Heat exchanger and water heater

Abstract

The utility model belongs to the technical field of hot water equipment, and discloses a heat exchanger and a water heater, the bypass ratio between a bypass pipeline and a cold water inlet pipe is less than 15%, an upstream hot water pipe is communicated with a downstream hot water pipe through a buffer pipeline, and a user stops using water after the water heater normally works for a period of time. Water in the main heat exchanger absorbs residual heat, the water temperature rising range is reduced, the water temperature in the main heat exchanger does not exceed the safety temperature limit value, it is avoided that when a user stops using water, a temperature controller acts, and water reusing of the user is affected, and the temperature difference between the water temperature in the main heat exchanger and the temperature of flue gas generated by combustion of the combustor can be increased; the heat exchange efficiency between water and flue gas in the main heat exchanger is improved; the time that hot water reaches the downstream hot water pipe is prolonged through the buffer pipeline, enough cold water is fed into the upstream hot water pipe through the bypass pipeline to be mixed with hot water in the upstream hot water pipe, the rising amplitude of the temperature of the hot water flowing out of the downstream hot water pipe can be obviously reduced, and the water cut-off temperature rising phenomenon is effectively improved.

Description

Technical Field

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

[0002] As is well known, existing gas water heaters have a problem with temperature rise during water outages. Specifically, when water usage stops, residual heat continues to heat the water in the main heat exchanger, causing the water in the main heat exchanger to rise in temperature. When water is used again, the water flowing out initially may be higher than the user's set temperature, potentially scalding the user.

[0003] To solve the above technical problems, a bypass pipe is generally added to connect the cold water inlet pipe and the hot water outlet pipe. When restarting, some of the cold water in the cold water inlet pipe enters the hot water outlet pipe through the bypass pipe. The cold water entering the hot water outlet pipe mixes with the hot water sent to the hot water outlet pipe by the main heat exchanger before being discharged. This can effectively avoid the problem of the water being too hot when it first flows out.

[0004] Currently, the bypass ratio between the bypass pipe and the cold water inlet pipe is generally 20% to 30%. The bypass pipe occupies a large space, which is not conducive to processing and production. Moreover, in actual application, it has been found that since the bypass pipe directly sends 20% to 30% of the cold water in the cold water inlet pipe into the hot water outlet pipe, the water flow into the main heat exchanger is reduced accordingly. In order to achieve the user-set outlet water temperature after the hot water in the main heat exchanger and the cold water in the bypass pipe are mixed, the hot water temperature in the main heat exchanger needs to be increased. When the user-set outlet water temperature is high, the water temperature in the main heat exchanger is very likely to exceed the safe temperature limit, causing the thermostat to activate and the burner of the gas water heater to stop working, thus affecting the normal use of the user.

[0005] Furthermore, because the bypass pipe sends 20% to 30% of the cold water in the cold water inlet pipe directly into the hot water outlet pipe without heating, the water flow rate into the main heat exchanger is reduced accordingly. Compared with the same combustion power and the same total water flow rate in the inlet pipe without a bypass pipe, the temperature of the hot water in the main heat exchanger is higher when the water is used again, which reduces the temperature difference between the water in the main heat exchanger and the flue gas generated by the burner. This reduces the heat exchange efficiency between the water in the main heat exchanger and the flue gas generated by the burner, resulting in a decrease in the thermal efficiency of the gas water heater. Utility Model Content

[0006] One of the technical problems solved by this utility model is to provide a heat exchanger that can improve the thermal efficiency of the water heater while reducing the temperature rise during water outages, and avoid the thermostat from activating due to the temperature rise during water outages.

[0007] The second technical problem solved by this utility model is to provide a water heater that can improve the thermal efficiency of the water heater while reducing the temperature rise during water outages, and avoid the thermostat from activating due to the temperature rise during water outages.

[0008] The first technical problem mentioned above is solved by the following technical solution:

[0009] A heat exchanger includes a main heat exchanger having a cold water inlet and a hot water outlet, a cold water inlet pipe connected to the cold water inlet, a hot water outlet pipe connected to the hot water outlet, and a bypass pipe having one end connected to the cold water inlet pipe. The hot water outlet pipe includes an upstream hot water pipe and a downstream hot water pipe. The other end of the bypass pipe is connected to the upstream hot water pipe, and one end of the upstream hot water pipe is connected to the hot water outlet.

[0010] The other end of the upstream hot water pipe is connected to the downstream hot water pipe through a buffer pipe, and the bypass ratio between the bypass pipe and the cold water inlet pipe is less than 15%.

[0011] The heat exchanger described in this utility model has the following advantages compared with the prior art:

[0012] After the water heater has been operating normally for a period of time, the user stops using the water. The water in the main heat exchanger then absorbs residual heat, causing its temperature to rise. Because the bypass ratio between the bypass pipe and the cold water inlet pipe has been reduced compared to existing technologies, the flow rate of cold water from the inlet pipe into the hot water outlet pipe through the bypass pipe is reduced. Correspondingly, the flow rate of cold water from the inlet pipe into the main heat exchanger increases, thus reducing the temperature rise of the hot water in the main heat exchanger. Actual verification shows that when the bypass ratio between the bypass pipe and the cold water inlet pipe is limited to less than 15%, the temperature rise of the water in the main heat exchanger after the user stops using the water has decreased and will not exceed the safe temperature limit. This effectively prevents the thermostat from activating due to the user stopping water use, thus avoiding disruption to the user's ability to use the water again.

[0013] The water in the main heat exchanger absorbs residual heat, reducing the rate of temperature increase in the water within the main heat exchanger. Consequently, this increases the temperature difference between the water in the main heat exchanger and the flue gas generated by the burner, thereby improving the heat exchange efficiency between the water and the flue gas in the main heat exchanger and thus enhancing the thermal efficiency of the water heater.

[0014] By setting the bypass ratio between the bypass pipe and the cold water inlet pipe to less than 15%, the temperature of the hot water sent to the upstream hot water pipe by the main heat exchanger is reduced. After the water heater has been working normally for a period of time, the user stops using water. When the user uses water again in a short period of time, the hot water sent to the upstream hot water pipe by the main heat exchanger and the cold water sent to the upstream hot water pipe by the bypass pipe are initially mixed and then enter the buffer pipe. From there, the hot water enters the downstream hot water pipe and is then sent to the user's shower or faucet. By setting the buffer pipe to extend the time for the hot water to reach the downstream hot water pipe, the bypass pipe sends enough cold water to the upstream hot water pipe to mix with the hot water in the upstream hot water pipe, and further mixes it in the buffer pipe. This significantly reduces the temperature rise of the hot water flowing out of the downstream hot water pipe, effectively improving the phenomenon of temperature rise during water outages.

[0015] In one embodiment, the inner diameter of the bypass pipe is no greater than 4 mm.

[0016] In one embodiment, the ratio between the cross-sectional area of ​​the bypass pipe and the cross-sectional area of ​​the cold water inlet pipe is less than 1:10.

[0017] In one embodiment, the volume of the buffer tubing is greater than 15 ml.

[0018] In one embodiment, the buffer conduit is a curved conduit.

[0019] In one embodiment, the upstream hot water pipe, the buffer pipe, and the downstream hot water pipe are integrally formed;

[0020] Alternatively, both ends of the buffer pipe are sealed to the upstream hot water pipe and the downstream hot water pipe, respectively;

[0021] Alternatively, the buffer pipe is integrally formed with the upstream hot water pipe and is sealed to the downstream hot water pipe;

[0022] Alternatively, the buffer pipe may be integrally formed with the downstream hot water pipe and sealed to the upstream hot water pipe.

[0023] In one embodiment, the orifice diameters of the upstream hot water pipe, the downstream hot water pipe, and the buffer pipe are all equal.

[0024] In one embodiment, the orifice diameter of the upstream hot water pipe is equal to that of the downstream hot water pipe and smaller than that of the buffer pipe.

[0025] In one embodiment, the upstream hot water pipe is located below the downstream hot water pipe and on the radial side of the downstream hot water pipe.

[0026] The second technical problem mentioned above is solved by the following technical solution:

[0027] A water heater includes a housing, a burner disposed within the housing, and a heat exchanger as described in any of the above embodiments, wherein the burner is capable of burning gas to heat the heat exchanger.

[0028] Compared with the prior art, the water heater described in this utility model has the following beneficial effects:

[0029] The water heater provided by this utility model includes the aforementioned heat exchanger. The bypass ratio between the bypass pipe and the cold water inlet pipe is less than 15%. After the water heater has been operating normally for a period of time, the user stops using water. Subsequently, the water in the main heat exchanger absorbs residual heat and its temperature rises. Because the bypass ratio between the bypass pipe and the cold water inlet pipe is reduced compared to existing technologies, the flow rate of cold water from the inlet pipe into the hot water outlet pipe through the bypass pipe is reduced. Correspondingly, the flow rate of cold water from the inlet pipe into the main heat exchanger is increased, thereby reducing the temperature rise of the hot water in the main heat exchanger. Actual verification shows that when the bypass ratio between the bypass pipe and the cold water inlet pipe is limited to less than 15%, the temperature rise of the water in the main heat exchanger after the user stops using water after a period of normal operation is reduced and will not exceed the safe temperature limit. This effectively prevents the thermostat from activating due to the user stopping water use, thus avoiding disruption to the user's ability to use water again.

[0030] Furthermore, the water in the main heat exchanger absorbs residual heat, reducing the rate of temperature increase in the water within the main heat exchanger. Consequently, this increases the temperature difference between the water in the main heat exchanger and the flue gas temperature generated by the burner, thereby improving the heat exchange efficiency between the water and the flue gas in the main heat exchanger and thus enhancing the thermal efficiency of the water heater.

[0031] By connecting the upstream hot water pipe to the downstream hot water pipe through a buffer pipe, and reducing the bypass ratio between the bypass pipe and the cold water inlet pipe, the temperature of the hot water sent to the upstream hot water pipe by the main heat exchanger is reduced. After the water heater has been working normally for a period of time, the user stops using water. When the user uses water again shortly afterward, the hot water sent to the upstream hot water pipe by the main heat exchanger and the cold water sent to the upstream hot water pipe by the bypass pipe are initially mixed before entering the buffer pipe. From there, the hot water enters the downstream hot water pipe and is then delivered to the user's shower or faucet. By setting up a buffer pipe to extend the time it takes for the hot water to reach the downstream hot water pipe, the bypass pipe sends enough cold water to the upstream hot water pipe to mix with the hot water in the upstream hot water pipe, and further mixes it in the buffer pipe. This significantly reduces the temperature rise of the hot water flowing out of the downstream hot water pipe, effectively improving the problem of temperature rise during water outages. Attached Figure Description

[0032] Figure 1 This is a front view of the heat exchanger provided in this embodiment of the utility model;

[0033] Figure 2 This is a side view of the heat exchanger provided in an embodiment of the present invention.

[0034] In the picture:

[0035] 1. Main heat exchanger; 11. Main heat exchange pipeline; 2. Cold water inlet pipe; 3. Hot water outlet pipe; 31. Upstream hot water pipe; 32. Downstream hot water pipe; 4. Buffer pipeline; 5. Bypass pipeline; 6. Thermostat. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0038] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0040] like Figure 1 and Figure 2As shown, an embodiment of this utility model provides a heat exchanger and a water heater. The water heater includes a housing, with a heat exchanger and a burner both disposed within the housing. The burner is capable of burning fuel to heat the heat exchanger. Exemplarily, the fuel is natural gas, and the water heater is a gas water heater, a gas-fired wall-hung boiler, or a gas-fired heating boiler, etc. The following description uses a gas water heater as an example to specifically describe the heat exchanger and the water heater including the heat exchanger.

[0041] The heat exchanger includes a main heat exchanger 1, a cold water inlet pipe 2, and a hot water outlet pipe 3. The main heat exchanger 1 has a cold water inlet and a hot water outlet. One end of the cold water inlet pipe 2 is connected to the cold water inlet, and the other end is connected to the water source. One end of the hot water outlet pipe 3 is connected to the hot water outlet, and the other end is connected to the shower head.

[0042] The water heater also includes a temperature sensor and a thermostat 6. The temperature sensor is used to detect the temperature of the hot water outlet of the main heat exchanger 1, and the thermostat 6 is used to control the start and stop of the burner. Once the temperature of the hot water outlet exceeds the safe temperature limit, the burner is controlled to stop working.

[0043] The heat exchanger also includes a bypass pipe 5, one end of which is connected to the cold water inlet pipe 2, and the other end of which is connected to the hot water outlet pipe 3.

[0044] After the water heater has been working normally for a period of time, the user stops using water. After that, the water in the main heat exchanger 1 absorbs residual heat and the water temperature rises. When the user uses water again, the cold water entering the hot water outlet pipe 3 through the bypass pipe 5 mixes with the high temperature water in the hot water outlet pipe 3, which lowers the water temperature in the hot water outlet pipe 3, thereby reducing the outlet water temperature of the hot water outlet pipe 3 and improving the temperature rise during water outage.

[0045] In the existing technology, the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 is generally between 20% and 30%. The bypass pipe 5 directly sends 20% to 30% of the cold water in the cold water inlet pipe 2 into the hot water outlet pipe 3. This portion of cold water accounts for a large proportion, resulting in a reduction in the water flow rate into the main heat exchanger 1. In order to achieve the user-set outlet water temperature after the hot water in the main heat exchanger 1 and the cold water in the hot water outlet pipe 3 from the bypass pipe 5 are mixed, it is necessary to increase the temperature of the hot water in the main heat exchanger 1. When the user-set outlet water temperature is high, the water temperature in the main heat exchanger 1 is very likely to exceed the safe temperature limit, causing the thermostat 6 to activate and the burner of the gas water heater to stop working, thus affecting the user's normal life.

[0046] Therefore, in the heat exchanger provided by the embodiments of this utility model, the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 is less than 15%.

[0047] After the water heater has been operating normally for a period of time, the user stops using the water. The water in the main heat exchanger 1 then absorbs residual heat, causing its temperature to rise. Because the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 has been reduced compared to existing technologies, the flow rate of cold water from the inlet pipe 2 into the hot water outlet pipe 3 via the bypass pipe 5 is reduced. Correspondingly, the flow rate of cold water from the inlet pipe 2 into the main heat exchanger 1 increases, thus reducing the temperature rise of the hot water in the main heat exchanger 1. Actual verification shows that when the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 is limited to less than 15%, the temperature rise of the water in the main heat exchanger 1 after the user stops using the water has decreased and will not exceed the safe temperature limit. This effectively prevents the thermostat 6 from activating due to the user stopping water use, thus avoiding disruption to the user's ability to use the water again shortly afterward.

[0048] Furthermore, the water in the main heat exchanger 1 absorbs residual heat, which reduces the rise in water temperature in the main heat exchanger 1. Correspondingly, it increases the temperature difference between the water in the main heat exchanger 1 and the flue gas temperature generated by the burner, thereby improving the heat exchange efficiency between the water and the flue gas in the main heat exchanger 1 and thus improving the thermal efficiency of the water heater.

[0049] However, in practical applications, it was found that limiting the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 to less than 15% resulted in the effect of improving the water outage temperature rise by setting the bypass pipe 5 being insignificant.

[0050] In view of this, the heat exchanger provided in the embodiment of the present invention includes an upstream hot water pipe 31 and a downstream hot water pipe 32. The upstream hot water pipe 31 is connected to the downstream hot water pipe 32 through a buffer pipe 4, and the other end of the bypass pipe 5 is connected to the upstream hot water pipe 31.

[0051] By setting the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 to less than 15%, the temperature of the hot water sent from the main heat exchanger 1 to the upstream hot water pipe 31 is reduced. After the water heater has been working normally for a period of time, the user stops using water. When the user uses water again in a short period of time, the hot water sent from the main heat exchanger 1 to the upstream hot water pipe 31 and the cold water sent from the bypass pipe 5 to the upstream hot water pipe 31 are initially mixed and then enter the buffer pipe 4. From the buffer pipe 4, the hot water enters the downstream hot water pipe 32. Then, the downstream hot water pipe 32 delivers the hot water to the user's shower or faucet. By setting the buffer pipe 4 to extend the time for the hot water to reach the downstream hot water pipe 32, the bypass pipe 5 sends enough cold water to the upstream hot water pipe 31 to mix with the hot water in the upstream hot water pipe 31. The water is further mixed in the buffer pipe 4, which significantly reduces the temperature rise of the hot water flowing out of the downstream hot water pipe 32 and effectively improves the phenomenon of temperature rise during water outages.

[0052] In some embodiments, the diameter of the bypass pipe 5 is no greater than 4 mm. By using a smaller diameter bypass pipe 5, the ease of processing the bypass pipe 5 can be improved. For example, the diameter of the bypass pipe 5 can be 4 mm, 3.9 mm, 3.8 mm, 3.7 mm, 3.6 mm, 3.5 mm, 3.4 mm, 3.3 mm, 3.2 mm, 3.1 mm, 3 mm, etc., and will not be listed here.

[0053] In some embodiments, the ratio between the cross-sectional area of ​​the bypass pipe 5 and the cross-sectional area of ​​the cold water inlet pipe 2 is less than 1:10. The orifice of the cold water inlet pipe 2 can be determined based on the orifice of the bypass pipe 5, the ratio between the cross-sectional area of ​​the bypass pipe 5 and the cross-sectional area of ​​the cold water inlet pipe 2, and the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2.

[0054] In some embodiments, the buffer pipe 4 is a curved pipe, which can make full use of the fragmented space inside the water heater without increasing the space occupied by the water heater; and it is also beneficial to extend the length of the buffer pipe 4.

[0055] For example, the buffer pipe 4 is a spiral pipe extending helically around the central axis of the water heater in the left-right direction. Specifically, the downstream hot water pipe 32 is located between the upstream hot water pipe 31 and the burner in the left-right direction. This facilitates extending the length of the buffer pipe 4 and making full use of the space in the left-right direction. It should be noted that the water heater has an operation panel, and when the user faces the operation panel, the user's left-right direction is the same as the left-right direction of the water heater.

[0056] It should be noted that the aforementioned buffer pipe 4 can also be a conventional buffer tank, which offers good buffering effect due to the variety of internal structures. However, in this embodiment of the invention, the buffer pipe 4 uses a curved pipe, which is simpler in structure and lower in cost compared to using a conventional buffer tank.

[0057] In some embodiments, the orifice diameter of the upstream hot water pipe 31 is equal to the orifice diameter of the downstream hot water pipe 32, and also equal to the orifice diameter of the buffer pipe 4. This allows for improvement in the temperature rise during water outages without altering the orifice diameters of the upstream hot water pipe 31 and the downstream hot water pipe 32, while also simplifying the fabrication of the buffer pipe 4 and reducing manufacturing costs.

[0058] In some other embodiments, the orifice diameter of the upstream hot water pipe 31 is equal to that of the downstream hot water pipe 32, and smaller than that of the buffer pipe 4. After the hot water in the upstream hot water pipe 31 enters the buffer pipe 4, the flow rate of the hot water entering the buffer pipe 4 decreases due to the increased orifice diameter of the buffer pipe 4. This helps to prolong the time it takes for the hot water to reach the downstream hot water pipe 32, and allows the hot water in the upstream hot water pipe 31 and the cold water entering the upstream hot water pipe 31 through the bypass pipe 5 to mix further in the buffer pipe 4, further improving the water heater's temperature rise effect during water outages.

[0059] In some embodiments, the buffer pipe 4 is integrally formed with the downstream hot water pipe 32 and is sealed to the upstream hot water pipe 31. In other embodiments, the buffer pipe 4, the upstream hot water pipe 31, and the downstream hot water pipe 32 can also be integrally formed, or the buffer pipe 4, the upstream hot water pipe 31, and the downstream hot water pipe 32 can be processed independently, and then the two ends of the buffer pipe 4 can be sealed to the upstream hot water pipe 31 and the downstream hot water pipe 32 respectively; or the buffer pipe 4 and the upstream hot water pipe 31 can be integrally formed, and the buffer pipe 4 and the downstream hot water pipe 32 can be sealed to each other.

[0060] In some embodiments, the upstream hot water pipe 31 is located below the downstream hot water pipe 32 and on the radial side of the downstream hot water pipe 32. This arrangement allows for the full utilization of surrounding space to arrange the buffer pipe 4 without increasing the space occupied by the water heater.

[0061] The main heat exchanger 1 includes a main heat exchange pipe 11, with a cold water inlet and a hot water outlet at its two ends. Taking the equal diameters of the main heat exchange pipe 11, the cold water inlet pipe 2, the upstream hot water pipe 31, the downstream hot water pipe 32, and the buffer pipe 4 as an example, the cross-sectional areas of each pipe are also equal. Ignoring energy losses caused by spontaneous heat exchange between water and the surrounding air during the flow of water through the hot water pipe 3, the buffer pipe 4, and the cold water inlet pipe 2, according to the law of conservation of energy, the following relationship exists:

[0062] (T2-T 入 )×V2+(T1-T 入 )×V1=(T 出 -T 入 )×(V 入 +V 出 ) / 2.

[0063] Wherein, V1 represents the water flow velocity within bypass pipe 5, T1 represents the water temperature within bypass pipe 5; V2 represents the water flow velocity at the hot water outlet, and T2 represents the water temperature at the hot water outlet; V 入 T represents the water flow velocity at the inlet of cold water inlet pipe 2. 入 V represents the inlet water temperature of cold water inlet pipe 2; 出 T represents the water flow velocity at the outlet of hot water outlet pipe 3. 出 This indicates the water temperature at the outlet of hot water outlet pipe 3.

[0064] Based on the above data relationships and actual test data, it is concluded that when the diameter of the cold water inlet pipe 2 and the hot water outlet pipe 3 is 12mm, the bypass pipe 5 is a copper pipe with a diameter of 4mm, and the wall thickness of the cold water inlet pipe 2, the hot water outlet pipe 3 and the bypass pipe 5 are all 0.5mm, the bypass ratio between the bypass pipe 5 and the cold water inlet pipe 2 is 9%. The water flow velocity V1 in the bypass pipe 5 is approximately 1.4 times the water flow velocity V2 at the hot water outlet, i.e., V1 > V2. The larger the volume of the buffer pipe 4, the lower the water temperature rise when the water is turned off.

[0065] Through testing, it was found that when the bypass ratio between bypass pipe 5 and cold water inlet pipe 2 was set to 9%, the water outage temperature rise was around 6K, while when the bypass ratio between bypass pipe 5 and cold water inlet pipe 2 was set to 20%, the water outage temperature rise was 13K, and the water outage temperature rise decreased by more than 50%.

[0066] The larger the volume of the buffer pipe 4, the longer the water takes to flow through the buffer pipe 4, and the better the effect of improving the water temperature rise during water outage. In some embodiments, in order to ensure that the temperature of the hot water flowing out of the downstream hot water pipe 32 is not too high, the volume of the buffer pipe 4 is required to be greater than 15ml.

[0067] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0068] The specific embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A heat exchanger, comprising a main heat exchanger (1) having a cold water inlet and a hot water outlet, a cold water inlet pipe (2) connected to the cold water inlet, a hot water outlet pipe (3) connected to the hot water outlet, and a bypass pipe (5) having one end connected to the cold water inlet pipe (2), wherein the hot water outlet pipe (3) includes an upstream hot water pipe (31) and a downstream hot water pipe (32), the other end of the bypass pipe (5) being connected to the upstream hot water pipe (31), and one end of the upstream hot water pipe (31) being connected to the hot water outlet; Its features are, The other end of the upstream hot water pipe (31) is connected to the downstream hot water pipe (32) through a buffer pipe (4), and the bypass ratio between the bypass pipe (5) and the cold water inlet pipe (2) is less than 15%.

2. The heat exchanger according to claim 1, characterized in that, The inner diameter of the bypass pipe (5) is no greater than 4 mm.

3. The heat exchanger according to claim 1, characterized in that, The ratio between the cross-sectional area of ​​the bypass pipe (5) and the cross-sectional area of ​​the cold water inlet pipe (2) is less than 1:

10.

4. The heat exchanger according to claim 1, characterized in that, The volume of the buffer pipeline (4) is greater than 15 ml.

5. The heat exchanger according to claim 1, characterized in that, The buffer pipe (4) is a curved pipe.

6. The heat exchanger according to claim 5, characterized in that, The upstream hot water pipe (31), the buffer pipe (4), and the downstream hot water pipe (32) are integrally formed; Alternatively, the two ends of the buffer pipe (4) are respectively sealed and connected to the upstream hot water pipe (31) and the downstream hot water pipe (32); Alternatively, the buffer pipe (4) is integrally formed with the upstream hot water pipe (31) and is sealed to the downstream hot water pipe (32); Alternatively, the buffer pipe (4) is integrally formed with the downstream hot water pipe (32) and is sealed to the upstream hot water pipe (31).

7. The heat exchanger according to claim 5, characterized in that, The diameters of the upstream hot water pipe (31), the downstream hot water pipe (32), and the buffer pipe (4) are all equal.

8. The heat exchanger according to claim 5, characterized in that, The diameter of the upstream hot water pipe (31) is equal to the diameter of the downstream hot water pipe (32) and smaller than the diameter of the buffer pipe (4).

9. The heat exchanger according to claim 5, characterized in that, The upstream hot water pipe (31) is located below the downstream hot water pipe (32) and on the radial side of the downstream hot water pipe (32).

10. A water heater, characterized in that, The device includes a housing, a burner disposed within the housing, and a heat exchanger as described in any one of claims 1 to 9, wherein the burner is capable of burning fuel gas to heat the heat exchanger.

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