US20120325437A1

US20120325437A1 - Flat heat pipe with capilllary structure

Info

Publication number: US20120325437A1
Application number: US13/169,149
Authority: US
Inventors: George Anthony Meyer, IV; Chien-Hung Sun; Chieh-Ping Chen; Te-Hsuan Chin
Original assignee: Celsia Technologies Taiwan Inc
Current assignee: Celsia Technologies Taiwan Inc
Priority date: 2011-06-27
Filing date: 2011-06-27
Publication date: 2012-12-27

Abstract

A flat heat pipe with a capillary structure includes a pipe body and a capillary tissue. The pipe body is substantially hollow and flat and includes a bottom wall and a top wall opposite to the bottom wall, and both walls are formed on the pipe body, and an appropriate quantity of working fluid is sealed inside the pipe body. The capillary tissue is covered onto an internal side of the bottom wall, and the capillary tissue includes a plurality of protrusions formed inside the pipe body and extended along the lengthwise direction of the pipe body, and a gap is reserved between the protrusions and the internal side of the top wall to form an air passage. The protrusions formed by the capillary tissue can provide sufficient capillary forces and also produce the gap to form the air passage.

Description

FIELD OF THE INVENTION

The present invention relates to a heat pipe, in particular to an improved heat pipe with a capillary structure.

BACKGROUND OF THE INVENTION

As the computing speed of central processing units (CPUs) for computers becomes increasingly faster, the heat generated by the CPU becomes increasingly higher, and conventional heat dissipating devices comprised of an extruded aluminum heat sink and a fan can no longer meet the heat dissipating requirement of present CPUs, and thus related manufacturers continue developing heat pipes or vapor chambers with a higher thermal conductivity and combine the heat pipe or vapor chamber with the heat sink to overcome the heat dissipating problem.
However, the conventional heat pipe usually uses a tubular object as a pipe body of the heat pipe and goes through a pressing process to manufacture a heat pipe with a flat pipe body. In general, a heat pipe with a pipe body having a thickness less than 2 mm is called a super thin heat pipe, and a heat pipe with a pipe body having a thickness greater than 2 mm is called a thin heat pipe. Regardless of the requirements of a thin heat pipe, the interior of the heat pipe should reserve sufficient space for conducting a vapor-liquid phase change. In addition to working fluid sealed in the heat pipe, a capillary tissue is also one of the major factors affecting the space inside the pipe body, particularly for the thin and super thin heat pipes having a very limited interior space. Therefore, how to utilize the limited internal space of the thin heat pipe effectively is one of the technical issues at present.
In view of the aforementioned shortcomings of the prior art, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally provides a feasible solution to overcome the shortcomings of the prior art.

SUMMARY OF THE INVENTION

Therefore, it is a primary objective of the present invention to provide an improved flat heat pipe with a capillary structure. With the installation of a capillary tissue and a pipe body, a smooth flow path is provided for a vapor or liquid working fluid to achieve good thermal conduction and backflow effects, when a vapor-liquid phase change of the working fluid takes place inside the heat pipe.
To achieve the foregoing objective, the present invention provides an improved flat heat pipe with a capillary structure, comprising a pipe body and a capillary tissue. The pipe body is hollow and flat and includes a bottom wall and a top wall disposed opposite to the top wall, and both walls are formed on the pipe body, and an appropriate quantity of working fluid is sealed inside the pipe body. The capillary tissue is covered onto an internal side of the bottom wall, and the capillary tissue has a plurality of protrusions formed inside the pipe body and extended along the lengthwise direction of the pipe body, and a gap is reserved between the protrusions and the internal side of the top wall to form an air passage. With the protrusions formed on the capillary tissue, sufficient capillary forces are provided, while a gap is formed to serve as the air passage to achieve the foregoing objective.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the first preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view of the first preferred embodiment of the present invention;

FIG. 3 is a cross-sectional view of the second preferred embodiment of the present invention; and

FIG. 4 is a cross-sectional view of the third preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The technical characteristics and contents of the present invention will become apparent with the following detailed description and related drawings. The drawings are provided for the purpose of illustrating the present invention only, but not intended for limiting the scope of the invention.
With reference to FIGS. 1 and 2 for a perspective view and a cross-sectional view of an improved flat heat pipe with a capillary structure in accordance with a first preferred embodiment of the present invention respectively, the improved flat heat pipe comprises a pipe body 1 and a capillary tissue 2.
The pipe body 1 is made of a good conductive material such as copper or aluminum, and the pipe body 1 is hollow and flat and includes a bottom wall 10 formed on a pipe wall of the pipe body 1 and a top wall 11 disposed opposite to the bottom wall 10, and an appropriate quantity of working fluid (not shown in the figure) is sealed inside the pipe body 1.
The capillary tissue 2 is covered onto the internal side of the bottom wall 10 of the pipe body 1, and the capillary tissue 2 can be a metal net or a sintered powder provided for sucking the working fluid sealed inside the pipe body 1 at room temperature.
The present invention is characterized in that the capillary tissue 2 includes at least two protrusions 20 formed inside the pipe body 1 and extended in the lengthwise direction of the pipe body 1, and a gap is reserved between the two protrusions 20 and the internal side of the top wall 11 of the pipe body 1 to form an air passage 12. Therefore, if a heat source (not shown in the figure) is in contact with the bottom wall 10 of the pipe body 1, the working fluid contained in the capillary tissue 2 at this portion absorbs the heat generated by the heat source to change its state from liquid to vapor, and the vapor working fluid can be transmitted to a far end of the heat pipe through the air passage 12 between the pipe body 1 and the capillary tissue 2 for cooling. Since the vapor working fluid is far away from the heat source and cooled, the vapor working fluid will be converted into its liquid state again and the liquid working fluid will be absorbed by the capillary tissue 2, and the protrusions 20 formed by the capillary tissue 2 can provide sufficient capillary forces (in other words, the capillary tissue 2 still has sufficient thickness for the required capillary action) to flow the liquid working fluid back to its original position in contact with the heat source quickly, so as to achieve good thermal conduction and backflow effects as well as a circular vapor-liquid phase change effect of the heat pipe.
With reference to FIG. 3 for a cross-sectional view of a second preferred embodiment of the present invention, the capillary tissue 2 may have a smaller space depending on the height (or thickness) of the pipe body 1, or the protrusions 20 of the capillary tissue 2 are attached onto the internal side of the top wall 11 of the pipe body 1 if a thicker capillary tissue 2 is required. Since the protrusions 20 of the capillary tissue 2 are not attached completely with the internal side of the top wall 11, therefore gaps are formed between them to form the air passage 12 for conducting the heat of the vapor working fluid.
With reference to FIG. 4 for a cross-sectional view of a third preferred embodiment of the present invention, a support structure 3 is installed between the protrusion 20 of the capillary tissue 2 and the internal side of the top wall 11 of the pipe body 1, and the support structure 3 is in a staggered wavy form for providing an internal support between the bottom wall 10 and the top wall 11 of the pipe body 1.
With the aforementioned components and structure, the improved flat heat pipe with a capillary structure of the present invention can be made.
In summation of the description above, the present invention improves over the prior art and complies with the patent application requirements, and thus is duly filed for patent application.
While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.

Claims

1. A flat heat pipe with a capillary structure, comprising:

a pipe body, being substantially hollow and flat, and having a bottom wall and a top wall disposed opposite to the bottom wall, both walls being formed on the pipe body, and an appropriate quantity of working fluid being sealed inside the pipe body; and

a capillary tissue, covered onto an internal side of the bottom wall;

wherein the capillary tissue includes a plurality of protrusions formed inside the pipe body and extended along the lengthwise direction of the pipe body, and a gap is reserved between the protrusions and the internal side of the top wall to form an air passage.

2. The flat heat pipe with a capillary structure as recited in claim 1, wherein the pipe body is made of copper or aluminum.

3. The flat heat pipe with a capillary structure as recited in claim 1, wherein the capillary tissue is a metal net or a sintered powder.

4. The flat heat pipe with a capillary structure as recited in claim 1, wherein the capillary tissue has two protrusions.

5. The flat heat pipe with a capillary structure as recited in claim 1, wherein the protrusion of the capillary tissue is attached onto the internal side of the top wall.

6. The flat heat pipe with a capillary structure as recited in claim 1, further comprising a support structure disposed between the protrusion of the capillary tissue and the internal wall of the top wall.

7. The flat heat pipe with a capillary structure as recited in claim 6, wherein the support structure is substantially in a staggered wavy form.