Heat pipe and method of making same

Abstract

The present application discloses a heat pipe and a manufacturing method thereof. The heat pipe comprises a capillary structure. The capillary structure has a condensing portion, an evaporating portion and a connecting portion connecting the condensing portion and the evaporating portion. The capillary structure is formed in a metal woven manner, and the cross section of the evaporating portion is larger than that of the condensing portion. The heat pipe of the present application is easy to manufacture different sizes, weaves and cross sections according to requirements in a woven manner, and can properly control the density, shape, porosity and permeability of the capillary structure, thereby improving the heat conduction efficiency.

Description

Technical Field

[0001] This invention relates to a heat pipe and a method for manufacturing the same, and more particularly to a heat pipe comprising a capillary structure formed by metal braiding. Background Technology

[0002] A heat pipe is a component with high thermal conductivity. Existing heat pipes mainly consist of a closed metal tube and a sintered structure, with the closed metal tube covering the sintered structure.

[0003] Due to their simple structure and advantages such as high thermal conductivity and low thermal resistance, heat pipes have been widely used in heat dissipation for electronic devices and other various heat dissipation needs. However, electronic devices are continuously evolving towards portability, thinness, and high added functionality. The internal structure of electronic devices is becoming increasingly compact, and their heat generation is also increasing. Existing heat pipes can no longer meet the requirements for thinness, high heat output, and high heat flux, so it is necessary to further improve the performance of heat pipes. Summary of the Invention

[0004] This invention provides a heat pipe comprising a capillary structure formed by a metal braiding method. The capillary structure has an evaporation section, a condensation section, and a connecting section for connecting the condensation section and the evaporation section, wherein the evaporation section has a first cross-section perpendicular to a central axis of the heat pipe, and the condensation section has a second cross-section perpendicular to the central axis, the first cross-section being larger than the second cross-section.

[0005] In one embodiment, the aforementioned heat pipe further has a shell covering the capillary structure.

[0006] In one embodiment, a gas channel is formed between the aforementioned evaporation section, connecting section, and condensation section and the shell.

[0007] In one embodiment, the aforementioned heat pipe further includes a working fluid that flows through the evaporation section, the connection section, or the condensation section.

[0008] In one embodiment, the aforementioned working fluid evaporates from a liquid state to a gaseous state in the evaporation section.

[0009] In one embodiment, the aforementioned working fluid condenses from a gaseous state to a liquid state in the condensation section.

[0010] In one embodiment, the aforementioned capillary structure forms a columnar cavity.

[0011] In one embodiment, the aforementioned heat pipe further includes a support rod disposed within the cylindrical cavity.

[0012] In one embodiment, the aforementioned columnar cavity extends through the capillary structure.

[0013] In one embodiment, the aforementioned capillary structure has a plain weave, satin weave, twill weave, plain Dutch weave, or twilled Dutchweave weave pattern.

[0014] In one embodiment, in the capillary structure of the aforementioned condensation section, a first included angle and a second included angle are formed between adjacent and interlaced strip braided yarns, wherein the first included angle is less than 90 degrees and the second included angle is greater than 90 degrees.

[0015] In one embodiment, the capillary structure of the aforementioned connecting portion forms a third included angle and a fourth included angle between adjacent and interlaced strip-shaped braided yarns, wherein the third included angle is less than 90 degrees and the fourth included angle is greater than 90 degrees.

[0016] The present invention provides a method for manufacturing a heat pipe, comprising: fabricating a capillary structure, wherein the capillary structure is formed by metal braiding; placing the capillary structure into and fixing it in a housing; and sealing the housing.

[0017] In one embodiment, the aforementioned capillary structure is fabricated using a weaving machine.

[0018] In one embodiment, before the step of fixing the capillary structure in the housing, the aforementioned method further includes placing a support rod in the capillary structure and making the support rod protrude from one end of the capillary structure.

[0019] The present invention has at least the following beneficial effects:

[0020] The heat pipe of this invention includes a capillary structure formed by a metal braiding method. The braiding method allows for the fabrication of cross-sections of different sizes, weaves, and patterns to meet specific needs, and enables appropriate control over the density, shape, porosity, and permeability of the capillary structure, thereby improving heat transfer efficiency. Furthermore, the braiding method is suitable for mass production of capillary structures, improving the quality and yield of heat pipe manufacturing while simultaneously reducing costs. Additionally, the braided capillary structure can be moderately bent as needed to increase the structural strength at the bends, and the braided structure itself is tough and not easily broken due to bending. Attached Figure Description

[0021] Figure 1A This is a three-dimensional schematic diagram of a heat pipe according to an embodiment of the present invention.

[0022] Figure 1B for Figure 1A A top view of the heat pipes in the image.

[0023] Figure 1C for Figure 1A A cross-sectional view along the Z1-Z1 end face.

[0024] Figure 1D for Figure 1C A sectional view along the X11-X11 end face.

[0025] Figure 1E for Figure 1C A sectional view along the X12-X12 end face.

[0026] Figure 2 This is a longitudinal sectional view of a heat pipe according to another embodiment of the present invention.

[0027] Figure 3A This is a longitudinal sectional view of a heat pipe according to another embodiment of the present invention.

[0028] Figure 3B They are respectively Figure 3A A sectional view along the X31-X31 end face.

[0029] Figure 3C They are respectively Figure 3A A sectional view along the X32-X32 end face.

[0030] Figure 3D They are respectively Figure 3A A sectional view along the X33-X33 end face.

[0031] Figure 3E for Figure 3A Enlarged view of section M1.

[0032] Figure 3F for Figure 3A Enlarged view of section M2.

[0033] Figure 4A This is a schematic diagram of a method for manufacturing a heat pipe according to an embodiment of the present invention.

[0034] Figure 4B This is a schematic diagram of a support rod located inside a cylindrical cavity according to an embodiment of the present invention.

[0035] Figure 4C This is a schematic diagram of a capillary structure placed inside a housing according to an embodiment of the present invention.

[0036] Figure 4D This is a schematic diagram of a finished heat pipe according to an embodiment of the present invention.

[0037] Figure 5A A cross-sectional view of a heat pipe according to another embodiment of the present invention.

[0038] Figure 5B This is a cross-sectional view of a heat pipe according to another embodiment of the present invention.

[0039] The attached figures are labeled as follows:

[0040] Heat pipes 100, 100a, 100b, 100c, 100d, 100e

[0041] C Central axis

[0042] 1. Shell

[0043] W width

[0044] H thickness

[0045] 11 Gas Channel

[0046] 2. Capillary Structure

[0047] 2A First capillary structure

[0048] 2B Second capillary structure

[0049] S1 Evaporation Section

[0050] S2 Connecting Part

[0051] S3 Condensation Section

[0052] B1 cylindrical cavity

[0053] a1 First included angle

[0054] a2 Second included angle

[0055] a3 Third angle

[0056] a4 Fourth angle

[0057] 3 Support rods Detailed Implementation

[0058] Please refer to the following first: Figures 1A-1E ,in Figure 1A This is a three-dimensional schematic diagram of a heat pipe 100a according to an embodiment of the present invention. Figure 1B for Figure 1A Top view of heat pipe 100a in the middle. Figure 1C for Figure 1A A sectional view along the Z1-Z1 end face. Figure 1D , Figure 1E They are respectively Figure 1C A sectional view along the X11-X11 and X12-X12 end faces. (See attached image.) Figures 1A-1CAs shown, the aforementioned heat pipe 100a mainly includes a shell 1 and a capillary structure 2, wherein the shell 1 covers or houses the capillary structure 2, and the capillary structure 2 has two evaporation sections S1, two connecting sections S2, and a condensation section S3. The two evaporation sections S1 are located at opposite ends of the capillary structure 2, and a working fluid (not shown) flows through the evaporation section S1, the connecting section S2, or the condensation section S3, and the working fluid evaporates from a liquid state to a gaseous state in the evaporation section S1. The condensation section S3 is located approximately at the center of the capillary structure 2, and the aforementioned working fluid condenses from a gaseous state to a liquid state in the condensation section S3. The two ends of the connecting section S2 are respectively connected to the corresponding evaporation section S1 and the condensation section S3. In addition, by Figures 1C-1E As can be seen, a gas channel 11 is formed between the two sides of the evaporation section S1, the connecting section S2 and the condensation section S3 and the inner wall of the shell 1, respectively. The aforementioned gas channel 11 can facilitate the flow of gas in the heat pipe 1.

[0059] like Figure 1C As shown, the evaporator S1 is arranged in a meandering manner at both ends of the heat pipe 100a, while the connecting part S2 and the condensing part S3 are approximately parallel to a central axis C of the heat pipe 100a. Furthermore, the cross-section of the evaporator S1 in the direction perpendicular to the central axis C is larger than the cross-section of the connecting part S2 or the condensing part S3 in the direction perpendicular to the central axis C (e.g., ...). Figure 1D , Figure 1E As shown, the cross-sections of the connecting part S2 and the condensing part S3 in the direction perpendicular to the central axis C are approximately equal. The lengths of the evaporating part S1, the connecting part S2, and the condensing part S3 in the direction parallel to the central axis C can be determined according to actual needs (such as heat generation, heat source location, etc.).

[0060] In this embodiment, the housing 1 is a long, cylindrical, hollow, sealed structure, and the cross-sectional shape of the housing 1 is rectangular, wherein the width W of the housing 1 in the y-axis direction is greater than the thickness H of the housing 1 in the z-axis direction (e.g., ...). Figure 1D , Figure 1E As shown), the width W and thickness H of the housing 1 are consistent along the central axis C. In one embodiment, the cross-sectional shape of the housing 1 may also be a rectangle, ellipse, semicircle or circle with chamfered corners, and the extension path of the housing 1 may include straight sections and / or curved sections. The dimensional ratio of the width W and thickness H may also be adjusted according to design requirements.

[0061] It should be understood that the shell 1 may be made of a metal with good thermal conductivity (such as copper), and the shell 1 is filled with a working fluid, such as a low-boiling-point liquid (such as water or alcohol). The capillary structure 2 is made of metal and is integrally molded and woven. For example, it can be made of three-dimensional woven material using a weaving machine or 3D printing technology. The density, thickness, width, length, porosity, or permeability of the capillary structure 2 can be made using different weaving methods according to application requirements. The weaving pattern of the capillary structure 2 can be plain weave, satin weave, twill weave, plain Dutch weave, or twill Dutch weave, etc.

[0062] When a user wants to dissipate heat from a heat-generating element (e.g., a central processing unit) through heat pipe 100a, the section or part of the housing 1 corresponding to the position of the evaporation section S1 can be brought into contact with the heat-generating element, and the section or part of the housing 1 corresponding to the position of the condensation section S3 can be brought into contact with a heat dissipation element (e.g., a fan or a water pump) to dissipate the heat absorbed by the evaporation section S1. The connection section S2 connects the evaporation section S1 and the condensation section S3.

[0063] The evaporator S1 roughly fills the internal space of the casing 1 (e.g. Figure 1E As shown), this allows the working fluid (liquid phase) to be adequately supplied to the evaporation section S1. After absorbing heat from the heating element in the evaporation section S1, the working fluid (liquid phase) rises to its boiling point and transforms into a gaseous phase through a phase change. It can then be transported to the condensation section S3 along the gas passage 11 between the connecting section S2 and the housing 1. The cross-sectional areas of both the connecting section S2 and the condensation section S3 are smaller than the cross-sectional area of ​​the evaporation section S1 (e.g., ...). Figure 1D , Figure 1E (as shown); In other words, the cross-sectional area of ​​the gas passages 11 on both sides of the connecting part S2 and the condensing part S3 in the direction perpendicular to the central axis C is larger than the cross-sectional area of ​​the connecting part S2 and the condensing part S3 themselves, which is conducive to the flow of gas.

[0064] Heat can be exchanged between the condenser S3 and the heat dissipation element to expel heat to the external environment. At this time, the working fluid (gas phase) cools down in the condenser S3 to reach the condensation point and transforms into a liquid phase. Then, the working fluid (liquid phase) located in the condenser S3 can flow along the capillary structure 2 to the evaporation S1 by utilizing capillary phenomenon. The working fluid (liquid phase) can absorb heat again in the evaporation S1 and repeat the above steps to continuously transfer the heat of the heating element to the external environment. Repeating the above steps achieves the purpose of continuous heat dissipation.

[0065] Please refer to the following: Figure 2 , Figure 2 This is a longitudinal sectional view of a heat pipe 100b according to another embodiment of the present invention. The aforementioned heat pipe 100b mainly includes a shell 1 and a capillary structure 2, wherein the shell 1 covers or accommodates the capillary structure 2, and the capillary structure 2 has an evaporation section S1, two connecting sections S2, and two condensation sections S3. Figure 2 As shown, this embodiment is similar to Figure 1A The main difference in the embodiments is that in this embodiment, the evaporation section S1 of the capillary structure 2 is approximately located in the center of the capillary structure 2, the two condensation sections S3 are located at opposite ends of the capillary structure 2, and the two ends of the connecting section S2 are respectively connected to the corresponding evaporation section S1 and condensation section S3. Furthermore, by Figure 2 As can be seen, the capillary structure 2 is arranged in a meandering manner at the center of the heat pipe 100b and roughly fills the internal space of the shell 1, while the connecting part S2 and the condensing part S3 are roughly parallel to the central axis C. A gas channel 11 is formed on both sides of the connecting part S2 and the condensing part S3 between them and the inner wall of the shell 1.

[0066] Please refer to the following as well. Figures 3A-3D ,in Figure 3A This is a longitudinal sectional view of a heat pipe 100c according to another embodiment of the present invention. Figures 3B-3D They are respectively Figure 3A A sectional view along the X31-X31, X32-X32, and X33-X33 end faces. (See attached image.) Figures 3A-3D As shown, the aforementioned heat pipe 100c mainly includes a shell 1, a capillary structure 2, and a support rod 3. The shell 1 covers or accommodates the capillary structure 2, wherein the capillary structure 2 has an evaporation section S1, a connecting section S2, a condensation section S3, and a columnar cavity B1 (e.g., Figures 3B-3D As shown, a gas channel 11 is formed between the two sides of the connecting part S2 and the condensing part S3 and the inner wall of the shell 1.

[0067] Depend on Figure 3A As can be seen, the evaporation section S1 is located at one end of the capillary structure 2, while the condensation section S3 is located at the opposite end of the capillary structure 2. The connecting section S2 connects the evaporation section S1 and the condensation section S3 at its two ends, respectively. Figures 3B-3D As shown, the columnar cavity B1 is roughly formed in the center of the capillary structure 2, and the support rod 3 is disposed inside the columnar cavity B1. The aforementioned evaporation section S1 roughly fills the internal space of the columnar closed shell 1 (e.g., Figure 3B As shown), the cross-section of the evaporation section S1 in the direction perpendicular to the central axis C is larger than the cross-sections of the connecting section S2 and the condensation section S3 in the direction perpendicular to the central axis C, and the cross-section of the condensation section S3 is larger than the cross-section of the connecting section S2 (as shown). Figures 3B-3D (As shown).

[0068] In this embodiment, the shell 1 is a long, cylindrical, hollow, sealed structure, and the cross-sectional shape of the shell 1 is rectangular (e.g., ...). Figures 3B-3D As shown in the diagram, the cylindrical cavity B1 and the support rod 3 have circular cross-sectional shapes in the direction perpendicular to the central axis C. The cylindrical cavity B1 penetrates the capillary structure 2, and the support rod 3 is essentially a rod-shaped auxiliary forming fixture, which can be made of metal, non-metal, or rigid plastic. In another embodiment, the shell 1, the capillary structure 2, and the support rod 3 can be made of a metallic thermally conductive material, which can improve the efficiency of the heat pipe 100c. In another embodiment, the support rod 3 can be a sintered powder structure of metal, non-metal, or alloy material, or a metal woven mesh structure. In another embodiment, the cross-sectional shapes of the shell 1, the cylindrical cavity B1, and the support rod 3 are rectangular, rectangular with chamfered corners, triangular, polygonal, elliptical, or circular.

[0069] Please refer to the following as well. Figure 3E , Figure 3F ,in Figure 3E for Figure 3A Enlarged view of section M1 in the middle. Figure 3F for Figure 3A An enlarged view of section M2. (See image below.) Figure 3E , Figure 3F As shown, the capillary structures in the evaporation section S1 have different densities, for example, the outer side is less dense and the inner side is denser, causing the working fluid to produce capillary action on the capillary structure 2, and the working fluid (liquid phase) will flow along the capillary structure 2 in the evaporation section S1. Figure 3E The flow direction indicated by the dashed arrow allows the working fluid (liquid phase) to be effectively concentrated on the heat pipe 100 near the heating element. Furthermore, in the capillary structure of the condenser section S3, a first angle a1 and a second angle a2 are formed between adjacent and interlaced braided strips (as shown in the image). Figure 3F As shown), the first included angle a1 is an angle less than 90 degrees (i.e., an acute angle), and the second included angle a2 is an angle greater than 90 degrees (i.e., an obtuse angle). This allows the working fluid (liquid phase) to flow in a specific direction, for example, causing the working fluid (liquid phase) to flow along the condenser section S3. Figure 3F The flow direction is indicated by the dashed arrow. Similarly, the capillary structure of the connecting part S2 can also be appropriately adjusted to guide the working fluid (liquid phase) to flow in a specific direction. For example, the third included angle (a3) ​​formed between adjacent and intersecting strip braided yarns is less than 90 degrees (i.e., an acute angle), and the fourth included angle a4 is greater than 90 degrees (i.e., an obtuse angle).

[0070] Please see Figure 4A , Figure 4AThis is a schematic diagram of a method for manufacturing a heat pipe 100 according to an embodiment of the present invention. The method includes: first, fabricating a capillary structure 2 (step S10); then, placing and fixing the capillary structure 2 into a housing 1 (step S20); and finally, sealing the housing 1 (step S30), thus isolating the interior of the housing 1, the capillary structure 2 it encloses or contains, and the working fluid from the external environment to prevent leakage. In step S20, a mandrel (not shown) can be inserted into the space outside the capillary structure 2 when it is placed into the housing 1, to make the braided structure of the capillary structure 2 more firmly connected to the housing 2. The mandrel is removed before step S30 to form the subsequent gas channel 11.

[0071] like Figure 4A As shown, in step S10, a capillary structure 2 with a woven pattern is first fabricated. The capillary structure 2 is formed by metal weaving, for example, by using a weaving machine or 3D printing technology to create a three-dimensional woven material. The weaving pattern of the woven material can be, for example, plain weave, satin weave, twill weave, Dutch plain weave, or Dutch twill weave. In addition, if the final heat pipe structure has a bending treatment, the structural strength of the capillary structure 2 at the bending point will be greater than that of other parts. This point can be made by double-thread winding weaving or by using multiple layers or thicker weaving patterns (such as twill weave) to avoid damage or breakage of the capillary structure 2 when the heat pipe is bent, thereby affecting the heat transfer efficiency.

[0072] Please refer to the following as well. Figures 4B-4D The manufacturing method of the aforementioned heat pipe 100 is described in detail below: First, the support rod 3 is inserted into the cylindrical cavity B1, or the capillary structure 2 is rolled onto the support rod 3. At this time, the support rod 3 is located in the cylindrical cavity B1 formed in the capillary structure 2 (e.g., Figure 4B As shown), and protruding from one end of the capillary structure 2, to facilitate the assembly personnel to hold and move the capillary structure 2 (step S10); then, the capillary structure 2 covered with the support rod 3 is placed into the not yet completely sealed shell 1 from one inlet end of the shell 1 (as shown). Figure 4C As shown), and fix the capillary structure 2 in a preset position inside the housing 1 (step S20); finally, seal the inlet end of the housing 1 (step S30) to complete the fabrication of the heat pipe 100 (as shown). Figure 4D (As shown). In another embodiment, after the capillary structure 2 is placed into the housing 1, the manufacturer can also remove the support rod 3 from the columnar cavity B1. That is, the present invention does not limit the heat pipe 100 to having a support rod 3.

[0073] Please refer to the following: Figure 5A This figure is a transverse sectional view of a heat pipe 100d according to another embodiment of the present invention. Figure 5AAs shown, the heat pipe 100d mainly includes a shell 1 and a capillary structure 2 formed by metal braiding, wherein the shell 1 covers or accommodates the capillary structure 2. Figure 1D , Figure 1E The embodiment shown differs in that the capillary structure 2 has a first capillary structure portion 2A and a second capillary structure portion 2B. The first capillary structure portion 2A is hollow and has a rectangular cross-section, with its outer wall surface adhering to the inner wall surface of the housing 1. The second capillary structure portion 2B has an elliptical cross-section and at least a portion on each of its opposite sides is connected to the inner wall surface of the first capillary structure portion 2A. Because the first capillary structure 2A is connected to the housing 1 and partially connected to the second capillary structure 2B, heat conduction efficiency is further enhanced. It should be understood that the present invention does not limit the second capillary structure portion 2B to an elliptical cross-section; its cross-section can also be rectangular, a rectangle with chamfered corners, a triangle, a polygon, or a circle.

[0074] Please see again Figure 5B This figure is a transverse sectional view of a heat pipe 100e according to another embodiment of the present invention. Figure 5B As shown, the heat pipe 100e mainly includes a shell 1 and a capillary structure 2 formed by metal braiding. The shell 1 covers or accommodates the capillary structure 2, and the capillary structure 2 has a U-shaped first capillary section 2A and a second capillary section 2B. The outer wall of the first capillary section 2A is attached to the corresponding inner wall of the shell 1. The second capillary section 2B has an elliptical cross-section and at least one part is connected to the corresponding inner wall of the first capillary section 2A, and at least another part is connected to the corresponding inner wall of the shell 1. In this embodiment, considering that the heating element and / or heat dissipation element are only attached to one side of the heat pipe 100e (e.g., Figure 5B (Illustrated lower edge of the housing), this configuration is relative to the aforementioned Figure 5A The illustrated embodiment can achieve cost savings.

[0075] In summary, this invention provides a heat pipe comprising a capillary structure formed by a metal braiding method. The braiding method facilitates the fabrication of cross-sections of varying sizes, weaves, and patterns to meet specific needs, and allows for appropriate control of the density, shape, porosity, and permeability of the capillary structure, thereby improving heat transfer efficiency. Furthermore, the braiding method is suitable for mass production of capillary structures, improving the quality and yield of heat pipe manufacturing while simultaneously reducing costs. Additionally, the braided capillary structure can be moderately bent as needed to increase the structural strength at the bends, and the braided structure itself possesses toughness, making it less prone to breakage due to bending.

[0076] While the present invention has been disclosed above with various embodiments, these are merely illustrative examples and not intended to limit the scope of the invention. Any person skilled in the art can make modifications and refinements without departing from the spirit and scope of the invention. Therefore, the above embodiments are not intended to limit the scope of the invention, and the scope of protection of the invention shall be determined by the appended claims.

Claims

1. A heat pipe, comprising: A capillary structure, integrally formed by metal weaving and having a columnar cavity, possesses: An evaporation section has a first cross-section perpendicular to a central axis of the heat pipe, wherein the capillary structure of the evaporation section is sparser on the outer side and denser on the inner side; A condensation section having a second cross-section perpendicular to the central axis, wherein the first cross-section is larger than the second cross-section; and A connecting part connects the condensing part and the evaporating part, wherein in the capillary structure of the condensing part, a first included angle and a second included angle are formed between adjacent and interlaced strip braided yarns, wherein the first included angle is less than 90 degrees and the second included angle is greater than 90 degrees; A shell encapsulates the capillary structure; A support rod is disposed within the columnar cavity and has a mesh structure. The support rod is a sintered structure of metal or non-metal powder. The capillary structures are arranged in a meandering manner and fill the interior space of the housing.

2. The heat pipe of claim 1, wherein a gas passage is formed between the evaporation section, the connecting section and the condensation section and the housing.

3. The heat pipe as claimed in claim 2 further comprises a working fluid flowing through the evaporation section, the connection section, or the condensation section.

4. The heat pipe of claim 3, wherein the working fluid evaporates from a liquid state to a gaseous state in the evaporation section.

5. The heat pipe of claim 3, wherein the working fluid condenses from a gaseous state to a liquid state in the condensation section.

6. The heat pipe of claim 1, wherein the columnar cavity extends through the capillary structure.

7. The heat pipe of claim 1, wherein the capillary structure has a plain, satin, or twill weave pattern.

8. The heat pipe of claim 7, wherein the capillary structure of the connection portion forms a third angle and a fourth angle between adjacent and interlaced braided strips, wherein the third angle is less than 90 degrees and the fourth angle is greater than 90 degrees.

9. A method of manufacturing a heat pipe, characterized by: The heat pipe is the heat pipe according to any one of claims 1 to 8, and the manufacturing method includes the following steps: Fabricate a capillary structure, wherein the capillary structure is formed by metal weaving. The capillary structure is fixed in a housing; and Seal the casing; Prior to the step of fixing the capillary structure into the housing, the method further includes: A support rod is placed in the capillary structure and protrudes from one end of the capillary structure. The support rod is a sintered structure of metal or non-metal powder.

10. The method of claim 9, wherein the capillary structure is made by a weaving machine.

Images