US20130126133A1

US20130126133A1 - Heat pipe structure

Info

Publication number: US20130126133A1
Application number: US13/300,648
Authority: US
Inventors: Chun-Ming Wu; Hsiu-Wei Yang
Original assignee: Asia Vital Components Co Ltd
Current assignee: Asia Vital Components Co Ltd
Priority date: 2011-11-20
Filing date: 2011-11-20
Publication date: 2013-05-23

Abstract

A heat pipe structure includes a tubular body. The tubular body has a chamber, a working fluid and a first capillary structure. The chamber is defined with at least one first section, a second section and a third section. The first, second and third sections are connected with each other. The first capillary structure is disposed in the second section. By means of the above arrangement, the pressure impedance of the chamber of the heat pipe is lowered to greatly increase vapor-liquid circulation efficiency of the working fluid in the chamber.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to a heat pipe structure in which the pressure impedance of the chamber of the heat pipe is lowered to greatly increase vapor-liquid circulation efficiency of the working fluid in the chamber.
2. Description of the Related Art
A heat pipe has heat conductivity several times to several tens times that of copper, aluminum or the like. Therefore, the heat pipe has excellent performance and serves as a cooling component applied to various electronic devices. As to the configuration, the conventional heat pipes can be classified into heat pipes in the form of circular tubes and heat pipes in the form of flat plates. For cooling an electronic component of an electronic device that generates heat in operation, such as a CPU, preferably a flat-plate heat pipe is used in view of easy installation and larger contact area. To catch up the trend toward miniaturization of cooling mechanism, the heat pipe has been more and more strictly required to be extremely thin in adaptation to the cooling mechanism.
The heat pipe is formed with an internal space as a flow path for the working fluid contained in the heat pipe. The working fluid is phase-changeable between liquid phase and vapor phase through evaporation and condensation and is transferable within the heat pipe for transferring heat.
The heat pipe is used as a heat conduction member. The heat pipe is fitted through a radiating fin assembly. The working fluid with low boiling point is filled in the heat pipe. The working fluid absorbs heat from a heat-generating electronic component (at the evaporation end) and evaporates into vapor. The vapor goes to the radiating fin assembly and transfers the heat to the radiating fin assembly (at the condensation end). A cooling fan then carries away the heat to dissipate the heat generated by the electronic component.
The heat pipe is manufactured in such a manner that metal powder is filled into a hollow tubular body and sintered to form a complete 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. On the demand of the electronic equipment for slim configuration, the heat pipe must be flattened and made with a thin and flat configuration.
In the conventional flat-plate heat pipe, the capillary structure is filled in the chamber for achieving vapor-liquid circulation of the working fluid. The capillary structure is distributed over the surface of the chamber of the flat-plate heat pipe. After the working fluid absorbs heat at the evaporation end and evaporates into vapor, the vapor spreads to the condensation end. At the condensation end, the vapor is gradually cooled and condensed into liquid. The liquid then flows back to the evaporation end through the capillary structure. Part of the working fluid has changed from vapor phase into liquid phase before fully reaching the condensation end. This part of working fluid will flow back to the evaporation end. Therefore, a part of the capillary structure at the condensation end has no effect and is wasted in material. Moreover, the chamber of the flattened heat pipe has a quite narrow space. As a result, the vapor is likely to be obstructed by the liquid from spreading to the condensation end. In this case, the vapor cannot be cooled to dissipate the heat.
Furthermore, the capillary structure disposed at the condensation end will cause pressure impedance to deteriorate the circulation of the liquid working fluid. As a result, part of the liquid working fluid will stagnate at the condensation end and cannot flow back to the evaporation end. This will lower the heat transfer efficiency of the heat pipe.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a heat pipe structure with higher heat transfer efficiency and heat dissipation effect.
To achieve the above and other objects, the heat pipe structure of the present invention includes a tubular body.
The tubular body has a chamber, a working fluid and a first capillary structure. The chamber is defined with at least one first section, a second section and a third section. The first, second and third sections are connected with each other. The first capillary structure is disposed in the second section.
By means of the above arrangement, the pressure impedance of the chamber of the heat pipe is lowered to greatly increase vapor-liquid circulation efficiency of the working fluid in the chamber.

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 perspective view of a first embodiment of the heat pipe structure of the present invention;

FIG. 2 is a sectional view of the first embodiment of the heat pipe structure of the present invention, taken along line A-A of FIG. 1;

FIG. 3 a is a sectional view of a second embodiment of the heat pipe structure of the present invention;

FIG. 3 b is a sectional view of the second embodiment of the heat pipe structure of the present invention;

FIG. 3 c is a sectional view of the second embodiment of the heat pipe structure of the present invention;

FIG. 4 is a sectional view of a third embodiment of the heat pipe structure of the present invention;

FIG. 5 is a sectional view of a fourth embodiment of the heat pipe structure of the present invention;

FIG. 6 is a sectional view of a fifth embodiment of the heat pipe structure of the present invention;

FIG. 7 is a sectional view of a sixth embodiment of the heat pipe structure of the present invention;

FIG. 8 is a sectional view of a seventh embodiment of the heat pipe structure of the present invention; and

FIG. 9 is a view showing the operation of the heat pipe structure of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2. FIG. 1 is a perspective view of a first embodiment of the heat pipe structure of the present invention. FIG. 2 is a sectional view of the first embodiment of the heat pipe structure of the present invention, taken along line A-A of FIG. 1. According to the first embodiment, the heat pipe structure of the present invention includes a tubular body 1.
The tubular body 1 has a chamber 11, a working fluid 12 and a first capillary structure 13. The chamber 11 is defined with at least one first section 111, a second section 112 and a third section 113. The first, second and third sections 111, 112, 113 are connected with each other. The first capillary structure 13 is disposed in the second section 112. The chamber 11 has a smooth inner wall.
The first capillary structure 13 is selected from a group consisting of sintered powder body, mesh body, fiber body and porous structure body. In this embodiment, the first capillary structure is, but not limited to, a sintered powder body for illustration purposes only.
Please refer to FIGS. 3 a, 3 b and 3 c. FIG. 3 a is a sectional view of a second embodiment of the heat pipe structure of the present invention. FIG. 3 b is a sectional view of the second embodiment of the heat pipe structure of the present invention. FIG. 3 c is a sectional view of the second embodiment of the heat pipe structure of the present invention. The second embodiment is substantially identical to the first embodiment in structure and thus will not be repeatedly described hereinafter. The second embodiment is different from the first embodiment in that a coating 15 is disposed in the third section 113 (as shown in FIG. 3 a). Alternatively, a coating 15 is disposed in the first section 111 (as shown in FIG. 3 b). Still alternatively, a coating 15 is disposed in each of the first and third sections 111, 113 (as shown in FIG. 3 c). The coating 15 is selected from a group consisting of hydrophilic microstructure body, hydrophobic microstructure body and capillary microstructure body.
Please refer to FIG. 4, which is a sectional view of a third embodiment of the heat pipe structure of the present invention. The third embodiment is substantially identical to the first embodiment in structure and thus will not be repeatedly described hereinafter. The third embodiment is different from the first embodiment in that the chamber 11 further has a first side 114 and a second side 115 opposite to the first side 114. The first capillary structure 13 is disposed on the first side 114 to define a first flow way 116.
Please refer to FIG. 5, which is a sectional view of a fourth embodiment of the heat pipe structure of the present invention. The fourth embodiment is substantially identical to the third embodiment in structure and thus will not be repeatedly described hereinafter. The fourth embodiment is different from the third embodiment in that the chamber 11 further has a third side 117 and a fourth side 118. The first capillary structure 13 is disposed between the third and fourth sides 117, 118 in connection with the third and fourth sides 117, 118 to define a first flow way 116 and a second flow way 119.
Please refer to FIG. 6, which is a sectional view of a fifth embodiment of the heat pipe structure of the present invention. The fifth embodiment is substantially identical to the fourth embodiment in structure and thus will not be repeatedly described hereinafter. The fifth embodiment is different from the fourth embodiment in that the chamber 11 further has a third side 117 and a fourth side 118. Multiple first capillary structures 13 are disposed between the third and fourth sides 117, 118 in connection with the third and fourth sides 117, 118 to define multiple first flow ways 116.
Please refer to FIG. 7, which is a sectional view of a sixth embodiment of the heat pipe structure of the present invention. The sixth embodiment is substantially identical to the first embodiment in structure and thus will not be repeatedly described hereinafter. The sixth embodiment is different from the first embodiment in that the surface of the chamber 11 is formed with a second capillary structure 14. The second capillary structure 14 is selected from a group consisting of channeled structure, hydrophilic/hydrophobic coating and capillary microstructure body. In this embodiment, the second capillary structure 14 is, but not limited to, a channeled structure for illustration purposes only. The wall face of the chamber 11 of the tubular body 1 is formed with channels and then the first capillary structure 13 is disposed in the second section 112.
Please refer to FIG. 8, which is a sectional view of a seventh embodiment of the heat pipe structure of the present invention. The seventh embodiment is substantially identical to the first embodiment in structure and thus will not be repeatedly described hereinafter. The seventh embodiment is different from the first embodiment in that the first capillary structure 13 extends from the second section 112 to the first section 111.
Please refer to FIG. 9, which is a view showing the operation of the heat pipe structure of the present invention. The first section 111 is defined as an evaporation section, while the third section 113 is defined as a condensation section. The condensation section is connected to at least one heat dissipation member 2. The evaporation section is connected to at least one heat source 3. The first capillary structure 13 is disposed in the second section 112. When the liquid working fluid 121 in the evaporation section absorbs heat of the heat source 3, the liquid working fluid 121 is converted into vapor working fluid 122. The vapor working fluid 122 spreads from the first section 111 (evaporation section) through the second section 112 to the third section 113 (condensation section). At this time, the vapor working fluid 122 is gradually condensed and converted into liquid working fluid 121. The first capillary structure 13 in the chamber 11 does not extend to the third section 113 (condensation section). That is, the third section 113 is free from the first capillary structure 13 so that the pressure impedance in the third section 113 (condensation section) is greatly lowered. In this case, the vapor working fluid 122 can more efficiently spread from the first section 111 (evaporation section) to the condensation section. Also, after condensed, the liquid working fluid 121 can quickly flow back to the first section 111 (evaporation section) through the first capillary structure 13. Accordingly, the liquid working fluid 121 can quickly flow back to the first section 111 (evaporation section) without stagnating in the third section 113 (condensation section). Therefore, the heat transfer effect is greatly enhanced.
Alternatively, reversely, the first section 111 can be defined as a condensation section, while the third section 113 can be defined as an evaporation section.
The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. It is understood that many changes and modifications of the above embodiments can be made without departing from the spirit of the present invention. The scope of the present invention is limited only by the appended claims.

Claims

What is claimed is:

1. A heat pipe structure comprising a tubular body, the tubular body having a chamber, a working fluid and a first capillary structure, the chamber being defined with at least one first section, a second section and a third section, the first, second and third sections being connected with each other, the first capillary structure being disposed in the second section.

2. The heat pipe structure as claimed in claim 1, wherein a surface of the chamber is further formed with a second capillary structure, the second capillary structure being selected from a group consisting of channeled structure, hydrophilic/hydrophobic coating and capillary microstructure body.

3. The heat pipe structure as claimed in claim 1, wherein the first capillary structure extends from the second section to the first section or the third section.

4. The heat pipe structure as claimed in claim 1, wherein the chamber has a smooth inner wall.

5. The heat pipe structure as claimed in claim 1, wherein the tubular body further includes a coating, the coating being disposed in the first section or the third section.

6. The heat pipe structure as claimed in claim 1, wherein the first capillary structure is selected from a group consisting of sintered powder body, mesh body, fiber body and porous structure body.

7. The heat pipe structure as claimed in claim 1, wherein the chamber further has a first side and a second side opposite to the first side, the first capillary structure being disposed on the first side to define a first flow way.

8. The heat pipe structure as claimed in claim 7, wherein the chamber further has a third side and a fourth side, the first capillary structure being disposed between the third and fourth sides in connection with the third and fourth sides to define a first flow way and a second flow way.

9. The heat pipe structure as claimed in claim 7, wherein the chamber further has a third side and a fourth side, multiple first capillary structures being disposed between the third and fourth sides in connection with the third and fourth sides to define multiple first flow ways.