Patent Publication Number: US-8985195-B2

Title: Condensing device and thermal module using same

Description:
FIELD OF THE INVENTION 
     The present invention relates to a condensing device, and more particularly to a condensing device enabling accelerated vapor-liquid circulation in a thermal module. The present invention also relates to a thermal module using the above-described condensing device. 
     BACKGROUND OF THE INVENTION 
     Due to the quick development in the electronic and semiconductor industrial fields, the progress in the process technology and the trends in market demands, various electronic devices have been designed to have compact volume and low weight. While the currently available electronic devices are gradually reduced in size, they actually have constantly increased functions and computing ability. For example, among other information electronic products, the most popular notebook computers and desktop computers all include many electronic components that generate heat during actual operation thereof. Particularly, the central processing unit (CPU) would generate the largest part of heat in the computer. Currently, a heat sink composed of radiating fins and a cooling fan is often used to provide heat dissipation function and plays an important role in protecting the CPU against accumulated heat, so that the CPU can be maintained at a normal working temperature to provide its intended functions. In brief, the CPU heat sink has become a highly important component in the present information electronic industry. 
     In recent years, water-cooling technique has been widely applied to personal computers for heat dissipation. With the water-cooling technique, the radiating fins occupying a large space are omitted, and heat generated by the heat source in an electronic system is collected by a working liquid; and then, a heat exchanger exchanges the collected heat with ambient air. Since the pipeline included in a water-cooling system for delivering the working liquid is length changeable according to actual need, the heat exchanger can be flexibly located at different places. That is, the heat exchanger, i.e. a radiating fin assembly, can be freely designed without being restricted by the space available for mounting it. However, the water-cooling system requires a pump for driving the working liquid to flow through the pipeline, and a water reservoir for storing the working liquid. Therefore, the water-cooling system is subject to some risks, such as the reliability of the pump and leakage of the pipeline. 
     Therefore, heat pipe is still the currently most frequently used technique in heat transfer, and radiating fins are still needed to exchange the heat transferred via the heat pipe with the ambient air. In some cases, the heat pipe and other heat dissipation elements are internally provided with a micro structure to enable increased heat dissipation efficiency. Meanwhile, other means are also tried to minimize the power consumption of the CPU in order to reduce the heat generated by the CPU. 
       FIG. 1  is a sectional view of a conventional loop-type thermal module  8 . As shown, the thermal module  8  includes a heat-absorption element  81  having an outlet  811  and an inlet  812 , and being filled with a working fluid  84 ; a condensing element  82  including a plurality of radiating fins  821 ; and a pipeline  83  connecting the condensing element  82  to the heat-absorption element  81  to form a heat-transfer loop. 
     The pipeline  83  includes a first section  831 , a second section  832 , and a third section  833 . The first section  831  is extended between the outlet  811  of the heat-absorption element  81  and the condensing element  82 ; the second section  832  is bent to extend through the condensing element  82  several times; and the third section  833  is extended between the condensing element  832  and the inlet  812  of the heat-absorption element  81 . It is noted the pipeline  83  including the first, second and third sections  831 ,  832 ,  833  is an integrally formed pipeline. 
     The heat-absorption element  81  is in contact with at least one heat-generating element  9  for absorbing heat generated by the element  9 . The working fluid  84  in the heat-absorption element  81  is heated by the absorbed heat to change from liquid phase into vapor phase. The vapor-phase working fluid  84  flows out of the heat-absorption element  81  via the outlet  811  and flows through the first section  831  of the pipeline  83  to carry and transfer the absorbed heat to the condensing element  82 . When the vapor-phase working fluid  84  flows through the second section  832  of the pipeline  83  that winds through the condensing element  82 , the heat carried by the vapor-phase working fluid  84  is absorbed by the condensing element  82 . The heat absorbed by the condensing element  82  is then radiated into the ambient air and dissipated, and the vapor-phase working fluid  84  flowed through the second section  832  is cooled and condensed into liquid phase again. The liquid-phase working fluid  84  keeps flowing through the second and the third section  832 ,  833  of the pipeline  83  back to the heat-absorption element  81  for the next cycle of vapor-liquid circulation. 
     After changing from vapor phase into liquid phase in the second section  832  of the pipeline  83 , the working fluid  84  slowly flows back to the heat-absorption element  81  simply under the action of the gravity force. Thus, areas at middle, rear and bent portions of the second section  832  form ineffective areas that are little helpful in increasing the flow-back efficiency of the working fluid  84 . 
     Therefore, the conventional thermal module  8  has the following disadvantages: (1) providing only low heat transfer effect; (2) forming areas of ineffective heat transfer; and (3) requiring high manufacturing cost. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a condensing device enabling accelerated vapor-liquid circulation therein. 
     Another object of the present invention is to provide a thermal module that enables accelerated vapor-liquid circulation therein and eliminates areas of ineffective thermal convection. 
     To achieve the above and other objects, the condensing device according to the present invention includes a hollow main body having at least one first inlet, at least one first outlet, and a flow-guiding zone. The first inlet and the first outlet are arranged on the hollow main body corresponding two substantially diagonally opposite ends of the flow-guiding zone. In the flow-guiding zone, there is provided a plurality of spaced flow-guiding members, such that a flow passage is defined between any two adjacent flow-guiding members and at least one flow passage is formed in the flow-guiding zone; and the flow-guiding members respectively have an end directing toward the first inlet and another opposite end directing toward the first outlet. 
     To achieve the above and other objects, the thermal module according to the present invention includes a condensing device, at least one heat-absorption unit, a first heat-transfer unit, and a second heat-transfer unit. The condensing device includes a hollow main body having at least one first inlet, at least one first outlet, and a flow-guiding zone. The first inlet and the first outlet are arranged on the hollow main body correspondingly two substantially diagonally opposite ends of the flow-guiding zone. In the flow-guiding zone, there is provided a plurality of spaced flow-guiding members, such that a flow passage is defined between any two adjacent flow-guiding members and at least one flow passage is formed in the flow-guiding zone; and the flow-guiding members respectively have an end directing toward the first inlet and another opposite end directing toward the first outlet. The heat-absorption unit includes a vaporizing section being provided at two opposite ends with a second inlet and a second outlet. The second inlet is connected to the first outlet via the first heat-transfer unit, and the second outlet is connected to the first inlet via the second heat-transfer unit. 
     By providing the flow-guiding zone in the condensing device of the present invention, it is able to accelerate the vapor-liquid circulation in the condensing device and in the thermal module using the condensing device, and to avoid the problem of having areas of ineffective heat transfer. 
     In brief, the present invention has the following advantages: (1) eliminating areas of ineffective heat transfer; (2) accelerating vapor-liquid circulation; (3) largely upgrading the heat transfer efficiency; and (4) reducing the manufacturing cost thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
         FIG. 1  is a sectional view of a conventional thermal module; 
         FIG. 2  is a sectional view of a first embodiment of a condensing device according to the present invention; 
         FIG. 3  is a sectional view of a second embodiment of the condensing device according to the present invention; 
         FIG. 4  is a sectional view of a third embodiment of the condensing device according to the present invention; 
         FIG. 5  is a sectional view of a fourth embodiment of the condensing device according to the present invention; 
         FIG. 6  is a sectional view of a fifth embodiment of the condensing device according to the present invention; 
         FIG. 7  is a sectional view of a first embodiment of a thermal module according to the present invention; 
         FIG. 8  is a sectional view of a second embodiment of the thermal module according to the present invention; and 
         FIG. 9  shows the operation manner of the thermal module according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described with some preferred embodiments thereof and with reference to the accompanying drawings. For the purpose of easy to understand, elements that are the same in the preferred embodiments are denoted by the same reference numerals. 
     Please refer to  FIG. 2  that shows a first embodiment of a condensing device  1  according to the present invention. As shown, the condensing device  1  includes a hollow main body  11 . 
     The hollow main body  11  has at least one first inlet  111 , at least one first outlet  112 , and a flow-guiding zone  113 . The first inlet  111  and the first outlet  112  are arranged on the hollow main body  11  correspondingly two substantially diagonally opposite ends of the flow-guiding zone  113 . In the flow-guiding zone  113 , there is provided a plurality of spaced flow-guiding members  1131 , so that a flow passage  1132  is defined between any two adjacent flow-guiding members  1131  and at least one flow passage  1132  is formed in the flow-guiding zone  113 . The flow-guiding members  1131  respectively have an end directing toward the first inlet  111  and another opposite end directing toward the first outlet  112 . 
     The flow passages  1132  respectively have a first end  1132   a  and an opposite second end  1132   b.    
       FIG. 3  is a sectional view of a second embodiment of the condensing device according to the present invention. As shown, the second embodiment is generally structurally similar to the first embodiment, except that, in the second embodiment, the hollow main body further includes an auxiliary diffusion section  114  outward projected from the first inlet  111 . The auxiliary diffusion section  114  has an outer or first diffusion end  1141  and an inner or second diffusion end  1142 . The first diffusion end  1141  has a size smaller than that of the second diffusion end  1142 . 
       FIG. 4  is a sectional view of a third embodiment of the condensing device according to the present invention. As shown, the third embodiment is generally structurally similar to the first embodiment, except that, in the third embodiment, the hollow main body  11  is provided on inner wall surfaces with a wick structure  11   a , which can be sintered metal powder or a net-like body. While the wick structure  11   a  for the third embodiment as illustrated in  FIG. 4  is sintered metal powder, it is understood the wick structure  11   a  can be otherwise a net-like body. 
       FIG. 5  is a sectional view of a fourth embodiment of the condensing device according to the present invention. As shown, the fourth embodiment is generally structurally similar to the first embodiment, except that, in the fourth embodiment, the hollow main body  11  is provided on inner wall surfaces with a plurality of grooves, dents or dots  11   b . While the fourth embodiment illustrated in  FIG. 5  is shown as having a plurality of dents  11   b  formed on the inner wall surfaces of the main body  11 , it is understood the hollow main body  11  may be otherwise provided on the inner wall surfaces with grooves or dots. 
       FIG. 6  is a sectional view of a fifth embodiment of the condensing device according to the present invention. As shown, the fifth embodiment is generally structurally similar to the first embodiment, except that, in the fifth embodiment, the hollow main body  11  is provided on outer wall surfaces with a plurality of radiating fins  11   c.    
     All the above-described first to fifth embodiments of the condensing device according to the present invention have a working fluid  2  filled in the hollow main body  11 . The working fluid  2  can be any type of coolant, such as purified water, methanol, acetone, or R134A. 
       FIG. 7  is a sectional view of a first embodiment of a thermal module  3  according to the present invention. As shown, the thermal module  3  in the first embodiment thereof includes a condensing device  1 , at least one heat-absorption unit  4 , a first heat-transfer unit  5 , and a second heat-transfer unit  6 . 
     The condensing device  1  for the thermal module  3  is structurally similar to the first embodiment of the condensing device  1  according to the present invention. Please refer to  FIGS. 2 and 7  at the same time. Since the condensing device  1  has been previously described with reference to  FIG. 2 , it is not repeatedly described herein. 
     The heat-absorption unit  4  includes a vaporizing section  41 , a second inlet  42 , and a second outlet  43 . The second inlet and outlet  42 ,  43  are located at two opposite ends of the vaporizing section  41 . The second inlet  42  is connected to the first outlet  112  via the first heat-transfer unit  5 ; and the second outlet  43  is connected to the first inlet  111  via the second heat-transfer unit  6 . 
     The first heat-transfer unit  5  and the second heat-transfer unit  6  are hollow tubular members, and can be made of a metal material or a plastic material. In the illustrated first embodiment of the thermal module  3 , the first heat-transfer unit  5  is a heat pipe without being limited thereto. The first heat-transfer unit  5  in the form of a heat pipe is provided on an inner wall surface with a wick structure  51  or a plurality of grooves. While the first heat-transfer unit  5  for the first embodiment of the thermal module  3  illustrated in  FIG. 7  is shown as being internally provided with a wick structure  51 , it is understood the first heat-transfer unit  5  can be otherwise provided on the inner wall surface with a plurality of grooves. 
     The condensing device  1  is provided on outer wall surfaces with a plurality of radiating fins  11   c.    
       FIG. 8  is a sectional view of a second embodiment of the thermal module  3  according to the present invention. As shown, the thermal module  3  in the second embodiment is generally structurally similar to the first embodiment, except that, in the second embodiment, the condensing device  1  further includes an auxiliary diffusion section  114  outward projected from the first inlet  111 . The auxiliary diffusion section  114  has an outer or first diffusion end  1141  and an inner or second diffusion end  1142 , and the first diffusion end  1141  has a size smaller than that of the second diffusion end  1142 . 
       FIG. 9  shows the operating manner of the thermal module  3  according to the present invention. As shown, the heat-absorption unit  4  is in contact with at least one heat source  7  to absorb heat generated by the heat source  7 . The working fluid  2  in the heat-absorption unit  4  is heated by the absorbed heat to change from a liquid-phase working fluid  22  into a vapor-phase working fluid  21  in the vaporizing section of the heat-absorption unit  4 . The vapor-phase working fluid  21  flows out of the heat-absorption unit  4  via the second outlet  43  and flows through the second heat-transfer unit  6  into the condensing device  1  via the first inlet  111 . With the high pressure produced by the flow-guiding zone  113  in the condensing device  1 , and a low-pressure end created by an adequate pressure-relief design for the flow-guiding zone  113 , it is able to from a pressure gradient in the condensing device  1  for accelerating the vapor-liquid circulation in the thermal module  3 . The vapor-phase working fluid  21  flowing through the condensing device  1  is changed into the liquid-phase working fluid  22  again. Finally, the liquid-phase working fluid  22  flows through the first heat-transfer unit  5  back to the heat-absorption unit  4  to absorb heat generated by the heat source  7 . With the above arrangements, the thermal module  3  according to the present invention can have increased heat transfer efficiency and overcome the problem of having areas of ineffective heat transfer as found in the conventional condensing device. 
     The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.