, the heat transfer of the high-temperature flue gas within the heat exchange plate group 7 to the second holes 62 is reduced to ensure the cold water temperature at the second holes 62. After the high-temperature water in the last second heat exchange tube 12 is cooled by the plurality of first holes 61 of the inner tube 6, it is further mixed and cooled with the cold water flowing out from the second holes 62 to precisely adjust the water temperature of the high-temperature water flowing into the water outlet pipe 4, further improving the cooling effect of the inner tube 6.

[0049] Specifically, there is one second hole 62 in this embodiment. The set distance between the second hole 62 and the heat exchange plate group 7 (an adjacent clamping plate 71) is L. The size of L is determined according to the heat conduction condition of the heat exchange plate group 7 (specifically including the heat conduction coefficient of the material of the heat exchange plate group 7, etc.) and the length of time from when the gas water heater shuts down to when it is restarted. Specifically, when the heat conduction of the heat exchange plate group 7 is good (high heat conduction coefficient), then L is relatively large, that is, the distance between the second hole 62 and the adjacent clamping plate 71 is relatively large; when the heat conduction of the heat exchange plate group 7 is poor (low heat conduction coefficient), then L is relatively small, that is, the distance between the second hole 62 and the adjacent clamping plate 71 is relatively small. When the time from when the gas water heater shuts down to when it is restarted is long, the flue gas waste heat has a long time to heat the water in the heat exchange tube 1, and the waste heat temperature rise is obvious, then L is relatively large, that is, the distance between the second hole 62 and the adjacent clamping plate 71 is relatively large. When the time from when the gas water heater shuts down to when it is restarted is short, the flue gas waste heat has a short time to heat the water in the heat exchange tube 1, and the waste heat temperature rise is not obvious, then L is relatively small, that is, the distance between the second hole 62 and the adjacent clamping plate 71 is relatively small. The specific value of the above L can be calculated according to the actual situation. Since the calculation process of L is prior art, it will not be elaborated here.

[0050] As Figure 2 and Figure 3 shown, a transfer shell 8 is connected and installed between the last second heat exchange tube 12 along the water flow direction and the water outlet pipe 4. The bypass pipe 5 is installed on the transfer shell 8, and the inner pipe 6 passes through the transfer shell 8 and extends into the corresponding second heat exchange tube 12. Specifically, the second hole 62 is located inside the conversion shell. By setting the transfer shell 8, it is convenient to realize the assembly of the last second heat exchange tube 12, the water outlet pipe 4 and the bypass pipe 5. At the same time, there is a mixing cavity in the transfer shell 8, so that the high-temperature water in the last second heat exchange tube 12 and the cold water flowing out of the second hole 62 can be fully mixed in the mixing cavity, further improving the cooling effect of the inner pipe 6.

[0051] Embodiment 2

[0052] This embodiment proposes a heat exchanger. The structure of this heat exchanger is basically the same as that of the heat exchanger in Embodiment 1. The main difference between the two is that: there is no second hole 62 on the inner pipe 6 in this embodiment, but the function of the second hole 62 is replaced by adding a bypass pipe 5.

[0053] Specifically, as Figure 4As shown, there are at least two bypass pipes 5. One end of one bypass pipe 5 is respectively connected to the water inlet pipe 3 and the inner pipe 6, and at least one end of another bypass pipe 5 is respectively connected to the water inlet pipe 3 and the water outlet pipe 4. In this embodiment, there are two bypass pipes 5. One bypass pipe 5 is connected to the water inlet pipe 3 and the inner pipe 6. Part of the cold water in the water inlet pipe 3 is transported to the second heat exchange pipe 12 after passing through the bypass pipe 5 and the inner pipe 6. Part of the cold water in the water inlet pipe 3 is directly transported to the water outlet pipe 4 through another bypass pipe 5 to cool down the high-temperature water in the water outlet pipe 4, without the need to additionally add a second hole 62 on the inner pipe 6.

[0054] In one of the embodiments, the number of bypass pipes 5 can also be three or more. The additionally added bypass pipes 5 can be installed between the water inlet pipe 3 and the water outlet pipe 4 to further improve the cooling effect on the high-temperature water in the water outlet pipe 4.

[0055] Embodiment Three

[0056] This embodiment provides a heat exchanger, which has basically the same structure as the heat exchanger in Embodiment One. The main difference between the two lies in: the number and installation positions of the bypass pipes 5 are different.

[0057] Specifically, as Figure 5 shown, there are at least two bypass pipes 5. One end of one bypass pipe 5 is respectively connected to the water inlet pipe 3 and the inner pipe 6, and at least one end of another bypass pipe 5 is respectively connected to the water inlet pipe 3 and the second heat exchange pipe 12 without the inner pipe 6 installed. In this embodiment, there are two bypass pipes 5. One bypass pipe 5 is connected to the water inlet pipe 3 and the inner pipe 6. Part of the cold water in the water inlet pipe 3 is transported to the second heat exchange pipe 12 after passing through the bypass pipe 5 and the inner pipe 6. Part of the cold water in the water inlet pipe 3 is transported to other second heat exchange pipes 12 through another bypass pipe 5 to cool down the high-temperature water in multiple second heat exchange pipes 12.

[0058] In one of the embodiments, the number of bypass pipes 5 can also be three or more. The additionally added bypass pipes 5 can be flexibly connected to different second heat exchange pipes 12, further improving the cooling effect on the high-temperature water in the water outlet pipe 4.

[0059] The above embodiments only illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, there are various changes and modifications to the present invention, and these changes and modifications all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. Heat exchanger, characterized in that, It includes heat exchange tubes (1), connecting tubes (2), a water inlet pipe (3) and a water outlet pipe (4). A plurality of the heat exchange tubes (1) are connected in series, and the ends of two adjacent heat exchange tubes (1) are connected by the connecting tube (2); the first heat exchange tube (11) among the heat exchange tubes (1) along the water flow direction, and the rest of the heat exchange tubes (1) are second heat exchange tubes (12). The water inlet pipe (3) is connected to the first heat exchange tube (11), and the water outlet pipe (4) is connected to the last second heat exchange tube (12) along the water flow direction; The heat exchanger further includes a bypass pipe (5) and an inner pipe (6). One end of the bypass pipe (5) is connected to the water inlet pipe (3), the other end of the bypass pipe (5) is connected to the inner pipe (6), and the inner pipe (6) extends into and communicates with one of the second heat exchange tubes (12).

2. The heat exchanger according to claim 1, wherein The inner pipe (6) is eccentrically arranged towards the inner bottom of the second heat exchange tube (12) within the second heat exchange tube (12).

3. The heat exchanger according to claim 1, wherein, The inner pipe (6) is provided with through holes. The second heat exchange tube (12) into which the inner pipe (6) extends is communicated with the inner pipe (6) through the through holes.

4. The heat exchanger according to claim 3, characterized in that, The heat exchanger further includes a heat exchange plate group (7). The heat exchange plate group (7) is provided with tube holes for the heat exchange tubes (1) to pass through; A plurality of the through holes are axially spaced along the inner pipe (6). The through holes located within the heat exchange plate group (7) are first holes (61). Along the water flow direction within the second heat exchange tube (12) into which the inner pipe (6) extends, the diameters of the plurality of first holes (61) are getting larger and / or the distances between the plurality of first holes (61) are getting smaller.

5. The heat exchanger according to claim 4, wherein, At least part of the first holes (61) are located at the bottom of the inner pipe (6) to face the inner bottom of the corresponding second heat exchange tube (12).

6. The heat exchanger according to claim 4, characterized in that The through holes located outside the heat exchange plate group (7) are second holes (62). There is a set distance between the second holes (62) and the heat exchange plate group (7).

7. The heat exchanger according to claim 4, characterized in that, At least two bypass pipes (5) are provided. One bypass pipe (5) has its two ends respectively connected to the water inlet pipe (3) and the inner pipe (6), and at least one other bypass pipe (5) has its two ends respectively connected to the water inlet pipe (3) and the water outlet pipe (4).

8. The heat exchanger according to any one of claims 1 to 7, characterized in that, A transfer shell (8) is connected and installed between the last second heat exchange tube (12) along the water flow direction and the water outlet pipe (4). The bypass pipe (5) is installed on the transfer shell (8), and the inner pipe (6) passes through the transfer shell (8) and then extends into the corresponding second heat exchange tube (12).

9. The heat exchanger according to any one of claims 1 to 7, characterized in that, At least two bypass pipes (5) are provided. One bypass pipe (5) has its two ends respectively connected to the water inlet pipe (3) and the inner pipe (6), and at least one other bypass pipe (5) has its two ends respectively connected to the water inlet pipe (3) and the second heat exchange tube (12) without the inner pipe (6) installed.

10. Gas water heater, characterized in that, It includes the heat exchanger according to any one of claims 1 to 9.

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