Abstract:
An apparatus and method for cooling heat generating components within a compartment are disclosed. A cooling assembly isolates heat produced by a processor in a personal computer (“PC”) system and exhausts it from the PC prior to adversely affecting other components within the PC. A fan causes air to blow across the processor having an attached heat sink disposed within the cooling assembly, and the air exits the cooling assembly without adversely affecting the other components surrounding the processor. In one example, an alternative passage is provided for the air.

Description:
RELATED APPLICATION 
   This application is a continuation of U.S. application Ser. No. 09/299,305, filed Apr. 26, 1999 now U.S. Pat. No. 6,356,435, which application is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates generally to computers. More particularly, it pertains to an assembly for dissipating heat generated by the central processing units of computers. 
   BACKGROUND OF THE INVENTION 
   Advances in semiconductor technology are creating increasing heat dissipation problems in electronic components and computer systems. Because electronic components have a relatively large amount of electrical current flow within an extremely small area, the components generate a substantial amount of heat. As electronic components get smaller and more powerful, they generate more heat in a smaller, more confined area. One such component is the central processing unit (“CPU”). The effect of the heat generated is intensified by the close spacing of the components on printed circuit boards and the close spacing of printed circuit boards within electrical devices. The excess heat surrounding the components can reduce the overall life of the components. Excessive heat degrades system performance and reliability, and can cause system failure. As a result, heat dissipation methods and devices are critical in the electronics industry. 
   A variety of well-known methods and devices for dissipating heat are available. These include various finned heat sinks which dissipate heat from the surfaces of fins. The finned heat sinks are attached to the electronic component to be cooled and are often used in computer systems with electric fans that drive air over the fins to enhance their cooling effect. Some CPU manufacturers, as another example, recommend the use of active heat sinks attached to CPUs. 
   There has been extensive work in developing effective methods of dissipating heat from the heat generating components, such as the CPU. However, prior attempts to dissipate heat did not allow for very exact modeling of airflow and cooling capabilities within compartments containing such heat generating components. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to an apparatus and method that allows for the isolation of heat generating components, such as the CPU, and the cooling of such components in such a manner that does not allow the heat generated by such heat generating components to affect adversely other components within the system. 
   One aspect of the present invention is directed to a CPU fan assembly (also referred herein to as “cooling assembly”) comprising a passage, a fan, and a CPU module with an attached heat sink disposed within the cooling assembly. The air passes across the passage, blowing over the CPU module and heat sink, and exits the cooling assembly. Another aspect of the present invention is directed to a method that includes the steps of drawing air into a cooling assembly containing a CPU with an attached heat sink, passing the air over the heat sink, and directing the air outside the cooling assembly. 
   One advantage of the present invention is the isolation of heat generating components so as not to allow the heat generated by such components to adversely affect other components within the system. This isolation can prevent the reduction of overall life of such components resulting from excessive heat. Another advantage is the prevention of degradation of system performance and reliability resulting from excessive heat. Moreover, the present invention obviates the need for using an active heat sink. In other words, with the present invention, the same cooling or better results can be achieved with the use of passive heat sinks. Also, because passive heat sinks are less expensive than active heat sinks, lower costs can be achieved with the present invention. 
   Still other and further aspects, advantages, and embodiments will be described in the detailed description of the preferred embodiments with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a computer case having disposed therein a cooling assembly constructed in accordance with the present invention. 
       FIG. 2  is a perspective view of the cooling assembly of  FIG. 1 . 
       FIG. 3  depicts a cooling assembly as a portion of a computer case. 
       FIG. 4A  shows an alternative cooling assembly in another embodiment of the present invention. 
       FIG. 4B  shows another alternative cooling assembly in another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the spirit and scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. 
     FIG. 1  is a perspective view of a computer case  10  having disposed therein a cooling assembly  12 . As shown in  FIG. 1 , computer case  10  contains therein various other computer components such as, for example, CD-ROM  13 , floppy drive  14 , power supply  15 , motherboard  16 , video card  17 , and at least one input/output card  18 . Computer case  10  comprises computer case walls  20 ,  22 , and  23 . Computer case wall  22  has a plurality of exhaust holes  2  thereon that are aligned with cooling assembly  12 . Computer case wall  23  has a plurality of inlet holes  4  thereon that are aligned with cooling assembly  12 . 
     FIG. 2  is a perspective view showing cooling assembly  12  in more detail. Cooling assembly  12  is an apparatus having cooling assembly walls  24 ,  26 ,  28 , and  30 . Cooling assembly wall  24  supports fan  32 . Disposed within cooling assembly  12  are CPU module  38  with attached heat sink  40 . Although CPU manufacturers such as Intel recommend the use of heat sinks actively moving air over the heat sink for CPUs such as the Klamath®, for example, in this embodiment, heat sink  40  is a passive heat sink, instead of an active heat sink. The use of a passive heat sink results in a lower cost than the use of an active heat sink. Further, the use of this embodiment results in better cooling of the CPU than the use of only active heat sinks. Moreover, although  FIG. 2  shows only one CPU module  38 , cooling assembly  12  may be used to cool more than one CPU. 
   Referring to  FIGS. 1 and 2 , cooling assembly  12  essentially encloses or isolates (with computer case wall  20  and cooling assembly walls  26 ,  28 , and  30 ) at least one CPU module  38  with attached heat sink  40  from the other components on board  16 , such as video card  17  and input/output card  18 . Also, as so disposed within computer case  10 , the walls of cooling assembly  12  essentially comprises, in addition to cooling assembly walls  24 ,  26 ,  28 , and  30 , computer case wall  20 , computer case wall  22 , and computer case wall  23 , the volume within which is adapted to contain CPU module  38  having at least one heat sink  40  attached thereto. 
   During operation of cooling assembly  12 , fan  32  draws air from outside of cooling assembly  12  through inlet holes  4  of computer case wall  23 , and the air is blown across the heat sink  40  attached to the CPU module  38  disposed within cooling assembly  12 . Because computer case wall  20  and cooling assembly walls  26 ,  28 , and  30  essentially enclose or isolate CPU module  38  and heat sink  40 , the air is forced to exit through exit holes  2  of computer case wall  22 . By way of example, but not by way of limitation, the path from inlet holes  4  of computer case wall  23  to exit holes  2  of computer case wall  22  defines a passage which the air travels within cooling assembly  12 . It is preferable that a significant amount of the air drawn from the outside of cooling assembly  12  is exhausted to the outside of computer case  10 . In one embodiment, at least approximately 80 percent of the air drawn from the outside of computer case  10  is exhausted to the outside of computer case  10 . It is important, however, that a significant amount of the air heated by heat sink  40  is exhausted by a path that minimizes heating of other heat-sensitive components. The isolating walls of assembly  12  serve to substantially restrict processor heat from reaching the other internal components of the computer such as video card  17 , power supply  15 , hard drives, and the like. 
     FIGS. 1 and 2  depict the air being drawn from outside of cooling assembly  12  as also coming from outside of computer case  10 . However, in another embodiment of the present invention (not shown), where, for instance, computer case wall  23  did not have inlet holes  4 , fan  32  during operation draws air from inside computer case  10 . Such an embodiment is still within the scope of the present invention. 
   Alternatively, the direction of fan  32  can be reversed from the operation as described above so that air is drawn from outside computer case  10  through outlet holes  2 . The air is then blown across heat sink  40  attached to CPU module  38  disposed within cooling assembly  12 . The air is finally forced to exit through inlet holes  4  of computer case wall  23 . 
   The use of computer case wall  20  and cooling assembly walls  26 ,  28 , and  30  to generally isolate CPU module  38  having the attached heat sink  40  is meant to be illustrative, not restrictive. For example, the use of a cylindrical assembly to enclose or isolate CPU module  38  having the attached heat sink  40  is within the spirit of the present invention. 
     FIG. 3  shows yet another embodiment of the present invention, wherein cooling assembly  42  forms a separately detachable portion of computer case  44 . This embodiment permits the installation of cooling assembly  42  without the need for opening computer case  44 . Cooling assembly  42  is an apparatus having cooling assembly wall  46  supporting a fan  48  passing therethrough and cooling assembly wall  50  having exhaust holes  52 . Cooling assembly  42  further has cooling assembly wall  54 , which, along with cooling assembly walls  46  and  50 , isolates a CPU module and heat sink (not shown in  FIG. 3 ) enclosed within cooling assembly  42 . By way of operation, fan  48  draws air from outside of computer case  44 , blows it across the CPU module and heat sink enclosed within cooling assembly  42 , and forces it through exhaust holes  52  on cooling assembly wall  50 . The path between fan  48  and exhaust holes  52  defines the passage within which the air moves while the fan is in operation. In an alternative embodiment, fan  48  can draw air from outside of computer case  44  through exhaust holes  52  and exhaust the air through fan  48  on cooling assembly wall  46 . 
   In one embodiment, assembly  42 , which may also be referred to as a processor assembly, is detachable from the computer case  44  without opening the case  44 . In this embodiment, a processor and an associated heat sink may be placed in the processor assembly  42  along with fan  48 . Assembly  42  may be configured to specifically fit a certain processor. For example, some processors and heat sinks may require more or less space for connection and placement. The processor assembly  42  may be tailored for a specific processor and heat sink within the confines of the size of the assembly  42 . 
   In this embodiment, the assembly  42  is provided with connections to connect a processor to the case and motherboard via a processor module connector  49 , and to connect the fan  48  to the power supply for the computer, located within computer case  44 . Power connection  47  allows fan  48  to be connected to the computer power supply when the assembly  42  is positioned within the case  44 . Similarly, processor module connector  49  allows the processor to be connected to power when the assembly  42  is positioned within the case  44 . In this manner, the processor assembly  42  may be separately detachable from the computer case  44 , and may be individually conformed to the specific processor desired. Assembly  42  is part of case  44  in one embodiment. In another embodiment, assembly  42  may connect to case  44  at a connection location determined by the power connection required between assembly  42  and the computer power supply within case  44 . 
   The operation of assembly  42 , with its fan  48  and processor with heat sink, may be tuned to the specific needs of the processor and heat sink placed within the assembly  42 . A specific thermal cooling system designed for the specific processor in the assembly  42 , with a common fan power connection  47 . Similarly, shielding from external electromagnetic (EM) interference and sealing from internal EM interference may be optimized for electromagnetically isolating the system and heat sink within the assembly  42 . 
   Preferably, the air that is drawn from outside computer case  44  and that is blown across the CPU module and heat sink should not mix with air that is within computer case  44  but outside cooling assembly  42 . In other words, it is preferable that all the air drawn from the outside of computer case  44  is exhausted to the outside of computer case  44 . However, it is also acceptable if at least 80 percent of the air drawn from the outside of computer case  44  is exhausted to the outside of computer case  44 . 
     FIG. 4A  shows a cooling assembly, also referred to as an isolating assembly, with an alternate passage as another embodiment of the present invention. Cooling assembly  60  is disposed within a computer case (not shown), and comprises cooling assembly wall  62  with fan  64 , cooling assembly wall  66 , cooling assembly wall  70  in communication with duct  72  through opening  74 , and cooling assembly wall  75 . Disposed within cooling assembly  60  are CPU module  76  with an attached heat sink  78 . Cooling assembly walls  62 ,  66 ,  70 , and  75  of isolation assembly  60  generally isolate heat generated from CPU module  76  with attached heat sink  78  from any other components, indicated by component  71 , that are mounted on board  80 . Heat sink  78  is a passive heat sink, instead of an active heat sink. As previously noted, the use of a passive heat sink results in a lower cost than the use of an active heat sink. Further, the use of this embodiment results in better cooling of the CPU than the use of only active heat sinks. Moreover, although  FIG. 4A  shows only one CPU module  76  with attached heat sink  78 , cooling assembly  60  may be used to cool more than one CPU. 
   A second passage in which the air travels is from opening  74  on cooling assembly wall  70 , across CPU module  76  and heat sink  78 , and out through fan  64  on cooling assembly wall  62 . This is referred to as a second passage because another passage is defined outside of isolation assembly  60  through which air is, e.g., drawn into the computer case (not shown) by a fan such as one or more of the unnumbered fans of  FIG. 1 . 
   The use of cooling assembly walls  62 ,  66 ,  70 , and  75  to generally isolate CPU module  76  and heat sink  78  is meant to be illustrative, not restrictive. For example, the use of a cylindrical assembly to enclose or isolate CPU module  76  and heat sink  78  is within the scope of the present invention. 
   Preferably, the air that is drawn from outside of the computer case that contains cooling assembly  60  and that is blown across CPU module  76  and heat sink  78  should not mix with air in the first passage that is within the computer case but outside of isolation or cooling assembly  60 . 
   In other words, it is preferable that all the air drawn from the outside of the computer case is exhausted to the outside of the computer case. In one embodiment, at least 80 percent of the air drawn from the outside of the computer case is exhausted to the outside of the computer case, although other percentages are contemplated. 
   In an alternative embodiment  82  shown in  FIG. 4B , fan  64  draws air from inside cooling assembly  60  during operation and blows the air across fan  64  through cooling assembly wall  62 . A first passage in which the air travels is from opening  68  on cooling assembly wall  66 , across CPU module  76  and heat sink  78 , and out through fan  64  on cooling assembly wall  62 . Alternatively, fan  64  (operated in reverse of what is described above) draws air from outside of cooling assembly  60  through cooling assembly wall  62 , blows the air across CPU module  76  and heat sink  78 , and forces the air out through slits  68  on cooling assembly wall  66  and opening  74  on cooling assembly wall  70 . 
   It is to be understood that the alternate passages, i.e., the first passage and second passage, are depicted in  FIGS. 4A and 4B  to illustrate that the passage in which air travels across CPU module  76  and attached heat sink  78  need not be a particular path. In other words, the air may travel in an essentially curved path across CPU module  76  and heat sink  78 , such as, for example, the first passage. Alternatively, the air may travel in an essentially straight path across CPU module  76  and heat sink  78 , such as, for example, the second passage. It is within the scope of this invention for cooling assembly  60  to comprise both first and second passages in an embodiment. 
   As can be seen, one advantage provided by the present invention is the isolation of heat generating components, such as the CPU, so as not to allow the heat generated by such components to adversely affect other components within the system. As previously noted, this isolation can prevent the reduction of overall life of such components resulting from excessive heat. A further advantage is the prevention of degradation of system performance and reliability resulting from excessive heat. Also, an active heat sink need not be used. In other words, a passive heat sink may be used with this present invention, thereby lowering the cost of dissipating heat generated by the CPU. 
   It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.