Heat transfer bridge
A heat transfer bridge for absorbing heat from electronic circuits and electrical distribution transformers to thereby cool said components is disclosed. The heat transfer bridge includes a passive pump for pumping a fluid having a low boiling point that readily creates bubbles when heated to its boiling point. The bubbles are directed via selected flow paths to effectively push or drive the fluid from adjacent a heat source such as an electronic circuit or transformer to heat dissipating components such as cooling fins. In one embodiment, the fluid in the inventive heat transfer bridge comprises a fluid comprising metallic slurry that provides many times the heat dissipation rate as compared to a clear fluid.
This utility application claims the benefit of the earlier filing date of the provisional application of the same title, “Heat Transfer Bridge”, Ser. No. 61/575,946 having a filing date of Aug. 31, 2011 and of the same inventor, Troy W. Livingston.
The present invention relates to system for removing heat from heat generating components, and more particularly to a method and system for removing heat from electronic circuit boards, electronic chips and transformers.
As is well known in the electrical industry, circuit boards and electronic chips and transformers create unwanted heat during operation. Heat build-up may cause a circuit board or transformer to malfunction or burn up and cause the entire system to also malfunction or to short out. The problem has become even more acute due to the fact that circuit boards have become smaller and/or more highly populated with components thus causing the source of heat to become more intense. Accordingly, the heat build-up in circuit boards and IC chips must be dissipated. In the case of transformers often many additional houses are built and connected to be serviced by transformers already operating at rated load and the additional loading heavy loads causes high heat resulting in damage and shorting of the transformer windings. Heat build-up in pole mounted power transformers is a primary cause of transformer failures.
There are many existing method of heat dissipation from electronic circuit boards, IC chips and electronic systems. These include providing layers of exotic metals, forced gas and liquid cooling, heat convection, pulsating heat pipes, coolant baths and heat transfer directly to the system housing. Liquid cooling systems mentioned above, which are generally the most effective, require a pump to move a coolant from the heat source to a remote heat sink where the heat is dissipated. These latter systems are voluminous and heavy.
There is a need for providing a method and system for developing a circuit board and IC chip cooling system which will enable designers and engineers to create and operate electronic systems that are smaller in size and lighter in weight. It is thus an object and purpose of the present invention to address the foregoing problem and to provide a system and method for efficiently removing heat from circuit boards and IC chips which system is itself small and of light weight.
There is also a need for increasing the output of power line transformers without having to replace the transformers, and accordingly to provide improved cooling of the transformer during operation which will result in an increased capability of operating the transformers at a higher rating and/or to reduce the heat stress on the transformers.
SUMMARY OF THE INVENTIONA basic feature of the present invention is the utilization of a system and structure including a passive transfer pump for cycling a liquid having or carrying a metallic slurry in the liquid. The pump is driven by the heat source itself. More specifically, the present invention rapidly removes thermal energy from a heat source to heat sink areas by incorporating a bubble generating effect of the low boiling point of a fluid to pump the liquid in a closed loop to the heat dissipating areas. The inventive system has no moving parts and therefore eliminates the maintenance and service life restrictions found in rotating or pulsating pump systems. An important feature of the invention is that it provides an efficient means of removing heat from a source wherein the liquid carries a metallic slurry that has been found to be multiple times more effective in transferring and conveying heat from one surface to another than does a liquid such as a fluorocarbon as water.
In one embodiment, the present invention provides a heat transfer bridge or dissipation module for electronic circuit boards and IC chips utilizing a passive pump cycling the cooling liquid. The liquid may include a slurry of metallic particles which enhances the transfer of heat. The invention can be utilized with a few or a large array of circuit boards as well as for circuit boards and IC chips mounted in a tight circuit configuration. Further, the heat dissipation system or module is small and can be mounted in practically any orientation.
In a second embodiment, the present invention provides a heat transfer bridge for power transformers that can be non evasively retrofitted onto transformers and can be included in building new transformers. Transformers as referred to herein comprise a primary winding and a secondary winding which must be physically and electrically separated from one another. Electrical separation is achieved by use of an insulating material. The dielectric strength of an insulating material is reduced with increasing temperature. Continuous transformer operation at elevated temperatures therefore results in faster aging of the insulating material with a consequent reduction of the insulating properties of the material. Reduction or loss of the insulating properties of the material results in the failure of the transformer.
Importantly, it has been found that the inventive heat transfer bridge or module which provides a unique system utilizing a passive heat pump to circulate a liquid slurry carrying metallic particle may be utilized in both the first embodiment of the invention for cooling electronic components and in a second embodiment for cooling power line transformers.
The foregoing features and advantages of the present invention will be apparent from the following more particular description of the invention. The accompanying drawings, listed herein below, are useful in explaining the invention.
As alluded to above, one of the problems for developing circuit boards and IC chips, is the need for dissipating the heat generated by the components which operate at higher output/wattage. Further a problem for dissipating heat from circuit boards and IC chips is that the boards and chips are mounted in various orientations and in environments which may restrict air flow. The restricted and oft times minimal air flow will reduce the cooling capacity of hot surface and heat sinks/dissipating structure. The electronic junctions used in circuit boards are very small, therefore to be effective as a heat dissipation module, a module heat must efficiently absorb and dissipate heat energy from this small area.
It has been found that liquid cooling for circuit boards and IC chips is one of the most effective ways of cooling these components. It is standard practice to utilize pumps and compressors and refrigeration cycles to provide the liquid flow in a closed loop to carry the heat energy from the heat source to a heat sink to dissipate the heat. While the foregoing structure may be useful, it is large, cumbersome and generally cannot be mounted to small circuit boards and IC chips such as used in present day computers and other electronic devices.
Accordingly, the present invention is directed to providing a method and system for utilizing liquid cooling of electronic circuits and IC chip utilizing a means of circulating the cooling liquid utilizing a passive heat transfer pump. The passive heat pump of the invention utilizes the heat energy of the components themselves to circulate the fluid. In researching the matter, the inventor herein found that the properties of dichloromethane (methylene chloride) would enable the development of the subject heat transfer pump. Dichloromethane is volatile and has a low boiling point. When the fluid is contained an essentially vertically oriented tube and heat is applied to the lowered end of the tube, the fluid will boil at one hundred three (103) degrees Fahrenheit. As the fluid is heated above its boiling point, bubbles of methylene chloride will form and rise to the top of the tube. As the bubbles rise the hot fluid above the bubbles will be pushed up by the bubbles. As the bubbles continue to be formed, more and more hot fluid will be pushed upwardly. The fluid it carries the heat energy from the heat applied to the tube. This action will continue as heat is present and more bubbles are formed. The distance between the bottom of the fluid to the top is great enough so that fluid at the top of the tube stays remains substantially below its boiling point. The fluid cools down. Thus, as the bubbles get near the top of the tube, the bubbles break up and condense, and the fluid is no longer pushed up by the bubbles and returns back down the tube. The inventive concept utilizes the foregoing principle and incorporates one or more heat sinks in the flow path of the hot fluid and provides fluid return paths forming closed loops to extract heat from the moving fluid. The bubbles thus provide the pushing or pumping force to drive the hot fluid in a closed loop and heat sinks are provided adjacent the fluid flow path to extract heat from the fluid.
In one basic embodiment of the invention, dichloromethane is used as the fluid due to its low boiling point. As will be explained more fully herein below, the bubbles developed by a circuit board or IC chip is utilized to pump the fluid dichloromethane (methylene chloride) up an enclosed tube to move the hot fluid up the tube through a first channel to a position adjacent a heat sink where the fluid cools. The cooled fluid is returned through a separate channel and connecting the top and bottom of the tube, and the cycle repeats. Thus, the present invention provides a passive heat transfer pump. Other fluids that have a low boiling point could likewise be used; however, methylene chloride is readily available, effective and inexpensive.
Referring to
A methylene chloride fluid which is the least toxic of the simple hydrocarbons, indicated at 31, is contained in the tube 14. Methylene chloride or dichloromethane is a volatile fluid which has a low boiling point of 39.6 degrees C. (103 degrees F.). This fluid low boiling point is utilized to transfer heat energy from the hot heat sources to external heat sinks or heat dissipating components.
Assuming a heat source is applied at the lower end 26 of tube 14 which is formed as a funnel. When the dichloromethane 31 adjacent end 26 reaches its boiling point of 39.6 degrees C. the fluid will start to produce bubbles 10 and the bubbles will rise and move (push) upwardly through the open funnel end of tube 18. The spaced bubbles 10 formed by the fluid boiling action are approximately 4 mm in diameter. Bubble guide tube 18 through which the bubbles move also has an internal diameter also of 4 mm. As the fluid 31 continues to boil, more bubbles 10 with a finite spacing between them are formed adjacent to the heat source and rise up the tube 18. A hot fluid 31 is confined (entrapped) in the spacing between the bubbles. It has been found that the bubbles 10 pushes (carry) the hot fluid 31 confined between the bubbles upwardly via flow path 17. The rising bubbles 10 thus provide a positive pumping, pushing and driving action to move the hot fluid 31. The hot methylene chloride fluid 31 is thus pumped up tube 18 by the rising bubbles 10 and as the fluid 31 flows past heat sinks (concentrators) 24 mounted adjacent to the top of housing 12, heat energy is absorbed and conveyed to fins or other external heat dissipating components. A required fluid expansion volume 19 is provided adjacent to the top of tube 14. The now cooled fluid 31 and exits at the top of the tube 18 and the cool fluid returns down paths 23 and 25 to the bottom of tube 14. The cooled fluid 30 is again next heated and the cycle is repeated. The apparatus of
To address the problem of varying physical orientations of circuit boards and IC chip and internal positioning of the heat generating sources therein another embodiment 11A of the pump is disclosed herein. Referring to
In operation, with the pump 11A mounted in a vertical orientation as shown in
When pump 11A is mounted in a horizontal orientation as depicted in
As depicted in
Refer now to
Referring now to
Referring now to
Refer now to
Refer now to
An axially extending screw 115 is positioned in tube 105, and has it lower end affixed to a horizontal plate 12 that in turned is rotatably supported on a pivot pin 121. The upper end of screw 105 is positioned against a pivot point 123. Screw 105 is freely rotatable. In operation, and as previously described, the fluid in chamber 106 is heated and bubbles 116A are formed that in turn coalesce into bubbles 116 and fluid is driven up pump tube 105. The moving slurry 99 rotates the screw and creates a vortex action that, as is known, enhances fluid flow. The slurry 99 and the included bubbles 116 exit the top of tube pump 105. The bubble 116 burst on reaching the fluid level 114. A fluid return tube 125 which has its opening at approximately the same level as the opening of pump tube 105 returns fluid 99 to bubble chamber 106 as indicated by the arrows 118 to thus complete the flow loop.
Refer now to
Refer now also to
Refer also to
The heat transfer bridge module 100A provides numerous advantages and features. The 100A bridge is retrofittable to most isolation transformers. No changes have to be made to the mounting pole/support, nor to the transformer, nor to the electrical connectors. The 100A bridge will not interfere with existing maintenance or power resetting procedure. The 100A automatically creates uniform bubble and flow generation in response to heat developed in the transformer tank 131 and requires no other input power. Importantly, the metallic slurry 99 provides five to seven times the thermal transport rate of fluid alone. Many other advantages and features could be enumerated.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims
1. A heat dissipation assembly for electronic and electrical components utilizing a liquid cycling heat transfer pump comprising:
- a) an elongated container;
- b) a metal slurry fluid having a selectable boiling point contained in said container;
- c) heat sink means thermally coupled to a first section of said container;
- d) thermally coupling said heat source to provide heat energy to said fluid for generating in a second section of said container spaced fluid bubbles with hot fluid between said bubbles;
- e) mounting said container to enable said bubbles to rise up said container;
- f) said rising bubbles moving said fluid between the bubbles in the direction of the rising bubbles and toward said second section of said container wherein said heat sink means are positioned; and
- h) said heat sink means removing heat energy from said fluid.
2. A heat dissipation assembly for electronic and electrical components as in claim 1 including,
- a) a closed tubular loop;
- b) a fluid having a low boiling point contained in said tubular loop and flowable through said loop;
- c) heat sink means thermally coupled to first sections of said loop;
- d) thermally coupling said heat source to provide heat energy to said fluid for generating spaced fluid bubbles in a section of said tubular loop;
- e) mounting said second section of said loop to enable said bubbles to rise up said second section of said tubular loop;
- f) conforming the dimensions of said second section and the dimensions of said bubbles section to confine hot liquid in said spaces between rising bubbles;
- g) said rising bubbles pushing and pumping said hot fluid through said second section of said loop toward said first section of said loop wherein said heat sink means are mounted; and
- h) said heat sink means removing heat energy from said hot fluid.
3. A heat dissipation assembly for electronic and electrical components as in claim 1 including:
- a) a housing having heat concentrators for said assembly;
- b) fluid retaining tubes within said assembly;
- c) a fluid slurry comprising a fluid having a low boiling point and micro metallic particles contained within said assembly;
- d) fluid pathways formed in said assembly;
- e) means for mounting said housing adjacent a heat source;
- f) said fluid forming bubbles when heated above said boiling point;
- g) positioning at least one of said fluid pathways to direct said bubbles to move upwardly away from said heat source;
- h) said bubbles pushing said slurry toward at least one heat concentrator to remove heat from said slurry; and
- i) fluid return pathways for cycling said cooled slurry back toward said heat source.
4. A heat dissipation assembly for electronic and electrical components as in claim 1 comprising
- a) multiple heat transfer pumps;
- b) means for mounting said pumps adjacent sources of heat;
- c) each pump utilizing a liquid having a low boiling point and forming bubbles when heated above said boiling point;
- d) each pump including multiple liquid flow paths;
- e) said bubbles providing a force to push said liquid through said flow paths;
- f) heat concentrators mounted adjacent said liquid flow paths for removing heat energy from said liquid.
5. A heat transfer bridge for providing cooling to a transformer tank, said bridge comprising
- a) an enclosed container;
- b) a slurry comprising formed of fluid having a low boiling point and metallic foam particles contained in said container;
- c) heat sink fins;
- d) tube means for circulating said slurry adjacent at least a portion of said transformer tank to absorb heat energy from said tank;
- e) a bubble generating chamber for developing bubbles in said slurry as a result of heat absorbed by said slurry from said tank;
- f) said bubbles creating a pressure force for moving and stirring said fluid to circulate through tube means; and
- h) said heat sink means removing heat energy from said fluid
- whereby said tank is cooled.
6. A heat dissipation assembly for electronic and electrical components as in claim 1 further including,
- a) an enclosed container for cooling a hot component or other hot spot on a circuit board,
- b) a fluid having a selectable boiling point contained in said container;
- c) heat sink means thermally coupled to a first section of said container;
- d) inserting at least a portion of said heat source in said fluid to provide heat energy to said fluid for generating, in a second section of said container, spaced fluid bubbles;
- e) mounting said container to enable said bubbles to move in said container;
- f) said bubbles creating a pressure force for moving and stirring said fluid to circulate toward said second section of said container wherein said heat sink means are positioned; and
- h) said heat sink means removing heat energy from said fluid.
7. A cooling container as in claim 6 further including,
- a) a fluid having a selectable boiling point contained in said container;
- b) heat sink means thermally coupled to a first section of said container;
- c) thermally coupling said heat source to provide heat energy to said fluid for generating in a second section of said container spaced fluid bubbles with hot fluid between said bubbles;
- e) mounting said container to enable said bubbles to rise up said container;
- f) said rising bubbles moving said fluid between the bubbles in the direction of the rising bubbles and toward said second section of said container wherein said heat sink means are positioned; and
- h) said heat sink means removing heat energy from said fluid.
8. A heat dissipation assembly for electronic and electrical components as in claim 1 including,
- a) a closed tubular loop;
- b) a fluid having a low boiling point contained in said tubular loop and flowable through said loop;
- c) heat sink means thermally coupled to first sections of said loop;
- d) thermally coupling said heat source to provide heat energy to said fluid for generating spaced fluid bubbles in a section of said tubular loop;
- e) mounting said second section of said loop to enable said bubbles to rise up said second section of said tubular loop;
- f) conforming the dimensions of said second section and the dimensions of said bubbles section to confine hot liquid in said spaces between rising bubbles;
- g) said rising bubbles pushing and pumping said hot fluid through said second section of said loop toward said first section of said loop wherein said heat sink means are mounted; and
- h) said heat sink means removing heat energy from said hot fluid.
9. A heat dissipation assembly for electronic and electrical components as in claim 1 further comprising,
- a) a housing including heat concentrators for said assembly;
- b) fluid retaining tubes within said assembly;
- c) a fluid having a low boiling point contained within said assembly;
- d) said tubes forming fluid pathways;
- e) means for mounting said housing adjacent a heat source;
- f) said fluid forming bubbles when heated above said boiling point;
- g) positioning at least one of said tubes pathways to direct said bubbles to move upwardly away from said heat source;
- h) said bubbles pushing said fluid toward at least one heat concentrator to remove heat from said; and
- i) fluid return pathways for cycling said cooled fluid chloride back toward said heat source; and
- j) repeating the cycle.
10. A heat dissipation assembly as in claim 9 wherein the boiling point of said fluid is below the temperature at which electronic and electrical components may be degraded.
Type: Application
Filed: Mar 5, 2012
Publication Date: Feb 28, 2013
Inventor: Troy W. Livingston (Northbrook, IL)
Application Number: 13/385,731
International Classification: F28D 15/00 (20060101);