Patent Publication Number: US-2018031328-A1

Title: Heat dissipation apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 105123891, filed on Jul. 28, 2016. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a heat dissipation apparatus, in particular, to a heat dissipation apparatus disposed in a portable electronic apparatus. 
     2. Description of Related Art 
     A single circulation of a general heat dissipation apparatus is referred to disposing a heat source below a tank, after flowing into the tank, a working fluid in a liquid state is heated by the heat source and boiled into its gaseous state, then flows out of the tank. While the working fluid in the gaseous state flows to the condenser, it is condensed to its liquid state again, then flows back to the tank, in order to complete the single circulation. However, when the temperature generated by the heat source is excessively high, the working fluid in the liquid state has been boiled into its gaseous state before flowing back to the tank, which leads to failure in completing the single circulation, so that the heat dissipation apparatus fails in effectively dissipating heat. Moreover, the working fluid flows in a closed loop composed by the tank and a pipe merely by its phase transformation, which results in unsatisfactory flowing condition, and there may not be sufficient amount of the working fluid to perform such reaction, so the dissipation efficiency of the heat dissipation apparatus is limited. 
     SUMMARY OF THE INVENTION 
     The present invention provides a heat dissipation apparatus, which has an improved heat dissipation efficiency. 
     The heat dissipation apparatus of the present invention is suited for dissipating heat of a heat source. The heat dissipation apparatus comprises a tank, a heat-insulation unit and a pipe. The tank has an outlet end, an inlet end and an accommodating space, wherein the tank is suited for receiving heat of the heat source from above. The heat-insulation unit is disposed in the accommodating space of the tank, and the heat-insulation unit comprises a heat-insulation nozzle. The heat-insulation nozzle has a first opening, a second opening and a neck portion, wherein the first opening communicates the inlet end, and the second opening communicates the accommodating space, and the neck portion is near the second opening. The pipe communicates the outlet end and the inlet end and forms a closed circulating loop with the tank. A working fluid enters the heat-insulation unit through the inlet end of the tank, and flows to the neck portion through the first opening of the heat-insulation nozzle, and is accelerated via the neck portion, so that the working fluid ejects to the accommodating space through the second opening. The working fluid in the accommodating space absorbs heat of the heat source and transforms to a gaseous state form a liquid state, and enters the pipe through the outlet end. 
     In an exemplary embodiment of the present invention, orthogonal projections of the heat source and the heat-insulation unit on a horizontal plane do not completely overlap. 
     In an exemplary embodiment of the present invention, the heat dissipation apparatus further comprises a condenser, disposed below the pipe, to assist the working fluid in the pipe with condensing into the liquid state and flowing back to the inlet end. 
     In an exemplary embodiment of the present invention, the heat dissipation apparatus further comprises a plurality of channels, disposed in the accommodating space of the tank, and communicate the second opening of the heat-insulation nozzle. 
     In an exemplary embodiment of the present invention, the heat dissipation apparatus further comprises: a plurality of bosses, disposed dispersively in the accommodating space of the tank, orthogonal projections of the bosses and the heat-insulation unit on a horizontal plane do not overlap. 
     In an exemplary embodiment of the present invention, a material of the pipe is metal. 
     In an exemplary embodiment of the present invention, a material of the heat-insulation unit comprises bakelite, plastics, glass fiber, ceramics or Teflon. 
     In an exemplary embodiment of the present invention, the tank comprises a first locking portion, and the heat-insulation unit further comprises a second locking portion, the first locking portion and the second locking portion are locked to each other to fix the heat-insulation unit in the tank. 
     In an exemplary embodiment of the present invention, the working fluid is a coolant. 
     In an exemplary embodiment of the present invention, the heat source comprises a heat pipe, a chip or a processor. 
     Based on the above, because the heat dissipation apparatus of the present invention has the heat-insulation unit, and the heat-insulation unit has an effect of heat insulation, the working fluid can be avoided from being vaporized while entering the inlet end of the tank, which hinder the working fluid from entering the tank, so that the resistance on circulative flow of the working fluid can be reduced, which means circulation efficiency and heat dissipation efficiency can be raised. In addition, the heat-insulation nozzle of the present invention is nozzle-shaped since it has the neck portion, thus the working fluid can exist the heat-insulation unit with acceleration then enter the accommodating space and fully disperse in the tank via the design of the neck portion. Therefore, the occurrence of a phenomenon that partial regions in the tank being dried out can be reduced, and the contact area of the working fluid and the tank can be maintained, which means efficiency of heat exchange can be maintained. In short, the heat dissipation apparatus of the present invention can effectively avoid the working fluid from being vaporized via the heat generated by the heat source before entering the tank, and can ensure that the tank has sufficient working fluid therein. As a result, the heat dissipation apparatus of the present invention can have an improved heat dissipation efficiency, and is suited for high wattage electronic products. 
     In order to make the aforementioned features and advantages of this invention comprehensible, embodiments of the invention accompanied with figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1A  is a schematic top view illustrating a heat dissipation apparatus according an exemplary embodiment of the present invention. 
         FIG. 1B  is a three-dimensional schematic view illustrating a tank and a heat-insulation unit of the heat dissipation apparatus shown in  FIG. 1A . 
         FIG. 2  is a top schematic view illustrating a heat dissipation apparatus according to another exemplary embodiment of the present invention. 
         FIG. 3  is a top schematic view illustrating a heat dissipation apparatus according to yet another exemplary embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
       FIG. 1A  is a schematic top view illustrating a heat dissipation apparatus according an exemplary embodiment of the present invention.  FIG. 1B  is a three-dimensional schematic view illustrating a tank and a heat-insulation unit of the heat dissipation apparatus shown in  FIG. 1A . Please refer to  FIG. 1A  and  FIG. 1B  simultaneously, a heat dissipation apparatus  100 A of the present exemplary embodiment is suited for dissipating heat of a heat source  10 , wherein the heat source  10  is a heat generating device, such as a chip in an electronic apparatus or a processor, or a heat pipe, which is capable of absorbing heat from the other heat generating devices and transmitting heat to the heat dissipation apparatus of the present invention. In other words, the heat dissipation apparatus  100 A of the present exemplary embodiment is suited for electronic apparatus, such as a portable electronic apparatus like a notebook computer, and the heat dissipation apparatus  100 A can be disposed in a casing of the electronic apparatus. Heat generated by the heat source  10  in the electronic apparatus can be transmitted to the casing according to an effect of structurally thermal contact, and thus it can be dissipated, in order to attain an effect of heat dissipation. 
     In particular, the heat dissipation apparatus  100 A of the present exemplary embodiment includes a tank  110 , a heat-insulation unit  120  and a pipe  130 . The tank  110  has an outlet end  112 , an inlet end  114  and an accommodating space  116 , wherein the heat source  10  is disposed below the tank  110 , so that the tank  110  is suited for absorbing heat of the heat source  10  from above. The heat-insulation unit  120  is disposed in the accommodating space  116  of the tank  110 , and the heat-insulation unit  120  includes a heat-insulation nozzle  122 . The heat-insulation nozzle  122  has a first opening  121 , a second opening  123  and a neck portion  125 , wherein the first opening  121  communicates the inlet end  114 , and the second opening  123  communicates the accommodating space  116 , and the neck portion  125  is near the second opening  123 . In the exemplary embodiment illustrated in  FIG. 1A  and  FIG. 1B , the cross-section area of the neck portion  125  is less than the cross-section areas of the first opening  121  and the second opening  123 , respectively. However, in another possible exemplary embodiment, the second opening can be closely adjacent to the neck portion, thus the second opening has a cross-section area similar to or the same as the cross-section area of the neck portion. The pipe  130  communicates the outlet end  112  and the inlet end  114  and forms a closed circulating loop with the tank  110  (as shown by the arrows in  FIG. 1A ). A working fluid (not shown) enters the heat-insulation unit  120  through the inlet end  114  of the tank  110 , and flows to the neck portion  125  through the first opening  121  of the heat-insulation nozzle  122 , and is accelerated via the neck portion  125 , so that the working fluid ejects to the accommodating space  116  through the second opening  123 . The working fluid in the accommodating space  116  transforms to a gaseous state form a liquid state because of absorbing heat of the heat source, and enters the pipe  130  through the outlet end  112 . 
     Please refer to  FIG. 1A  again, the heat source  10  is located right below the tank  110  and directly contacted to the tank  110 , wherein orthogonal projections of the heat source  10  and the heat-insulation unit  120  on a horizontal plane do not completely overlap. In other words, the orthogonal projections of the heat source  10  and the heat-insulation unit  120  can absolutely not overlap (as shown in  FIG. 1A ) or partially overlap (not shown), which is not limited hereto. Herein, a material of the heat-insulation unit  120  is such as an insulating material with low thermal conductivity, such as bakelite, plastics, glass fiber, ceramics or Teflon. Because the heat dissipation apparatus  100 A of the present exemplary embodiment has the heat-insulation unit  120 , wherein the heat-insulation unit  120  has an effect of heat insulation, the working fluid can be avoided from being excessively heated near the inlet end and vaporized instantly, so that the working fluid has maintained in the liquid state before entering the tank  110 . 
     Moreover, in order to effectively fix the heat-insulation unit  120 , the tank  110  of the present exemplary embodiment further includes a first locking portion  118 , and the heat-insulation unit  120  further includes a second locking portion  124 , wherein the first locking portion  118  and the second locking portion  124  are locked to each other, to fix the heat-insulation unit  120  in the tank  110 . In addition, the heat dissipation apparatus  110 A of the present exemplary embodiment can further include a condenser  140 , such as a metal fin, disposed below the pipe  130 , to assist with heat dissipation. Thus, the working fluid in the gaseous state in the pipe  130  is condensed into the liquid state and flows back to the inlet end  114 . Herein, the material of the pipe  130  is such as metal, like copper, and the working fluid is such as a coolant. 
     As shown in  FIG. 1A , the tank  110  and the pipe  130  communicate to each other to form a closed circulating loop (as shown by the arrows in  FIG. 1A ), and the working fluid is filled in the closed circulating loop. When the heat generated by the heat source  10  is transmitted to the tank  110 , it can heat the working fluid therein, which thus transforms to the gaseous state from the liquid state. As a result, the working fluid flows in the closed circulating loop. In addition, when the working fluid in the gaseous state flows through the pipe  130  and the condenser  140  via the manner of being propelled by the vapor pressure, it is condensed and transformed to the liquid state, and flows back to the inlet end  114  of the tank  110  along the closed circulating loop. Therefore, the working fluid can generate circulative phase transformation in the closed circulating loop (which is referred to transforming to the gaseous state from the liquid state, and then transforming to the liquid state from the gaseous state), so that the heat dissipation apparatus  100 A of the present exemplary embodiment can dissipate heat of the heat source  10  according to the design described above. 
     In particular, because the heat-insulation unit  120  of the present exemplary embodiment has the heat-insulation nozzle  122 , wherein the heat-insulation nozzle  122  has the neck portion  125 , while the working fluid entering the heat-insulation nozzle  122  through the first opening  121  flows to the neck portion  125 , the working fluid can be squeezed by the design of the neck portion  125 , and exist with an accelerated manner from the heat-insulation nozzle  122  through the second opening  123 , and enter the accommodating space  116 . In a state of ejection with acceleration, the working fluid in the liquid state can be fully dispersed in the accommodating space  116 , so that the tank  110  has a sufficient amount of the working fluid therein, which reduces or avoids partial regions in the tank from occurring a phenomenon of drying out. Furthermore, flow velocity of the working fluid is increased because of the neck portion  125  of the heat-insulation nozzle  122 , thus while the working fluid absorbs the heat generated by the heat source  10  and transforms to the gaseous state from the liquid state, it can flow to the pipe  130  in only one direction. As a result, a property of the working fluid being propelled in only one direction in the closed circulating loop can be maintained. 
     In short, because the heat dissipation apparatus  100 A of the present exemplary embodiment has the heat-insulation unit  120 , and the heat-insulation unit  120  has the effect of heat insulation, heating the working fluid near the inlet end  114  by the heat source  10  can be reduce or avoided, so that the working fluid has maintained in the liquid state before entering the tank  110 . In addition, the heat-insulation nozzle  122  of the heat-insulation unit  120  of the present exemplary embodiment has the neck portion  125 , thus the working fluid can exist the heat-insulation unit  120  with acceleration, then enter the accommodating space  116  and fully disperse in the tank  110  via the design of the neck portion  125 , in order to increase or maintain the contact area between the tank  110  and the working fluid. As a result, the heat dissipation apparatus  100 A of the present exemplary embodiment can increase the heat dissipation efficiency effectively, and is suited for high wattage electronic products. 
     It should be noted that, numerals and a portion of description of the exemplary embodiment described above will still be applied in the exemplary embodiments described below. The same numerals will be applied to represent the same elements or similar elements, and the description of the same technology will be omitted in the exemplary embodiments described below. The description of the omitted portion can be referred to the exemplary embodiment described above, it will not be repeated in the exemplary embodiments described below. 
       FIG. 2  is a top schematic view illustrating a heat dissipation apparatus according to another exemplary embodiment of the present invention. Please refer to  FIG. 2 , a heat dissipation apparatus  100 B of the present exemplary embodiment is similar to the heat dissipation apparatus  100 A as shown in  FIG. 1A , a major difference between the two is: the heat dissipation apparatus  100 B of the present exemplary embodiment further includes a plurality of channels  150 , wherein the channels  150  are disposed in the accommodating space  116  of the tank  110 , and are separated by a plurality of ribs in the tank  110 . The channels  150  are distributed and communicated to the second opening  123  of the heat-insulation nozzle  122  and the outlet end  112  of the tank, and diverges from the second opening  123 , while converges toward the outlet end  112  at each end of the channels  150 . Herein, disposing the channel  150  is aimed for allowing the working fluid in the tank  110  to have a larger heat exchange area, and for guiding the working fluid to converge toward the outlet end. Thus, the heat dissipation efficiency is raised. 
       FIG. 3  is a top schematic view illustrating a heat dissipation apparatus according to another exemplary embodiment of the present invention. Please refer to  FIG. 3 , a heat dissipation apparatus  100 C of the present exemplary embodiment is similar to the heat dissipation apparatus  100 A as shown in  FIG. 1A , a major difference between the two is: the heat dissipation apparatus  100 C of the present exemplary embodiment further includes a plurality of bosses  160 , disposed dispersively in the accommodating space  116  of the tank  110 , and orthogonal projections of the bosses  160  and the heat-insulation unit  120  on a horizontal plane do not overlap. Herein, disposing the bosses  160  is aimed for allowing the working fluid in the tank  110  to have a larger heat exchange area, thus the time of heat exchange is prolonged. Thus the heat dissipation efficiency is raised. 
     As above, because the heat dissipation apparatus of the present invention has the heat-insulation unit, and the heat-insulation unit has the effect of heat insulation, the working fluid can be avoided from being heated directly by the heat source, which attains an effect of lowering the temperature of the working fluid. In addition, the heat-insulation nozzle of the heat-insulation unit of the present invention has the neck portion, thus the working fluid can exist the heat-insulation unit with acceleration via the design of the neck portion, then enter the accommodating space and fully disperse in the tank, which can ensure that the tank has a sufficient amount of the working fluid. In short, the heat dissipation apparatus of the present invention can effectively avoid the working fluid from being vaporized by the heat generated by the heat source before entering the tank, and can ensure that the tank has a sufficient amount of the working fluid therein. As a result, the heat dissipation apparatus of the present invention can have an improved heat dissipation efficiency, and is suited for high wattage electronic products. 
     Although the present invention has been disclosed by the exemplary embodiments described above, they are not applied to limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.