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We are specifically focusing on patented technologies to show the breadth of development in thermal management product sectors. Please note that there are many patents within these areas. Limited by article space, we are presenting a small number to offer a representation of the entire field. You are encouraged to do your own patent investigation. <\/p>\n\n\n\n
Further, if you have been awarded a patent and would like to have it included in these reviews, please send us your patent number or patent application. <\/p>\n\n\n\n
In this issue our spotlight is on spray cooling for electronics thermal management. <\/strong><\/p>\n\n\n\n There are several US patents in this area of technology, and those presented here are among the more recent. These patents show some of the salient features that are the focus of different inventors.<\/p>\n\n\n\n Full\nCoverage Spray and Drainage System and Method for Orientation-Independent\nRemoval of High Heat Flux<\/strong><\/p>\n\n\n\n <\/strong>US 8550372 B2 – Timothy A. Shedd and Adam G. Pautsch<\/a> <\/p>\n\n\n\n A cooling system and\nmethod that significantly improves spray evaporative cooling by using arrays of\nslot or plane sprays to create coverage of the entire heated surface to be\ncooled without allowing interaction between plumes that are spraying from the\nnozzles. The sprays are directed at an angle to the surface to take advantage\nof the high droplet momentum possessed by the spray to direct a flow of coolant\nfluid across the surface toward desired draining points, thereby enabling\ndrainage regardless of the orientation of the unit. <\/p>\n\n\n\n The present invention provides a spray cooling system and\nmethod that significantly improves spray evaporative cooling by creating a\ndirected momentum flow of cooling fluid across a surface to be cooled. In\naccordance with the present invention, a spray of cooling fluid is directed\ndirectly onto the surface of a work piece to be cooled at an angle with respect\nto the work piece surface so as to create a flow of cooling fluid in a\nsubstantially single direction along the work piece surface. The spray of cooling\nfluid preferably may be delivered via a plurality of generally fan shaped\nsprays. The sprays are positioned and aligned to create cooling fluid coverage\nof the entire heated surface to be cooled without allowing interaction between\nthe spray plumes in a manner that may cause areas of cooling fluid stagnation\non the surface.<\/p>\n\n\n\n A full coverage spray and drainage system in accordance with the present invention may be implemented in an otherwise conventional spray cooling system including a reservoir of an appropriate cooling fluid (e.g., Fluorinert-72 for the cooling of electronic circuitry, preferably saturated with a non-condensable inert gas, such as nitrogen), a pump for delivering the cooling fluid under pressure from the reservoir to a spray chamber to be sprayed therein from nozzles onto the work piece to be cooled, and appropriate filtering, metering, and control systems. Cooling fluid is returned from the spray chamber to the coolant reservoir via a drainage point or points in the spray chamber. <\/p>\n\n\n\n In accordance with the present invention, the drainage point or points in the spray chamber may be positioned with respect to the coolant spray such that the flow of cooling fluid directed in a substantially single direction along the work piece surface also is directed toward the drainage point or points. Thus, the cooling fluid momentum directs the fluid toward the drainage point, thereby assuring proper drainage of the cooling fluid despite changes in the orientation of the cooling system.<\/p>\n\n\n\n Directly\nInjected Forced Convection Cooling for Electronics<\/strong><\/p>\n\n\n\n US 8824146 B2 – Gerrit Johannes Hendrikus Maria Brok, Wessel Willems Wits, Jan Hendrik Mannak and Rob Legtenberg<\/a> <\/p>\n\n\n\n Electronic circuitry includes a circuit board and at\nleast one component mounted on the circuit board, with the at least one\ncomponent generating heat while in use. The circuit board includes one or more\napertures aligned with one or more respective components, and the electronic\ncircuitry is configured to provide, while in use, a path for coolant fluid to\nflow through each aperture and past the respective component.<\/p>\n\n\n\n By providing at least one aperture aligned with a\ncomponent that generates heat in use, improved cooling of the electronic\ncircuitry may be provided, as cooling effects can more efficiently be targeted\nat those parts of the circuitry that generate or dissipate heat.<\/p>\n\n\n\n Each aperture may be, but is not necessarily positioned\nat that point or within that region of the circuit board that is a minimum\ndistance from the component or a respective one of the components.<\/p>\n\n\n\n The central axis of each aperture may be, but is not\nnecessarily, perpendicular to the plane of the circuit board and at least one\ncomponent. Preferably each aperture is arranged such that a straight line\nextending out of the aperture along the central axis of the aperture would pass\nthrough the component with which the aperture is aligned. Preferably each\naperture is arranged such that, in use, coolant fluid exits the aperture\ntowards the component with which the aperture is aligned.<\/p>\n\n\n\n The coolant fluid may be liquid or gas. The coolant fluid\nmay be water. The coolant fluid may comprise a dielectric fluid, for example\npoly-alpha-olefin (PAO), or an inert gas, for instance nitrogen. Preferably the\ncoolant fluid is air. In some circumstances, the coolant fluid may be supplied\nfrom a pressurized source, for instance a pressurized gas cylinder.<\/p>\n\n\n\n The position of each aperture may be such that, in use,\ncoolant fluid passing through the aperture approaches the surface of the component\nwith which the aperture is aligned from a perpendicular direction.<\/p>\n\n\n\n Thereby a jet impingement effect may be provided such\nthat, preferably, the coolant fluid breaks through a respective thermal\nboundary layer next to the or each at least one heat generating component. Such\nthermal boundary layers are stable layers of air or other fluid which may build\nup next to the or each component and which exhibit a temperature gradient away\nfrom the component. The presence of such thermal boundary layers can reduce\nconvective cooling effects.<\/p>\n\n\n\n Narrow\nGap Spray Cooling in a Globally Cooled Enclosure<\/strong><\/p>\n\n\n\n US 8174828 B2 – Charles L. Tilton, Donald E. Tilton, Randall T. Palmer, William J. Beasley, Douglas W. Miller and Norman O. Alder<\/a><\/p>\n\n\n\n Electronic circuit boards are arranged as respective\nparallel pairs defining a narrow gap there between. One or more such pairs of\nboards are supported within a hermitically sealable housing and cooled by way\nof spraying an atomized liquid coolant from a plurality of nozzles into each\nnarrow gap. Transfer of heat from the circuit boards results in vaporization of\nat least some of the atomized liquid within the narrow gap. The housing further\nserves to guide a circulation of vapors out of each narrow gap, back toward the\nnozzles, and back into each narrow gap. A heat exchanger exhausts heat from the\nhousing and overall system, wherein vapor is condensed back to liquid phase\nduring contact and heat transfer therewith. Condensed liquid is collected and\nre-pressurized for delivery back to the nozzles such that a sustained cooling\noperation is performed.<\/p>\n\n\n\n One embodiment provides for a system, including a first\nentity and a second entity that are respectively disposed such that they define\na narrow gap between them. The system also includes at least one nozzle,\nwherein the nozzle is configured to spray an atomized liquid so that a flow of\nthe atomized liquid and a vapor is induced through the narrow gap. The system\nalso includes a heat exchanger that is configured to condense some of the vapor\nto liquid, the condensed vapor defining a condensate. The system further\nincludes a housing configured to guide a circulation of at least some of the\nvapor, which is flowing out of the narrow gap, away from the heat exchanger and\ninto proximity with the at least one nozzle.<\/p>\n\n\n\n Another embodiment provides for a system, the system\ncomprising a housing configured to selectively open-ably enclose a plurality of\nelectronic circuit boards. The system further includes a plurality of\nelectronic circuit boards supported in the housing, wherein at least some of\nthe electronic circuit boards are arranged to define respective pairs of\nboards. At least one pair of boards defines a narrow gap there between. The\nsystem also includes at least one nozzle associated with each narrow gap, each\nnozzle being configured to spray an atomized liquid into the narrow gap defined\nby the associated pair of boards. The housing is also configured to guide a\ncirculation of a vapor exiting each narrow gap into proximity with the at least\none nozzle associated with the at least one narrow gap.<\/p>\n\n\n\n Still another embodiment provides an apparatus. The\napparatus includes a nozzle configured to spray an atomized liquid in a\ngenerally conical distribution pattern. The apparatus further includes a\nre-shaper that is configured to reform the spray of atomized liquid into a\ngenerally planar distribution pattern.<\/p>\n\n\n\n Enhanced\nSpray Cooling Technique for Wedge Cooling<\/strong><\/p>\n\n\n\n US 8729752 B2 – Balwinder Singh Birdi, Simon Waddell and William Scherzinger <\/a> <\/p>\n\n\n\n The\npresent invention relates to apparatus and methods for heat removal and, more\nparticularly, apparatus and methods for spray cooling a wedge of a generator\nrotor.<\/p>\n\n\n\n In\ngenerators, electromagnetic losses occur in the magnetic iron and the copper.\nThese losses result in production of heat which must be removed to maintain\noverall temperature below that allowable for the copper coating and the\ninsulation used in the construction of the generators. The rotor core, which is\nmade of magnetic iron, can be conduction cooled by flowing fluid through the\nrotor shaft. However, the removal of heat from copper is better managed if oil\nis passed through the hollow wedges. Due to lower thermal resistance, the flow\nof fluid in the vicinity of copper is much more effective in removing heat from\nthe copper and in keeping the overall temperature below the allowable limit.\nThis is done with conduction mode of heat removal.<\/p>\n\n\n\n Since\nthe heat transfer coefficient (HTC) depends upon the velocity of the fluid, the\nremoval of heat is not very efficient, and a very high flow is needed to create\na reasonable HTC for conduction cooling. Further, because the rotor is a\nrotating component, having a large amount of fluid at a radius away from the\nrotor shaft is not desirable, especially for high powered larger diameter and high-speed\nmachines.<\/p>\n\n\n\n In one\naspect of the present invention, a spray cooling manifold comprises a manifold\nferrule adapted to circumscribe a shaft of a rotating machine; a manifold pipe\nhaving a bend of about 90 degrees having a first end attached to the manifold\nferrule and a second, opposite end; a cooling fluid channel running from an\ninside surface of the manifold ferrule to the second, opposite end of the\nmanifold pipe; and a pipe extending from the second, opposite end of the\nmanifold pipe, the pipe adapted to extend into a wedge of the rotating machine,\nthe pipe having a plurality of holes formed there along.<\/p>\n\n\n\n In another aspect of the present invention, a rotating machine rotor comprises a shaft; a plurality of coils disposed on the shaft; a plurality of wedges disposed between the coils; bands securing the wedges on the rotor; and a manifold comprising a manifold ferrule adapted to circumscribe the shaft; a plurality of manifold pipes, each having a bend of about 90 degrees, each having a first end attached to the manifold ferrule and a second, opposite end attached to a wedge pipe extending into the wedges; a cooling fluid channel running from an inside surface of the manifold ferrule to the wedge pipe; and a plurality of holes disposed along the wedge pipe.<\/p>\n\n\n\n For more information about Advanced Thermal Solutions, Inc. (ATS) thermal management consulting and design services, visit <\/em>https:\/\/www.qats.com\/consulting<\/em><\/a> or contact ATS at 781.769.2800 or <\/em>ats-hq@qats.com<\/em><\/a>. To register for Qpedia and to get access to its archives, visit <\/em>https:\/\/www.qats.com\/Qpedia-Thermal-eMagazine<\/em><\/a>.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" Qpedia continues its review of technologies developed for electronics cooling applications. We are presenting selected patents that were awarded to developers around the world to address cooling challenges. After reading the series, you will be more aware of both the … Continue reading ![\"\"](\"http:\/\/www.qats.com\/cms\/wp-content\/uploads\/Fig-1-26.jpg\")
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