US20110088872A1

US20110088872A1 - Heat pipe structure

Info

Publication number: US20110088872A1
Application number: US12/626,620
Authority: US
Inventors: Shyy-Woei Chang; Kuei-feng Chiang
Original assignee: Asia Vital Components Co Ltd
Current assignee: Asia Vital Components Co Ltd
Priority date: 2009-10-16
Filing date: 2009-11-26
Publication date: 2011-04-21
Also published as: TWM384988U

Abstract

A heat pipe structure includes a pipe body and a convection device. The pipe body defines a chamber enclosed in an inner wall of the pipe body. The convection device includes a rotary unit and a driving unit for creating a fluid pressure gradient in the chamber of the pipe body. The rotary unit and the driving unit are respectively located at an interior and an exterior of the pipe body. When the driving unit is excited, the rotary unit is driven to rotate under magnetic induction. With the fluid pressure gradient created in the chamber of the pipe body, the circulation of the working fluid in the chamber can be improved, and a forced convection flow of the working fluid in the pipe body is enabled to largely increase the heat transfer efficiency and heat transfer effect of the heat pipe.

Description

The application claim the priority benefit of Taiwan patent application number 098219100 filed on Oct. 16, 2009.

FIELD OF THE INVENTION

The present invention relates to a heat pipe structure, and more particularly to a heat pipe structure that includes a heat pipe having a convection device arranged thereon to produce force convection of working fluid in the heat pipe to thereby largely upgrade the heat transfer efficiency of the heat pipe.

BACKGROUND OF THE INVENTION

A heat pipe is a special material that enables rapid temperature equalization. The heat pipe is a hollow metal tubular body and is therefore very low in weight. With the ability of rapid temperature equalization thereof, the heat pipe enables excellent performance of super heat transfer. The heat pipe has been widely applied in many different fields. In the early stage, the heat pipe was employed in the aviation and space industrial field. Now, the heat pipe has been widely employed in heat exchangers, coolers, apparatus for extraction of geothermal energy, etc. to play an important role of rapid heat transfer. The heat pipe has also been considered as the most efficient heat transfer element (not heat dissipation element) in the heat dissipating devices for electronic products.
Basically, the heat pipe is a sealed chamber having a working fluid contained therein. With the constant change of the working fluid in the chamber between the liquid phase and the vapor phase, and the convection of the vapor-phase and liquid-phase working fluid between a heat-receiving end and a heat-releasing end of the heat pipe, the principle of low-pressure boiling is utilized to transfer heat on the inner surface of the chamber at the heat-receiving end, so as to increase the heat transfer coefficient at the heat-receiving end and achieve the object of heat transfer through rapid temperature equalization. According to the working mechanism of the heat pipe, a local high pressure is produced at the instant the working fluid in the liquid phase is evaporated at the heat-receiving end and converted into the vapor phase, driving the vapor-phase working fluid to flow toward the heat-releasing end, at where the vapor-phase working fluid is condensed into liquid phase again. Through the force of gravity, the capillary action, the centrifugal force and so on, the liquid-phase working fluid flows back to the heat-receiving end again. And, through the liquid/vapor phase cycle, the working fluid keeps circulating in the heat pipe.
From the above description, it is understood the vapor-phase working fluid in the heat pipe is driven to flow by a pressure difference, while the liquid-phase working fluid requires a properly designed backflow driving force according to the working state of the heat pipe in use.
According to an ideal working state of the heat pipe, the working fluid is in the liquid phase and the vapor phase at the same time with only a very small temperature difference existed between the two phases. That is, the whole chamber of the heat pipe is in a temperature equalized state. At this point, even if there is heat transmitted to the chamber of the heat pipe system due to a temperature difference between the external environment and the chamber, the temperature at the heat-receiving end and the heat-releasing end of the heat pipe chamber is the same. As a result, the condition of super heat transfer at equalized temperature occurs.
However, the above-described heat pipe operating principle exists only in an ideal condition, and the liquid/vapor phase cycle in the conventional heat pipe exists only through the capillary structure inside the heat pipe and an external heat source. Therefore, the heat transfer efficiency of the conventional heat pipe is not so good due to the limited liquid/vapor phase cycle in the heat pipe.
It is therefore tried by the inventor to develop a heat pipe structure that is able to provide increased heat transfer efficiency.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a heat pipe structure capable of providing increased heat transfer efficiency.
To achieve the above and other objects, the heat pipe structure according to a preferred embodiment of the present invention includes a pipe body and a convection device. The pipe body defines a chamber enclosed in an inner wall of the pipe body. The convection device includes a rotary unit and a driving unit respectively located at an interior and an exterior of the pipe body. When the driving unit is excited, the rotary unit is driven to rotate under magnetic induction. When the rotary unit rotates, a forced convection occurs in the chamber of the pipe body to thereby improve the heat transfer efficiency of the heat pipe and obtain excellent heat transfer effect. Therefore, the present invention provides the following advantages: (1) creating the effect of forced convection; and (2) providing excellent heat transfer efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is an exploded perspective view showing a heat pipe structure according to a first embodiment of the present invention;

FIG. 2 is an assembled view of FIG. 1;

FIG. 3 is a sectional view of a rotary unit for a heat pipe structure according to a second embodiment of the present invention;

FIG. 4 is a schematic view showing a first example of application of the heat pipe structure of the present invention and the working manner thereof;

FIG. 5 is a schematic view showing a second example of application of the heat pipe structure of the present invention and the working manner thereof; and

FIG. 6 is a schematic view showing a third example of application of the heat pipe structure of the present invention and the working manner thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2 that are exploded and assembled perspective views, respectively, of a heat pipe structure according to a first embodiment of the present invention. As shown, the heat pipe structure 1 in the first embodiment includes a pipe body 11 and a convection device 12.
The pipe body 11 defines a chamber 111 enclosed in an inner wall 112 of the pipe body 11. On the inner wall 112, at least one capillary structure layer (not shown) is provided. The capillary structure layer can be formed by sintering copper particles or aluminum particles on the inner wall 112. The chamber 111 is filled with a working fluid (not shown), which can be water or a coolant liquid.
The convection device 12 includes a rotary unit 121 and a driving unit 122, which are respectively arranged at an interior and an exterior of the inner wall 112 of the chamber 111 of the pipe body 11.
The rotary unit 121 is arranged in the chamber 111, and includes a ring body 1211 and a blade assembly 1212.
The ring body 1211 includes an outer side 1211 a facing toward the inner wall 112 of the chamber 111 and provided with a plurality of magnetic bodies 1211 c, and an inner side 1211 b. The blade assembly 1212 is located in the ring body 1211.
On the outer side 1211 a of the ring body 1211, there is formed a plurality of first teeth 1211 d, which are radially outward extended from the outer side 1211 a of the ring body 1211. A space 1211 e is formed between two adjacent first teeth 1211 d for receiving one of the magnetic bodies 1211 c therein.
On the outer side 1211 a of the ring body 1211, there is also formed a plurality of second teeth 1211 f, which are radially outward extended from the outer side 1211 a of the ring body 1211. Each of the second teeth 1211 f is formed at a free end thereof with a recess 1211 g for receiving a ball 1211 h therein. The balls 1211 h are rotatable between the recesses 1211 g and the inner wall 112 of the pipe body 11. The balls 1211 h and the recesses 1211 g cooperate with one another to serve as bearings. Since the balls 1211 h are in point contact with the recesses 1211 g and the inner wall 112 of the pipe body 11 to enable a low friction coefficient between them, the rotary unit 121 is advantageously allowed to smoothly rotate relative to the inner wall 112 of the pipe body 11.
The blade assembly 1212 includes a hub 1212 a and a plurality of blades 1212 b. Each of the blades 1212 b has a first end 1212 c connected to the hub 1212 a, and a second end 1212 d connected to the inner side 1211 b of the ring body 1211.
The driving unit 122 is externally fitted around the pipe body 11, and has a plurality of magnetic poles 1221 corresponding to the rotary unit 121. Each of the magnetic poles 1221 is formed from a plurality of silicon steel plates 1222 wound around by a plurality of coils (not shown). The magnetic poles 1221 are arranged corresponding to the magnetic bodies 1211 c on the rotary unit 121. When an electric current is supplied to the magnetic poles 1221, the magnetic poles 1221 are excited to drive the rotary unit 121 and accordingly, the blade assembly 1212 to rotate.
When the rotary unit 121 is driven to rotate, the blade assembly 1212 is brought to rotate at the same time to thereby produce forced convection in the heat pipe structure 1, which largely upgrades the heat transfer efficiency of the heat pipe structure 1.
Please refer to FIG. 3 that is a sectional view showing a rotary unit for a second embodiment of the present invention. As shown, in the second embodiment, the rotary unit includes a blade assembly 2 that includes a movable blade set 21, a fixed blade set 22, a first hub 23, a first shaft base 24, a bearing 25, and a rotary shaft 26.
The movable blade set 21 has a plurality of blades 27, each of which has a first end 27 a connected to the first hub 23 and a free second end 27 b.
The bearing 25 is received in the first hub 23.
The fixed blade set 22 has a plurality of blades 28, each of which has a third end 28 a connected to the first shaft base 24 and a fourth end 28 b connected to the inner side 1211 b of the ring body 1211.
The rotary shaft 26 has an end inserted in the bearing 25 and another end rotatably connected to the first shaft base 24.
Please refer to FIGS. 4, 5 and 6. The pipe body 11 includes a first working section 3, a second working section 4, an evaporating end 5, and a condensing end 6. The rotary unit 121 and the driving unit 122 are selectively arranged at the first working section 3 as shown in FIG. 4, at the second working section 4 as shown in FIG. 5, or at both of the first and the second working section 3, 4 as shown in FIG. 6.
The first working section 3 includes a first portion 31 and a second portion 32, which are serially connected to each other. The first portion 31 is made of a copper material or an aluminum material; and the second portion 32 is made of a polymeric material.
The second working section 4 includes a third portion 41 and a fourth portion 42, which are serially connected to each other. The third portion 41 is made of a copper material or an aluminum material; and the fourth portion 42 is made of a polymeric material.
The rotary unit 121 and the driving unit 122 are arranged on one or both of the second portion 32 and the fourth portion 42. Since the rotary unit 121 is driven to rotate when a magnetic induction is produced between the rotary unit 121 and the driving unit 122, the use of a polymeric material to make the second portion 32 and the fourth portion 42 can advantageously avoid interference with the magnetic induction between the rotary unit 121 and the driving unit 122. The polymeric material for forming the second and the fourth portion 32, 42 can be Teflon, for example.
Please refer to FIG. 4 that shows a first example of application of the present invention. As shown, in the first example of application, the rotary unit 121 and the driving unit 122, which work together to serve as a pump, are arranged at the first working section 3. When the driving unit 122 is excited to drive the rotary unit 121 to rotate, a forced convection occurs at the evaporating end 5, bringing the vapor at the evaporating end 5 to flow toward the condensing end 6 at increased convection efficiency to thereby upgrade the overall heat transfer efficiency of the heat pipe structure 1.
Please refer to FIG. 5 that shows a second example of application of the present invention. As shown, in the second example of application, the rotary unit 121 and the driving unit 122, which work together to serve as a pump, are arranged at the second working section 4. Similarly, when the driving unit 122 is excited to drive the rotary unit 121 to rotate, a forced convection occurs at the condensing end 6, bringing the liquid at the condensing end 6 to flow toward the evaporating end 5 at increased convection efficiency to thereby upgrade the overall heat transfer efficiency of the heat pipe structure 1.
FIG. 6 shows a third example of application of the present invention. As shown, in the third example of application, two sets of the rotary unit 121 and driving unit 122, which work together to serve as a pump, are separately arranged at the first and the second working section 3, 4. Similarly, when the driving units 122 are excited to drive the rotary units 121 to rotate, forced convection occurs at both of the evaporating end 5 and the condensing end 6 to largely upgrade the heat transfer coefficient and the heat transfer efficiency of the heat pipe structure 1.
Unlike the conventional heat pipe that relies on only the capillary structure to cycle the vapor and liquid phases in the heat pipe, the heat pipe structure 1 according to the present invention is provided with the convection device 12 to achieve even better heat transfer effect.
The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.

Claims

1. A heat pipe structure, comprising:

a pipe body defining a chamber enclosed in an inner wall of the pipe body; and

a convection device including a rotary unit and a driving unit, which are respectively arranged at an interior and an exterior of the pipe body.

2. The heat pipe structure as claimed in claim 1, wherein the rotary unit is fitted in the chamber and includes a ring body and a blade assembly; the ring body having an outer side and an inner side, the outer side being faced toward the inner wall of the pipe body and having a plurality of magnetic bodies provided thereon, and the blade assembly being mounted to the inner side of the ring body; and wherein the driving unit is externally mounted around the pipe body and has a plurality of magnetic poles formed thereon to correspond to the rotary unit.

3. The heat pipe structure as claimed in claim 2, wherein each of the magnetic poles includes a plurality of silicon steel plates wound around by a plurality of coils.

4. The heat pipe structure as claimed in claim 2, wherein the blade assembly includes a hub and a plurality of blades; and each of the blades having a first end connected to the hub and a second end connected to the inner side of the ring body.

5. The heat pipe structure as claimed in claim 1, wherein the rotary unit includes a movable blade set, a fixed blade set, a first hub, a first shaft base, a bearing, and a rotary shaft; the movable blade set including a plurality of blades, each of which has a first end connected to the first hub and a free second end; the bearing being received in the first hub; the fixed blade set including a plurality of blades, each of which has a third end connected to the first shaft base and a fourth end connected to the inner side of the ring body; and the rotary shaft having an end inserted in the bearing and another end rotatably connected to the first shaft base.

6. The heat pipe structure as claimed in claim 1, wherein the chamber is filled with a working fluid.

7. The heat pipe structure as claimed in claim 2, wherein the ring body has a plurality of first teeth formed on the outer side thereof, and a space being formed between two adjacent first teeth for receiving one of the magnetic bodies therein.

8. The heat pipe structure as claimed in claim 2, wherein the ring body has a plurality of second teeth formed on the outer side thereof, and each of the second teeth being formed at a free end thereof with a recess for receiving a ball therein.

9. The heat pipe structure as claimed in claim 1, wherein the pipe body further includes a first working section and a second working section.

10. The heat pipe structure as claimed in claim 1, wherein the pipe body further includes an evaporating end and a condensing end.

11. The heat pipe structure as claimed in claim 9, wherein the first working section includes a first portion and a second portion, which are serially connected to each other; the first portion being made of a material selected from the group consisting of a copper material and an aluminum material; and the second portion being made of a polymeric material.

12. The heat pipe structure as claimed in claim 9, wherein the second working section includes a third portion and a fourth portion, which are serially connected to each other; the third portion being made of a material selected from the group consisting of a copper material and an aluminum material; and the fourth portion being made of a polymeric material.

13. The heat pipe structure as claimed in claim 11, wherein the rotary unit and the driving unit are arranged on the second portion.

14. The heat pipe structure as claimed in claim 12, wherein the rotary unit and the driving unit are arranged on the fourth portion.

15. The heat pipe structure as claimed in claim 11, wherein the polymeric material is Teflon.

16. The heat pipe structure as claimed in claim 12, wherein the polymeric material is Teflon.

17. The heat pipe structure as claimed in claim 13, wherein the polymeric material is Teflon.

18. The heat pipe structure as claimed in claim 14, wherein the polymeric material is Teflon.