Thermal chimney for a computer

[0002] 1. Field of the Invention

[0003] The present invention relates generally to a heat removal system for computer systems, and more specifically, to a heat removal system using a heat sink and a thermal chimney.

[0004] 2. Brief Description of the Related Art

[0005] It is generally an accepted principle that computer systems generate heat during operation. It is also well known that when excessive heat occurs inside a computer system, there is a potential for damage to the components and possibly even irrecoverable disabling of the system. Accordingly, it is desirable to provide a method of removing heat from a computer system and one of the most common methods which has been used is a fan which forces air across hot components and directs the heated air out of the computer system.

[0006] Forced air convection systems, such as those using fans, have several disadvantages. Fans are loud and are distracting to the computer user. Fans also take up valuable space in computer systems and must be strategically placed in order to function properly. Further, fans draw available power away from the computer system and thus decrease the overall efficiency thereof.

[0007] There therefore remains a need in the art to provide a computer system with a more effective heat removal system, which functions without disturbing the user and facilitates a computer system with a more compact design and high efficiency.

[0008] According to an exemplary embodiment of the invention, a heat removal system for a computer system comprises a casing enclosing a hard drive and a microprocessor, said casing including an opening in an exterior surface thereof; a heat sink positioned between the hard drive and the microprocessor, said heat sink being aligned with said opening in the casing so as to form a thermal chimney; and a spreader plate disposed between the microprocessor and said heat sink, said spreader plate conducting heat from the microprocessor to said heat sink.

[0009] Still other objects, features, and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of embodiments constructed in accordance therewith, taken in conjunction with the accompanying drawings.

[0010] The invention of the present application will now be described in more detail with reference to preferred embodiments of the apparatus, given only by way of example, and with reference to the accompanying drawings, in which:

[0011] FIG. 1A is a perspective, schematic view of a computer including an embodiment of the heat removal system of the present invention; and

[0012] FIG. 1B is a cross-sectional schematic view of the heat removal system of FIG. 1A;

[0013] FIGS. 2A and 2B are perspective views of a core structure of the computer shown in FIGS. 1A and 1B; and

[0014] FIGS. 3A and 3B are exploded views thereof.

[0015] Referring to FIGS. 1A and IB, a computer C including the heat removal system 10 of the present invention comprises a casing 12 having an opening 14 in an exterior surface 16 thereof. Additionally, the computer C preferably includes a hard drive 18, a microprocessor 20, a heat sink 22, and a spreader plate 24. The heat sink 22 is preferably arranged between the hard drive 18 and the microprocessor 22 for maximum effectiveness and is aligned with the opening 14 in the casing 12 so as to form a thermal chimney 26. The spreader plate 24 is disposed between the microprocessor 20 and the heat sink 22 so as to conduct heat from the microprocessor 20 to the heat sink 22. The hard drive 18 is preferably connected directly to the heat sink 22.

[0016] As the computer system operates, the microprocessor 20 and the hard drive 18 generate heat. Heat is transferred from the microprocessor 20 to the heat sink 22, by conduction, through the spreader plate 24. Heat is also directly transferred by conduction from the hard drive 18 to the heat sink 22. As the heat sink 22 becomes hot, air immediately surrounding the heat sink 22 will be heated. The heat sink 22 is preferably located directly below the opening 14 in the exterior surface 16 of the casing 12. The hot air immediately surrounding the heat sink 22 will rise up along the sides of the heat sink 22 and finally out of the opening 14 formed in the external surface 16 of the casing 12. This area including the heat sink 22 and the space directly below the opening 14 thus defines a thermal chimney 26 through which the hot air rises. As illustrated, the chimney 26 is preferably vertically disposed within a central location in the casing 12; however, other locations and orientations are of course possible as well.

[0017] As hot air escapes, cooler air will be drawn into the casing 12. Preferably, there is at least one other opening 30 in the casing 12 through which cooler air enters the casing 12. Air thereby circulates through the casing 12 to transfer heat out of the computer system using well known thermodynamic principles and a fan is not required to cool the components, although one could also be provided to enhance the cooling effect, as shown by fan 46. As a result, heat removal is a silent, efficient process which can be incorporated into compact computer designs.

[0018] According to the present invention, the casing 12 encloses a computer system, other electronic components, or the like. The casing 12 preferably has an opening 14 in the top exterior surface 16 thereof to allow air to escape from inside the casing 12. The opening may be covered by a grate 28 which allows air to freely escape, but prevents larger objects from penetrating into the casing 12. The casing 12 can be made from either metal or plastic depending upon the particular performance and aesthetic characteristics that are desired. The casing 12 also preferably has a second opening 30 or a defined cut out in an external surface thereof for facilitating air intake. In an exemplary embodiment of the invention, as shown best in FIG. 1A, second opening 30 is in a lower portion of one of the side surfaces 32 of the casing 12. Openings 14, 30 in the casing 12 allow for air to freely circulate through the casing 12 and thereby cool the components housed therewithin.

[0019] In a preferred embodiment of the invention, the casing 12 encloses a core structure 34 which supports components of the computer system, such as the microprocessor, the hard drive, and the like. The core structure 34 also includes areas in air communication with and preferably aligned with the openings 14, 30 in the casing 12 which allow for air flow. In a preferred embodiment of the invention, the core structure 34 includes multiple openings 35 in a lower surface 36 thereof to facilitate air intake, and a larger opening 37 in a top surface 38 thereof to allow air to exit. The openings 35, 37 are preferably arranged directly below and directly above the heat sink 22, respectively. More preferably, and as most clearly shown in FIG. 1B, the core structure 34 is mounted within the casing 12 such that the bottom surface 36 of the core structure is spaced a predetermined distance above the support surface for the casing 12, thus promoting air flow up through the bottom surface 36 of the core structure 34. The core structure 34 is preferably made of metal or other suitable material.

[0020] The casing 12 preferably encloses the heat sink 22. The heat sink 22 is preferably arranged in a central location within the computer system. The heat sink 22 may be made of metal or any other material suitable for conducting heat efficiently. The heat sink preferably has a plurality of fins 40. The fins 40 are arranged to allow air to flow near the fin surfaces 42. The air flow past the fins 40 removes heat from the heat sink 22 and allows the hot air to escape through the opening 14 in the casing 12. The heat sink 22 is preferably enclosed in the core structure 34 and held in place by one or more heat sink holders 44, which are preferably a bracket assembly of the core structure 34.

[0021] The casing 12 encloses the microprocessor 20, the hard drive 18, and other components of the computer system. These components are well known in the art. Many computer components give off heat during operation of the computer. Components that give off heat are preferably placed near or in contact with the heat sink 22 to facilitate heat dispersal. The hard drive 18 is preferably disposed directly adjacent to the heat sink 22. A spreader plate 24 is preferably fixed between the microprocessor 20 and the heat sink 22. The spreader plate 24 preferably is made of metal or another material which can conductively draw heat from the microprocessor to the heat sink. Other components that give off heat, such as disk drives, may be placed in direct contact with the heat sink 22, or alternatively, may be located near the heat sink 22. Placing components near the heat sink 22 allows for convective transfer of the heat generated by these components into the air that is circulating through the casing 12.

[0022] The heat sink 22 is aligned with the opening 14 in the casing 12 so as to form the outlet for the thermal chimney 26. By concentrating the heat generated by the computer components in the heat sink 22, the air surrounding the heat sink is heated. The hot air rises along the heat sink 22 and exits through the opening 14 in the casing 12. As hot air escapes from the system, cooler air is preferably drawn into the system. The section of the computer system through which the air circulates defines the thermal chimney 26. Preferably, air naturally enters the thermal chimney 26, it is heated by components of the computer, and it naturally exits out of the thermal chimney 26. The thermal chimney 26 is preferably a generally vertical column. Heat generated by the various components of the computer is preferably concentrated in the heat sink 22, which should therefore be located along an open column of air within the thermal chimney 26.

[0023] While the invention has been described in detail with reference to preferred embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention, which is to be limited only by the claims appended hereto.