Abstract:
An integrated liquid cooling unit comprising a liquid pump and a U-shaped flat tube. An adapter rigidly connects and establishes fluid communication between the pump and the tube creating an integrated unit for cooling an electronic chip via a closed loop. Heat is rejected from the coolant through cooling fins disposed between the legs of the U-shaped tube to passing air being propelled by a blower assembly.

Description:
FIELD OF INVENTION 
       [0001]    An integrated liquid cooling unit for cooling a heat-producing electronic device. 
       BACKGROUND OF THE INVENTION 
       [0002]    The operating speed of computers is constantly being improved to create faster and faster computers. With this comes increased heat generation and a need to effectively dissipate that heat. 
         [0003]    Heat exchangers and heat sink assemblies have been used that apply natural or forced convection cooling methods to dissipate heat from electronic devices that are highly concentrated heat sources such as microprocessors and computer chips. These heat exchangers typically use air to directly remove heat from the electronic devices; however air has a relatively low heat capacity. Thus, many heat exchangers used to remove heat from electronic applications are liquid-cooled units, which employ a cold plate in conjunction with high heat capacity fluids. 
         [0004]    One such heat exchanger is illustrated in U.S. Pat. No. 6,166,907 to Chien wherein a liquid pump cycles a liquid coolant through a tube to a first radiator mounted atop an electronic device. Heat is then transferred from the electronic device to the liquid coolant. The heated liquid coolant is directed via a pipe to a second radiator including a flat tube extending in serpentine fashion. Cooling fins of varying heights are disposed between the spaced and parallel legs of each of the U-shapes. A fan blows air between the legs of the second radiator and through the cooling fins. 
         [0005]    U.S. Pat. No. 6,867,973 illustrates a heat exchanger which includes a passage mounted atop an electronic device producing heat. The passage includes a plurality of recessed and raised portions for increasing turbulence in the liquid coolant and increasing the rate at which heat is transferred from the electronic device to the liquid coolant. 
       SUMMARY OF THE INVENTION AND ADVANTAGES 
       [0006]    The invention provides for an integrated liquid cooling unit assembly including an adapter that is an integral component rigidly connecting the liquid pump to the tube to prevent relative movement between the liquid pump and the tube. The adapter includes an input manifold establishing fluid communication between the outlet of the liquid pump and the heat exchange leg of the tube and an output manifold establishing fluid communication between the inlet of the liquid pump and the return leg of the tube. 
         [0007]    Accordingly, the subject invention provides a unitary or integrated liquid cooling unit which can be mounted as a single unit to a heat-producing electronic device for removing heat. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0009]      FIG. 1  is a perspective view of a first embodiment of the subject invention. 
           [0010]      FIG. 2  is a cross sectional view taken along the line  2 - 2  of  FIG. 1 . 
           [0011]      FIG. 3  is an exploded and perspective view of a second embodiment of the subject invention. 
           [0012]      FIG. 4  is a perspective view of an alternate embodiment of the blower assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an integrated liquid cooling unit  20  for cooling an electronic device constructed in accordance with the subject invention is generally shown in  FIG. 1 . 
         [0014]    A liquid pump  22 , generally indicated, includes a housing  24  having a housing width w h  and a housing height h and an inlet  26  and an outlet  28 . The liquid pump  22  is preferably either an electrokinetic or a thermokinetic pump but any suitable pump may be employed. The pump housing  24  is typically made of plastic but any suitable material may be used. An accumulator, or a coolant volume compensator, may be disposed in the liquid pump  22  to regulate an increase in pressure in the coolant caused by thermal expansion. A coolant charge port may also be disposed in the liquid pump  22 . 
         [0015]    A flat tube  30 , generally indicated, extends in a U-shape through a heat exchange leg  32  defining an entrance  34  and a return leg  36  defining an exit  38 . The flat tube  30  has a cross-section presenting an interior surface  40 . Each leg of the folded flat tube  30  presents an outside wall  42  and an inside wall  44  interconnected by rounded sides  46  defining a tube width w t . The distance between the outside walls  42  of the flat tube  30  is no less than the housing height h of the liquid pump  22  and the tube width w t  is no less than the housing width w h  of the liquid pump  22 . The tube  30  has a wall thickness preferably in the range of 2-3 mm but a thickness outside of this range may also be employed depending on the pressure exerted by the working fluid. The tube  30  is preferably made of aluminum but any suitable material may be employed. 
         [0016]    An adapter  48 , generally indicated, is an integral component rigidly connecting the liquid pump  22  to the flat tube  30 , as by brazing. The adapter  48  includes an input manifold  50  establishing fluid communication between the outlet  28  of the liquid pump  22  and the entrance  34  of the flat tube  30  and the adapter  48  includes an output manifold  52  establishing fluid communication between the inlet  26  of the liquid pump  22  and the exit  38  of the flat tube  30 . 
         [0017]    In one embodiment as shown in  FIGS. 1 and 2 , the adapter  48  is fan-shaped and has a rectangular cross-sectional area increasing in size from the liquid pump  22  to the flat tube  30 . The input manifold  50  of the adapter  48  diverges in a fan-shape from the outlet  28  of the liquid pump  22  to the entrance  34  of the flat tube  30  and the output manifold  52  extends parallel to the input manifold  50  and diverges in a fan-shape from the inlet  26  of the liquid pump  22  to the exit  38  of the flat tube  30 . 
         [0018]    In another embodiment as shown in  FIG. 3 , the adapter  48  is a plate  54  perpendicular to and covering the entrance  34  and the exit  38  of the flat tube  30 . The input manifold  50  of the plate  54  includes a first port  56  extending from the outlet  28  of the liquid pump  22  to the entrance  34  of the flat tube  30 . The output manifold  52  of the plate  54  includes a second port  58  extending parallel to the first port  56  from the inlet  26  of the liquid pump  22  to the exit  38  of the flat tube  30 . The first and second ports  56 ,  58  have the same opening area as the inlet  26  and the outlet  28  of the liquid pumps  22  and extend across the adapter  48  to the wider entrance  34  and exit  38  of the flat tube  30 . 
         [0019]    A plurality of flow interrupters, defined by ribs  60 , is disposed on the inside wall  44  of the heat exchange leg  32  of the flat tube  30 . The ribs  60  extend across the interior surface  40  of the flat tube  30  for creating turbulence in the flow of the coolant to increase the rate at which heat is transferred from the flat tube  30  to the coolant. The ribs  60  define a reduced cross-sectional area along a section of the inside wall  44  of the heat exchange leg  32  and a rectangular recess  62  extending across the inside wall  44  of the heat exchange leg  32  between the rounded sides  46  thereof and define an un-recessed section  64  of the heat exchange leg  32 . 
         [0020]    A plurality of long cooling fins  66  extend along and into the rectangular recess  62  of said flat tube  30  and between the legs  32 ,  36  of the flat tube  30 . A plurality of short cooling fins  68  extend along the un-recessed section  64  of the heat exchange leg  32  and between the legs  32 ,  36  of the flat tube  30 . The fins  66 ,  68  preferably have a height in the range of 8-9 mm but a height outside of this range may also be employed depending on the pump housing height h, which is about 25 mm. 
         [0021]    A blower assembly  70 , generally indicated, is attached to and extends between the rounded sides  46  on one side  46  of the flat tube  30 . The blower assembly  70  includes at least one fan  72  for blowing air over the cooling fins  66 ,  68  between the legs  32 ,  36  of the flat tube  30 . 
         [0022]    In the embodiment shown in  FIG. 1 , the blower assembly  70  includes a first cover  74  extending axially along and between the legs  32 ,  36  of the flat tube  30 . The first cover  74  of the blower assembly  70  defines a plurality of holes  76 . A fan  72  is disposed in each of the holes  76  for propelling air between the heat exchange and the return legs  32 ,  36  of the flat tube  30  and through the cooling fins  66 ,  68 . 
         [0023]    In the embodiment shown in  FIG. 3 , the blower assembly  70  includes a fan housing  78  having a spiral periphery extending about a first fan axis A to an exhaust  80 . A fan  72  is supported for rotation about the first fan axis A. A hood  82  extends between the exhaust  80  of, the fan housing  78  and the legs  32 ,  36  of the flat tube  30  for directing air from the exhaust  80  to the space between the legs  32 ,  36  of the flat tube  30  and through the cooling fins  66 ,  68 . The hood  82  has a rectangular cross-sectional area that increases in size from the exhaust  80  of the fan housing  78  to the rounded sides  46  of the legs  32 ,  36  of the flat tube  30 . The invention may also include a cross-flow blower assembly  70  having a blower motor  84  at one end and an air intake at the other end. 
         [0024]    In the embodiment shown in  FIG. 4 , the blower assembly  70  includes a second fan axis B extending parallel to the heat exchange and return legs  32 ,  36  of the flat tube  30  and disposed on one side  46  of the flat tube  30 . A blower motor  84  is disposed along the second fan axis B and a hub  86  is operatively connected to the blower motor  84 . The hub  86  extends along the second fan axis B from the blower motor  84  to a distal end. A plurality of fan vanes  88  are disposed about the hub  86  and extend radially from and axially along the hub  86  between the blower motor  84  and the distal end. A second cover  90  being L-shaped is disposed about the hub  86  and extends from the blower motor  84  to the distal end. The L-shaped cover has a lower edge  92  rigidly attached to said heat exchange leg  32  of said flat tube  30 . An end plate  94  is disposed at the distal end of the second cover  90  and perpendicular to the hub  86 . 
         [0025]    The liquid pump  22  and the adapter  48  and the blower assembly  70  are all disposed between the planes of the outside walls  42  of the legs  32 ,  36  of the flat tube  30  and are rigidly connected together to define a unified integrated liquid cooling unit  20  for removing heat from an electronic device engaging the outside wall  42  of the heat exchange leg  32  opposite to the recess in the inside wall  44  of the heat exchange leg  32 . Heat is transferred from the electronic device through the outside wall  42  of the heat exchange leg  32  of the flat tube  30  to the turbulent flow of the liquid coolant. The heat is then rejected from the liquid coolant flowing through the return leg  36  of the flat tube  30  to the cooling fins  66 ,  68  and to the air moved over the cooling fins  66 ,  68  by the blower assembly  70 . 
         [0026]    Accordingly, the invention provides a method of fabricating an integrated liquid cooling unit  20  of the type including a flat tube  30  having an entrance  34  and an exit  38  and having a cross-section presenting outside and inside flat walls  42 ,  44  in each leg interconnected by rounded sides  46 . The method includes the steps of forming a rectangular recess  62  in the outside wall  42  of the flat tube  30  to define a rib  60  extending across the interior surface  40  of the flat tube  30  and to define a rectangular recess  62  in the inside wall  44  of the flat tube  30  and an un-recessed section  64  of the flat tube  30 . 
         [0027]    The method also includes the step of bending the flat tube  30  into a U-shape defining a heat exchange leg  32  including the rectangular recess  62  and defining a return leg  36 . The method includes the steps of inserting a plurality of long cooling fins  66  between the heat exchange and return legs  32 ,  36  of the flat tube  30  along the recessed section of the heat exchange leg  32  and inserting a plurality of short cooling fins  68  between the heat exchange and return legs  32 ,  36  of the flat tube  30  along the un-recessed section  64  of the heat exchange leg  32 . 
         [0028]    The method also includes the step of connecting an adapter  48  having an input manifold  50  and an output manifold  52  to the flat tube  30  to a liquid pump  22  having an inlet  26  and an outlet  28 . The method also includes the step of establishing fluid communication between the outlet  28  of the liquid pump  22  and the entrance  34  of the flat tube  30  through the input manifold  50  of the adapter  48  and establishing fluid communication between the inlet  26  of the liquid pump  22  and the exit  38  of the flat tube  30  through the output manifold  52  of the adapter  48 . 
         [0029]    The method also includes the step of positioning a blower assembly  70  including at least one fan  72  for propelling air across the cooling fins  66 ,  68  against one side  46  of the flat tube  30 . 
         [0030]    The method of fabricating the integrated liquid cooling unit  20  is completed by brazing the adapter  48  to the flat tube  30  and the liquid pump  22 , brazing the blower assembly  70  to the one side  46  of the flat tube  30 , and brazing the cooling fins  66 ,  68  to the inner walls  42 ,  44  of the legs  32 ,  36  of the flat tube  30  to form one integral unit. The components of the integrated liquid cooling unit  20  are preferably brazed together but any suitable means of rigidly connecting the components of the integrated liquid cooling unit  20  may be employed. 
         [0031]    While the invention has been described with reference to an exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.