Abstract:
The present invention is a vapor chamber including a housing that forms a recess within; at least one wicking structure manufactured from a bundle of wires having capillary voids therebetween that is disposed within the recess; and an amount of working fluid disposed within the recess and in fluid contact with the wicking structure such that fluid may move within the capillary voids in the wicking structures through capillary action.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims the benefit of priority of United States Provisional Patent Application No. 61/862,625, filed on Aug. 6, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to vapor chambers for use in spreading heat to be dissipated and, in particular, to a vapor chamber having an improved wicking structure. 
       BACKGROUND 
       [0003]    Semiconductors and other electrical components generate heat as a by-product of their operation. The generated heat can reduce or impede performance of the component if not effectively dissipated. As technology has advanced, the amount of heat to be dissipated from many of these components has risen dramatically, while the acceptable cost of heat dissipating devices has remained constant or dropped. Therefore there is a need for inexpensive products for dissipating heat that are capable of dissipating ever greater amounts of heat from an ever widening array of components and devices. 
         [0004]    A heat pipe is a simple vapor chamber type heat-exchange device that can quickly transfer heat from one point to another. Heat pipes provide high thermal conductivity with small temperature differences; have a fast thermal response; are small in size and lightweight; come in a large variety of shapes; require no electrical power supply; are maintenance free; and reduce the overall system size and costs. The three basic components of a common heat pipe are a housing, a working fluid, and a wick or capillary structure. An efficient heat pipe system can be affected by the heat pipe length, the type of working fluid, the return wick type, and the number of bends in the heat pipe. 
         [0005]    The housing isolates the working fluid from the outside environment. By necessity, the housing must be leak-proof, maintain the pressure differential across its walls, and enable transfer of heat to take place from and into the working fluid. Selection of the housing&#39;s fabrication material depends on many factors including compatibility; strength-to-weight ratio; thermal conductivity; ease of fabrication; porosity, etc. The housing acts to transfer heat contained within the working fluid to the outside environment. 
         [0006]    Working fluids are many and varied. The prime consideration is the operating vapor temperature range. Often, several possible working fluids may exist within the approximate temperature band. Various characteristics must be examined in order to determine the most acceptable of these fluids for the application considered such as: thermal stability; compatibility with wick and wall materials; vapor pressure relative to the operating temperature range; latent heat; thermal conductivity; liquid and vapor viscosities; surface tension; and acceptable freezing or pour point. The selection of the working fluid must also be based on thermodynamic considerations that are concerned with the various limitations to heat flow occurring within the heat pipe, including viscous, sonic, capillary, entrainment, and nucleate boiling levels. Most heat pipes use water and methanol/alcohol as working fluid. 
         [0007]    The typical wick is a porous structure—made of materials like steel, aluminum, nickel or copper in various pore size ranges—fabricated using metal foams, and more particularly felts, the latter being more frequently used. By varying the pressure on the felt during assembly, various pore sizes can be produced. By incorporating removable metal mandrels, an arterial structure can also be molded in the felt. The prime purpose of the wick is to generate capillary pressure to transport the working fluid from the condenser section of the housing to the evaporator section. It must also be able to distribute the liquid around the evaporator section to any area where heat is likely to be received by the heat pipe. Often these two functions require wicks of different forms. The selection of the wick for a heat pipe depends on many factors, several of which are closely linked to the properties of the working fluid. 
         [0008]    In operation, one end of the heat pipe attaches to a heat source. As the heat rises to the desired operating temperature, the tube boils the working fluid and transforms it into a vapor state. As the evaporating fluid fills the hollow center of the wick, it spreads throughout the heat pipe toward to the cold end. Vapor condensation occurs wherever the temperature is even slightly below that of the evaporation area. As it condenses, the vapor releases the heat acquired during evaporation and the now-condensed working fluid then recedes back to the evaporation section. In most cases, the application must have gravity working with the system; that is, the evaporator section (heated) must be lower, with respect to gravity, than the condenser (cooling) section. When a wick structure is present in the heat pipe, the fluid recedes therein; otherwise, the fluid recedes gravimetrically. The above thermodynamic cycle continues and helps maintain constant temperatures. 
         [0009]    Heat pipes are effective in a number of applications but, unfortunately, traditional heat pipes have significant drawbacks. First, although heat pipes are good at moving heat from one point to another, they are not particularly effective at spreading heat from multiple inputs on a surface. Second, the wicking structures used in heat pipes are difficult and expensive to manufacture. Finally, although heat pipes may be flattened to increase their surface area, such flattening adds to the overall cost of manufacture and reduces the effective heat dissipating capacity of the heat pipe. 
         [0010]    In order to overcome the downsides of traditional heat pipes, other types of vapor chambers have been developed. One common type of vapor chamber includes a flat hollow rectangular housing into which is disposed a wicking structure and a working fluid. The wicking structure is typically a mesh type screen, metal foam, or felts that is specifically fabricated for this purpose and fills substantially all of the inside of the housing. The wicking structure allows the vapor chamber to work against gravity like a wick type heat pipe. These wicking structures are again difficult and expensive to manufacture and the use of these wicking structures limits the versatility of the layout of the heat dissipating components. Further, the use of traditional wicking structures requires the vapor chambers to be fairly thick, which limits their application. 
         [0011]    Therefore, there is a need for a vapor chamber that may be easily and inexpensively manufactured, that has substantial versatility in layout of wicking structures, that may be made thinner than current vapor chambers or flattened heat pipes, and that are not limited to transferring heat from one point to another. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention is a vapor chamber. 
         [0013]    In its most basic form, the present invention is a vapor chamber including a housing that forms a recess within; at least one wicking structure manufactured from a bundle of wires having capillary voids therebetween that is disposed within the recess; and an amount of working fluid disposed within the recess and in fluid contact with the wicking structure such that fluid may move within the capillary voids in the wicking structures through capillary action. 
         [0014]    The wicking structure preferably includes a plurality of individual wires, preferably between twenty and forty, but less than twenty or greater than forty may be included. The wicking structures are preferably made of a non-reactive metal, such as copper. Other materials out of which the wicking structures may be manufactured include aluminum, carbon fiber and certain plastics, as well as any material commonly used in the art. In some embodiments, standard off-the-shelf wire ropes may be used. The individual wires have capillary voids between the wires, within the wicking structure. These capillary voids may be three cornered or four cornered depending on the type and orientation of the wires within the bundle. The individual wires within a wicking structure are packed tightly, but not fluid tightly, so that fluid may still traverse within the capillary voids. There are also “v”-shaped vacancies between the individual wires on the surface of the wicking structures. In practice, the working fluid moves through these capillary voids and “v”-shaped vacancies toward the heat source, through capillary action. It is preferred that the wicking structures be twisted so that the distance through a capillary void or “v”-shaped vacancy from one side of the wicking structure to the other is short. More tightly twisted wire bundles will have a shorter distance than more loosely twisted wire bundles. The wires may also be braided, twisted in pairs and then aligned within the bundle, or twisted in pairs or groups and then twisted all together, for example. Herein, the term “twisted” may refer to any of these possibilities. The wicking structures may also be straight, or not twisted, but this is less effective in many applications, and therefore non-preferred. The capillary action occurs regardless of orientation of the vapor chamber and heat source relative to gravitational forces. 
         [0015]    The housing is designed to fit its application, but preferably includes a base and a cover and is small and flat. The recess is formed between the base and the cover. The preferred housing is preferably substantially rectangular. Herein, “substantially rectangular” may mean that the housing is rectangular or that it may be rectangular, but with rounded corners. It is understood that some embodiments may also have a shape other than substantially rectangular. When the cover and base are united, the preferred housing is 2.5″×5″×0.125″, but may be of smaller or larger dimensions. The housing is preferably made of copper, but may be made of other materials, such as aluminum, stainless steel, nickel, or refrasil fiber. The working fluid within the recess of the housing is preferably water, but may be other working fluids, such as acetone, ammonia, methanol, or ethylene-based glycol ether products. The base and cover of the housing are preferably sealed together through welding, but may also be sealed using epoxy, screws, o-rings, gaskets, or any other method commonly used in the art. 
         [0016]    In some embodiments, the inside of the housing may be sprayed or otherwise coated with polytetrafluoroethylene (“PTFE,” commonly sold under the brand name TEFLON) or other non-reactive hydrophobic materials with similar characteristics to PTFE. With such embodiments, aluminum wire structures, which traditionally have only been usable with non-water working fluids, may be used with water as the working fluid. This is a significant advantage, as water is dramatically more effective, even with the added resistance. 
         [0017]    The housing may or may not be vacuum sealed. When the housing is vacuum sealed, the base of the housing may include several separators for maintaining a distance between the cover and base of the housing. The separators are small posts extending upward from the floor of the recess in the base to a height so that the cover rests on the top of the separators. The separators provide mechanical support for the cover so that it does not buckle into the recess under pressure. When the housing is not vacuum sealed, expansion may be a problem. In these embodiments, at least one, and preferably two, locations may be selected to weld the cover and base together from the outside so as to prevent the cover and base from expanding away from one another. 
         [0018]    The housing preferably includes a fluid input for introducing the working fluid into the recess. The fluid input is preferably disposed within the height of the base, so that the base remains flat. The fluid input is preferably a small hole within the height of the base with a removable cap that fits snugly within the hole and prevents leakage of the working fluid when in place. The cap may be welded or otherwise permanently attached, or may be removable to allow the working fluid to be recharged. Alternatively, any art recognized means of sealing the hole may be utilized. References herein to a “side” of the housing always refer to the larger, flat sides of the cover or base of the housing. The height of the housing, which is on all four sides of the housing, will be referred to as the “height” rather than a “side,” so as to avoid confusion. 
         [0019]    In operation, at least one heat source is applied to the outside of the base or cover of the housing. The wicking structures are preferably wire bundles that act as wicks so that the working fluid moves toward the heat source through the wicking structures by capillary action. 
         [0020]    In a preferred embodiment, heat is absorbed on one side of the housing, either the base or the cover depending on where the heat source is located, and is emitted on the other side of the housing, therefore moving through the height of the housing. The operation of the heat chamber takes advantage of similar physical properties used with heat pipes, described, for example, in Wallin, Per. “Heat Pipe, selection of working fluid.” Project Report MVK160 Heat and Mass Transfer, 7 May 2012, hereby incorporated by reference. The traditional heat pipe generally moves heat from one end of the heat pipe to the other end. In some embodiments of the vapor chamber of the present invention, heat is moved similarly to a traditional heat pipe where the heat is moved through the length or width of the housing, rather than through the height of the housing, as described above. Distinctions between the traditional heat pipe and the vapor chamber of the present invention will be evident to one of ordinary skill in the art. 
         [0021]    The preferred housing is as described above. It is understood, however, that the housing may also be of the type used traditionally with heat pipes. Heat pipe housings may take any of a variety of forms, such as sealed metal tubes. Such a heat pipe housing used in combination with the wicking structure of the present invention would have significant differences from a traditional heat pipe. Where a traditional heat pipe typically includes some sort of porous or sponge-like material as its wick, a heat pipe housing in combination with the wicking structure of the present invention would use the wicking structure as its wick. The wicking structure is unique as a wick because although the individual wire strands are not porous, the bundle of wire strands together is porous, after a fashion, in that it includes the capillary voids, and “v”-shaped vacancies, as discussed above. A heat pipe housing used in combination with a wicking structure of the present invention would also move heat via the working fluid in multiple dimensions. 
         [0022]    Moreover, a traditional heat pipe typically moves heat via the working fluid from one end of the heat pipe to the other. A heat pipe housing used in combination with a wicking structure of the present invention, on the other hand, would move heat via the working fluid not only from one end of the wicking structure to the other, but also from one side of the wire bundle to the other through the twists in the wire bundle, as discussed above. A traditional tube-like heat pipe housing used in combination with a wicking structure of the present invention would preferably have twisted wire bundle wicking structures aligned around the inner surface of the tube, parallel with one another, and stretching from one end of the heat pipe to the other. In this way, the wicking structure moves heat via the working fluid from one end of the heat pipe to the other, as in a traditional heat pipe, but also from the inside cavity of the heat pipe to the outer surface of the heat pipe through the twists in the wire bundles of the wicking structure. 
         [0023]    The wicking structures may be oriented within the recess in any pattern. Patterns of the wicking structures include expanding out from the middle like a star, in a big swirl, in parallel lines, or in any other configuration that makes sense considering where the heat sources will be applied to the vapor chamber. 
         [0024]    If we consider the side of the vapor chamber on which a heat source is applied the “hot side” and the other side the “cold side,” liquid working fluid present in the recess of the housing will move toward the hot side through the capillary voids and “v”-shaped vacancies. On the hot side, the working fluid will evaporate and move back toward the cold side, where it will then condense and be drawn back toward the heat, et cetera. In some embodiments, some sort of additional heat sink or “cold source” may be applied to the cold side of the housing. 
         [0025]    In addition to their utility as described in detail above, most embodiments of the vapor chamber of the present invention are relatively easy and inexpensive to manufacture. It is understood, however, that some embodiments may include complex machining details that may increase the ease and price of manufacture. 
         [0026]    These aspects of the present invention are not meant to be exclusive and other features, aspects, and advantages of the present invention will be readily apparent to those of ordinary skill in the art when read in conjunction with the following description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1A  is a perspective view of a housing of the present invention with the cover and base separated. 
           [0028]      FIG. 1B  is a 40:1 magnification of the wicking structures shown in  FIG. 1A . 
           [0029]      FIG. 1C  is a cross sectional view of the wicking structures shown in  FIG. 1B . 
           [0030]      FIG. 1D  is a magnification of the shape of a three cornered capillary void. 
           [0031]      FIG. 1E  is a magnification of the shape of a four cornered capillary void. 
           [0032]      FIG. 2A  is a top down view of a housing of the present invention. 
           [0033]      FIG. 2B  is a height view of the housing shown in  FIG. 2A . 
           [0034]      FIG. 2C  is a magnified view of section C-C shown in  FIG. 2B . 
           [0035]      FIG. 2D  is a cross section view of the housing shown in  FIG. 2A  across line A-A. 
           [0036]      FIG. 2E  is a 4:1 magnification of section B shown in  FIG. 2D . 
           [0037]      FIG. 2F  is a perspective view of a housing of the present invention with the cover and base separated. 
           [0038]      FIG. 2G  is a perspective view of a vapor chamber of the present invention. 
           [0039]      FIGS. 3A-3D  are perspective views of various embodiments of a vapor chamber of the present invention with the cover and base separated and different formations of the wicking structures. 
           [0040]      FIGS. 4A-4J  are various embodiments of the wicking structures. 
           [0041]      FIG. 5A  is a cutaway top down diagram showing the direction of vapor within the vapor chamber. 
           [0042]      FIG. 5B  is a cutaway height diagram showing the direction of heat and working fluid within the vapor chamber. 
           [0043]      FIG. 6A  is a cutaway top down diagram showing a vapor chamber with three heat sources. 
           [0044]      FIG. 6B  is a cutaway height diagram of the vapor chamber shown in  FIG. 6A . 
           [0045]      FIG. 7A  is a cutaway top down diagram showing a vapor chamber with one heat source. 
           [0046]      FIG. 7B  is a cutaway height diagram of the vapor chamber shown in  FIG. 7A . 
           [0047]      FIG. 8A  is a cutaway top down diagram showing a vapor chamber with two heat sources. 
           [0048]      FIG. 8B  is a cutaway height diagram of the vapor chamber shown in  FIG. 8A  along the short edge. 
           [0049]      FIG. 8C  is a cutaway height diagram of the vapor chamber shown in  FIG. 8A  along the long edge. 
           [0050]      FIG. 9A  is a cutaway top down diagram showing a vapor chamber with one heat source. 
           [0051]      FIG. 9B  is a cutaway height diagram of the vapor chamber shown in  FIG. 9A  along the short edge. 
           [0052]      FIG. 9C  is a cutaway height diagram of the vapor chamber shown in  FIG. 9A  along the long edge. 
       
    
    
     DETAILED DESCRIPTION 
       [0053]    Referring first to  FIG. 1A , a perspective view of the housing  10  of the vapor chamber of the present invention with cover  12  and base  14  separated is provided. Cover  12  mates with rim  13  of base  14 . Rim  13  provides the height of housing  10  that allows for recess  11  within the housing  10 . Each corner of base  14  includes a hole  18  for affixing the housing  10  in a specific place or orientation, such as with screws. Wicking structures  20  and separators  16  are disposed within the recess  11 . The inclusion of separators  16  indicates that this housing  10  will be under vacuum sealing. In the embodiment shown, wicking structures  20  are spreading out from the center in a star-like pattern, but this is just one of many different patterns in which the wicking structures  10  may be oriented, as discussed in more detail below with reference to  FIGS. 3A-3D . Although not shown, it is understood that a quantity of working fluid  36  will also be disposed within the recess  11  of housing  10 . 
         [0054]    Now referring to  FIGS. 1B and 1C , 40:1 magnified views of wicking structures  20  are provided.  FIG. 1B  shows a portion of a wicking structure  20  from the side, along a short length of the thin individual wires  22  within the wicking structure  20 . Although not apparent in other views,  FIG. 1B  illustrates that wires  22  are twisted within wicking structure  20 .  FIG. 1C  shows a cross section of the wicking structure  20  including capillary voids  26  between the wires  22  within the wicking structure  20  and “v”-shaped vacancies  24  between the wires  22  on the surface of the wicking structure  20 .  FIG. 1E  is a magnification of the shape of a three cornered capillary void  30 , such as those included within wicking structure  20  shown in  FIG. 1C .  FIG. 1D  is a magnification of the shape of a four cornered capillary void  32 , shown in  FIGS. 4A and 4J , for example. 
         [0055]    Referring to  FIG. 2A , a top down view of a housing  10  is provided. The preferred housing  10  is 2.5″ wide and 5″ long. In this view cover  12  and base  14  are united so that only cover  12 , rim  13 , within which cover  12  sits, and the corners of base  14  with holes  18  are visible. Referring to  FIG. 2B , the height  15  of the housing  10  along the long edge is shown. The height  15  is preferably 0.125″, as indicated in  FIG. 2E .  FIG. 2C  is a 2:1 magnification of section C-C shown in  FIG. 2B . This view shows fluid input  28 . Working fluid  36 , which is preferably water, may be introduced to or removed from the recess  11  through fluid input  28 . As evidenced by the presence of separators  16 , the embodiment shown will be under vacuum. Fluid input  28  therefore must be able to seal the recess  11  airtight. One of ordinary skill in the art will recognize that the fluid input  28  shown in  FIG. 2C  is merely exemplary and that many variations thereof may be substituted in other embodiments.  FIG. 2D  is a cross sectional view of the housing  10  shown in  FIG. 2A  across line A-A. In this view, we see cover  12  and base  14  maintaining height  15  by separators  16 .  FIG. 2E  is a 4:1 magnification of section B shown in  FIG. 2D . In this view, we see that cover  12  is very thin and sits within rim  13  of base  14 . We also see that the flat portion of base  14  is also thin like cover  12 . Separators  16  provide mechanical support for the housing  10  under vacuum seal so that the cover  12  and base  14  do not buckle toward one another. Recess  11  is shown with wicking structures  20 .  FIGS. 2F and 2G  are perspective views of the housing  10  shown in  FIGS. 2A-2E  with the cover  12  and base  14  separated and united, respectively. 
         [0056]    Now referring to  FIGS. 3A-3D , perspective views of various embodiments of the vapor chamber of the present invention are provided, with the cover  12  and base  14  separated and with different formations of wicking structures  20 .  FIGS. 3A and 3B  show a similar pattern to that shown in  FIG. 1A , with the wicking structures  20  spreading outward from the middle of the base  14 . As indicated by the presence of separators  16 , the housing  10  shown in  FIG. 3A  will be under vacuum seal. The patterns depicted in  FIGS. 1A ,  2 F,  3 A, and  3 B and similar patterns where wicking structures  20  expand outward in several lines from the middle of recess  11  are referred to herein collectively as “star-like patterns.” The vapor chambers  10  shown in  FIGS. 3B-3D  do not include separators and therefore will not be under vacuum seal. In such embodiments, when the cover  12  and base  14  are united, the cover  12  and base  14  may be welded together in one or more locations so as to prevent them from separating due to expansion. The sealing of cover  12  and base  14  may also be effected by epoxy, screws, o-rings, gaskets, or any other method commonly used in the art.  FIG. 3C  shows the wicking structure  20  in a swirled pattern. The pattern depicted in  FIG. 3C  and similar patterns where wicking structures  20  expand outward from the middle of recess  11  in a round or spiral trajectory are referred to herein collectively as “swirl patterns.”  FIG. 3D  shows a combination of straight parallel wicking structures  20  and curved wicking structures  20 . It is understood that wicking structures  20  that are in a straight pattern within the recess  11 , such as in  FIGS. 3A ,  3 B, and  3 D, preferably still have twisted individual wires  22  within the wicking structure  20 . One of ordinary skill in the art will recognize that these patterns are merely exemplary and that the wicking structures  20  may be in any pattern. The pattern is preferably determined considering the application of the vapor chamber and where a heat source  34 , as shown in  FIGS. 5A and 5B , for example, will be applied. 
         [0057]    Now referring to  FIGS. 4A-4J , various embodiments of wicking structures  20  are provided.  FIGS. 4A and 4B  show cross sections of wicking structures  20 , with each individual wire  22  visible, as well as capillary voids  26  and “v”-shaped vacancies  24 . In  FIG. 4A , all wires  22  are the same size and are packed so as to include both three cornered capillary voids  30  and four cornered capillary voids  32 . In  FIG. 4B , a larger lead wire  22  is surrounded by smaller wires  22  twisted around it. In this embodiment, all of the capillary voids  26  are three cornered capillary voids  30 .  FIG. 4C  shows wires  22  in a tight twist formation.  FIG. 4D  shows wires  22  in a loose twist formation. More tightly twisted wire structures  20 , such as that shown in  FIG. 4C  versus  FIG. 4D , have shorter capillary voids  26  from one side to the other (e.g. from the left side to the right side). Shorter capillary voids  26  provide a shorter distance for the working fluid  36  to travel. The preferred length of this distance will vary depending on the application of the vapor chamber.  FIG. 4E  shows wires  22  in a straight formation.  FIG. 4F  shows wires  22  as small twisted ropes twisted together.  FIG. 4G  shows wires  22  as braided ropes twisted together. Each of  FIGS. 4C-4G  may have wires  22  of all of the same size, as shown in  FIG. 4A , or with a larger wire  22  in the middle, as shown in  FIG. 4B .  FIG. 4H  shows wires  22  all of the same size twisted together in a loose twist similar to that shown in  FIG. 4D .  FIG. 4I  shows wires  22  all of the same size in a straight formation similar to that shown in  FIG. 4E .  FIG. 4J  shows wires  22  all of the same size twisted around each other or braided in several sets of pairs that are brought together to form the wicking structure  20 . This embodiment is something of a hybrid of twisted and straight as the pairs of wires  22  are twisted around one another, but each pair is essentially straight. In other embodiments, the wires  22  may be both twisted around one another and twisted as a group within the wicking structure  20 . Although the wicking structures  20  may be in a straight formation, as shown in  FIGS. 4E and 4I , it is understood that such embodiments are non-preferred and that it is preferred that the wires  22  within wicking structure  20  be twisted, such as shown in  FIGS. 4C ,  4 D,  4 F,  4 G,  4 H, and  4 J. The twisted formations provide a short path from the hot side of a housing  10  to the cold side. One of ordinary skill in the art will recognize that there are many ways in which the wires  22  may be arranged within the wicking structures  20 , and the embodiments shown in  FIGS. 4A-4J  are merely exemplary. 
         [0058]    Now referring to  FIGS. 5A and 5B , cutaway top down and height diagrams, respectively, showing the direction of vaporous working fluid  36  within housing  10  are provided. The position of heat source  34  shown on top of housing  10  in  FIG. 5B  in dashed lines is also indicated in  FIG. 5A  in dashed lines. Regarding  FIG. 5B , it is understood that the surface on which heat source  34  is being applied may be either cover  12  or base  14  of housing  10 . In  FIG. 5A , the arrows show the direction of the vaporous working fluid  36  moving away from heat source  34 , the working fluid  36  having just absorbed heat from the heat source  34  and evaporated. 
         [0059]    In  FIG. 5B , the bold straight arrows show the direction of heat and the smaller squiggly arrows show the direction of the liquid working fluid  36 . The small squiggly arrows show the liquid working fluid  36  moving in the “v”-shaped vacancies  24  on the surface of the wicking structure  20  between the individual wires  22 . It is understood that the working fluid  36  is also moving through the capillary voids  26  within the wicking structure  20 , but not visible in this view. In this way, wicking structure  20  is acting as a wick. The working fluid  36  is drawn toward the heat source  34  through capillary action. The twisted nature of the wicking structure  20  makes the distance that the working fluid has to travel from the non-heated side of the housing  10  to the side of the housing  10  on which the heat source  34  is applied very short. The twist formation of the wires  22  within the wicking structure  20  shown in  FIGS. 5A and 5B  is similar to that shown in  FIG. 4C . One can see that if the embodiment of the wicking structure  20  shown in  FIG. 4D , with a looser twist formation, were substituted, the distance the working fluid  36  would have to travel would be longer. 
         [0060]    In practice, the working fluid  36  moves toward the heat source  34 , as shown in  FIG. 5B , through capillary action through the “v”-shaped vacancies  24  and capillary voids  26  of the wicking structure  20 , acting as a wick. As the working fluid  36  approaches the heat source  34 , it will evaporate and move away from the heat source  34 , as shown in  FIG. 5A . It will then condense on the cold side of the housing  10 , or the side of the housing  10  on which the heat source  34  is not disposed. The condensation releases heat which leaves the housing  10  through the cold side, as shown in  FIG. 5B . It is understood that this cycle will occur regardless of orientation of the housing  10 , so that it will occur even when the capillary action of the working fluid  36  moving toward the heat source  34  is going upward or against gravity. Although not shown, in some embodiments, a cold source may be included opposite from the heat source or in a position to which it is desirable for the vaporous working fluid  36  to travel to condense. 
         [0061]    Referring to  FIGS. 6A and 6B , cutaway top down and height diagrams, respectively, of a housing  10  with three heat sources  34  applied to the housing  10  are provided. Referring to  FIGS. 7A and 7B , cutaway top down and height diagrams, respectively, of a housing  10  with one heat source  34  applied to the housing  10  are provided. In each of these  FIGS. 6A-7B , wicking structures  20  are twisted as is preferred so that the heat is moved from the hot side of the housing  10  to the cold side. These figures demonstrate that the housing  10  may operate with multiple heat sources  34  applied and with those heat sources  34  applied anywhere on the housing  10 . 
         [0062]    In addition to the heat moving from the hot side to the cold side of the housing  10 , the heat may also move toward cooler portions of the vapor chamber along the length of the wicking structures  20 . In  FIG. 6A , for example, there is a relatively large space between the middle heat source  34  and the heat source  34  on the right. This relatively large space that has no heat applied to it may be relatively cool on both sides of the housing  10 . Therefore, vaporous working fluid  36  moving away from those heat sources  34 , in an action similar to that shown in  FIG. 5A , may move through the wicking structures  20  both from one side of the vapor chamber  20  to the other through the short path created by the twists, but also along the length of the wicking structure  20  toward that space to condense on either side of the housing  10  in that space so that the housing  10  may dispel heat on both sides in that space. The vaporous working fluid  36  may also move directly through the recess  11  to get to cooler space where it will condense. 
         [0063]    Referring to  FIGS. 8A-8C , cutaway top down and cutaway height diagrams, respectively, of a housing  10  with two heat sources  34  are provided. Referring to  FIGS. 9A-9C , cutaway top down and cutaway height diagrams, respectively, of a housing  10  with one heat source  34  are provided. These embodiments of housing  10  are more similar to traditional heat pipes than the embodiments illustrated in and described with reference to  FIGS. 5A-7B . The embodiments shown in  FIGS. 8A-9C  are similar to heat pipes in that the heat is moved along the length of the wicking structures  20 , akin to a straw, underscoring the discussion regarding  FIG. 6A  of the relatively large, cool space between two heat sources  34 . Especially if the wicking structures  20  shown in  FIGS. 8A-9C  are twisted, there will still be heat moving from the hot side of the housing  10  to the cold side. The embodiments shown in  FIGS. 8A-9C , however, lend themselves to wicking structures  20  where the wires  22  within the wicking structures  20  are in a straight formation, as shown in  FIGS. 4E and 4I , for example. Liquid working fluid  36  will be drawn from the left of the housing  10 , as shown in  FIGS. 8A and 9A  through the wicking structures  20 , acting as wicks, toward the heat sources  34 , where it will evaporate and then move away from the heat sources  34  as a gas until it condenses toward the left again and dispels the heat. 
         [0064]    Comparing the patterns of the wicking structures  20  in  FIGS. 6A-7B  with those of  FIGS. 8A-9C  is illustrative to show how the vapor chamber application may determine the best wicking structure pattern. In  FIGS. 6A-7B , the wicking structures  20  are twisted so that the main heat movement is going to be from the side of the housing  10  on which the heat source  34  is applied to the other side. The other side of the housing  10  therefore needs to be relatively cool so that the heat may be dispelled there. In other words, it will not work well if there is another heat source on the other side, or if there is a component that should not absorb the heat being dispelled from the housing  10  on the other side. In  FIGS. 8A-9C , on the other hand, one might imagine that on the other side of the housing  10  (under the housing  10  shown in  FIGS. 8C and 9C , for example) is a component that should be protected from heat or perhaps even another heat source. In such a scenario, as it is undesirable or impossible for the heat to go to the other side of the housing  10 , the heat is instead directed more to the left of the housing  10 . This would be facilitated by wires  22  in a straight orientation within the wicking structures  20  so that the fluid is encouraged to move more along the length of the wicking structure  20  than between the sides of the housing  10 , as it would be with a twisted wicking structure  20 . 
         [0065]    Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions would be readily apparent to those of ordinary skill in the art. Therefore, the spirit and scope of the description should not be limited to the description of the preferred versions contained herein.