Abstract:
A circuit type modularized heat exchanger system comprises a heat exchange unit and a vapor chamber. The vapor chamber is jointed to the bottom of the heat exchange unit. The vapor chamber has a hollow space with a wick layer and the hollow space communicates with the tube tubes of the heat exchange unit so as to form a circuit. The heat exchanger system provides the advantages such as a better efficiency of heat transfer, less component parts and easy assembly and manufacture.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a heat exchanger system, particularly to a loop heat pipe modularized heat exchanger system.  
           [0003]    2. Description of Related Art  
           [0004]    A conventional CPU-mounted heat exchanger, as shown in FIG. 1, comprises an attach block  10 ′, a heat pipe  11 ′, a heat exchanging unit  12 ′, and a fan  13 ′. The attach block  10 ′ is mounted on a CPU  20 ′. The heat pipe  11 ′ connects with the attach block  10 ′ and the heat exchanging unit  12 ′ respectively. The fan  13 ′ is disposed by the heat exchanging unit  12 ′ to supply air for dissipating heat from the heat exchanging unit. As shown in FIG. 2, the heat pipe  11 ′ is filled with a wick layer  111 ′ so that fluid which evaporates easily flows inside the heat pipe  11 ′ along the wick layer  111 ′. The heat pipe  11 ′ has a heated end connected to the attach block  10 ′ and a cooled end connected to a lower side of the heat exchanging unit  12 ′. The attach block  10 ′ conducts heat generated by the CPU  20 ′ and cause fluid in the heat pipe  11 ′ to evaporate as vapor so that the vapor can absorb the heat and cool the CPU  20 ′. At the cooled end of the heat pipe  11 ′, the vapor condensates and returns to the heated end  112 ′ to be heated and evaporated again, performing a heat-exchange cycle. Liquid and vapor in the heat pipe  11 ′ flow counter to each other in a single pipe and pressure loss is large. If the heat pipe  11 ′ is long, the efficiency of heat exchange is worse. There is no way tightly to engage the cooling end to a base or fins of the heat exchange unit  12 ′ so that it results in a relatively large thermal resistance. The contact area between the heated end and the attach block is limited and it is not possible to eliminate a generated clearance between the heated end and the attach block so that the efficiency of heat transfer is low. If the attach block  10 ′ is thicker, it will result in a larger thermal resistance to affect the efficiency of heat dissipation. Conventional heat exchangers not only have the shortcomings mentioned above but are also expensive to manufacture due to a large number of single components.  
         SUMMARY OF THE INVENTION  
         [0005]    It is the main object of the present invention to provide a loop heat pipe modularized heat exchanger system with good efficiency of heat transfer.  
           [0006]    Another object of the present invention is to provide a loop heat pipe modularized heat exchanger system with less component parts and easy assembly and manufacture. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The present invention can be more fully understood by reference to the following description and accompanying drawings, in which:  
         [0008]    [0008]FIG. 1 is a perspective view of a conventional heat exchanger.  
         [0009]    [0009]FIG. 2 is a schematic illustration of a conventional heat pipe;  
         [0010]    [0010]FIG. 3 is a perspective view of a heat exchanger according to the present invention during use;  
         [0011]    [0011]FIG. 4 is a perspective view of a base plate of the present invention in a first embodiment;  
         [0012]    [0012]FIG. 5 is a perspective view of an external plate of the present invention in the first embodiment;  
         [0013]    [0013]FIG. 6 is a sectional view illustrating the plates shown in FIGS. 4 and 5 after being assembled;  
         [0014]    [0014]FIG. 7 is a sectional view illustrating the base plate shown in FIG. 4 and a flat plate being in a state of being assembled;  
         [0015]    [0015]FIG. 8 is a top view of a base plate of the present invention in the second embodiment thereof;  
         [0016]    [0016]FIG. 9 is a top view of a base plate of the present invention in the third embodiment thereof;  
         [0017]    [0017]FIG. 10 is a top view of a base plate of the present invention in the fourth embodiment thereof;  
         [0018]    [0018]FIG. 11 is a side view of the base plate shown in FIG. 10;  
         [0019]    [0019]FIG. 12 is a top view of the base plates of the present invention in the fifth embodiment;  
         [0020]    [0020]FIG. 13 is a sectional view of the base plate shown in FIG. 12;  
         [0021]    [0021]FIG. 14 is a top view of the base plate of the present invention in the sixth embodiment thereof;  
         [0022]    [0022]FIG. 15 is a top view of the external plate of the present invention in the sixth embodiment;  
         [0023]    [0023]FIG. 16 is a sectional view of an external plate shown in FIG. 15; and  
         [0024]    [0024]FIG. 17 is a perspective view illustrating a heat exchanger of the present invention in the sixth embodiment during use.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    As shown in FIG. 3, a heat exchanger  30  of the present invention comprises a heat exchange unit  40  and a vapor chamber  50  connected thereto. As shown in FIG. 4, the heat exchange unit  40  further comprises a plurality of metal base plates  10  worked by a press or rolled by a cutter. Each of the base plates  10  at two ends thereof has a first projection  11  and a second projection  12 , respectively, and at a middle part thereof having a plurality of depressions  13  and projections  14  alternately disposed side by side. The first and second projections  11 ,  12  have regularly arranged inward extending projecting sections  111 ,  121 , and the projections  14  each have regularly arranged projecting sections  141 ,  142  extending to opposite sides. An elongated ridge  131  is placed in each depression  13 , both ends thereof having connecting tubes  132  that reach up to the level of the top surfaces of the projections  14 . Similarly, a groove  143  is placed in each projection  14 , both ends thereof having connecting tubes  144  that reach down to the level of the bottom surfaces of the depressions  13 . The connecting tubes  132  have through holes  133  at upper ends thereof, and the connecting tubes  144  have through holes  145  at lower ends thereof so that the ridges  131  and the grooves  143  have shapes corresponding to each other.  
         [0026]    Referring to FIGS. 4 and 5, an external plate  20  of the present invention closes the through holes  133  and the grooves  143  from above. The external plate  20  is shaped like the base plates  10 , but connecting tubes  211  at the upper ends thereof and the connecting tubes  221  at the lower ends thereof provide no through hole.  
         [0027]    Referring to FIG. 6, several base plates  10  and an external plate  20  are disposed in a way of touching each other oppositely and joined together by brazing. Once the plates are fixedly attached to each other after brazing, pairs of ridges  21 ,  131 , areas between two ridges  131  and areas between grooves  143  form horizontal tubes  15  respectively. Ridges  21 ,  131  and connecting tubes  132  constitute longitudinal series connection to form vertical tubes  16 . Similarly, grooves  143  and connecting tubes  144  also constitute longitudinal series connection to form vertical tubes  16 . Air holes  17  are disposed between adjacent horizontal tubes  15 . It can be seen in FIG. 4 that the air holes  17  are formed at respective clearance between each projection and each ridge  131  and respective clearance between each depression and each groove  143 . Due to design of the projecting sections  111 ,  121 ,  141 ,  142 , turbulent effect can be enhanced while air passes through the air tubes  17  and a greater area of the base plates  10  can be contacted by air so that efficiency of heat exchange is promoted.  
         [0028]    Referring to FIG. 7, alternatively a flat plate  23  replaces the external plate  20  shown in FIG. 6 to close the through holes  133  and the depressions  143  so that the same heat exchange effect as the plate assembly shown in FIG. 6 is attained.  
         [0029]    Referring to FIG. 7 in company with FIG. 3, the vapor chamber  50  has a hollow space  51  attached with a wick layer  52  and an upper end thereof provides holes  53  corresponding to the through holes in the connecting tubes of the ridges  131  on the lowermost base plate  10  and corresponding to the grooves  143  so that the hollow space  51  is able to communicate with vertical tubes  41  of the heat exchange unit  40 . The vapor chamber  50  is filled with easily evaporated liquid and the liquid flows along the wick layer  52 . The hollow space  51  further houses a liquid tank  54  and a primary evaporation space  55 . The liquid tank  54  stores and pre-heats the liquid and the liquid tank  54  and the evaporation space  55  at upper side thereof are connected to the vertical tubes  41  of the heat exchange unit  40  respectively so that a circuit is formed.  
         [0030]    Once the present invention is in use, the metal vapor chamber  50  is placed on a heat source such as a CPU and heat dissipation paste is coated on the contact surface of the vapor chamber  50  and the CPU such that the primary evaporation space  55  can be adhered to the CPU. After the liquid in the hollow space  51  having been heated, the liquid is vaporized and rises to pass through the most of the holes  53  and enter the heat exchange unit  40 . Further, the vapor rises in the vertical tubes  41  thereof and moves along the horizontal tubes  42  from the right to the left. During the vapor flowing in the tubes, the vapor contacts the lower temperature tube wall and condenses as liquid. The vapor further flows toward the right side of the figure along the horizontal tubes  42  and falls down along the vertical tubes  41  to the liquid tank  54  of the vapor chamber  50  via the holes  53 . Then, the liquid passes through the wick layer  52  and arrives the evaporation space  55  to be heated and vaporized again such that heat exchange cycle can be repeated over and over. The cold air  60  or other fluid utilized in the present invention is blown to the right toward the heat exchange unit  40  from the left as shown in FIG. 3. Further, the cold air  60  enters the heat exchange unit  40  via air holes at both lateral sides of the horizontal tubes  42  to perform heat exchange. Since flow direction of the cold air is reversed to that of the liquid in the horizontal tubes  42 , a counter flow arrangement is formed so that a best efficiency of heat exchange can be obtained. The liquid tank  54  and the primary evaporation space  55  at the bottom thereof can be paved with a wick layer  52 . Also, the hollow chamber  51  at the lateral side and the upper side thereof can be optionally paved with another wick layer  52 .  
         [0031]    The present invention combines a conventional attach block and heat guide pipes as a single base and the heat guide pipes and tubes in the heat exchange unit can be designed as a single circuit. In this way, not only thermal resistance resulting from a conventional attach block is eliminated but also thermal resistance resulting from the attach block, the heat guide pipes and the heat exchange unit being insufficiently tight fit is eliminated. Further, pressure losses resulting from flow of the vapor being reversed to the liquid in heat guide pipes can be eliminated and the efficiency of heat exchange can be promoted greatly. Furthermore, the modular design of the present invention is advantageous for the automatic assembly and manufacture so that it is capable of saving the manufacturing cost greatly.  
         [0032]    Referring to FIG. 8 in company with FIG. 4, a second embodiment of the present invention provides a further base plate  80  in which oval-shaped connecting tubes  801 ,  802 , has replaced the circular connecting tubes  132 ,  144  shown in the first embodiment. Because the oval shaped cross section has a larger area than the circular cross section, the connecting tubes on two adjacent levers can be joined more easily and firmly.  
         [0033]    Referring to FIG. 9 in company with FIG. 8, a third embodiment of the present invention has base plates  81 . Each of the base plates  81  provides with additional circular connecting tubes  811  with or without through holes on each ridge thereof instead of the ridge  803  on the base plates  80  shown in FIG. 8. Furthermore, each groove on the base plate  81  has additional circular connecting tubes  812  with or without through holes instead of the groove  804  shown in FIG. 6. Thus, the connecting tubes  811 ,  812  make two adjacent base plates  81  be assembled more easily and firmly.  
         [0034]    As shown in FIGS. 10 and 11 in company with FIG. 8, a fourth embodiment of the present invention has base plates  82  and each of the base plates  82  is provided with reinforcing ribs  821  under each of the projecting sections.  
         [0035]    As shown in FIGS. 12 and 13 in company with FIG. 8, a fifth embodiment of the present invention provides a further base plate  83  in which ridges  831  are arranged to replace the grooves  804  and projection sections  805  shown in FIG. 8 and projecting sections  806 ,  807 ,  808 ,  809  shown in FIG. 8 are replaced with reinforcing ribs  832 ,  833 ,  834 ,  835 , respectively.  
         [0036]    As shown in FIG. 14 in company with FIG. 8, a sixth embodiment of the present invention provides a further base plate  71  which is similar to the base plate  80  shown in FIG. 8 except connecting tubes  713 ,  714  being placed at one ends of each ridge  711  and each groove  712  respectively and projecting sections  715 ,  716  being placed at the other ends of each ridge  711  and each groove  712  respectively.  
         [0037]    Referring to FIGS. 15 and 16 in company with FIG. 14, a seventh embodiment of the present invention provides a further external plate  72  which is a flat plate with grooves  721  and projecting sections  722  corresponding to the grooves  712  and the projecting sections  716  of the base plates  71 . The external plate  72  can be joined to a side of the base plate  71  in a way of the grooves  721  in the external plate  72  closing the grooves  712  in the base plate  71 . Alternatively, the external plate  72  is a flat plate without grooves  721  to cover the grooves  712  in the base plate  71  only.  
         [0038]    Referring to FIG. 17 in company with FIGS. 14 and 15, an eighth embodiment of the present invention provides another heat exchange unit  70 , which is composed of multiple base plates  71  being disposed to oppositely overlap each other. Two opposite sides of the base plates  71  are connected to an external plate  72  respectively. The base plates  71  and the external plates  72  at the joining sections  715 ,  716 ,  722  thereof are disposed over and connected to a vapor chamber  90 . Ridges  711  and grooves  712  of the base plate  71  are formed as vertical tubes  73  and the connecting tubes  713  and the ridges  711  as well as connecting tubes  714  and the grooves  712  are form horizontal tubes  74  respectively. The vapor chamber  90  has a hollow space  91  with two lateral sides thereof having a liquid tank  911  and a primary evaporation space  912 . Liquid in the hollow space  91  is heated up and forms vapor to rise along the vertical tubes  73  via the primary evaporation  912 . Further, the vapor flows along the horizontal tubes  74  toward two lateral sides thereof and moves downward along vertical tubes  73  at the lateral sides. The condensed liquid flows back to the wick layer  92  in the vapor chamber  90  for being heated up and vaporized again. In this way, the heat exchange cycle can be repeated over and over.  
         [0039]    While the invention has been described with reference to preferred embodiments thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention which is defined by the appended claims.