US20160069616A1

US20160069616A1 - Heat pipe with complex capillary structure

Info

Publication number: US20160069616A1
Application number: US14/477,879
Authority: US
Inventors: Ching-Hang Shen
Original assignee: Asia Vital Components Co Ltd
Current assignee: Asia Vital Components Co Ltd
Priority date: 2014-09-05
Filing date: 2014-09-05
Publication date: 2016-03-10

Abstract

A heat pipe with complex capillary structures includes a tubular body in which a first capillary section and a second capillary section are disposed. The tubular body has a chamber and a bottom wall disposed under the chamber. The chamber is sequentially divided into an evaporation section, a transfer section and a condensation section. The first capillary section is a knitted mesh body attached to the bottom wall of the evaporation section of the tubular body. The second capillary section is a braid body extending in axial direction of the tubular body from the evaporation section through the transfer section to the condensation section. The second capillary section in the evaporation section is overlapped on the first capillary section. Accordingly, the heat pipe has an ultrathin structure, while still able to transfer heat at higher efficiency.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to a heat pipe with capillary structures, and more particularly to a heat pipe with complex capillary structures composed of different capillary structures.
2. Description of the Related Art
There is a trend to miniaturize various electronic and electrical apparatuses such as computers and intelligent electronic apparatuses. Therefore, these apparatuses have become thinner and thinner. Also, the performances of these apparatuses have become higher and higher. This means that the internal heat transfer components and heat dissipation components of these apparatuses must be miniaturized and thinned in adaptation to the miniaturized apparatuses to meet the requirements of consumers.
A heat pipe is a heat conduction component with excellent heat conductivity. The heat pipe has heat conductivity several times to several tens times that of copper, aluminum or the like. Therefore, the heat pipe serves as a cooling component applied to various electronic apparatuses.
There are many manufacturing methods for the conventional heat pipe structures. For example, in a conventional manufacturing method of the heat pipe, metal powder is filled into a hollow tubular body. Then the metal powder is sintered to form a capillary structure layer on the inner wall face of the tubular body. Then the tubular body is vacuumed and filled with the working fluid and then sealed. Alternatively, a metal-made mesh body is placed into a tubular body. The mesh capillary structure body will naturally stretch and outward extend to attach to the inner wall face of the tubular body to form a capillary structure layer. Then the tubular body is vacuumed and filled with the working fluid and then sealed. On the demand of the electronic equipment for slim configuration, the heat pipe must be made with the form of a flat plate.
The flat-plate heat pipe has a thinned structure. However, such flat-plate heat pipe has a shortcoming. That is, in the conventional flat-plate heat pipe, the metal powder is sintered to form a capillary structure layer on the inner wall face of the tubular body. The sintered body is fully coated on the inner wall face of the tubular body. When the tubular body is compressed and flattened, the capillary structures, (that is, the sintered metal powder or the mesh capillary structure body) on two sides of the compressed face in the flat-plate heat pipe are likely to damage due to compression. After damaged, the capillary structures will detach from the inner wall face of the flat-plate heat pipe. In this case, the heat transfer performance of the flat-plate heat pipe will be greatly deteriorated or even the flat-plate heat pipe will be disabled. Moreover, the thin flat-plate heat pipe is applied to an intelligent mobile phone, a tablet or an ultrathin notebook computer. However, the capillary structures such as the sintered metal powder or the mesh capillary structure body or the channeled structure is fully coated on the wall face of the flat-plate heat pipe. As a result, the thickness of the wall of the flat-plate heat pipe plus the thickness of the capillary structures fully coated on the wall face of the flat-plate heat pipe will lead to a considerable total thickness of the flat-plate heat pipe. Under such circumstance, the heat pipe can be hardly truly thinned and applied to the intelligent mobile phone, the tablet and the ultrathin notebook computer or other portable electronic apparatuses.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide a heat pipe with complex capillary structures. A capillary structure is disposed in the tubular body of the heat pipe in the longitudinal direction to provide axial transfer effect. Another large-area capillary structure is disposed on the bottom of one end of the tubular body to provide radial transfer effect.
It is a further object of the present invention to provide the above heat pipe in which a first capillary structure coated on an inner face of the evaporation section opposite to the outer heated face of the evaporation section. In addition, a second capillary structure extends from the evaporation section to the condensation section and is overlapped on and connected with the first capillary structure. Accordingly, the working fluid can axially flow from the condensation section along the second capillary structure back to the evaporation section. Then the working fluid can be radially spread along the first capillary structure to the entire inner surface of the evaporation section. Therefore, on the demand of the electronic apparatus for extremely thinned structure, the heat pipe of the present invention has an ultrathin structure, while still able to bear the high heat of the heat source to transfer the heat at higher efficiency.
To achieve the above and other objects, the heat pipe with complex capillary structures of the present invention includes a tubular body having a chamber and a bottom wall disposed under the chamber. The chamber is sequentially divided into an evaporation section, a transfer section and a condensation section. A first capillary section is attached to the bottom wall of the evaporation section of the tubular body. The first capillary section is a knitted mesh body formed of multiple fiber wires interlaced with each other. The heat pipe further includes a second capillary section, which is a braid body formed of multiple strands or bundles of fiber wires interlaced and tangled with each other. The second capillary section extends in axial direction of the tubular body from the evaporation section through the transfer section to the condensation section.
In the above heat pipe, the second capillary section in the evaporation section is overlapped on the first capillary section.
In the above heat pipe, the fiber wires of the first and second capillary sections are made of metal material or nonmetal material such as fiber glass or fiber carbon.
In the above heat pipe, the first and second capillary sections are made of the same material or different materials.
In the above heat pipe, the density of the first capillary section is smaller than or larger than the density of the second capillary section.
In the above heat pipe, the evaporation section has an inner surface on an inner side of the bottom wall and an outer surface on an outer side of the bottom wall, the outer surface being removably in contact with a heat generation component.
In the above heat pipe, the second capillary section is positioned at the center of the chamber.
In the above heat pipe, the second capillary section is positioned on one side of the chamber.
The above heat pipe further includes another second capillary section positioned on the other side of the chamber.
In the above heat pipe, the first capillary section is attached to and coated on the inner surface of the evaporation section.
In the above heat pipe, the first capillary section has a left side and a right side in adjacency to two sidewalls of the tubular body respectively. The left and right sides define a first width.
In the above heat pipe, the second capillary section has a left side and a right side. The left and right sides define a second width. The second width is smaller than the first width.
In the above heat pipe, at least one face of the tubular body in adjacency to the chamber is a free face.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein:

FIG. 1 is a top view of the heat pipe of the present invention;

FIG. 2 is a sectional view taken along line A-A′ of FIG. 1, showing the evaporation section of the heat pipe of the present invention;

FIG. 3 is a sectional view showing the first and second capillary structures of the present invention;

FIG. 4 is a sectional view taken along line B-B′ of FIG. 1, showing the condensation section of the heat pipe of the present invention;

FIG. 5 is a sectional view showing that the second capillary section of the present invention is positioned in the chamber of the tubular body in another position; and

FIG. 6 is a sectional view showing that the second capillary section of the present invention is positioned in the chamber of the tubular body in still another position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be described hereinafter with reference to the drawings, wherein the same components are denoted with the same reference numerals.
Please refer to FIGS. 1 to 3. FIG. 1 is a top view of the heat pipe of the present invention. FIG. 2 is a sectional view taken along line A-A′ of FIG. 1, showing the evaporation section of the heat pipe of the present invention. FIG. 3 is a sectional view showing the first and second capillary structures of the present invention. According to the drawings, the heat pipe 10 of the present invention includes a tubular body 11 having an evaporation section 101, a transfer section 102 and a condensation section 103. The evaporation section 101 and the condensation section 103 are positioned at two ends of the tubular body 11. The transfer section 102 is positioned in the middle of the tubular body 11 in communication with the evaporation section 101 and the condensation section 103. In this embodiment, the heat pipe 10 is, but not limited to, an elongated body. Alternatively, the heat pipe 10 can be an L-shaped or U-shaped body according to the use requirement.
Referring to FIGS. 2 and 3 as well as FIG. 1, the tubular body 11 has a top wall 111, a bottom wall 112 and two sidewalls 113, 114. The top wall 111 is oppositely spaced from the bottom wall 112. The two sidewalls 113, 114 are positioned between the top wall 111 and the bottom wall 112. The top wall 111, the bottom wall 112 and the two sidewalls 113, 114 together define a chamber 115. The chamber 115 is sequentially divided into the evaporation section 101, the transfer section 102 and the condensation section 103. A working fluid (not shown) is contained in the chamber 115. For example, the working fluid is, but not limited to, pure water, inorganic compound, alcohol group, ketone group, liquid metal, coolant, organic compound or a mixture thereof. The evaporation section 101 has an inner surface 1011 on an inner side of the bottom wall 112 in adjacency to the chamber 115 and an outer surface 1012 on an outer side of the bottom wall 112 opposite to the inner surface 1011. The outer surface 1012 is removably in contact with a heat generation component (such as a CPU). The heat generated by the heat generation component can be transferred through the bottom wall 112 into the chamber 115 of the evaporation section 101.
A first capillary section 12 and a second capillary section 13 are disposed in the chamber 115. When the working fluid in the chamber 115 of the evaporation section 101 is heated to change into vapor, the vapor passes through the transfer section 102 to the condensation section 103 to be cooled into liquid. Then, by means of the capillary attraction of the first and second capillary sections 12, 13, the liquid flows back to the evaporation section 101. Accordingly, the liquid-vapor phase change of the working fluid is circulated between the evaporation section 101 and the condensation section 103 to achieve convection effect and the object of heat transfer.
It should be noted that in order to extremely thin the heat pipe, at least one face of the tubular body 11 in adjacency to the chamber is a free face. The first capillary section 12 is only attached to the bottom wall 112 of the evaporation section 101 of the tubular body 11. That is, the first capillary section 12 is only attached to and coated on the inner surface 1011 of the evaporation section 101. Therefore, the inner surfaces of the top wall 111 and the two sidewalls 113, 114 of the evaporation section 101 in adjacency to the chamber 115 are free faces. In addition, the inner surfaces of the top wall 111 and the two sidewalls 113, 114 of the transfer section 102 and the condensation section 103 in adjacency to the chamber 115 are also free faces without any characteristic or structure such as channeled structure or sintered texture. The first capillary section 12 has a right side 122 and a left side 121 near the two sidewalls 113, 114 of the tubular body 11 respectively. The left and right sides 121, 122 define a first width b1. The first capillary section 12 is a knitted mesh body formed of multiple fiber wires interlaced with each other. In this embodiment, the first capillary section 12 is a mesh body formed of longitudinal and latitudinal fiber wires interlaced with each other. The first capillary section 12 has excellent radial capillary attraction.
The second capillary section 13 is disposed in an axial (longitudinal) direction of the tubular body 11. That is, the second capillary section 13 extends from the evaporation section 101 through the transfer section 102 to the condensation section 103. In the evaporation section 101, the second capillary section 13 is overlapped on the first capillary section 12. The overlapping sections of the first and second capillary sections 12, 13 are tightly mated with each other to ensure that the capillary transfer path is continued without interruption. The second capillary section 13 has a left side 131 and a right side 132. The left and right sides 131, 132 define a second width b2 smaller than the first width b1 of the first capillary section 12. In this embodiment, the second capillary section 13 is positioned at the center of the chamber 115. Therefore, the spaces of the chamber 115 are positioned between upper side of the second capillary section 13 and the top wall 111 and between the left and right sides 131, 132 of the second capillary section 13 and the two sidewalls 113, 114 of the tubular body. These spaces form the flow passage of the working fluid. The second capillary section 13 is a braid body formed of multiple strands or bundles of fiber wires interlaced and tangled with each other. Accordingly, the second capillary section 13 is a solid capillary structure with excellent axial capillary attraction.
Especially, the fiber wires of the first and second capillary sections 12, 13 are made of metal material or nonmetal material such as fiber glass or fiber carbon. In a preferred embodiment, the first and second capillary sections 12, 13 are made of the same material. In another preferred embodiment, the first and second capillary sections 12, 13 are made of different materials. In addition, the diameters of the fiber wires of the first and second capillary sections 12, 13 can be equal or unequal to each other.
It should be noted that the density of the first and second capillary sections 12, 13 can be adjusted as necessary. The density of the first capillary section 12 can be larger than, smaller than or equal to the density of the second capillary section 13. In the case that the density of the first capillary section 12 is larger than or smaller than the density of the second capillary section 13, the capillary transfer forces of the first and second capillary sections 12, 13 for the working fluid in the chamber are different. In the case that the density of the first capillary section 12 is equal to the density of the second capillary section 13, the capillary transfer forces of the first and second capillary sections 12, 13 for the working fluid are equal to each other.
FIG. 4 is a sectional view taken along line B-B′ of FIG. 1, showing the condensation section of the heat pipe of the present invention. Also referring to FIG. 1, the second capillary structure 13 is disposed on the inner face of the bottom wall 112 in adjacency to the chamber 115 and extends through the transfer section 102 of the tubular body 11 to the condensation section 103.
When the working fluid in the evaporation section 101 is heated and evaporated into vapor, the vapor with the heat passes through the transfer section 102 to the condensation section 103 to be cooled into liquid. Then, via the axially arranged second capillary section 13, the liquid quickly flows back to the evaporation section 101. Then, via the first capillary section 12, the working fluid is radially spread to the entire inner surface 1011 of the evaporation section 101.
Please now refer to FIGS. 5 and 6. FIG. 5 is a sectional view showing that the second capillary section of the present invention is positioned in the chamber of the tubular body in another position. FIG. 6 is a sectional view showing that the second capillary section of the present invention is positioned in the chamber of the tubular body in still another position. As shown in FIG. 5, in another embodiment, the second capillary section 13 can be alternatively disposed on one side of the chamber 115, such as the right side of the chamber 115 in adjacency to the sidewall 113 of the tubular body 11. Alternatively, as shown in FIG. 6, two second capillary sections 13 a, 13 b are disposed on two sides of the chamber 115, such as the left and right sides of the chamber 115 in adjacency to the sidewalls 113, 114 of the tubular body 11 respectively.
In conclusion, on the demand of the electronic apparatus for extremely thinned structure, the heat pipe of the present invention has an ultrathin structure, while still able to bear the high heat of the heat source to transfer the heat at higher efficiency. Therefore, the heat pipe of the present invention is applicable to various electronic apparatuses and handheld apparatuses such as mobile phones, tablets, PDA, digital displays and ultrathin notebook computers to effectively solve the heat dissipation problem of these apparatuses.
The present invention has been described with the above embodiments thereof and it is understood that many changes and modifications in the above embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.

Claims

What is claimed is:

1. A heat pipe with complex capillary structures, comprising:

a tubular body having a chamber and a bottom wall disposed under the chamber, the chamber being sequentially divided into an evaporation section, a transfer section and a condensation section, a first capillary section being attached to the bottom wall of the evaporation section of the tubular body, the first capillary section being a knitted mesh body formed of multiple fiber wires interlaced with each other; and

a second capillary section, which is a braid body formed of multiple strands or bundles of fiber wires interlaced and tangled with each other, the second capillary section extending in axial direction of the tubular body from the evaporation section through the transfer section to the condensation section.

2. The heat pipe as claimed in claim 1, wherein the second capillary section in the evaporation section is overlapped on the first capillary section.

3. The heat pipe as claimed in claim 2, wherein the fiber wires of the first and second capillary sections are made of metal material or nonmetal material such as fiber glass or fiber carbon.

4. The heat pipe as claimed in claim 3, wherein the first and second capillary sections are made of the same material or different materials.

5. The heat pipe as claimed in claim 3, wherein the density of the first capillary section is smaller than or larger than the density of the second capillary section.

6. The heat pipe as claimed in claim 1, wherein the evaporation section has an inner surface on an inner side of the bottom wall and an outer surface on an outer side of the bottom wall, the outer surface being removably in contact with a heat generation component.

7. The heat pipe as claimed in claim 6, wherein the second capillary section is positioned at the center of the chamber.

8. The heat pipe as claimed in claim 6, wherein the second capillary section is positioned on one side of the chamber.

9. The heat pipe as claimed in claim 8, further comprising another second capillary section positioned on the other side of the chamber.

10. The heat pipe as claimed in claim 6, wherein the first capillary section is attached to and coated on the inner surface of the evaporation section.

11. The heat pipe as claimed in claim 10, wherein the tubular body has two sidewalls, the first capillary section having a left side and a right side in adjacency to the two sidewalls of the tubular body respectively, the left and right sides defining a first width.

12. The heat pipe as claimed in claim 11, wherein the second capillary section has a left side and a right side, the left and right sides defining a second width, the second width being smaller than the first width.

13. The heat pipe as claimed in claim 2, wherein at least one face of the tubular body in adjacency to the chamber is a free face.