Capillary tube heat exchanger

Abstract

The invention relates to a capillary tube heat exchanger. The capillary tube heat exchanger comprises a heat exchange cylinder, a heat exchange tube and two outer tube plates, and a containing cavity and two medium inlets and outlets communicating with the containing cavity are formed in the heat exchange cylinder. The heat exchange tube is arranged in the containing cavity in a penetrating mode, and the two ends of the heat exchange tube penetrate out of the two ends of the heat exchange cylinder respectively. The two outer tube plates are connected to the two ends of the heat exchange tube respectively, each outer tube plate is provided with a first tube hole allowing the heat exchange tube to penetrate through, the hole wall of each first tube hole is welded to the heat exchange tube, and the hole wall of each first tube hole is provided with a first filling groove used for being filled with welding flux. According to the capillary tube heat exchanger, the welding flux is buried in the first filler groove in a hidden mode, and the problems of welding flux accumulation, welding omission, welding lack and the like caused by exposed welding flux can be avoided. The sealing performance between the outer tube plate and the heat exchange tube is further improved, the sealing performance of the capillary tube heat exchanger is further improved, and meanwhile the overall appearance of the capillary tube heat exchanger can be kept clean and simple.

Description

Technical Field

[0001] The present application relates to the technical field of heat exchangers, and in particular to a capillary heat exchanger. Background Art

[0002] Capillary heat exchangers have excellent heat transfer performance due to their small internal heat exchange tube diameter, thin tube wall and low thermal resistance. Therefore, capillary heat exchangers are widely used in heat exchange fields such as medicine, petrochemicals, and heating and cooling engineering.

[0003] In the related art, a capillary heat exchanger usually includes a cylinder, two tube sheets connected to the two ends of the cylinder, and a heat exchange tube passing through the two tube sheets. By injecting a first medium into the cylinder and a second medium into the heat exchange tube, heat exchange between the first medium and the second medium can be achieved. The tube sheet of a capillary heat exchanger is usually welded to the heat exchange tube. However, in the related art, the welding point between the tube sheet and the heat exchange tube is prone to solder accumulation, welding leakage, and lack of welding, which not only affects the sealing between the tube sheet and the heat exchange tube, but also fails to ensure the cleanliness of the product appearance. Summary of the invention

[0004] Based on this, it is necessary to provide a capillary heat exchanger to avoid the problem of solder accumulation, welding leakage and lack of welding at the welding point.

[0005] The present application provides a capillary heat exchanger, comprising:

[0006] A heat exchange cylinder, wherein the heat exchange cylinder is formed with a cavity and two medium inlets and outlets communicating with the cavity;

[0007] A heat exchange tube, wherein the heat exchange tube is passed through the cavity, and two ends of the heat exchange tube are passed through two ends of the heat exchange tube respectively;

[0008] Two outer tube sheets, the two outer tube sheets are respectively connected to the two ends of the heat exchange tube, each heat exchange tube is provided with a first tube hole for the heat exchange tube to pass through, the hole wall of the first tube hole is welded to the heat exchange tube, wherein the hole wall of the first tube hole is provided with a first filling groove for filling with solder.

[0009] The technical solution is further described below:

[0010] In one embodiment, the heat exchange tube comprises:

[0011] A cylinder, wherein the cylinder is a hollow structure with openings at both ends;

[0012] Two short tubes, the two short tubes are respectively connected to the two ends of the cylinder, and the two short tubes and the cylinder together enclose the cavity, wherein one end of the short tube is an open end with an opening, the open end is connected to the end of the cylinder, and the other end of the short tube is connected to an inner tube sheet to form a closed end, the two ends of the heat exchange tube respectively pass through the two inner tube sheets, and the two medium inlets and outlets are respectively opened on the side walls of the two short tubes.

[0013] In one of the embodiments, the inner tube plate is provided with a second tube hole for the heat exchange tube to pass through, and the hole wall of the second tube hole is welded to the heat exchange tube, wherein the hole wall of the second tube hole is provided with a second filling groove for filling with solder.

[0014] In one embodiment, the first filling groove and / or the second filling groove is an annular groove arranged around the circumference of the heat exchange tube.

[0015] In one embodiment, the end of the cylinder is inserted into the open end of the short tube section, and the outer wall of the cylinder is welded to the inner wall of the open end.

[0016] In one of the embodiments, a third filling groove for filling solder is provided on the outer wall of the cylinder and / or the inner wall of the open end.

[0017] In one embodiment, the number of the third filling grooves is two or more, and each of the third filling grooves is spaced apart along the axial direction of the cylinder.

[0018] In one embodiment, the third filling groove is an annular groove arranged circumferentially around the cylinder.

[0019] In one embodiment, the cross section of the third filling slot is rectangular or trapezoidal, and the slot opening width of the third filling slot with a trapezoidal cross section is greater than the slot bottom width.

[0020] In one embodiment, there are multiple heat exchange tubes, which are arranged in parallel and at intervals, and a plurality of first tube holes are opened on the outer tube plate. The heat exchange tubes are inserted into the first tube holes one by one, and the hole wall of each first tube hole is provided with the first filling groove.

[0021] In the above-mentioned capillary heat exchanger, by opening a first tube hole on the outer tube sheet, and inserting the end of the heat exchange tube into the first tube hole, and welding the hole wall of the first tube hole to the heat exchange tube, the connection stability and sealing between the outer tube sheet and the heat exchange tube are enhanced, so that the outer tube sheet can effectively isolate the end of the heat exchange tube from the volume of the heat exchange tube, and avoid cross-contamination between the first medium and the second medium. At the same time, by opening a first filling groove on the hole wall of the first tube hole, during the assembly process, the solder can be evenly applied to the first filling groove, wherein the solder includes but is not limited to brazing. When the welding process is performed, the solder will melt in a high temperature environment and fill the space in the entire first filling groove to firmly weld the outer tube sheet and the heat exchange tube together. Compared with the traditional solution of welding with exposed solder, in the present application, by burying the solder in the first filling groove, the problems of solder accumulation, welding leakage and lack of welding caused by exposed solder can be avoided. The sealing performance between the outer tube sheet and the heat exchange tube is further improved, thereby improving the sealing performance of the capillary heat exchanger, while keeping the overall appearance of the capillary heat exchanger clean and simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] In addition, the drawings are not drawn to a 1:1 scale, and the relative sizes of the various elements are drawn only as examples in the drawings and are not necessarily drawn according to the true scale.

[0025] Figure 1 It is a structural cross-sectional view of a capillary tube heat exchanger according to one embodiment.

[0026] Figure 2 It is a left side view of a capillary tube heat exchanger according to one embodiment.

[0027] Figure 3 The figure is a schematic diagram of the structure of the outer tube sheet and the heat exchange tubes of one embodiment.

[0028] Figure 4 It is a schematic diagram of the coordination between the short tube section, the heat exchange tube and the cylinder according to one embodiment.

[0029] Figure 5 It is a schematic diagram of the cooperation between the short tube section, the heat exchange tube and the cylinder in another embodiment.

[0030] Figure 6 It is a schematic diagram of the coordination between the short tube section, the heat exchange tube and the cylinder in another embodiment.

[0031] Figure 7 The figure is a schematic diagram of the cooperation between the short tube section, the heat exchange tube and the cylinder in another embodiment.

[0032] Description of reference numerals:

[0033] 10. heat exchange tube; 11. tube body; 111. cavity; 12. short tube section; 121. medium inlet and outlet; 122. third filling groove; 13. inner tube sheet; 131. second tube hole; 132. second filling groove; 20. outer tube sheet; 21. first tube hole; 22. first filling groove; 30. heat exchange tube; 40. baffle. DETAILED DESCRIPTION

[0034] 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.

[0035] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0036] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0038] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the 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. The first feature being "below", "below" and "below" the 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.

[0039] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0040] Specifically, the heat exchange tube bundles in the traditional capillary heat exchanger are arranged closely, and because the coaxiality requirements between the various components of the capillary heat exchanger are high, during the assembly process, the solder needs to be placed on the welding part. Before welding into the furnace, the capillary heat exchanger with assembled fillers needs to be placed horizontally on the tooling. If the open filling method is used, the solder may flow to the lowest end under the action of gravity under high-temperature processing. At this time, the weld at the high end will have leaks, and the weld at the low end will have solder accumulation, which directly affects the welding sealing and appearance of the capillary heat exchanger.

[0041] Based on this, an embodiment of the present application provides a capillary heat exchanger. Specifically, see Figure 1 as well as Figure 2The capillary heat exchanger of one embodiment includes a heat exchange tube 10, a heat exchange tube 30 and two outer tube sheets 20, wherein the heat exchange tube 10 is formed with a cavity 111 and two medium inlets and outlets 121 connected to the cavity 111. The heat exchange tube 30 is arranged in the cavity 111, and the two ends of the heat exchange tube 30 are respectively passed through the two ends of the heat exchange tube 10. The two outer tube sheets 20 are respectively connected to the two ends of the heat exchange tube 30. Figure 3 Each outer tube sheet 20 is provided with a first tube hole 21 for the heat exchange tube 30 to pass through, and the hole wall of the first tube hole 21 is welded to the heat exchange tube 30, wherein the hole wall of the first tube hole 21 is provided with a first filling groove 22 for filling with solder.

[0042] Exemplarily, when the capillary heat exchanger is working, the first medium can be introduced into the cavity 111 of the heat exchange tube 10 through one of the medium inlets and outlets 121, and the first medium in the cavity 111 can be discharged through another medium inlet and outlet 121, so as to realize the circulation of the first medium in the cavity 111. The first medium can be a refrigerant or a heat medium. The outer tube sheet 20 is used to connect with external equipment, and the external equipment can introduce the second medium into the heat exchange tube 30, and the second medium can be a liquid or gas that needs heat exchange. In this way, the first medium in the cavity 111 and the second medium in the heat exchange tube 30 can be heat exchanged through the tube wall of the heat exchange tube 30.

[0043] In the above-mentioned capillary heat exchanger, by opening a first tube hole 21 on the outer tube sheet 20, and inserting the end of the heat exchange tube 30 into the first tube hole 21, and welding the hole wall of the first tube hole 21 to the heat exchange tube 30, the connection stability and sealing of the outer tube sheet 20 and the heat exchange tube 30 are strengthened, so that the outer tube sheet 20 can effectively isolate the end of the heat exchange tube 30 from the cavity 111 of the heat exchange cylinder 10, and avoid cross contamination between the first medium and the second medium. At the same time, by opening a first filling groove 22 on the hole wall of the first tube hole 21, during the assembly process, the solder can be evenly applied in the first filling groove 22, wherein the solder includes but is not limited to brazing. When the welding process is performed, the solder will melt in a high temperature environment and fill the entire space in the first filling groove 22, so as to firmly weld the outer tube sheet 20 and the heat exchange tube 30 together. Compared with the conventional solution of welding with exposed solder, in the present application, the solder is buried in the first filler groove 22, thereby avoiding the problems of solder accumulation, welding leakage and lack of welding caused by exposed solder. The sealing between the outer tube sheet 20 and the heat exchange tube 30 is further improved, thereby improving the sealing performance of the capillary heat exchanger, and keeping the overall appearance of the capillary heat exchanger clean and simple.

[0044] Optionally, in one embodiment, the first filling groove 22 is an annular groove arranged circumferentially around the heat exchange tube 30. In this way, after the solder in the first filling groove 22 melts, an annular weld can be formed between the hole wall of the first tube hole 21 and the heat exchange tube 30, thereby improving the sealing performance between the outer tube sheet 20 and the heat exchange tube 30. Further, the number of the first filling grooves 22 is not limited to one. In other embodiments, the number of the first filling grooves 22 can also be two, three, four or more, and each first filling groove 22 is arranged at intervals along the axial direction of the heat exchange tube 30. In this way, after the solder melts, multiple annular welds can be formed between the hole wall of the first tube hole 21 and the heat exchange tube 30, thereby improving the sealing performance between the outer tube sheet 20 and the heat exchange tube 30.

[0045] See also Figure 1 In one embodiment, the heat exchange tube 10 includes a cylinder 11 and two short tube sections 12, wherein the cylinder 11 is a hollow structure with openings at both ends; the two short tube sections 12 are respectively connected to the two ends of the cylinder 11, and the two short tube sections 12 and the cylinder 11 together enclose a cavity 111, wherein one end of the short tube section 12 is an open end with an opening, and the open end is connected to the end of the cylinder 11, and the other end of the short tube section 12 is connected to an inner tube sheet 13 to form a closed end, and the two ends of the heat exchange tube 30 respectively penetrate the two inner tube sheets 13, and the two medium inlets and outlets 121 are respectively opened on the side walls of the two short tube sections 12.

[0046] By arranging short tubes 12 at both ends of the cylinder 11, and forming a closed end at the inner tube sheet 13 of a section of each short tube 12 away from the cylinder 11, and making the two ends of the heat exchange tube 30 pass through the two inner tube sheets 13 respectively, and cooperating with the outer tube sheet 20 connected to the end of the heat exchange tube 30, the port of the heat exchange tube 30 and the cavity 111 of the heat exchange cylinder 10 can be isolated and sealed by double tube sheets (the inner tube sheet 13 and the outer tube sheet 20), further preventing the first medium in the cavity 111 from entering the heat exchange tube 30 from both ends of the heat exchange tube 30, thereby preventing the first medium from being cross-contaminated with the second medium.

[0047] Further, see Figure 4The inner tube sheet 13 is provided with a second tube hole 131 for the heat exchange tube 30 to pass through, and the hole wall of the second tube hole 131 is welded to the heat exchange tube 30, wherein the hole wall of the second tube hole 131 is provided with a second filling groove 132 for filling solder. In this way, during the assembly process, the solder can be evenly applied to the second filling groove 132. When the welding process is performed, the solder will melt in a high temperature environment and fill the entire space in the second filling groove 132, so as to weld and fix the outer tube sheet 20 and the heat exchange tube 30 together, thereby improving the connection stability and sealing of the inner tube sheet 13 and the heat exchange tube 30. At the same time, compared with the traditional method of welding with exposed solder, in the present application, by burying the solder in the second filling groove 132, the problems of solder accumulation, welding leakage and lack of welding caused by exposed solder can be avoided. The sealing between the inner tube sheet 13 and the heat exchange tube 30 is further improved, while the overall appearance of the capillary heat exchanger can be kept clean and simple.

[0048] Optionally, in one embodiment, the second filling groove 132 is an annular groove arranged circumferentially around the heat exchange tube 30. In this way, after the solder in the second filling groove 132 melts, an annular weld can be formed between the hole wall of the second tube hole 131 and the heat exchange tube 30, thereby improving the sealing performance between the inner tube sheet 13 and the heat exchange tube 30. Further, the number of the second filling grooves 132 is not limited to one. In other embodiments, the number of the second filling grooves 132 can also be two, three, four or more, and each second filling groove 132 is arranged at intervals along the axial direction of the heat exchange tube 30. In this way, after the solder melts, multiple annular welds can be formed between the hole wall of the second tube hole 131 and the heat exchange tube 30, thereby improving the sealing performance between the inner tube sheet 13 and the heat exchange tube 30.

[0049] See also Figure 1 In one embodiment, the end of the cylinder 11 is inserted into the open end of the short tube 12, and the outer wall of the cylinder 11 is welded to the inner wall of the open end. By inserting the end of the cylinder 11 into the open end of the short tube 12, the connection stability between the cylinder 11 and the short tube 12 can be strengthened, and the coaxiality between the outer tube sheet 20 and the short tube 12 can be ensured, and the installation accuracy can be further improved, avoiding the problem of dimensional deviation during the assembly process or the processing process leading to unqualified products. By welding the outer wall of the cylinder 11 to the inner wall of the open end of the short tube 12, the connection stability between the cylinder 11 and the short tube 12 is further strengthened, and the sealing between the cylinder 11 and the short tube 12 is also strengthened. Exemplarily, the cylinder 11 and the short tube 12 can be welded and fixed by a brazing process.

[0050] Further, see Figure 4The inner wall of the open end is provided with a third filler groove 122 for filling solder. During the assembly process, the solder is first evenly applied to the third filler groove 122, and then the outer wall of the cylinder 11 and the inner wall of the open end are welded, so that the cylinder 11 and the short tube 12 are firmly welded and fixed together. Compared with the traditional method of welding with exposed solder, in this application, by burying the solder in the third filler groove 122, the problems of solder accumulation, welding leakage and lack of welding caused by exposed solder can be avoided. The sealing between the cylinder 11 and the short tube 12 is further improved, and the overall appearance of the capillary heat exchanger can be kept clean and simple.

[0051] It is worth noting that in other embodiments, the outer wall of the cylinder 11 may also be provided with a third filling groove 122. In this way, during the assembly process, the solder is first evenly applied to the third filling groove 122, and then welding is performed. This can also achieve the goal of firmly welding the cylinder 11 and the short section pipe 12 together, and avoid problems such as solder accumulation, welding leakage, and missing welding.

[0052] Optionally, in one embodiment, the third filling groove 122 is an annular groove arranged circumferentially around the cylinder 11. In this way, after the solder in the third filling groove 122 melts, an annular weld can be formed between the short tube 12 and the cylinder 11, thereby improving the sealing performance between the short tube 12 and the cylinder 11.

[0053] Optionally, in one embodiment, the number of the third filling slots 122 is not limited to one. Figure 5 as well as Figure 6 As shown, in other embodiments, the number of the third filling grooves 122 can also be two, three, four or more, and the third filling grooves 122 are arranged at intervals along the axial direction of the heat exchange tube 30, so that after the solder melts, multiple annular welds can be formed between the cylinder 11 and the short tube 12, thereby improving the sealing performance between the cylinder 11 and the short tube 12.

[0054] See also Figure 6 In one embodiment, the cross section of the third filling groove 122 is rectangular, wherein the cross section of the third filling groove 122 refers to the cross section of the third filling groove 122 parallel to the radial direction of the short tube 12. Figure 7 In another embodiment, the cross-section of the third filling slot 122 is trapezoidal, and the slot width of the third filling slot 122 with a trapezoidal cross-section is greater than the slot bottom width, so that it is easier to fill the solder into the first filling slot 22.

[0055] Continue to see Figure 1Optionally, the capillary heat exchanger includes a plurality of baffles 40, which are arranged in the cavity 111 at intervals along the length direction of the cylinder 11, so that a tortuous flow channel is formed in the cavity 111, and each baffle 40 is provided with a through hole for the heat exchange tube 30 to pass through. For example, Figure 1 As shown, some of the multiple baffles 40 are arranged at intervals on the top wall of the cavity 111, and another part of the baffles 40 are arranged at intervals on the bottom wall of the cavity 111, and along the length direction of the cylinder 11, the baffles 40 arranged on the top wall of the cavity 111 and the baffles 40 arranged on the bottom wall of the cavity 111 are alternately arranged, so that a tortuous flow channel can be formed in the cavity 111, extending the distance and time for the first medium to flow through the cavity 111, so that the first medium can more fully contact with the heat exchange tube 30, thereby further improving the heat exchange efficiency.

[0056] See also Figure 4 , there are multiple heat exchange tubes 30, and the multiple heat exchange tubes 30 are arranged in parallel and at intervals, and multiple first tube holes 21 are opened on the outer tube plate 20. The heat exchange tubes 30 are arranged in the first tube holes 21 one by one, and the hole wall of each first tube hole 21 is provided with a first filler groove 22, so that each heat exchange tube 30 can be tightly connected to the outer tube plate 20. By passing the second medium through multiple heat exchange tubes 30 at the same time, the flow rate of the second medium is increased, and the heat exchange efficiency of the second medium is also improved. Exemplarily, the heat exchange tube 30 is a capillary tube with a small diameter and a thin tube wall, which can effectively improve the heat exchange efficiency.

[0057] 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.

[0058] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A capillary heat exchanger, characterized in that: include: A heat exchange cylinder, wherein the heat exchange cylinder is formed with a cavity and two medium inlets and outlets communicating with the cavity; A heat exchange tube, wherein the heat exchange tube is passed through the cavity, and two ends of the heat exchange tube are passed through two ends of the heat exchange tube respectively; Two outer tube sheets, the two outer tube sheets are respectively connected to the two ends of the heat exchange tube, each outer tube sheet is provided with a first tube hole for the heat exchange tube to pass through, the hole wall of the first tube hole is welded to the heat exchange tube, wherein the hole wall of the first tube hole is provided with a first filling groove for filling with solder.

2. The capillary tube heat exchanger according to claim 1, characterized in that: The heat exchange tube comprises: A cylinder, wherein the cylinder is a hollow structure with openings at both ends; Two short tubes, the two short tubes are respectively connected to the two ends of the cylinder, and the two short tubes and the cylinder together enclose the cavity, wherein one end of the short tube is an open end with an opening, the open end is connected to the end of the cylinder, and the other end of the short tube is connected to an inner tube sheet to form a closed end, the two ends of the heat exchange tube respectively pass through the two inner tube sheets, and the two medium inlets and outlets are respectively opened on the side walls of the two short tubes.

3. The capillary tube heat exchanger according to claim 2, characterized in that: The inner tube plate is provided with a second tube hole for the heat exchange tube to pass through, and the hole wall of the second tube hole is welded to the heat exchange tube, wherein the hole wall of the second tube hole is provided with a second filling groove for filling with solder.

4. The capillary tube heat exchanger according to claim 3, characterized in that: The first filling groove and / or the second filling groove is an annular groove arranged around the circumference of the heat exchange tube.

5. The capillary tube heat exchanger according to claim 2, characterized in that: The end of the cylinder is inserted into the open end of the short tube section, and the outer wall of the cylinder is welded to the inner wall of the open end.

6. The capillary tube heat exchanger according to claim 5, characterized in that: The outer wall of the cylinder and / or the inner wall of the open end is provided with a third filling groove for filling solder.

7. The capillary tube heat exchanger according to claim 6, characterized in that: The number of the third filling grooves is two or more, and each of the third filling grooves is arranged at intervals along the axial direction of the cylinder.

8. The capillary tube heat exchanger according to claim 6, characterized in that: The third filling groove is an annular groove arranged circumferentially around the cylinder.

9. The capillary tube heat exchanger according to claim 6, characterized in that: The cross section of the third filling groove is rectangular or trapezoidal, and the groove width of the third filling groove with a trapezoidal cross section is greater than the groove bottom width.

10. The capillary tube heat exchanger according to any one of claims 1 to 9, characterized in that: There are multiple heat exchange tubes, which are arranged in parallel and at intervals. The outer tube plate is provided with multiple first tube holes, and the heat exchange tubes are passed through the first tube holes one by one. The hole wall of each first tube hole is provided with the first filling groove.

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