US20070034358A1

US20070034358A1 - Heat dissipation device

Info

Publication number: US20070034358A1
Application number: US11/416,555
Authority: US
Inventors: Hsin-Ho Lee
Original assignee: Hon Hai Precision Industry Co Ltd
Current assignee: Hon Hai Precision Industry Co Ltd
Priority date: 2005-08-12
Filing date: 2006-05-03
Publication date: 2007-02-15
Also published as: CN1913137A; CN1913137B

Abstract

A heat dissipation device includes a first assembly having a first shell portion and a wick layer formed thereon, a second assembly having a second shell portion and a clapboard formed thereon, and a circumfluence cavity and an evaporation cavity formed by coupling the first assembly and the second assembly together and separated by the clapboard. The circumfluence cavity and the evaporation cavity are communicated via the wick layer.

Description

TECHNICAL FIELD

The present invention relates to a heat dissipation device, and more particularly to a heat dissipation device which utilizes a phase change heat transfer.

BACKGROUND

Electronic components such as semiconductor chips are becoming progressively smaller, while at the same time heat dissipation requirements thereof are increasing. In many contemporary applications, a heat pipe is one of the most efficient systems in use for transmitting heat away from such components.
Numerous kinds of heat pipes have been developed for cooling electronic components. A typical heat pipe comprises an evaporator section to take in heat and a condenser section to pass out heat. Working fluid is contained in the heat pipe to transfer heat from the evaporator section to the condenser section. Heat entering the evaporator section of the heat pipe boils the fluid and turns it into a vapor. The vapor expands in volume and travels to the condenser section where it condenses to a liquid and releases its heat. The liquid is then returned to the evaporator section by gravity and/or a wick, whereupon the cycle starts again. However, the heat transfer rate of a single heat pipe is limited. Furthermore, when a heat pipe is directly connected with a heat source, the contact surface therebetween is small, and the thermal conduction performance of the heat pipes can not be fully used.
In order to satisfy the increasing heat dissipation requirements, a typical heat dissipation apparatus always employs a plurality of heat pipes, the evaporator sections of the heat pipes are combined with a heat sink and disposed in thermal communication with a heat source via the heat sink. Therefore, the contact surface of the evaporator sections is increased, and the thermal conduction performance of the heat pipes can be fully used. However, the size of the heat dissipation apparatus is thereby increased. Furthermore, the evaporator sections of the heat pipes are disposed in thermal communication with the heat source indirectly through the heat sink. That is to say, the heat transmission between the evaporator sections and the heat sink is further restricted by the thermal conductivity of the heat sink.
What is needed, therefore, is a heat dissipation device which provides high heat transfer rate with a small size.

SUMMARY

In a preferred embodiment, a heat dissipation device comprises a first assembly having a first shell portion and a wick layer formed thereon, a second assembly having a second shell portion and a clapboard formed thereon, and a circumfluence cavity and an evaporation cavity formed by coupling the first assembly and the second assembly together and separated by the clapboard. The circumfluence cavity and the evaporation cavity are communicated via the wick layer.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present heat dissipation device can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present heat dissipation device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is a schematic, exploded view of a heat dissipation device in accordance with a preferred embodiment;
FIG. 2 is a schematic isometric of the heat dissipation device of FIG. 1;
FIG. 3 is a schematic cross-sectional view taken along line III-III of FIG. 2; and
FIG. 4 is a schematic, sectional view of the heat dissipation device of FIG. 1 employed in a heat dissipation apparatus.
The exemplifications set out herein illustrate at least one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the present heat dissipation device will now be described in detail below and with reference to the drawings.
Referring to FIG. 1 to FIG. 3, a heat dissipation device 10 according to a preferred embodiment is provided. The heat dissipation device 10 comprises a first assembly 100 having a first shell portion 110 and a wick layer 120 formed thereon, and a second assembly 200 having a second shell portion 210 and a clapboard 220 formed thereon. The wick layer 120 and the clapboard 220 each has a top surface (not labeled). The first assembly 100 and second assembly 200 are coupled together by jointing or sticking, and the top surface of the wick layer 120 is substantially coplanar with the top surface of the clapboard 220, thereby a circumfluence cavity 11 and an evaporation cavity 12 separated by the clapboard 220 are thereby formed. The circumfluence cavity 11 and the evaporation cavity 12 are communicated via the wick layer 120. Two through holes 211 and 212 are defined in the second shell portion 210 and connected with the circumfluence cavity 11 and the evaporation cavity 12 respectively. Alternatively, the through holes 211 and 212 can be defined in the first shell portion 110, or be defined in the first shell portion 110 and the second shell portion 210 respectively.
The first shell portion 110 employs a base plate comprises a rectangular portion 111 and an arc-shaped portion 112 extending from one side of the rectangular portion 111. Preferably, the first shell portion 110 further comprises a narrow raised strip 115 protruded from the junction of the rectangular portion 111 and the arc-shaped portion 112 perpendicularly. The wick layer 120 is shaped in accordance with the rectangular portion 111 of the first shell portion 110 and formed thereon. The narrow raised strip 115 has a top surface substantially coplanar with the top surface of the wick layer 120. The wick layer 120 can be made from a sintered layer or a carbon nanotube layer. The sintered layer can be sintered with metal powder. The metal powder can be selected from the group comprising of copper (Cu) powder, aluminum (Al) powder, and iron (Fe) powder. In the preferred embodiment, the wick layer 120 employs a sintered layer of copper powder.
The second shell portion 210 of the second assembly 200 comprises a flat portion 213 in accordance with the first shell portion 110, and a side wall portion 215 extended from the edge of the flat portion 213 perpendicularly In the preferred embodiment, the second assembly 200 further comprises a plurality of guiding pieces 230 extended from the flat portion 213 of the second shell portion 210. The top surfaces of the guiding pieces 230 are substantially coplanar with the top surface of the clapboard 220. The side wall portion 215, the clapboard 220, and the guiding pieces 230 are extended from the flat portion 213 on the same side. Preferably, the second shell portion 210, the clapboard 220, and the guiding pieces 230 are integrally formed. More preferably, the guiding pieces 230 are substantially parallel to each other and orthogonal to the clapboard 220. Furthermore, one end of each guiding pieces 230 is coupled to the clapboard 220. The first shell portion 110 and the second assembly 200 can be made from material selected from the group comprising of copper, aluminum, iron, and any suitable alloy thereof.
The evaporation cavity 12 comprises a arc-shaped gas collecting chamber 121 in accordance with the arc-shaped portion 112 of the first shell portion 110, and a plurality guiding channels 122 defined by the guiding pieces 230 together with the flat portion 213 and the side wall portion 215. The through hole 212 is defined in the side wall portion 215 of the second shell portion 210 and positioned at the vertex of the arc-shaped gas collecting chamber. The through hole 211 is defined in the side wall portion 215 of the second shell portion 210 provided around the circumfluence cavity 11.
Referring to FIG. 1 to FIG. 4, the heat dissipation device 10 is employed in a heat dissipation apparatus 50 for cooling down a heat source 30. In the preferred embodiment, a section of evaporation cavity 12 is in thermal communication with the heat source 30, and the section is overlapped with the wick layer 120. In detail, the heat source 30 is connected with the first shell portion 110 directly. The two through holes 211 and 212 of the heat dissipation device 10 are connected with a condenser 20 via two pipes 21 and 22 of the condenser 20 respectively. During the cooling process, a liquid operating fluid (not shown) is injected into the circumfluence cavity 11 via the through hole 211. The operating fluid is moved from the circumfluence cavity 11 to the evaporation cavity 12 through the wick layer 120 by capillary action of the wick layer 120. When the heat of the heat source 30 is absorbed by the wick layer 120 via the first shell portion 110, and further absorbed by the operating fluid inside the wick layer 120, the operating fluid is then vaporized to steam. The steam is guided to the gas collecting chamber 121 via the guiding channels 122, and then flows to the condenser 20 via the through hole 212 and the pipe 22. The steam changes back to the liquid operating fluid in the condenser 20 and then flows back to the circumfluence cavity 11 via the through hole 211 and the pipe 21. The heat source 30 is then cooled down by phase change cycles of the operating fluid.
As stated above, the wick layer 120 is formed on the first shell portion 110, the size of the wick layer 120 can be adjusted according to different heat dissipation requirements, and the evaporation cavity 12 is in thermal communication with the heat source 30 directly, thereby high contact surface and low thermal contact resistance can be provided by the present heat dissipation device at the same time. Therefore, the present heat dissipation device can provide high heat transfer rate with a small size. Furthermore, the guiding channels 122 formed by the guiding pieces 230 lead to the arc-shaped gas collecting chamber 121, the flow resistance of the steam can be reduced.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.

Claims

1. A heat dissipation device comprising:

a first assembly comprising a first shell portion and a wick layer formed thereon;

a second assembly comprising a second shell portion and a clapboard formed thereon; and

a circumfluence cavity and an evaporation cavity being formed by coupling the first assembly and the second assembly together and separated from each other by the clapboard;

wherein, the circumfluence cavity and the evaporation cavity are communicated via the wick layer of the first assembly.

2. The heat dissipation device in accordance with claim 1, wherein the circumfluence cavity and the evaporation cavity each having a through hole defined in one of the shell portions.

3. The heat dissipation device in accordance with claim 1, wherein a top surface of the wick layer is coplanar with a top surface of the clapboard.

4. The heat dissipation device in accordance with claim 1, wherein the second shell portion comprises a flat portion in accordance with the first shell portion, and a side wall portion extending from the edge of the flat portion perpendicularly.

5. The heat dissipation device in accordance with claim 4, wherein the second assembly further comprises a plurality of guiding pieces extending from the second shell portion.

6. The heat dissipation device in accordance with claim 5, wherein the guiding pieces form top surfaces coplanar with a top surface of the clapboard.

7. The heat dissipation device in accordance with claim 5, wherein the guiding pieces are substantially parallel to each other and orthogonal to the clapboard.

8. The heat dissipation device in accordance with claim 5, wherein one end of each guiding pieces is coupled to the clapboard.

9. The heat dissipation device in accordance with claim 5, wherein the second shell portion, the clapboard, and the guiding pieces are integrally formed.

10. The heat dissipation device in accordance with claim 5, wherein the evaporation cavity comprises a gas collecting chamber and a plurality of guiding channels defined by the guiding pieces with the second shell portion.

11. The heat dissipation device in accordance with claim 10, wherein the gas collecting chamber is an arc-shaped gas collecting chamber.

12. The heat dissipation device in accordance with claim 1, wherein the first shell portion and the second assembly are made from material selected from the group comprising of copper, aluminum, iron, and any alloy thereof.

13. The heat dissipation device in accordance with claim 1, wherein the wick layer is made from a sintered layer.

14. The heat dissipation device in accordance with claim 13, wherein the sintered layer is sintered with material selected from the group comprising of copper powder, aluminum powder, and iron powder.

15. The heat dissipation device in accordance with claim 1, wherein the wick layer is made from a carbon nanotube layer.

16. The heat dissipation device in accordance with claim 1, wherein the first assembly and second assembly are coupled together by jointing.

17. The heat dissipation device in accordance with claim 1, wherein the first assembly and second assembly are coupled together by sticking.

18. A heat dissipation device comprising:

a cavity having a circumfluence portion and an evaporation portion formed by coupling the first assembly and the second assembly together;

wherein, the circumfluence portion and the evaporation portion are separated by the clapboard of the second assembly and communicated with each other via the wick layer of the first assembly, each of the circumfluence portion and the evaporation portion having a through hole defined in one of the shell portions of the first assembly and the second assembly.