Flat tube, heat exchanger and water heater thereof

Abstract

The utility model relates to the technical field of water heaters, in particular to a flat tube, a heat exchanger and a water heater thereof. The flat pipe is provided with a flow channel allowing a medium to flow through, the flat pipe is provided with an inner side face used for being connected with the water tank and an outer side face back to the inner side face, and the width of the flow channel in the width direction of the flat pipe is gradually reduced from the inner side face of the flat pipe to the outer side face of the flat pipe. The heat exchanger has the advantages that the width of the side, close to the inner side face, of the flat pipe is large, and due to the fact that the inner side face is attached to the water tank, the width of the position is large, namely the circulation amount of heat exchange media is large, the contact area of the heat exchange media and the inner side face is large, and the heat exchange efficiency is higher. On the side close to the outer side face, due to the fact that the heat exchange medium does not exchange heat with the inner side face, the structural strength of the flat pipe can be improved due to the fact that the flow channels are formed to be small, and the influence of the flow channels on the structural strength of the flat pipe is reduced.

Description

Technical Field

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

[0002] The water heater includes a heat exchanger and a water tank. The heat exchanger includes a plurality of flat tubes, which are arranged at intervals. Each flat tube is provided with a plurality of flow channels for medium circulation. Both ends of the flat tubes are inserted into and connected with a collecting pipe. The heat exchange medium flows into the flow channel through the collecting pipe. The flat tubes are bent and fitted to the water tank to exchange heat with the water tank, thereby heating the water stored in the water tank.

[0003] The ends and side wall thicknesses of multiple flow channels in the existing flat tubes are all the same, resulting in the same heat dissipation effect of the flat tubes in all directions during the operation of the water heater, resulting in poor heat exchange effect of the water heater. Utility Model Content

[0004] Based on this, the utility model provides a flat tube to solve the above technical problems.

[0005] A flat tube is used in a water heater, and the flat tube is bent and fitted to a water tank. The flat tube is characterized in that the flat tube is constructed with a flow channel for medium circulation, the flat tube has an inner side surface for connecting to the water tank and an outer side surface facing away from the inner side surface, and the width of the flow channel in the width direction of the flat tube gradually decreases along the inner side surface of the flat tube to the outer side surface of the flat tube.

[0006] With this arrangement, the width of the flat tube is larger on the side close to the inner side. Since the inner side is in contact with the water tank, the width here is larger, which means that the heat exchange medium has a larger flow rate, the contact area between the heat exchange medium and the inner side is larger, and the heat exchange efficiency is higher. On the side close to the outer side, since the heat exchange medium here does not exchange heat with the inner side, the flow channel is smaller, which can improve the structural strength of the flat tube and reduce the impact of the flow channel on the structural strength of the flat tube.

[0007] In one embodiment, the cross-section of the flow channel (11) is semicircular, the thickness of the flat tube is T0, the shortest distance between the flow channel (11) and the outer side surface (13) is T2, and the shortest distance between the flow channel (11) and the inner side surface (14) is T3, satisfying: 0.2≤(T2+T3) / T0≤0.5; and / or, 1.1*T3≤T2≤2*T3.

[0008] In one embodiment, the cross-section of the flow channel (11) is trapezoidal, the thickness of the flat tube is T0, the shortest distance between the flow channel (11) and the outer side surface (13) is T4, and the shortest distance between the flow channel (11) and the inner side surface (14) is T5, satisfying: 0.2≤(T4+T5) / T0≤0.5; and / or, 1.1*T5≤T4≤2*T5.

[0009] In one embodiment, the cross-section of the flow channel (11) is a trapezoid, both sides of the width direction of the flow channel (11) are hypotenuses, and the angle between the extension lines of the mutually adjacent hypotenuses of two adjacent flow channels (11) is α, satisfying: 10°≤α≤60°.

[0010] In one embodiment, the inner wall of the flow channel (11) close to the outer side surface (13) is arc-shaped, the shortest distance between the flow channel (11) and the outer side surface (13) is T6, and the shortest distance between the flow channel (11) and the inner side surface (14) is T7, satisfying: 0.2≤(T6+T7) / T0≤0.5; and / or, 1.1*T7≤T6≤2*T7.

[0011] In one embodiment, the fillet radius of the arc-shaped portion of the inner wall of the flow channel (11) is R3, satisfying: 0.15≤R3 / T0≤0.6.

[0012] In one embodiment, a plurality of protrusions (12) are provided on the inner wall of the flow channel (11), and the protrusions (12) are located on the inner wall of the flow channel (11) close to the inner side surface (14).

[0013] In one embodiment, along the width direction of the flat tube, both side edges of the outer side surface (13) of the flat tube have first rounded corners (15), and both side edges of the inner side surface (14) of the flat tube have second rounded corners (16), the rounded corner radius of the first rounded corner (15) is R1, and the rounded corner radius of the second rounded corner (16) is R2, satisfying: R1>R2.

[0014] In one embodiment, 0≤R2≤0.5mm; and / or, 1.1*R2≤R1≤8*R2.

[0015] The utility model also provides a heat exchanger, which includes a first header, a second header and the flat tubes as described above, wherein the first header and the second header are arranged at intervals, a plurality of the flat tubes are provided, and the plurality of flat tubes are arranged at intervals and in parallel, and one end of each of the flat tubes is connected to the first header, and the other end is connected to the second header.

[0016] The utility model also provides a water heater, which comprises the heat exchanger as described above and a water tank, wherein the heat exchanger is fitted and fixed to the outer peripheral side of the water tank.

[0017] Compared with the prior art, the utility model uses a flow channel that gradually narrows along the thickness direction of the flat tube, so that the flow channel ensures the structural strength of the flat tube while improving the heat exchange efficiency between the inner side of the flat tube and the water tank. A first rounded corner and a second rounded corner with different circumferential radii are set on the inner side and the outer side of the flat tube, so that the inner side facing the water tank and the outer side facing away from the water tank can be distinguished during the processing and installation of the flat tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0019] Figure 2 A partial cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0020] Figure 3 A partial cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0021] Figure 4 A partial cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0022] Figure 5 A partial cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0023] Figure 6 A schematic diagram of the structure of the heat exchanger provided by the utility model installed on a water tank;

[0024] Figure 7 A cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0025] Figure 8 A cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0026] Fig. 9 A cross-sectional view of one embodiment of the flat tube provided by the utility model;

[0027] Fig.10 A partial structural schematic diagram of one embodiment of the flat tube provided by the utility model;

[0028] Fig.11 A schematic diagram of the structure of the heat exchanger provided by the utility model being inserted into a header;

[0029] Fig.12A partial structural schematic diagram of one embodiment of the flat tube provided by the utility model;

[0030] Fig.13 This is a cross-sectional view of the heat exchanger provided by the utility model being inserted into a collecting pipe.

[0031] The symbols in the figure mean the following:

[0032] 100. heat exchanger; 10. flat tube; 11. flow channel; 12. protrusion; 13. outer side surface; 14. inner side surface; 15. first chamfered corner; 16. second chamfered corner; 20. convex rib; 21. first convex rib; 22. second convex rib; 30. water tank; 40. first collecting pipe. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] It should be noted that when a mechanism is referred to as being "fixed to" or "set on" another mechanism, it may be directly on the other mechanism or there may be a central mechanism. When a mechanism is considered to be "connected to" another mechanism, it may be directly connected to the other mechanism or there may be a central mechanism at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, a first feature being “above”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0038] The utility model provides a flat tube 10, which is applied to a water heater. The flat tube 10 is bent and fitted to a water tank 30. The flat tube 10 is installed on the outer peripheral side of the water heater. The rounded corners with different fillet radii make it easy for an operator to distinguish the inner side surface 14 and the outer side surface 13 of the flat tube 10 to prevent reverse installation.

[0039] See also Figure 1 The flat tube 10 is configured with a flow channel 11 for medium circulation. The flat tube 10 has an inner side surface 14 for connecting with the water tank 30 and an outer side surface 13 facing away from the inner side surface 14. The width of the flow channel 11 in the width direction of the flat tube 10 gradually decreases along the inner side surface 14 of the flat tube 10 to the outer side surface 13 of the flat tube 10. In this way, the width of the flat tube 10 is larger on the side close to the inner side surface 14. Since the inner side surface 14 is in contact with the water tank 30, the width here is larger, that is, the flow rate of the heat exchange medium is larger, the contact area between the heat exchange medium and the inner side surface 14 is large, and the heat exchange efficiency is higher. On the side close to the outer side surface 13, since the heat exchange medium here does not exchange heat with the inner side surface 14, the flow channel 11 is opened smaller, which can improve the structural strength of the flat tube 10 and reduce the influence of the flow channel 11 on the structural strength of the flat tube 10.

[0040] Along the width direction of the flat tube 10, both side edges of the outer side surface 13 of the flat tube 10 have first rounded corners 15, and both side edges of the inner side surface 14 of the flat tube 10 have second rounded corners 16. The fillet radius of the first rounded corner 15 is R1, and the fillet radius of the second rounded corner 16 is R2, satisfying: R1>R2.

[0041] In this way, since the edges of the inner side surface 14 and the outer side surface 13 of the flat tube 10 are both provided with rounded corners, the rounded corners can prevent stress concentration and prevent the flat tube 10 from being deformed and damaged during the bending process. Moreover, since the first rounded corner 15 and the second rounded corner 16 have different fillet radii, the user can distinguish the inner side surface 14 and the outer side surface 13 of the flat tube 10 by the first rounded corner 15 and the second rounded corner 16 during the bending process, so as to avoid reversing the bending direction when the flat tube 10 is bent. In addition, since the second rounded corner 16 is located on the inner side surface 14, and the inner side surface 14 is used to contact the water tank, the opening of the second rounded corner 16 will reduce the contact area between the inner side surface 14 and the water tank, so the fillet radius of the second rounded corner 16 is set to be smaller than the first rounded corner 15, which can minimize the influence of the opening of the second rounded corner 16 on the heat exchange area between the flat tube 10 and the water tank.

[0042] It needs to be explained that the thickness direction of the flat tube 10 refers to the thickness of the flat tube 10 in the direction away from the water tank, that is, in the radial direction of the water tank. The flat tube 10 is connected to the outer peripheral side of the water tank in a surrounding form, so the width direction of the flat tube 10 refers to the circumferential direction of the water tank. Along the axial direction of the water tank, multiple flat tubes 10 are evenly spaced, so the length direction of the flat tube 10 refers to the direction parallel to the axial direction of the water tank.

[0043] Furthermore, 0≤R2≤0.5mm. In this way, it is possible to prevent the second rounded corner 16 from being too large to affect the heat exchange area between the flat tube 10 and the water tank, and to prevent the second rounded corner 16 from being too small to play a role in stress distribution.

[0044] Exemplarily, the value of R2 may be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, etc., but is not limited to the above two endpoint values.

[0045] Moreover, 1.1*R2≤R1≤8*R2, thus preventing the first rounded corner 15 from being too small to play a role in stress distribution, and also preventing the first rounded corner 15 from being too large to affect the opening of the flow channel 11 in the flat tube 10.

[0046] See also Figure 5 A plurality of protrusions 12 are provided on the inner wall of the flow channel 11, and the protrusions 12 are located on the inner wall of the flow channel 11 near the inner side surface 14. The protrusions 12 can also increase the contact area between the flow channel 11 and the heat exchange medium, further improve the heat exchange efficiency, and can also have a disturbing effect on the heat exchange medium, so that the heat exchange medium generates turbulence, and the temperature mixing and transfer are more uniform.

[0047] Furthermore, a protrusion 12 is also provided on the inner wall of the flow channel 11 close to the outer side surface 13, so as to further increase the heat exchange area and heat exchange efficiency and optimize the temperature uniformity.

[0048] The height of the protrusion 12 close to the inner side surface 14 is greater than the height of the protrusion 12 close to the outer side surface 13 , thereby optimizing the heat exchange efficiency of the inner side surface 14 and specifically improving the heat exchange capacity of the inner side surface 14 of the flat tube 10 .

[0049] In this embodiment, three protrusions 12 are provided on the inner wall surfaces on both sides of the flow channel 11 in the thickness direction to balance the processing cost, heat exchange efficiency and structural strength. In other embodiments, one, two or four protrusions 12 may also be provided on the inner wall surface on each side of the flow channel 11, without being limited to the above embodiments.

[0050] See also Figure 1-Figure 2 The cross section of the flow channel 11 can be set to a variety of shapes. Taking the semicircular flow channel 11 as an example, the thickness of the flat tube 10 is T0, the shortest distance between the flow channel 11 and the outer side surface 13 is T2, and the shortest distance between the flow channel 11 and the inner side surface 14 is T3, which satisfies: 0.2≤(T2+T3) / T0≤0.5. In this way, the ratio of the wall thickness on both sides of the flow channel 11 in the thickness direction to the thickness of the flat tube 10 is reasonably set, which not only avoids the ratio being too large, that is, the inner wall is too thick to affect the heat transfer capacity of the flat tube 10, but also prevents the wall thickness from being too thin to affect the service life of the flat tube 10.

[0051] Preferably, 1.1*T3≤T2≤2*T3, the smaller T3 is, the higher the heat exchange efficiency between the flat tube 10 and the water tank 30 is. Taking into account the structural strength and service life, the ratio of T2 to T3 is reasonably specified to make the performance of the flat tube 10 more balanced.

[0052] See also Figure 3 The cross section of the flow channel 11 can also be set to a trapezoid. When the cross section of the flow channel 11 is defined as a trapezoid, the shortest distance between the flow channel 11 and the outer side surface 13 is T4, and the shortest distance between the flow channel 11 and the inner side surface 14 is T5. At this time, the following conditions are satisfied: 0.2≤(T4+T5) / T0≤0.5; and / or, 1.1*T5≤T4≤2*T5. The technical effect is the same as that of a semicircular cross section, which will not be described in detail here.

[0053] Furthermore, when the cross section of the flow channel 11 is a trapezoid, both sides of the width direction of the flow channel 11 in the shape of a trapezoid are hypotenuses, and the angle between the extension lines of the mutually close hypotenuses of two adjacent flow channels 11 is α, which satisfies: 10°≤α≤60°. In this way, it is prevented that α is set too large, which will limit the flow area of ​​the flow channel 11 and make it too small, resulting in insufficient heat exchange capacity, and it is also prevented that α is too small, the inclination angle of the hypotenuse is too small, and the contact area increment between the medium and the inner wall of the flow channel 11 is too small, and the setting of the trapezoidal shape is not meaningful.

[0054] See also Figure 4In another embodiment, the inner wall of the flow channel 11 close to the outer side surface 13 is in an arc shape, and the shortest distance between the flow channel 11 and the outer side surface 13 is defined as T6, and the shortest distance between the flow channel 11 and the inner side surface 14 is defined as T7, which satisfies: 0.2≤(T6+T7) / T0≤0.5; and / or, 1.1*T7≤T6≤2*T7. Its technical effect is the same as that of a semicircular cross section, which will not be repeated here.

[0055] Furthermore, the fillet radius of the arc-shaped portion of the inner wall of the flow channel 11 is R3, satisfying: 0.15≤R3 / T0≤0.6. The smaller the ratio, the smaller the flow area of ​​the flow channel 11, the higher the pressure resistance, but the lower the heat exchange efficiency; the larger the ratio, the larger the flow area of ​​the flow channel 11, but the lower the pressure resistance. The above ratio setting reasonably balances the heat exchange efficiency and pressure resistance.

[0056] See also Figure 6-Figure 7 The utility model also provides a heat exchanger 100, wherein a plurality of flat tubes 10 are arranged in parallel to form the heat exchanger 100, and the heat exchanger 100 is connected to the outside of the water tank 30 of the water heater, and a limiter is arranged between adjacent flat tubes 10 to ensure that the position of the flat tubes 10 relative to the first collecting pipe 40 is more fixed, thereby avoiding the problem of position displacement of the flat tubes 10.

[0057] The heat exchanger 100 further includes a first header 40, in which at least one end of the flat tube 10 is inserted and communicated with the first header 40, and the plurality of flat tubes 10 are evenly arranged, and a limiting member is provided between adjacent flat tubes 10, and the two ends of the limiting member are respectively in contact with two adjacent flat tubes 10. In this way, the flat tube 10 is in contact with the first header 40, and the limiting member can limit the two adjacent flat tubes 10 through its abutment effect, so as to prevent the flat tube 10 from deflecting during the bending process, ensure that the position of the flat tube 10 relative to the first header 40 is fixed, prevent stress concentration from occurring at the connection position between the flat tube 10 and the first header 40, and avoid medium leakage caused by damage to the flat tube 10 and / or the first header 40.

[0058] See also Figure 7-Figure 9 The stopper is set as a convex rib 20. The two adjacent flat tubes 10 are the first flat tube 10 and the second flat tube 10. At least one of the first flat tube 10 and the second flat tube 10 is provided with a convex rib 20. The convex rib 20 extends toward and abuts against the other of the first flat tube 10 and the second flat tube 10. In this way, the structure of the convex rib 20 is simple and stable, and the processing is simple and the cost is low. The convex rib 20 is connected to one of the first flat tubes 10 and abuts against the other, so that the position between the two adjacent flat tubes 10 is relatively fixed.

[0059] In other embodiments, the limiting member may also be configured as other structures, such as a limiting block or an elastic pad, etc., and is not limited to the above-mentioned rib 20 embodiment, and only needs to be able to prevent the flat tube 10 from being displaced during the bending process.

[0060] Furthermore, the first flat tube 10 is provided with a first convex rib 21 protruding in the direction of the second flat tube 10, and the second flat tube 10 is provided with a second convex rib 22 protruding in the direction of the first flat tube 10, and the end of the first convex rib 21 close to the second flat tube 10 abuts against the end of the second convex rib 22 close to the first flat tube 10. In this way, the ends of the two convex ribs 20 close to each other abut against each other, so compared with only providing the convex rib 20 on the first flat tube 10 or the second flat tube 10, the protruding lengths of the first convex rib 21 and the second convex rib 22 respectively provided on the first flat tube 10 and the second flat tube 10 can be set shorter, the structural strength is higher, and the assembly and abutment of the first flat tube 10 and the second flat tube 10 are more convenient.

[0061] Preferably, the first convex rib 21 and the second convex rib 22 have the same width in the width direction of the first flat tube 10 and the second flat tube 10, so the molds of the first convex rib 21 and the second convex rib 22 are the same, which is convenient for processing and low in cost. The resistance force of the first convex rib 21 and the second convex rib 22 is also more balanced.

[0062] It should be explained that the thickness direction of the flat tube 10 refers to the thickness of the flat tube 10 in the direction away from the water tank 30, that is, the radial direction of the water tank 30. The flat tube 10 is connected to the outer peripheral side of the water tank 30 in a surrounding form. Therefore, the length direction of the flat tube 10 refers to the circumferential direction of the water tank 30. Along the axial direction of the water tank 30, multiple flat tubes 10 are evenly spaced. Therefore, the width direction of the flat tube 10 refers to the direction parallel to the axial direction of the flat tube 10 and the water tank 30.

[0063] In another embodiment, the first convex rib 21 and the second convex rib 22 are arranged in parallel, and the first convex rib 21 abuts against the second flat tube 10, and the second convex rib 22 abuts against the first flat tube 10. In this way, four force points are formed between the first flat tube 10 and the second flat tube 10 through the first convex rib 21 and the second convex rib 22. Compared with the solution in which the first convex rib 21 and the second convex rib 22 abut against each other, this arrangement makes the relative position of the first flat tube 10 and the second flat tube 10 more stable.

[0064] See also Fig.10 Along the thickness direction of the flat tube 10, the thickness of the rib 20 is T1, and T1 satisfies 0.3mm≤T1≤1.5mm. In this way, it is possible to avoid the rib 20 being too thick, resulting in a waste of material cost, and to prevent the rib 20 from being too thin, resulting in insufficient structural strength, and causing the abutment between two adjacent flat tubes 10 to be unstable.

[0065] Exemplarily, the value of T1 is 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1.1 mm, 1.3 mm or 1.5 mm, etc., but is not limited to the above two endpoint values.

[0066] Along the width direction of the flat tube 10, the width of the rib 20 is W, and W satisfies 0.2≤W / T1≤2. In this way, the width of the rib 20 is reasonably set, which can prevent the rib 20 from being too wide and affecting the structural strength, which can easily cause breakage. Moreover, when the rib 20 is connected to the water tank 30 on the side facing the water tank 30, the rib 20 can increase the contact area between the flat tube 10 and the water tank 30, thereby improving the heat exchange efficiency between the flat tube 10 and the water tank 30. Therefore, 0.2≤W / T1 can prevent the rib 20 from being too narrow and failing to improve the heat exchange efficiency.

[0067] Exemplarily, the value of W / T1 is 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 or 2, as long as it can achieve the above technical effect, and is not limited to the above two endpoint values.

[0068] Along the width direction of the flat tube 10, convex ribs 20 are arranged on both sides of the flat tube 10, and the convex ribs 20 on both sides of the flat tube 10 are arranged alternately, or the convex ribs 20 on both sides of the flat tube 10 are connected to the same thickness of the flat tube 10. In this way, the position and arrangement of the convex ribs 20 can be flexibly adjusted and changed, and adaptive adjustments can be made according to different working environments and requirements of the flat tube 10, so that the application range of the flat tube 10 is wider.

[0069] See also Figure 11-13 Furthermore, along the length direction of the flat tube 10, the two ends of the stopper are spaced from the two ends of the flat tube 10. As the two ends of the flat tube 10 are inserted into the first header 40, the two ends of the stopper abut against the outer tube wall of the first header 40. In this way, the stopper can also play the role of positioning the relative position of the flat tube 10 and the first header 40. When the stopper abuts against the outer tube wall of the first header 40, the flat tube 10 cannot be further extended into the first header 40, thereby ensuring that the flat tube 10 will not be excessively extended into the first header 40, so that the depth of the flat tube 10 inserted into the first header 40 is relatively fixed, thereby ensuring the normal flow of the medium between the flat tube 10 and the first header 40, and also ensuring the consistency of the product, and facilitating the processing of the heat exchanger 100.

[0070] Furthermore, along the length direction of the flat tube 10, both ends of the stopper are spaced apart from both ends of the flat tube 10 by a first distance X, the outer diameter of the first header 40 is set to D, and X and D satisfy: 0.25≤X / D≤0.75. In this way, the depth of the flat tube 10 inserted into the first header 40 is reasonably specified, which not only prevents the flat tube 10 from being easily blocked by welding due to the shallow insertion depth, or the flat tube 10 from falling off from the first header 40, but also prevents the insertion depth from being too deep, which leads to poor flow of the medium, and causes problems such as excessive weight and high cost.

[0071] Exemplarily, the ratio of X to D may be 0.25, 0.5 or 0.75, as long as the above technical effects can be achieved, and is not limited to the above example ratios.

[0072] The utility model also provides a heat exchanger, including a first header 40, a second header (not shown) and the flat tubes 10 as described above, the first header 40 and the second header are arranged at intervals, a plurality of flat tubes 10 are provided, and the plurality of flat tubes 10 are arranged in parallel at intervals, one end of each flat tube 10 is connected to the first header 40, and the other end is connected to the second header.

[0073] The utility model further provides a water heater, comprising the heat exchanger 100 and the water tank 30 as described above, wherein the heat exchanger 100 is connected to the outer peripheral side of the water tank 30 .

[0074] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A flat tube, used in a water heater, wherein the flat tube is bent and attached to a water tank (30), characterized in that: The flat tube is configured with a flow channel (11) for medium flow, the flat tube having an inner side (14) for connecting to a water tank (30) and an outer side (13) facing away from the inner side (14), and the width of the flow channel (11) in the width direction of the flat tube gradually decreases along the inner side (14) of the flat tube to the outer side (13) of the flat tube.

2. The flat tube according to claim 1, characterized in that: The cross section of the flow channel (11) is semicircular, the thickness of the flat tube is T0, the shortest distance between the flow channel (11) and the outer side surface (13) is T2, and the shortest distance between the flow channel (11) and the inner side surface (14) is T3, satisfying: 0.2≤(T2+T3) / T0≤0.5; and / or, 1.1*T3≤T2≤2*T3.

3. The flat tube according to claim 1, characterized in that: The cross section of the flow channel (11) is a trapezoid, the thickness of the flat tube is T0, the shortest distance between the flow channel (11) and the outer side surface (13) is T4, and the shortest distance between the flow channel (11) and the inner side surface (14) is T5, satisfying: 0.2≤(T4+T5) / T0≤0.5; and / or, 1.1*T5≤T4≤2*T5.

4. The flat tube according to claim 1, characterized in that: The cross section of the flow channel (11) is a trapezoid, both sides of the flow channel (11) in the width direction are oblique sides, and the angle between the extension lines of the mutually adjacent oblique sides of two adjacent flow channels (11) is α, satisfying: 10°≤α≤60°.

5. The flat tube according to claim 1, characterized in that: The inner wall of the flow channel (11) close to the outer side surface (13) is in an arc shape, the shortest distance between the flow channel (11) and the outer side surface (13) is T6, and the shortest distance between the flow channel (11) and the inner side surface (14) is T7, satisfying: 0.2≤(T6+T7) / T0≤0.5; and / or, 1.1*T7≤T6≤2*T7.

6. The flat tube according to claim 5, characterized in that: The fillet radius of the arc-shaped portion of the inner wall of the flow channel (11) is R3, satisfying: 0.15≤R3 / T0≤0.

6.

7. The flat tube according to claim 1, characterized in that: A plurality of protrusions (12) are provided on the inner wall of the flow channel (11), and the protrusions (12) are located on the inner wall of the flow channel (11) close to the inner side surface (14).

8. The flat tube according to any one of claims 1 to 7, characterized in that: Along the width direction of the flat tube, the two side edges of the outer side surface (13) of the flat tube have first rounded corners (15), and the two side edges of the inner side surface (14) of the flat tube have second rounded corners (16), the rounded corner radius of the first rounded corner (15) is R1, and the rounded corner radius of the second rounded corner (16) is R2, satisfying: R1>R2.

9. The flat tube according to claim 8, characterized in that: 0≤R2≤0.5mm; and / or, 1.1*R2≤R1≤8*R2.

10. A heat exchanger, characterized in that: The heat exchanger includes a first header, a second header, and a flat tube according to any one of claims 1 to 9, wherein the first header and the second header are arranged at intervals, a plurality of the flat tubes are provided, and the plurality of flat tubes are arranged at intervals and in parallel, and one end of each of the flat tubes is connected to the first header, and the other end is connected to the second header.

11. A water heater, characterized in that: The water heater comprises the heat exchanger according to claim 10 and a water tank (30), wherein the heat exchanger is attached and fixed to the outer peripheral side of the water tank (30).

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