Patent Publication Number: US-2007107873-A1

Title: Water-Cooling Head and Method for making the same

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a water-cooling heat-dissipating structure and a method for making the same, and in particular to a water-cooling head suitable for electronic elements and a method for making the same.  
      2. Description of Prior Art  
      The operation of any electrical apparatus will inevitably generate excessive heat due to the low efficiency and friction. Especially, the products made by modern technological industries tend to be developed with increasing precision. For example, integrated circuits or personal electronic products are gradually miniaturized in size but the heat generated by those products is increasing. Especially, since the arithmetic efficiency of the computer improves continuously, the total heat generated by the computer itself increases accordingly. Further, the heat-generating source in the computer is not limited to CPU only, other high-speed devices such as chip model, graph processing unit, dynamic memory and hard disc also generate considerable amount of heat. Therefore, in order to make the computer to operate normally under an allowable working temperature, it is necessary to use additional heat-dissipating devices to reduce the unfavorable effect of the heat on the operation of computer elements.  
      The fan is a kind of heat-dissipating device, which is simple, convenient and most wildly used. The rotation of fan blades causes the air around the heat-generating element to flow rapidly, so that the heat generated by the heat-generating element can be rapidly taken away, thereby to achieve the heat-dissipating effect. However, the actual heat-dissipating effect of the fan falls short of expectation because the heat-dissipating area cannot satisfy its heat-conducting efficiency. Thereafter, a plurality of heat-dissipating pieces are attached to the heat-generating element to increase the heat-dissipating area and thus the heat-conducting efficiency, with the airflow generated by the fan, the heat generated by the heat source can be taken away. However, the amount of the airflow generated by the fan is so limited that the heat-dissipating effect of the fan cannot be efficiently improved. Therefore, in conventional art, several sets of heat-dissipating fans are connected in series to increase the total airflow, however, such a measure is difficult to implement because of the restriction of space. If the rotation speed of the motor is raised to increase the amount of airflow, it becomes more difficult to manufacture the motor. In addition, there is still an upper limit in increasing the rotation speed of the motor, and the larger rotation speed of the motor will generate unfavorable noise, vibration and heat, which further restrict the implementation thereof.  
      According to the above, the increase of the efficiency of the fan is limited so that the heat-dissipating effect and the range for reducing temperature cannot be improved to a large extent. In order to satisfy the demand for the heat dissipation of electronic elements operated in high speed, it is necessary to find out other solutions. Therefore, a conventional art discloses a water-cooling heat-dissipating device, in which a water-cooling head is adhered onto a heat-generating element such as CPU or disk driver. A motor is used to draw out the cooling liquid from a tank and introduce the cooling liquid into the water-cooling head. After the cooling liquid is heat-exchanged with the heat absorbed by the water-cooling head from the heat-generating element, the cooling liquid flows to a heat-dissipating module via the water-cooling head. After being cooled, the cooling liquid returns to the tank. With the circulation of the cooling liquid, the heat-dissipating effect can be facilitated. As a result, the temperature of the heat-generating element can be reduced, thereby to smooth the operation of the whole system.  
      Although the cooling liquid can be heat-exchanged with the heat source via the water-cooling head, which produces a heat-dissipating effect superior to that caused by airflow, in the above-mentioned water-cooling head, the heat-absorbing surface of the water-cooling head is only concentrated in the same place, so that only a portion of the cooling liquid entering the water-cooling head can be heat-exchanged with the heat-absorbing surface. Further, the staying time of the cooling liquid within the water-cooling head is too short, so that the cooling liquid is immediately guided out via another pipe without absorbing enough heat. Therefore, another conventional art discloses a water-cooling heat-dissipating structure, as shown in  FIG. 1 , in which the inside of the water-cooling head  101  is fixedly provided with a plurality of heat-dissipating pieces  102  to form a plurality of one-way flowing paths. After the cooling liquid is introduced into the water-cooling head  101 , the plurality of heat-dissipating pieces can increase the heat-dissipating area. When the cooling liquid passes through the plurality of one-way flowing paths, the cooling liquid is heat-exchanged with the heat-dissipating pieces, thereby to improve the heat-dissipating effect.  
      In the above-mentioned heat-dissipating structure, the heat-dissipating pieces can increase the heat-dissipating area and the plurality of flowing paths formed by the heat-dissipating pieces can guide the flowing direction of the cooling liquid within the water-cooling head, so that the contacting area between the cooling liquid and the heat-dissipating pieces is substantially increased to enhance the heat exchange, however, the space of the one-way flowing path is not fine enough, so that the cooling liquid still passes through the one-way flowing paths rapidly. As a result, the staying time of the cooling liquid still cannot be substantially increased, so that the cooling liquid cannot absorb enough heat from the heat-dissipating pieces to efficiently improve the heat-dissipating effect. Therefore, there is still plenty of room for improvement.  
     SUMMARY OF THE INVENTION  
      In view of the above drawbacks, the object of the present invention is to provide a water-cooling head and a method for making the same. Fine flowing paths formed by irregularly stacking heat-conducting particles can disturb the flow of the cooling liquid, thereby to substantially increase the staying time of the cooling liquid within the water-cooling head. Further, by means of the heat exchange with the contacting area formed by the heat-conducting particles, the cooling liquid can substantially absorb the heat from the heat-generating element. As a result, the heat-dissipating effect can be efficiently improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded perspective view showing a conventional water-cooling head;  
       FIG. 2  is a top view showing the second cover of the water-cooling head of the present invention;  
       FIG. 3  is an exploded perspective view of the present invention;  
       FIG. 4  is a schematic view showing the manufacturing process of the flowing path microstructure of the present invention;  
       FIG. 5  is a schematic view showing the forming process of the flowing path microstructure of the present invention;  
       FIG. 6  is a schematic view showing the flowing path microstructure of the present invention;  
       FIG. 7  is a schematic view showing the operation of the flowing path microstructure of the present invention;  
       FIG. 8  is a flowchart showing the manufacturing method of the present invention;  
       FIG. 9  is a schematic view showing the flowing path microstructure according to another embodiment of the present invention;  
       FIG. 10  is a schematic view showing the structure of parallel heat-dissipating pieces of the present invention;  
       FIG. 11  is a schematic view showing the structure of a heat-conducting pillar of the present invention; and  
       FIG. 12  is a schematic view showing the flowing path microstructure according to a further embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      With reference to  FIG. 2 , it can be seen that, the water-cooling head  1  of the present invention is formed into a hollow sealed box by a first cover  11  and a second cover  12 . The profile of the water-cooling head  1  can be suitably changed according to different demands. The first cover  11  and the second cover  12  of the present embodiment can be formed into a rectangular body (but not limited thereto) and made of suitable materials such as metal or ceramic. The first cover  11  and the second cover  12  are connected by means of welding, riveting or binding. In addition, an intake pipe  111  and a drainpipe  112  extend outwardly (also upwardly) from the surfaces of left and right sides of the first cover  11 , respectively, thereby to provide the cooling liquid with pipes for entering and draining from the water-cooling head  1 . Further, the bottom surface of the second cover  12  is provided with a contacting surface  121  thereon for contacting with a heat-generating source (not shown).  
      With reference to  FIG. 3 , it is an exploded perspective view of the present invention. The inside of the second cover  12  is further provided with a flowing path microstructure  122 . The flowing path microstructure  122  is formed by irregularly stacking a plurality of heat-conducting particles  2 . The gaps among the particles are formed into fine flowing paths. The heat-conducting particles  2  are formed into circular, square or other irregular shape having different dimensions. Further, the plurality of heat-conducting particles  3  is made of heat-conducting materials such as metal or ceramic.  
      With reference to  FIG. 4  first, the method for making the water-cooling head  1  is described as follows. A mold  3  is disposed into a predetermined position inside the second cover  12 . Then, the plurality of heat-conducting particles  2  which are previously made and formed are poured into the mold  3  and irregularly stacks to completely fill the mold  3 . With reference to  FIG. 5 , after the heat-conducting particles  2  have completely filled the mold  3 , the plurality of heat-conducting particles  2  within the mold  3  are tightly combined with each other and fixedly provided on the surface of the second cover  12  by means of high-temperature sintering. After being taken out of the mold  3 , the plurality of heat-conducting particles  2  can be formed into the flowing path microstructure  122  as shown in  FIG. 6 . Next, with reference to  FIG. 7 , the first cover  11  and the second cover  12  are finally connected by means of welding, riveting or binding, thereby to finish the water-cooling head  1 .  
      With reference to  FIG. 8 , the flowchart illustrates the method for making the water-cooling head  1 . First, the mold  3  is disposed into a predetermined position of the second cover  12  (S 1 ). Then, the heat-conducting particles  2  are poured into the mold  3  and irregularly stack to fill the mold  3  (S 2 ). Gaps are formed among each heat-conducting particles  2 . By means of high-temperature sintering, the heat-conducting particles are tightly combined with each other to form the flowing path microstructure  122  (S 3 ). Finally, the first cover  11  and the second cover  12  are connected to each other by means of welding, riveting or binding, thereby to finish the water-cooling head  1  (S 4 ).  
      With reference to  FIG. 7  again, when the water-cooling head  1  is adhered onto the heat-generating element  1 , the heat generated by the heat-generating element  4  can be absorbed by the contacting surface  121 . Then, the heat is conducted to the heat-conducting particles  2  inside the water-cooling head  2 . After the cooling liquid enters the water-cooling head  1  via the intake pipe  111 , the flowing path microstructure  122  disturbs the flow of the cooling liquid to substantially prolong the staying time of the cooling liquid within the water-cooling head  1 . As a result, the cooling liquid is heat-exchanged with the plurality of heat-conducting particles  2  to absorb enough heat. Finally, the cooling liquid is drained out via the drainpipe  112 . In this way, the heat-dissipating operation is completed.  
      With reference to  FIG. 9 , it shows another embodiment of the resent invention. The first cover  11  and the second cover  12  are provided with a plurality of heat-dissipating pieces (fins)  113 ,  123  perpendicular to the surface thereof, respectively. The heat-dissipating pieces  113 ,  123  are alternatively arranged to form a plurality of intervals. Those intervals are communicated with each other to form circuitous one-way flowing paths. Thereafter, the plurality of heat-conducting particles  2  are disposed into the intervals to form the flowing path microstructure  122 . Therefore, when the contacting surface  121  of the water-cooling head  1  is adhered to the heat-generating element  4 , the heat is absorbed by the contacting surface  121 , conducted to the heat-dissipating pieces  113 ,  123  and dissipated onto the heat-conducting particles  2 . After the cooling liquid enters the one-way flowing paths via the intake pipe  111 , the flowing path microstructure  122  disturbs the flow of the cooling liquid and the plurality of heat-dissipating pieces  113 ,  123  and the heat-conducting particles  2  are heat-exchanged, so that the cooling liquid can take the heat away and drain out via the drainpipe  112 . In this way, the heat-dissipating operation can be achieved. Alternatively, as shown in  FIG. 10 , only the plurality of heat-dissipating pieces  123  are vertically provided on the surface of the second cover  12  to form a plurality of parallel flowing paths. Then, the flowing path microstructure  122  formed by the heat-conducting particles  2  are disposed into the flowing path.  
      Alternatively, at a position of the second cover  12  in which the flowing path microstructure  122  is to be provided, as shown in  FIG. 11 , at least one (one shown in the figure) heat-conducting post  5  is previously provided to erect upright on the inside surface of the second cover  12 . Then, the flowing path microstructure  122  formed by the heat-conducting particles  2  are provided around the heat-conducting post  5 .  
      With reference to  FIG. 12 , it shows another embodiment of the present invention. On the first cover  11 , a third pipe  114  is provided to be opposite to the contacting surface  121 . At the same time, a hole is provided at a position in which the microstructure  122  within the water-cooling head  1  is opposite to the third pipe  114 . Therefore, after the cooling liquid is introduced via the third pipe  114 , it directly flows through the contacting surface  121  adhered to the heat-generating element  4  and is heat-exchanged with the contacting surface  121 . After this, the cooling liquid drains out via the flowing path microstructure  122  and the drainpipe  112 . Therefore, the number of the pipes is not limited.  
      Although the present invention has been described with reference to the foregoing preferred embodiments, it will be understood that the invention is not limited to the details thereof Various equivalent variations and modifications can still be occurred to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims.