Heat exchange – Intermediate fluent heat exchange material receiving and... – Liquid fluent heat exchange material
Reexamination Certificate
2000-11-15
2002-06-25
Bennett, Henry (Department: 3743)
Heat exchange
Intermediate fluent heat exchange material receiving and...
Liquid fluent heat exchange material
C165S104220, C165S104250, C165S104310, C361S700000, C257S715000, C257S716000, C174S015100
Reexamination Certificate
active
06408937
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of heat sink devices such as cold plates for transferring heat away from a heat source such as an electronic component or board to maintain the component within an optimum operating temperature range, so that the component can operate continuously and with maximized efficiency. A typical heat source would be an IGBT module used in power electronics such as in rectifiers, inverters and in welding equipment. More specifically the present invention relates to an active heat sink in the form of a cooling fluid circulating apparatus containing a fluid circulation path which is configured to prevent the formation of stagnant fluid dead spaces and which mechanically moves fluid at high velocity adjacent to the heat source.
The apparatus includes a housing containing a heat transfer chamber which in turn contains a heat transfer fluid, part of the chamber being defined by a heat transfer wall through which heat is received from the heat source, a fluid circulation path, a heat dissipating enclosure and fluid propelling means for causing the fluid to circulate through the circulation path and across the heat transfer wall so that the fluid absorbs heat from the heat transfer wall and flows into the heat dissipating enclosure remote from the heat transfer wall where the heat is dissipated into the surrounding environment. The fluid propelling means is preferably an impeller mounted so that the impeller blades pass very close to the heat transfer wall.
2. Description of the Prior Art
There have long been heat transfer devices in the form of heat sinks and cold plates for transferring heat away from various electronic elements so that the temperatures of these devices remain within acceptable limits so that the devices operate at higher efficiency and require less shut down time for cooling. These have included simple heat sinks mounted on individual components to provide larger surface areas for enhanced dissipation of heat to the surrounding atmosphere either by natural or forced convection. For high power systems, entire boards have been mounted on liquid-cooled heat exchangers such as cold plates which transfer the waste heat to the atmosphere via a liquid-air radiator. The entire flow loops usually include pumps, valves, drive motors, other components as required for specific applications.
Paterson, U.S. Pat. No. 5,390,077, issued on Feb. 14, 1995, discloses an integrated circuit cooling device having an internal baffle. Paterson includes a cooling fluid chamber which rests on top of a heat source and contains cooling fluid in both liquid and gaseous phases. The cooling fluid evaporates within the chamber, rises between two upwardly tapering barrier structures to emerge from the middle of these structures and make contact with cooler upper and side chamber walls having heat fins, where it condenses and falls back around the outer periphery of the barrier structures into the liquid phase pool of cooling fluid.
Remsburg, U.S. Pat. No. 5,864,466, issued on Jan. 26, 1999 teaches a thermosyphon-powered jet-impingement cooling device similar in general design to Paterson, except that the condensed cooling fluid returns to the pool of liquid fluid at the center of the barrier structure and causes a boundary layer minimizing jet action against the heat source abutting wall of the chamber.
Other liquid and gaseous fluid flow cooling devices found in the search are Schneider, et al., U.S. Pat. No. 5,950,714, issued on Sep. 14, 1999 for a tubular cooling apparatus for an electronic component, the tube containing a venturi member; Messina, U.S. Pat. No. 5,309,319, issued on May 3, 1994 for an integral cooling system for electric components; Mansingh, U.S. Pat. No. 5,020,586, issued on Jun. 4, 1991 for an air-cooled heat exchanger for electronic circuit modules; and Reichard, U.S. Pat. No. 5,316,077, issued on May 31, 1994 for a heat sink for electrical circuit components.
It is thus an object of the present invention to provide a heat sink apparatus containing a heat transfer fluid which transfers heat away from a heat source through a heat transfer wall with greater efficiency than existing cold plates by mechanically forcing cooling fluid flow within the flow layer of the fluid along the heat transfer wall.
It is another object of the present invention to provide such a heat sink apparatus which distributes fluid uniformly over the entire heat transfer wall so that there are no dead spaces in which fluid flow is substantially static.
It is still another object of the present invention to provide such a heat sink apparatus in which very high heat transfer rates are possible over large surface areas, system pressures are relatively low, both modular and integrated designs are feasible, special heat transfer fluids can be used in modules, and in which design is scalable.
It is yet another object of the present invention to provide such a heat sink apparatus which provides an internal pumping effect so that the external pump may be omitted in many cases.
It is finally an object of the present invention to provide such a heat sink apparatus which is economical to manufacture and reliable.
SUMMARY OF THE INVENTION
The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.
A heat sink apparatus is provided for gathering and dissipating heat from a heat source having a heat source housing, the apparatus including an impeller chamber having a chamber interior containing a heat transfer fluid and comprising a heat transfer wall for transferring heat from the heat source into the chamber; a heat transfer fluid within the chamber; a fluid circulation path including the chamber interior; a fluid propelling mechanism for propelling the fluid through the circulation path and across the heat transfer wall so that the fluid absorbs heat at the heat transfer wall and flows to a heat discharge region remote from the heat transfer wall where the heat is dissipated into the surrounding environment; where the fluid propelling mechanism includes a mechanical fluid driving structure including blades within the chamber rotatably secured to the apparatus with a blade mounting structure to move adjacent to and along the heat transfer wall and within the flow layer of the fluid adjacent to the heat transfer wall to mechanically force convection of the fluid close to the heat transfer wall.
The impeller chamber preferably includes a first chamber end wall and a second chamber end wall and a circumferential side wall sealingly interconnecting the first chamber end wall and the second chamber end wall, and where the first chamber end wall is the heat transfer wall and where the second chamber end wall includes an outer periphery and a central fluid entry port and a fluid exit port at the outer periphery of the first chamber end wall; so that the fluid is delivered into the chamber through the fluid entry port and the fluid impinges upon an opposing central region of the first chamber end wall and flows radially outward from the central region in all directions, across the first chamber end wall and toward the circumferential side wall, and then diverts away from the first chamber end wall, through the fluid exit port and into the heat dissipating enclosure from which heat gathered from the heat source is dissipated into the outside environment, and the fluid within the heat dissipating chamber then flows again through the fluid entry port into the chamber thereby completing a repeating flow cycle.
The central fluid port preferably contains a fluid guide tube extending substantially perpendicular to the second chamber end wall, so that the fluid guide tube receives and passes fluid as the fluid passes from the heat dissipating enclosure into the chamber. The blades preferably include an impeller having a central impeller hub and several impeller blades secured to and extending radially from the central impelle
Bennett Henry
Kubler Frank L.
McKinnon Terrell
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