US20050274495A1

US20050274495A1 - Cylindrical heat pipe structure

Info

Publication number: US20050274495A1
Application number: US10/855,833
Authority: US
Inventors: Chin Wang; Pei Wang; Ching Wang
Original assignee: Augux Co Ltd
Current assignee: Augux Co Ltd
Priority date: 2004-05-28
Filing date: 2004-05-28
Publication date: 2005-12-15

Abstract

A cylindrical heat pipe structure includes a hollow pipe body. A working fluid is contained in the pipe body. Several trenches are formed on the inner surface of the pipe body. The cylindrical heat pipe structure further includes several rib pillars, which are powder sintered on the inner surface of the pipe body. The rib pillars are extended from the inner surface of the pipe body toward the center of the pipe body. A porous wick structure is formed on the surface of said rib pillars. The rib pillars are firmly sintered on the pipe body due to the presence of the trenches. The presence of trenches may also increase the condensation area, thereby increasing the condensation performance. The hot air generated by heat exchanging with the heat source may thus more rapidly be condensed into liquid. The condensed liquid may also rapidly move to the porous rib pillar and transfer to the bottom portion of the pipe body. The overall heat dissipation rate is thus enhanced.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to a cylindrical heat pipe structure, and more particularly to a cylindrical heat pipe for exchanging heat with a heat generating electronic device (such as a CPU), having a structure to enhance the overall heat dissipation performance thereof.
The rapid development of technological industries has succeeded in developing faster and faster computers. When a central processing unit is running in a faster speed, the heat generated during operation becomes higher. In order to dissipate the generated heat to the exterior of the computer mainframe and to maintain the central processing unit running under an operation temperature, a heat dissipation device is normally installed on the central process unit for assisting heat dissipation, so as to enhance the heat dissipation capacity. However, the faster a central processing unit runs, the greater amount of heat is generated. Conventional heat dissipation apparatus, which is composed of an aluminum extruded heat dissipater and a heat dissipation fan, may no longer support sufficient heat dissipation capacity for the central processing unit.
Therefore, there is provided a heat pipe design. As shown in FIG. 1, the heat pipe 10 a includes a hollow pipe body 1 a, and a wick structure 2 a attached to the inner surface of the hollow pipe body 1 a, wherein a working fluid is contained in the pipe body 1 a. In operation, the heat pipe 10 a is connected to the heat dissipater, and the heat pipe 10 a is correspondingly disposed on the central processing unit. The heat generated by the central processing unit is absorbed by and thermally exchanged with the working fluid. The hot air generated after the thermal exchange is then transferred upward. Since the top portion of the pipe body 1 a away from the heat source has lower temperature, the hot air is then condensed into liquid at the top portion of the pipe body 1 a. The condensed liquid is transferred back to the bottom portion of the pipe body 1 a along the wick structure 2 a for subsequent heat exchange.
However, the aforementioned conventional heat pipe comprises the following drawbacks:

- (a) The wick structure 2 a in the heat pipe 10 a is only attached to the inner surface of the pipe body 1 a without complete adhesion. If there is a gap present therebetween, the speed for transferring the liquid to the bottom of the pipe body 1 a becomes slower. Thus, the heat dissipation rate is not satisfied.
- (b) Since only the top portion of the pipe body 1 a acts as the condensation end, there is not enough area for the condensation end to rapidly condense the hot air into liquid. Therefore, the heat dissipation rate is again not satisfied.
- (c) Since only the wick structure 2 a is disposed on the inner surface of the conventional heat pipe 10 a, the wick structure 2 a may not rapidly absorb the condensed liquid. The heat exchange rate of the working fluid is thus decreased.

Therefore, an improved heat pipe that has an enhanced heat dissipation rate is demanding.

BRIEF SUMMARY OF THE INVENTION

The present invention is to provide a cylindrical heat pipe structure, the wick structure of which is firmly attached to the inner surface of the heat pipe so as to enhance the liquid transfer speed of the wick structure.
Furthermore, the present invention is to provide a cylindrical heat pipe structure, wherein the area of the condensation end in the heat pipe is increased, for rapidly condensing the hot air generated from the heat exchange with the heat source into liquid.
One feature of the present invention is in that the heat pipe includes a hollow pipe body. The pipe body contains a working fluid. A plurality of trenches is formed on the inner surface of the pipe body. The heat pipe further includes a plurality of rib pillars, which are powder sintered to the inner surface of the pipe body. The rib pillars extend from the inner surface of the pipe body toward the center of the pipe body. A porous wick structure is formed on the surface of the rib pillars. In this manner, the rib pillars are firmly sintered on the pipe body due to the presence of the trenches. The presence of trenches also increase the condensation area, thereby increasing the condensation performance. The hot air generated by heat exchanging with the heat source is thus more rapidly condensed into liquid. The condensed liquid also rapidly moves to the porous rib pillar and transfer to the bottom portion of the pipe body for subsequent heat exchange.
Another feature of the present invention is in that the trenches are radially formed on the inner surface of the pipe body, while a plurality of rib pillars having wick structure is axially erected upright in the pipe body. The trenches effectively guide the condensed liquid to the rib pillars, while the hot air generated by heat exchange is also upwardly diffused between the rib pillars.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will be become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
FIG. 1 illustrates a cross-sectional view of a conventional heat pipe.
FIG. 2 illustrates a perspective view of a heat pipe in accordance with the present invention, wherein a rib pillar is not yet formed.
FIG. 3 illustrates a perspective view of a heat pipe in accordance with the present invention, wherein a rib pillar is formed.
FIG. 4 illustrates a perspective cross-sectional view of a heat pipe in accordance with the present invention.
FIG. 5 illustrates a top elevation of a heat pipe in accordance with the present invention.
FIG. 6 illustrates a cross-sectional view of a heat pipe in accordance with the present invention.
FIG. 7 illustrates an enlarged view of part A in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
Referring to FIG. 2, a cylindrical heat pipe structure of the present invention is illustrated. The heat pipe 10 of the present invention is applicable to a heat generating device such as a central process unit, so as to dissipate heat on the heat generating device by means of heat exchange. The heat pipe 10 includes a hollow pipe body 1. In this particular embodiment, the hollow pipe body 1 is a cylindrical pipe body 1. A working fluid is contained in the hollow pipe body 1. A plurality of trenches 11 is formed on the inner surface of the pipe body 1. The trenches 11 are radially formed on the inner surface of the pipe body 1 (as illustrated in FIG. 7).
Referring to FIG. 3, FIG. 4 and FIG. 5, a plurality of rib pillars 2 are powder sintered on the inner surface of the pipe body 1. The rib pillars 2 are extended from the inner surface of the pipe body 1 toward the center of the pipe body 1. Each rib pillar 2 stands upright relative to the cylindrical pipe body 1. A porous wick structure is formed on the surface of the rib pillars 2.
Since a plurality of trenches 11 is formed on the inner surface of the pipe body 1, the rib pillar 2 and the trenches 11 are mutually imbedded when sintering the rib pillars 2. The rib pillars 2 and the pipe body 1 are thus firmly connected to each other.
Referring to FIG. 4 and FIG. 6, when the heat pipe 10 is installed on a heat generating device, the heat generated by the heat generating device is transferred to the working fluid inside of the heat pipe 10 by means of heat exchange. The hot air generated from the heat exchange diffuses upwardly through the passageways 12 formed by the rib pillars 2 (as shown in FIG. 5). Since the top portion of the heat pipe 10 is away from the central processing unit, the temperature thereof is lower, thereby condensing the upwardly diffused hot air into liquid. The liquid is then absorbed by the wick structure formed on the rib pillar 2 along the trenches 11 on the inner surface of the pipe body 1. Furthermore, the liquid is transferred back to the bottom portion of the pipe body 1 for subsequent heat exchange with the heat generating device.
In accordance with the above descriptions, it is appreciated that the cylindrical heat pipe 10 of the present invention has the following advantages:

- (a) Since a plurality of trenches are formed on the inner surface of the heat pipe 10, the rib pillars 2 having wick structure formed thereon are firmly connected on the inner surface of the heat pipe 10. The performance of the wick structure is thus enhanced.
- (b) The upwardly diffused hot air is cooled in the trenches 11. Since the trenches 11 increases the area of the condensation end of the heat pipe, the performance of condensation is thus enhanced. Therefore, the hot air generated by the heat source may rapidly be condensed into liquid.
- (c) Furthermore, the wick structure is homogeneously arranged on the rib pillars 2 in the heat pipe 2, the overall heat dissipation performance of the heat pipe 10 is thus enhanced.

In summary, the cylindrical heat pipe structure of the present invention may indeed achieve the functions as set forth above. However, the detailed descriptions above and the accompanied drawings are for illustrative purposes only. Since, any person having ordinary skill in the art may readily find various equivalent alterations or modifications in light of the features as disclosed above, it is appreciated that the scope of the present invention is defined in the following claims. Therefore, all such equivalent alterations or modifications without departing from the subject matter as set forth in the following claims is considered within the spirit and scope of the present invention.

Claims

1. A cylindrical heat pipe structure, comprising:

a hollow pipe body, containing a working fluid, the inner surface of said hollow pipe body having a plurality of trenches; and

a plurality of rib pillars formed on the inner surface of said hollow pipe, extending toward the center of said hollow pipe body, wherein a porous wick structure is formed on the surface of said rib pillars.

2. The cylindrical heat pipe structure as recited in claim 1, wherein said trenches are radially formed on the inner surface of said pipe body.

3. The cylindrical heat pipe structure as recited in claim 1, wherein said rib pillars are powder sintered and firmly connected to said pipe body.