US20080308257A1

US20080308257A1 - Heat dissipating assembly

Info

Publication number: US20080308257A1
Application number: US11/808,661
Authority: US
Inventors: Ji-Ping PENG; Yi-Shen CHIEN
Original assignee: Cooler Master Co Ltd
Current assignee: Cooler Master Co Ltd
Priority date: 2007-06-12
Filing date: 2007-06-12
Publication date: 2008-12-18

Abstract

A heat dissipating assembly for dissipating heat of a heat source is provided. The heat dissipating assembly includes a body, at least one circulation pipe, and a working fluid. The body has a chamber defined therein and least one pipeline formed in a wall of the body. The body further has at least one first orifice in communication with the chamber of the body, and at least one second orifice in communication with the pipeline. The circulation pipe has two end portions respectively connected to the first orifice and the second orifice. The working fluid is accommodated in the chamber of the body, wherein the working fluid flows into the circulation pipe through the first orifice, and flows into the pipeline through the second orifice to flow back to the chamber of the body, thereby forming a two phase circulation loop.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention
The present invention relates to a heat dissipating assembly, and more particularly to a heat dissipating assembly having a gaseous/liquid phase circulation loop.
2. Related Art
Along with the development of semiconductor and electronics, the performance of computers is sufficiently enhanced. Currently, as the size of electronic components is gradually miniaturized, and the clock time of the electronic components becomes more faster, the heat generated by these electronic components is increased accordingly. If the heat generated by the electronic components cannot be dissipated in time, the temperature of the electronic components will rise quickly, the electronic components may bum out and be damaged, and thus the computer is malfunctioned.
In order to cool electronic components to maintain the operation of the computer, a heatsink made of a metal is used in the prior art to absorb heat generated by the electronic components, and exchange the heat to the atmospheric environment outside. Generally, the heatsink has a fin assembly is added to the heatsink, so as to enlarge the surface area of the heatsink. However, as the heatsink or fin assembly has a limited heat dissipation surface area, the conventional heatsink using air cooling has poor heat dissipation efficiency, and cannot meet the heat dissipation requirements of great heat generated by the electronic components with high-speed clock time.
In order to dissipate heat generated by the electronic components as much as possible in a short time, a pump is additionally added to the heatsink, for pumping working fluid, such as cooling water, to flow in circulation in the heatsink, so as to dissipate the heat rapidly.
Two pipes are required to connect the pump and the heatsink for allowing a continuous circulation of the cooling water. After a long-term usage, the pipe may have problems in terms of poor junction due to factors such as material deformation, and especially the water leakage. Moreover, the pump can work only when driven by a power source, so that the entire assembly of the heatsink may be too complex.
Recently, it has been developed to adding a plurality of heat pipes connected to the fin assembly to the conventional heatsink, so as to further overcome the problem of circulation cooling through the pump. The working fluid in the heat pipes flows to a condensation end connected to the fin assembly after being gasified by absorbing the heat from a heat source. The working fluid is then condensed into a liquid through the heat dissipation of the fin assembly. After that, the working fluid flows back to the heat source under capillary force or gravitational force without depending on the pumping of the pump, and thus the circulation can be performed in the heat pipes spontaneously. The heatsink makes use of the potential heat of the working fluid caused by gaseous/liquid phase change to conduct great amount of heat from the electronic components to the fin assembly, thereby enhancing the heat dissipation performance of the heatsink.
In order to enhance the heat dissipation efficiency of the conventional heat pipes, the heat pipes usually extend to a large extent, resulting in that the gaseous working fluid is easily condensed into liquid in the middle section of the heat pipes. The liquid working fluid staying in the middle section of the heat pipes becomes a resistance force for the flow of the gaseous working fluid in the heat pipes, thus seriously affecting the operation of the circulation of the working fluid in the heat pipes, and even generating counter flow, and causing dry out phenomenon at evaporation ends of the heat pipes since the supply of the liquid working fluid is interrupted. As a result, the overall heat dissipation effect of the heat pipes will be significantly reduced, and the electronic components may bum put under the over-high temperature.
In order to prevent the dry out phenomenon, the conventional heat pipes are usually designed to be disposed on the heatsink in vertical direction, so that the vapor rises upward and the liquid working fluid flows downward under the gravitational force based on the physical phenomena. However, the circuit layout of the electronic device must be modified in accordance with the structure configuration of the heatsink, or the overall volume of the electronic device must be increased to accommodate the heatsink of a large volume. The alteration of the circuit layout in the circuit electronic device may increase the complexity of the process, and the manufacturing cost will rise accordingly. In addition, the over-sized electronic device does not meet the consumers' requirement of light, thin, short, small current electronic products.

SUMMARY OF THE INVENTION

Accordingly, the objects of the invention of the present invention is to provide a heat dissipating assembly to solve the problem is the heat pipe in the prior art, such as the dry out caused by the counter flow of the working fluid in the heat pipe, or complicated manufacturing process and high cost due to the limitation of the configuration of the heat pipe in the heatsink.
To achieve the aforementioned objects, a heat dissipating assembly for dissipating heat generated by a heat source is provided. The heat dissipating assembly includes a body, at least one circulation pipe, and a working fluid. The body has a chamber defined therein, a base, and at least one pipeline. The base is used to contact the heat source, and the pipeline is formed in a wall of the body and extends to the base. The body further includes a first orifice in communication with the chamber, and a second orifice in communication with the pipeline. The circulation pipe has two end portions respectively connected to the first orifice and the second orifice. The working fluid is accommodated in the chamber of the body and is in contact with the base. The working fluid is circulated between the circulation pipe and the chamber of the body. After absorbing the heat of the heat source from the base, the liquid working fluid is evaporated into a gaseous working fluid. The gaseous working fluid is introduced into the circulation pipe through the first orifice and condensed by heat release into a liquid working fluid. The working fluid condensed into a liquid is introduced into the pipeline through the second orifice and flows back to the base under the gravitational force, so as to form a gaseous/liquid phase circulation loop.
In the present invention, the pipeline is disposed to allow the working fluid introduced into the circulation pipe through the first orifice, and into the pipeline through the second orifice, so as to flow back to the chamber of the body, thus forming a gaseous/liquid phase circulation loop in a single direction, so as to significantly enhance the heat dissipation efficiency of the heat dissipating assembly in the present invention.
The present invention can avoid mutual conflicts of the gaseous and liquid working fluids in operation, and eliminate the phenomenon of counter flow or dry out phenomenon in pipeline as the working fluid stays in the heat pipe in the conventional art.
The features and practice of the preferred embodiments of the present invention will be illustrated in detail below with the accompanying drawings.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is an exploded view according to a first embodiment of the present invention;

FIG. 2 is a perspective view according to the first embodiment of the present invention;

FIG. 3 is a cross-sectional view according to the first embodiment of the present invention;

FIG. 4 is a perspective view according to a second embodiment of the present invention; and

FIG. 5 is a perspective view according to a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 to 3, a heat dissipating assembly 100 of a first embodiment of the present invention is provided for dissipating heat generated by a heat source 200. The heat source 200 includes, but not limited to, electronic components such as CPU, functional chip, display card in an electronic device, that generate great heat in operation.
The heat dissipating assembly 100 of the first embodiment includes a body 110, a plurality of circulation pipes 120, and a working fluid 130. The body 110 has a chamber 117 defined therein, a base 111, and a plurality of pipelines 112. The base 111 is used to contact the heat source 200, and the pipelines 112 are formed in a wall of the body 110 and extend to the base 111. The body 110 further includes a plurality of first orifices 113 and a plurality of second orifices 114. The first orifices 113 are formed in the upper portion of the body 110 in communication with the chamber 117. The second orifices 114 are formed in the lower portion of the body 110 in communication with the pipelines 112 of the body 110. Each circulation pipe 120 has two end portions 121 respectively connected to a corresponding first orifice 113 and a corresponding second orifice 114. The working fluid 130 is accommodated in the chamber 117 of the body 110 and is in contact with the base 111, and the working fluid 130 is circulated between the circulation pipes 120 and the chamber 117 of the body 110. In the present invention, the circulation pipes 120 are made of copper alloy of high thermal conductivity. One with ordinary skill in the art can choose any metal of high thermal conductivity to fabricate the circulation pipes, which will not be limited to the embodiment of the present invention.
Further, the body 110 further has an injection hole 115 formed in the body 110 and an injection pipe 116 connected to the injection hole 115. The injection pipe 116 is used for injecting the working fluid 130 to flow through the injection hole 115 into the chamber 117 of the body 110. The injection pipe 116 and the injection hole 115 can also be used for air extraction, so as to form a vacuum working environment in the chamber 117 of the body 110.
As shown in FIG. 3, the liquid working fluid 130 in the chamber 117 of the body 110 is stored on the base 111 and is in contact with the base 111 under the gravitational force. As the base 111 is in contact with the heat source 200, the liquid working fluid 130 absorbs heat generated by the heat source 200 through the base 111 to be evaporated into a gaseous working fluid 130, and flows toward the upper portion of the chamber 117 from the base 111. The gaseous working fluid 130 flows into the circulation pipes 120 through the first orifices 113, and condenses by heat release into a liquid working fluid 130 in the circulation pipes 120. The working fluid 130 condensing into liquid in the circulation pipes 120 flows through the lower portions of the circulation pipes 120 under the downward traction of the gravitational force, and flows into the pipelines 112 in the wall of the body 110 through the second orifices 114, and flows back to the base 111, thus forming a gaseous/liquid phase circulation loop.
Next, referring to FIGS. 1 to 3, in order to accelerate the heat release of the working fluid 130 in the circulation pipes 120, the first embodiment of the present invention further includes a fin assembly 140 having a plurality of fins. Each circulation pipe 120 penetrates through the fin assembly 140 to fix the fin assembly 140 to the circulation pipe 120 and to have the fin assembly to exchange heat with the circulation pipe 120. The fin assembly 140 has a large contact area with the air to effectively enhance the heat dissipation efficiency of the heat dissipating assembly 100. The gaseous working fluid 130 flowing into the circulation pipe 120 can rapidly dissipate heat through the fin assembly 140, so as to further improve the flow rate of the circulation loop for condensing the gaseous working fluid 130 into liquid. In addition, the fin assembly 140 of the present invention is formed by punching aluminum alloy or copper of high thermal conductivity. One with ordinary skill in the art in the art can select the metal of high thermal conductivity.
Further, in order to improve the flow condition of the liquid working fluid 130 in the body 110, the base 111 further has a flow channel 1111 formed on the surface of the base 111 for guiding the flow of the working fluid 130. The liquid working fluid 130 flowing through the pipelines 112 can stably flow back to the surface of the base 111 through the flow channel 1111. Moreover, the base 111 further has a capillary layer 1112, and the capillary layer 1112 is a porous structure layer formed by sintering metal powder, such as copper powder. The porous structure of the capillary layer 1112 can effectively attract the liquid working fluid 130 to the surface of the base 111, and store the working fluid 130 in the capillary layer 1112, thereby enlarging the actual contact area of the working fluid 130 with the base 111, and enhancing the heat exchange efficiency between the working fluid 130 and the base 111.
FIGS. 4 and 5 are perspective views of a second embodiment and a third embodiment, respectively. The circulation pipes 120 in FIG. 2 are parallel to the base 111 of the body 110. In addition, the circulation pipes 120 and the fin assemblies 140 of the present invention can also be disposed perpendicular to the base 111 of the body 110, or disposed inclined with a inclined angle between the circulation pipes 120 and base 111 of the body 110 according to the circuit layout of the electronic device, so as to effectively utilize the space inside the electronic device. Therefore, the electronic device obtains effective heat dissipation ability and meanwhile achieves the design purpose of miniaturization.
In the heat dissipating assembly of the present invention, the opening of the pipelines are disposed in the lower portion of the body and under the level surface of the liquid working fluid, so as to allow the gaseous working fluid conducted into the circulation pipes in a single direction, and converted into a liquid working fluid in the circulation pipes. The counter flow caused by mutual conflicts between the gaseous working fluid and the liquid working fluid in the circulation pipes is reduced. As such, the heat dissipation efficiency of the heatsink can be significantly improved, and the dry out phenomenon can be avoided without reducing the service life of the circulation pipes.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A heat dissipating assembly, for dissipating heat of a heat source, comprising:

a body, having:

a chamber defined therein;

a base used to contact the heat source;

at least one pipeline formed in a wall of the body and extending to the base;

at least one first orifice in communication with the chamber; and

at least one second orifice in communication with the pipeline;

at least one circulation pipe, having two end portions respectively connected to the first orifice and the second orifice; and

a working fluid, accommodated in the chamber of the body and being in contact with the base, wherein the working fluid is circulated between the circulation pipe and the chamber of the body.

2. The heat dissipating assembly as claimed in claim 1, further comprising at least one fin assembly, wherein the circulation pipe penetrates through the fin assembly to fix the fin assembly to the circulation pipe and to have the fin assembly to exchange heat with the circulation pipe.

3. The heat dissipating assembly as claimed in claim 1, wherein the body further comprises an injection hole for injecting the working fluid into the chamber of the body.

4. The heat dissipating assembly as claimed in claim 3, further comprising an injection pipe, connected to the injection hole for the working fluid to flow through the injection hole and be injected into the chamber.

5. The heat dissipating assembly as claimed in claim 1, wherein the base further has at least one flow channel formed on the surface of the base for guiding the working fluid.

6. The heat dissipating assembly as claimed in claim 1, wherein the circulation pipe is parallel to the base of the body.

7. The heat dissipating assembly as claimed in claim 1 wherein the circulation pipe is perpendicular to the base of the body.

8. The heat dissipating assembly as claimed in claim 1, wherein an inclined angle is formed between the circulation pipe and base of the body.

9. The heat dissipating assembly as claimed in claim 1, wherein the base further has a capillary layer formed thereon for attracting the working fluid.

10. The heat dissipating assembly as claimed in claim 9, wherein the capillary layer is a porous structure layer formed by sintered metal powder.

11. The heat dissipating assembly as claimed in claim 9, wherein the metal powder is copper power.