Patent Publication Number: US-2007110559-A1

Title: Integrated liquid cooling system

Description:
CROSS-REFERENCES TO RELATED APPLICATION  
      This application is related to U.S. patent application Ser. No. 11/308,547 filed on Apr. 5, 2006 and entitled “INTEGRATED LIQUID COOLING SYSTEM”; the co-pending U.S. patent application is assigned to the same assignee as the instant application. The disclosure of the above-identified application is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to a liquid cooling system for dissipation of heat from heat-generating components, and more particularly to an integrated liquid cooling system suitable for removing heat from electronic components of computers.  
     DESCRIPTION OF RELATED ART  
      With the continuing development of computer technology, electronic packages such as central processing units (CPUs) are generating more and more heat that requires immediate dissipation. Conventional heat dissipating devices such as combined heat sinks and fans are not effective enough to dissipate the heat generated by modern integrated chip packages. Liquid cooling systems have therefore been increasingly used in computer technology to cool these electronic packages.  
      A typical liquid cooling system generally comprises a heat-absorbing member, a heat-dissipating member and a pump. These individual components are connected together in series so as to form a heat transfer loop. In practice, the heat-absorbing member is maintained in thermal contact with a heat-generating component (e.g. a CPU) for absorbing heat generated by the CPU. The liquid cooling system employs a coolant circulating through the heat transfer loop so as to continuously transport the thermal energy absorbed by the heat-absorbing member to the heat-dissipating member where the heat is dissipated. The pump is used to drive the coolant, after being cooled in the heat-dissipating member, back to the heat-absorbing member.  
      In the typical liquid cooling system, the heat-absorbing member, the heat-dissipating member and the pump are connected together generally by a plurality of connecting tubes so as to form the heat transfer loop. However, the typical liquid cooling system has a big volume and occupies more room in a computer system, and is not adapted to the small size necessary for a personal computer. Furthermore, the liquid cooling system has many connecting tubes with a plurality of connections, which are prone to leakage of the coolant so giving the system low reliability and high cost. Moreover, the heat-absorbing member, the heat-dissipating member and the pump are to be located at different locations when mounted to the computer system. In this situation, mounting of the liquid cooling system to the computer system or demounting of the liquid cooling system from the computer system is tiresome and time-consuming work. In addition, vibration and noise produced by the reciprocating pump adversely affect the heat-generating component and the computer system.  
      Therefore, it is desirable to provide a liquid cooling system which overcomes the foregoing disadvantages.  
     SUMMARY OF THE INVENTION  
      An integrated liquid cooling system in accordance with an embodiment for removing heat from a heat-generating electronic component includes a base, a pump mounted in the base and a heat-dissipating member communicating with the pump and coupling with the base. The pump includes a casing having a chamber. A rotor, a partition seat and a stator are in turn received in the chamber. A top cover is attached on the casing. The casing includes a bottom plate absorbing heat generated by the electronic component. A plurality of pairs of interconnecting surfaces are formed between the partition seat and the rotor and the bottom plate, one surface of the at least one pair of interconnecting surfaces forming a plurality of grooves or protrusions, thereby forming a fluid film therebetween for dynamically supporting thrust on the rotor during rotation of the rotor.  
      Other advantages and novel features of the present invention will become more apparent from the following detailed description of preferred embodiment when taken in conjunction with the accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Many aspects of the present apparatus and method can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.  
       FIG. 1  is an assembled, isometric view of a liquid cooling system in accordance with a preferred embodiment of the present invention;  
       FIG. 2  is an exploded view of  FIG. 1 , but shown from another aspect;  
       FIG. 3  is an isometric view of a heat-dissipating member of the liquid cooling system of  FIG. 2 ;  
       FIG. 4  is an exploded view of a pump of the liquid cooling system of  FIG. 2 ;  
       FIG. 5  is a view similar to  FIG. 4 , but shown from a different aspect;  
       FIGS. 6-8 ,  11 ,  14  are isometric views of a rotor in accordance with other embodiments.  
       FIG. 9  is an exploded view of a pump of the liquid cooling system of  FIG. 2  with a minor modification;  
      FIGS.  10 , 12 - 13  are isometric views of a partition seat in accordance with other embodiments.  
       FIG. 15  is an exploded view of a pump of a liquid cooling system in accordance with a second embodiment;  
       FIG. 16  is an exploded view of a pump of a liquid cooling system in accordance with a third embodiment;  
       FIG. 17  is an exploded view of a pump and a base of a liquid cooling system in accordance with a fourth embodiment;  
       FIG. 18  is an exploded view of a pump and a base of a liquid cooling system in accordance with a fifth embodiment; and  
       FIG. 19  is an assembled, cross-sectional view of the pump and the base of  FIG. 18 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  and  FIG. 2  illustrate a liquid cooling system in accordance with a preferred embodiment of the present invention. The liquid cooling system includes a base  10 , a pump  20  mounted in the base  10 , and a heat-dissipating member  30  communicating with the pump  20  and coupling with the base  10 . The base  10 , the pump  20  and the heat-dissipating member  30  are connected together in series without any connecting tubes. A heat transfer loop is formed by the base  10 , the pump  20  and the heat dissipating member  30 . A coolant such as water is filled into the pump  20  and is circulated through the heat transfer loop under force from the pump  20 .  
      The base  10  is made from Polyethylene (PE) or Acrylonitrile Butadiene Styrene (ABS), and has a rectangular configuration. The base  10  defines an opening  100  in a central portion thereof for receiving and securing the pump  20  therein. The base  10  forms a pair of ears  12  extending from left and right sides thereof, wherein a pair of mounting holes  120  is defined in each ear  12  for receiving screws  40  with springs  42  therein. Annular rings  44  are used to snap into recesses (not labeled) defined in lower portions of the screws  40  thereby to attach the screws  40  and the springs  42  to the base  10  before the liquid cooling system is mounted on a supporting member (not shown), for example, a printed circuit board on which a heat-generating electronic component is mounted. A pair of rectangular slots  102 ,  104  is symmetrically defined at two opposite sides of the base  10  beside the opening  100 . A pair of rectangular channels  106 ,  108  is respectively defined between the opening  100  and the slots  102 ,  104 . The channels  106 ,  108  communicate the opening  100  with the slots  102 ,  104 .  
      With reference also to  FIGS. 4-5 , the pump  20  comprises a hollow casing  21 , a magnetic rotor  22 , a partition seat  23 , a stator  24  and a top cover  25  hermetically attached to a top end of the casing  21 .  
      The casing  21  is made of a metallic material with good heat conductivity, and defines a chamber  212  for receiving the rotor  22 , the partition seat  23  and the stator  24  one on top of the other in that order therein. The casing  21  comprises a bottom plate  214  having a blind hole  213  defined in a central portion thereof. The bottom plate  214  serves as a heat-absorbing plate to contact with the heat-generating electronic component and absorb heat generated by the electronic component. An inlet  26  corresponding to the channel  106  of the base  10  and an outlet  27  corresponding to the channel  108  of the base  10  are formed at two opposite sides of an outer surface of the casing  21 , so that the coolant is capable of entering into casing  21  via the inlet  26  and exiting the casing  21  via the outlet  27 .  
      The magnetic rotor  22  has a hollow cylindrical configuration and is mounted in the chamber  212  of the casing  21 . The rotor  22  includes an impeller having a wall  220  and a substrate  227  connecting with a bottom end of the wall  220 , and a magnetic ring  222  securely abutting against an inner surface of the wall  220  of the impeller. An upper axle  226  extends upwardly from a center of the substrate  227  of the impeller. A lower axle  228  extends downwardly from the center of the substrate  227  of the impeller, for engaging in the blind hole  213  of the bottom plate  214  of the casing  21 . Referring to  FIGS. 6-8 , an agitator  223  is formed on a bottom surface of the substrate  227  and received in the chamber  212  of the casing  21 , for agitating the coolant of the chamber  212 . The agitator  223  comprises a plurality of agitating plates  225 . The shape of the agitating plate  225  is linear (shown in  FIG. 6 ). Alternatively, the agitating plates  225  may have a curvilinear configuration (shown in  FIGS. 7-8 ), wherein the agitating plates  225  of  FIG. 8  are configured circularly around the lower axle  228  without connection with the lower axle  228 . The impeller forms a plurality of plate-shaped vanes  224  extending radially and outwardly from an outer surface of the wall  220 . When the rotor  22  rotates, the plate-shaped vanes  224  agitate the coolant in the chamber  212  of the casing  21 , for providing a pressure to the coolant and to thereby circulate the coolant in the liquid cooling system.  
      The partition seat  23  is mounted between the rotor  22  and the stator  24  for isolating the coolant from the stator  24  to prevent the coolant from entering the stator  24  and short-circuiting the stator  24 . The partition seat  23  comprises a cylindrical body  231  having an outer circumferential surface mating with the magnetic ring  222 . The body  231  has an inner space  230  and an annular plate  233  extending outwardly from a top of the cylindrical body  231 . A shaft  236  extends upwardly from a center of a bottom portion  232  of the cylindrical body  231 . A mating hole  238  is defined in a center of the bottom portion  232 , for receiving the upper axle  226  of the rotor  22  therein.  
      The rotor  22  mates with the casing  21  and the partition seat  23  to form a plurality of interconnecting surfaces therebetween, such as between a bottom surface of the annular plate  233  and a top surface of the wall  220  of the rotor  22 , and between the outer surface of the body  231  of the partition seat  23  and the inner surface of the magnetic ring  222  of the rotor  22 , between a bottom surface of the substrate  227  of the rotor  22  and a top surface of the bottom plate  214  of the casing  21 , and between an outer surface of the lower axle  228  and an inner surface of the blind hole  213 . Among the plurality of pairs of interconnecting surfaces, one surface of the at least one pair of interconnecting surfaces forms a plurality of dynamic pressure generating grooves or protrusion means, thereby forming a fluid film therebetween for dynamically supporting a radial or axial thrust on the impeller and reducing friction therebetween during rotation of the rotor  22 .  
      Again referring to  FIGS. 4-5 , a plurality of dynamic pressure generating grooves  235  is formed on the outer circumferential surface of the body  231  mating with the smooth inner surface of the magnetic ring  222  of the impeller. The plurality of grooves  235  has a herringbone groove pattern. The herringbone groove pattern of the radial dynamic pressure generating grooves  235  are so formed as to provide a pumping action for thrusting the coolant between the outer circumferential surface of the body  231  and the inner surface of the magnetic ring  222  of the rotor  22  as the rotor  22  rotates, thereby forming a fluid film therebetween for dynamically supporting a radial thrust on the impeller. Referring to  FIG. 9 , according to a minor modification of the pump  20  of this embodiment, the thrust dynamic pressure generating grooves  235  may be formed on the inner surface of the magnetic ring  222  of the rotor for mating with the outer surface of the body  231  which is smooth according to the modification.  
      Referring to  FIG. 10 , the dynamic pressure generating grooves  235  of the partition seat  23  of  FIGS. 4-5  may be replaced by a plurality of protrusions  234  which are formed on the outer circumferential surface of the body  231  mating with the smooth inner surface of the magnetic ring  222  of the impeller to form a fluid film therebetween for dynamically supporting a radial thrust on the impeller. Referring  FIG. 11 , the dynamic pressure generating grooves  235  of the magnetic ring  222  of  FIG. 9  may be replaced by a plurality of protrusions  234  formed on the inner surface of the magnetic ring  222  of the rotor  20  mating with the smooth outer surface of the body  231  to form a fluid film therebetween for dynamically supporting a radial thrust on the impeller.  
      Referring  FIG. 12 , a plurality of dynamic pressure generating grooves  237  is formed on the bottom surface of the annular plate  233  engaging with the smooth top surface of the wall  220  of the impeller of  FIG. 5 . The plurality of grooves  237  has a herringbone groove pattern. The herringbone groove pattern of the dynamic pressure generating grooves  237  are so formed as to provide a pumping action for thrusting the coolant toward the bottom surface of the annular plate  233  of the partition seat  23  and the top surface of the impeller as the rotor  22  rotates, thereby forming a fluid film therebetween for dynamically supporting an axial thrust on the impeller. Referring to  FIG. 13 , the dynamic pressure generating grooves  237  is formed on the bottom surface of the bottom portion  232  engaging with the smooth top surface of the substrate  227  of the rotor  22 . Referring to  FIG. 14 , the dynamic pressure generating grooves  237  may be formed on a bottom surface of the substrate  227 . Referring to  FIG. 5 , the dynamic pressure generating grooves (not shown) may be formed on the top surface of the wall  220  of the impeller to engage with the smooth bottom surface of the annular plate  233  of the partition seat  23 . The grooves formed on the top surface of the wall  220  of the impeller may be replaced by a plurality of protrusions  2222  (shown in  FIG. 9 ), thereby forming a fluid film between the top surface of the wall  220  and the smooth bottom surface of the annular plate  233  of the partition seat  23  for dynamically supporting an axial thrust on the impeller.  
      Referring to  FIG. 4 , the stator  24  is received in the space  230  of the partition seat  23 . The stator  24  comprises a cylindrical center portion  241  having a center hole  243  defined therein, six generally T-shaped pole members  240  extending radially and outwardly from the center portion  241 . The center hole  243  of the center portion  241  fittingly receives the shaft  236  of the partition seat  23 . Each pole member  240  of the stator  24  is surrounded by a coil  242 . A printed circuit board (not shown) is mounted on a top of the center portion  241  and electrically connects with the coils of the stator  24 .  
      The top cover  25  defines a center hole  250  therein, for providing passage of lead wires of the printed circuit board therethough. An edge of the top cover  25  hermetically contacts with the top of the casing  21 .  
      Referring to  FIG. 2  and  FIG. 3 , the heat-dissipating member  30  includes a plurality of metal fins  301 , a plurality of heat-dissipating conduits  304 , and a pair of opposite fluid tanks  302 ,  303  connected to ends of the heat-dissipating conduits  304 . The fluid tanks  302 ,  303  have openings  3020 ,  3030  corresponding to openings  1020 ,  1040  of the slots  102 ,  104  of the base  10 .  
      In assembly, the pump  20  is mounted in the center opening  100  of the base  10 , wherein the inlet  26  and the outlet  27  are respectively received in the channels  106 ,  108 , and a pair of blocks  110 ,  112  surrounding around the inlet  26  and the outlet  27  is clamped in the channels  106 ,  108 , for fixing the inlet  26  and the outlet  27  to the channels  106 ,  108 . The inlet  26  and the outlet  27  communicate with the slots  102 ,  104 , respectively. The heat-dissipating member  30  is mounted on the base  10 , wherein the openings  3020 ,  3030  of the fluid tanks  302 ,  303  are communicated with the openings  1020 ,  1040  of the slots  102 ,  104 , respectively, so that the fluid tanks  302 ,  303  of the heat-dissipating member  30  are in fluid communication with the slots  102 ,  104  of the base  10 . Thus, the base  10 , the pump  20  and the heat-dissipating member  30  are connected together without any connecting tubes, and the pump  20  is in fluid communication with both the base  10  and the heat-dissipating member  30  so as to drive the coolant to circulate through the chamber  212  of the pump  20 , the slots  102 ,  104  of the base  10  and the fluid tanks  302 ,  303  and the conduits  304  of the heat-dissipating member  30 . The combination of the base  10 , the pump  20  and the heat-dissipating member  30  is fixed to the printed circuit board such that the bottom plate  214  of the pump  20  intimately contacts with the electronic component on the printed circuit board.  
      In operation, the coils  242  of the stator  24  are powered firstly to drive the magnetic ring  222  to rotate. The impeller is driven to rotate with the magnetic ring  222 . The impeller thus rotates with the plate-shaped vanes  224  to circulate the coolant in the liquid cooling system. Simultaneously, heat generated by the electronic component is absorbed by the bottom plate  214  of the pump  20  and then is transferred to the coolant contained in the chamber  212  of the casing  21  of the pump  20 . The rotatable impeller quickly agitates the coolant via the plate-shaped vanes  224  thereof and forces the coolant to circulate in the liquid cooling system. The coolant absorbing the heat has a higher temperature and is driven out of the casing  21  of the pump  20  via the outlet  27 , and flows to the heat-dissipating member  30  via the slot  104  of the base  10  and the fluid tank  303  of the heat-dissipating member  30 . Thereafter, the coolant flows to the fluid tank  302  through the conduits  304  where the heat is dissipated to ambient air via the fins  301 . After releasing the heat, the coolant having a lower temperature is brought back to the chamber  212  of the pump  20  via the inlet  26 , thus continuously transporting the heat away from the electronic component.  
       FIG. 15  shows a pump  20  in accordance with a second embodiment. The pump  20  of the second embodiment is similar to that of the previous preferred embodiment. However, a magnetic ring  222 ′ replaces the magnetic ring  222  of the rotor  22  of the previous preferred embodiment. The magnetic ring  222 ′ is embedded in the top annular surface of the substrate  227  of the rotor  22  and abuts against an inner surface of the wall  220 ′. The magnetic ring  222 ′ is so configured as to reduce weight of the rotor  22 . The partition seat  23  has a larger inner space  230 ′ than the inner space  230  of the previous preferred embodiment. In the second embodiment, one surface of the at least one pair of interconnecting surfaces between the partition seat  23  and the rotor  22  and the casing  21  may form a plurality of dynamic pressure generating grooves or protrusion means  234 ,  2222 , thereby forming a fluid film therebetween for dynamically supporting a radial or axial thrust on the impeller and reducing friction therebetween during rotation of the rotor  22 .  
       FIG. 16  shows a pump  20  in accordance with a third embodiment. The pump  20  of the third embodiment is similar with that of the previous preferred embodiment of  FIG. 5 . However, a rotor  22 ′ replaces the rotor  22 . The rotor  22 ′ includes an annular impeller having a wall  220 , and a magnetic ring  222  securely abutting against the inner surface of the wall  220  of the impeller. The impeller forms a plurality of plate-shaped vanes  224  extending radially and outwardly from an outer surface of the wall  220 . An agitator  223  in a form like spokes is formed at a bottom of the rotor  22 ′ below the magnetic ring  222  and received in the chamber  212  of the casing  21 , for agitating the coolant of the chamber  212 . The agitator  223  comprises a plurality of agitating plates  225  extending radially and outwardly around a center hole  221  of the rotor  22  to connect an inner surface of the wall  220 . The partition seat  23  forms a lower shaft  238 ′ at a center of the bottom portion  232  thereof, for passing through the hole  221  of the rotor  22 ′ and engaging in the blind hole  213  of the bottom plate  214  of the casing  21 . In the third embodiment, one surface of the at least one pair of interconnecting surfaces between the partition seat  23  and the rotor  22 ′ and the casing  21  may form a plurality of dynamic pressure generating grooves  235  or protrusion means  234 ,  2222 , thereby forming a fluid film therebetween for dynamically supporting a radial or axial thrust on the impeller and reducing friction therebetween during a rotation of the rotor  22 ′.  
       FIG. 17  shows a pump  20  and a base  10 ′ in accordance with a fourth embodiment. In the fourth embodiment, a base  10 ′ replaces the base  10  of the aforementioned embodiments. The base  10 ′ forms joint flanges  105 ,  107  at a top of the slots  102 ,  104  thereof, for hermetically engaging in the openings  3020 ,  3030  of the fluid tanks  302 ,  303  of the heat-dissipating member  30 . In the fourth embodiment, one surface of the at least one pair of interconnecting surfaces between the partition seat  23  and the rotor  22  and the casing  21  may form a plurality of dynamic pressure generating grooves (not shown) or protrusion means  234 , thereby forming a fluid film therebetween for dynamically supporting a radial or axial thrust on the impeller and reducing friction therebetween during a rotation of the rotor  22 .  
       FIGS. 18-19  show a pump  20 ′ and a base  10 ′ in accordance with a fifth embodiment. In the fifth embodiment, a pump  20 ′ replaces the pump  20  of the aforementioned embodiments and the base  10 ′ is the same as the base  10 ′ of the fourth embodiment. Most parts of the pump  20 ′ of the fifth embodiment are the same as the aforementioned embodiments. A main difference is that in the fifth embodiment the pump  20 ′ comprises a casing  21 ′ having a plate-shaped configuration, while in the aforementioned embodiments the casing  21  has a cylindrical chamber. The casing  21 ′ comprises a disk-like plate  214 ′ having a top surface and a bottom surface. The bottom surface contacts with the heat-generating electronic component and absorbs the heat generated by the electronic component. A protrusion portion  215 ′ extends upwardly from the top surface of the plate  214 ′, for extending into the base  10 ′ and hermetically engaging in the opening  100  of the base  10 ′. The protrusion portion  215 ′ defines a blind hole  216 ′ in a central portion thereof, for receiving the lower axle  228  of the rotor  22  therein. After the casing  21 ′ is mounted to a bottom of the base  10 ′ with the protrusion  215 ′ fitted in a lower part of the opening  100 , a chamber  212 ′ of the pump  20 ′ is defined by a part of the opening  100  above the casing  21 ′. In the fifth embodiment, one surface of the at least one pair of interconnecting surfaces between the partition seat  23  and the rotor  22  and the casing  21  may form a plurality of dynamic pressure generating grooves  235  or protrusion means  2222 , thereby forming a fluid film therebetween for dynamically supporting a radial or axial thrust on the impeller and reducing friction therebetween during a rotation of the rotor  22 . In the fifth embodiment, the magnetic rotor  22 , the partition seat  23 , the stator  24  are sequentially mounted in the opening  100 . Finally, the top cover  25  is secured to the base  10 ′ and covers a top of the opening  100 .  
      It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.