Patent Application
20110088872
The application claim the priority benefit of Taiwan patent application number 098219100 filed on Oct. 16, 2009.
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.
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.
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.
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
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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 1211a facing toward the inner wall 112 of the chamber 111 and provided with a plurality of magnetic bodies 1211c, and an inner side 1211b. The blade assembly 1212 is located in the ring body 1211.
On the outer side 1211a of the ring body 1211, there is formed a plurality of first teeth 1211d, which are radially outward extended from the outer side 1211a of the ring body 1211. A space 1211e is formed between two adjacent first teeth 1211d for receiving one of the magnetic bodies 1211c therein.
On the outer side 1211a of the ring body 1211, there is also formed a plurality of second teeth 1211f, which are radially outward extended from the outer side 1211a of the ring body 1211. Each of the second teeth 1211f is formed at a free end thereof with a recess 1211g for receiving a ball 1211h therein. The balls 1211h are rotatable between the recesses 1211g and the inner wall 112 of the pipe body 11. The balls 1211h and the recesses 1211g cooperate with one another to serve as bearings. Since the balls 1211h are in point contact with the recesses 1211g 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 1212a and a plurality of blades 1212b. Each of the blades 1212b has a first end 1212c connected to the hub 1212a, and a second end 1212d connected to the inner side 1211b 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 1211c 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.
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The movable blade set 21 has a plurality of blades 27, each of which has a first end 27a connected to the first hub 23 and a free second end 27b.
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 28a connected to the first shaft base 24 and a fourth end 28b connected to the inner side 1211b 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.
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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.
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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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 098219100 | Oct 2009 | TW | national |
