US20110232874A1

US20110232874A1 - Heat dissipation apparatus with heat pipe

Info

Publication number: US20110232874A1
Application number: US12/770,784
Authority: US
Inventors: Chao Xu; De-Yu Wang; Jiang-Jun Hu
Original assignee: Fuzhun Precision Industry Shenzhen Co Ltd; Foxconn Technology Co Ltd
Current assignee: Fuzhun Precision Industry Shenzhen Co Ltd; Foxconn Technology Co Ltd
Priority date: 2010-03-26
Filing date: 2010-04-30
Publication date: 2011-09-29
Also published as: CN102202488A

Abstract

A heat dissipation apparatus includes an evaporator receiving heat from a heat source, a condenser releasing the heat of the heat source, and a pipeline inter connecting the evaporator and the condenser. The condenser defines a flat rectangular chamber therein. A working fluid is contained in the evaporator. The working fluid vaporizes upon receiving the heat of the heat source. The pipeline conducts the vaporized working fluid from the evaporator to the condenser. The vaporized working fluid condenses upon releasing the heat in the chamber.

Description

BACKGROUND

1. Technical Field
The present disclosure generally relates to heat dissipation, and particularly to a heat dissipation apparatus with a heat pipe.
2. Description of Related Art
A typical heat pipe often used for heat dissipation includes a vacuum casing containing a working fluid. Preferably, a wick structure is provided inside the heat pipe, lining an inner wall of the casing. The heat pipe has an evaporating section for absorbing heat from a heat source such as a heat-generating electronic component, and a condensing section for releasing the heat absorbed by the evaporating section. When the heat is introduced to the heat pipe at the evaporating section thereof, the working fluid contained therein absorbs the heat and vaporizes. Due to the difference in vapor pressure between the two sections of the heat pipe, the generated vapor moves, bearing the heat, towards the condensing section. The vapor is condensed at the condensing section, whereby the heat is released into the ambient environment or, for example, transferred to a heat sink thermally attached to the condensing section. Due to the difference in capillary pressure of the wick structure between the two sections of the heat pip, the condensate is then drawn back by the wick structure to the evaporating section where it is again available for evaporation.
To increase the contact area between the condensing section of the heat pipe and the heat sink and thereby accelerate condensation, the condensing section of the heat pipe is usually curved or staved. However, such changes normally destroy the wick structure of the heat pipe and increase a flow resistance of the vapor in the heat pipe. This negative effect reduces the speed at which the condensate can reach the evaporating section of the heat pipe. If the condensate is not promptly returned to the evaporating section, the heat pipe will suffer drying.
Therefore, what is needed is a heat dissipation apparatus which can overcome the described limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric, assembled view of a first embodiment of a heat dissipation apparatus.

FIG. 2 is an exploded view of the heat dissipation apparatus of FIG. 1.

FIG. 3 is an enlarged view of a circled portion III of FIG. 2.

FIG. 4 is an isometric, assembled view of a second embodiment of a heat dissipation apparatus.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a first embodiment of a heat dissipation apparatus 100 according to the disclosure is shown. The heat dissipation apparatus 100 is configured for dissipating heat from an electronic component (not shown), such as a CPU (central processing unit) of a portable computer. The heat dissipation apparatus 100 includes an evaporator 10, a condenser 20, a pipeline 30 connecting the evaporator 10 with the condenser 20, and two heat sinks 40 attached on two opposite sides of the condenser 20.
The evaporator 10 is a flat rectangular casing with a flat rectangular chamber (not shown) defined therein. A first wick structure (not shown) is provided lining an inner wall of the evaporator 10. Working fluid (not shown), such as water or alcohol with low boiling point, is filled in the evaporator 10.
The condenser 20 is an elongated, flat, and rectangular casing with a flat rectangular chamber 28 defined therein. The condenser 20 includes a first cap 21 and a second cap 22, connected with each other to form the condenser 20. The first cap 21 and the second cap 22 are each provided with a second wick structure 23 lining an inner wall thereof. A plurality of supporting posts 24 is provided in the condenser 20. The supporting posts 24 provide support between the first cap 21 and the second cap 22, avoiding denting of the condenser 20. The second wick structure 23 defines a plurality of through holes 230 receiving opposite ends of the supporting posts 24.
Referring also to FIG. 3, the pipeline 30 includes a tube 31 and a third wick structure 32 lining an inner wall of the tube 31. The tube 31 communicates with the chamber of the evaporator 10 and with the chamber 28 of the condenser 20. The pipeline 30 defines a vapor passage 321 therein along an axial direction thereof. The third wick structure 32 of the pipeline 30 connects the first wick structure of the evaporator 10 with the second wick structure 23 of the condenser 20, and the vapor passage 321 of the pipeline 30 communicates with the chamber of the evaporator 10 and the chamber 28 of the condenser 20.
The first wick structure, the second wick structure 23 and the third wick structure 32 each can be sintered powder or a mesh screen of metal or organic woven fibers, etc. In this embodiment, the first wick structure, the second wick structure 23 and the third wick structure 32 are sintered powder.
Each of the heat sinks 40 includes a base plate 41, and a plurality of fins 42 extending perpendicularly from the base plate 41. The base plate 41 has a contour mating with a corresponding part of the condenser 20. The base plates 41 of the two heat sinks 40 are respectively attached on two opposite sides (i.e., top and bottom sides) of the condenser 20.
In manufacturing, air in the heat dissipation apparatus 100 is evacuated, creating a vacuum therein, such that the working liquid in the evaporator 10 is easily evaporated. During operation, the evaporator 10 of the heat dissipation apparatus 100 is attached to a heat source to absorb heat therefrom. The working fluid at the evaporator 10 absorbs the heat and vaporizes. The vapor moves, bearing the heat, towards the condenser 20 through the vapor passage 321 of the pipeline 30, due to the different vapor pressure between the evaporator 10 and the condenser 20. When the vapor reaches the condenser 20, the vapor is condensed, thereby transferring the heat to the two heat sinks 40. The heat sinks 40 release the heat into the ambient environment. Due to the different capillary pressure between the first wick structure and the second wick structure 23, the condensate is then drawn back by the third and the second wick structures 32, 23 and the first wick structure to the evaporator 10, where the condensate is again available for evaporation.
In the heat dissipation apparatus 100, the condenser 20 has a large heat transfer area, and a large inner space due to its flat rectangular chamber 28. Thereby, the heat dissipation apparatus 100 provides not only a large contact area between the vapor and the condenser 20 but also reduced flow resistance of the vapor. The vapor in the condenser 20 is condensed quickly, avoiding drying out at the evaporator 10. In addition, the condenser 20 does not need to be curved or staved. Therefore the second wick structure 23 in the condenser 20 avoids being destroyed during manufacturing of the condenser 20. Furthermore, the working fluid is drawn back by the third wick structure 32, the second wick structure 23 and the first wick structure, whereby any impeding influence of gravity acting on the working fluid is essentially eliminated.
FIG. 4 shows an alternative embodiment of a heat dissipation apparatus 100 a. The heat dissipation apparatus 100 a differs from that of the previous embodiment only in that a second pipeline 50 is also included. The second pipeline 50 connects the evaporator 10 with the condenser 20 to form a loop together with the pipeline 30. The second pipeline 50 is a hollow tube communicating the chamber of the evaporator 10 with the chamber 28 of the condenser 20. Thereby, the second pipeline 50 allows condensate in the condenser 20 to flow back to the evaporator 10, and thus provides the heat dissipation apparatus 100 a with a loop-based heat dissipation capability.
It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. A heat dissipation apparatus, comprising:

an evaporator receiving heat from a heat source;

a working fluid contained in the evaporator and vaporizing upon receiving heat from the heat source;

a condenser releasing the heat of the heat source, and defining a flat rectangular chamber therein; and

a pipeline interconnecting the evaporator and the condenser, and conducting the vaporized working fluid from the evaporator to the condenser, the vaporized working fluid condensing upon releasing the heat in the chamber.

2. The heat dissipation apparatus of claim 1, wherein the condenser comprises a first cap and a second cap connected with each other to form the condenser.

3. The heat dissipation apparatus of claim 1, wherein a plurality of supporting posts are provided in the condenser, the supporting posts providing support between the first cap and the second cap to maintain the chamber therebetween.

4. The heat dissipation apparatus of claim 1, wherein the evaporator, the pipeline and the condenser are each provided with a wick structure on an inner wall thereof.

5. The heat dissipation apparatus of claim 4, wherein the pipeline defines a vapor passage therein along an axial direction thereof, communicating a chamber of the evaporator with the chamber of the condenser.

6. The heat dissipation apparatus of claim 5, further comprising another pipeline communicating the chamber of the evaporator with the chamber of the condenser to form a loop in cooperation with the pipeline.

7. The heat dissipation apparatus of claim 1, wherein the condenser has an elongated profile.

8. The heat dissipation apparatus of claim 1, wherein the evaporator comprises a flat rectangular casing, and the chamber of the evaporator is a flat rectangular chamber receiving the working fluid.

9. The heat dissipation apparatus of claim 1, further comprising at least one heat sink attached on the condenser.

10. The heat dissipation apparatus of claim 9, wherein the at least one heat sink comprises two heat sinks respectively attached to top and bottom sides of the condenser.

11. The heat dissipation apparatus of claim 9, wherein the at least one heat sink comprises a base plate attached to the condenser and a plurality of fins extending from the base plate.