|Publication number||USRE39774 E1|
|Application number||US 10/387,234|
|Publication date||Aug 14, 2007|
|Filing date||Mar 12, 2003|
|Priority date||Mar 2, 1999|
|Also published as||US6244818|
|Publication number||10387234, 387234, US RE39774 E1, US RE39774E1, US-E1-RE39774, USRE39774 E1, USRE39774E1|
|Original Assignee||Delta Electronics, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (40), Non-Patent Citations (12), Referenced by (6), Classifications (30), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention is related to a fan guard structure, and more particular to an improved fan guard structure which imparts a supercharging function to a fan for efficient heat dissipation.
Currently, heat-dissipating fans commonly used in personal computers include an axial-flow fan, a centrifugal fan and a cross-flow fan. Of these, the most popular one is supposed to be an axial-flow fan.
A fan is primarily consisted of a rotor device and a fan guard arranged beside the rotor device for supporting the rotor device. Referring to
Unfortunately, when the airflow further flows through the fan guard having the structure as shown in FIG. 1 and as described above, turbulent flows will be generated after the airflow encounters the ribs so as to have an adverse effect on the blast pressure enhancement. Consequently, the efficiency of the fan is reduced.
Therefore, an object of the present invention is to provide an improved fan guard structure which has a function of supercharging a fan in addition to supporting a rotor device.
The present invention is related to a fan guard to be mounted beside a rotor device of a fan for supporting the rotor device. Additionally, the fan guard according to the present invention interacts with an airflow generated by the revolution of the rotor blades to supercharge the fan.
The fan guard essentially includes a main frame, and a set of guard blades radially arranged inside the main frame and fixed onto an inner surface of the main frame by each one end thereof. Generally but not definitely, a count of the guard blades is about 1-2 times of that of the rotor blades. Preferably, the other ends of the guard blades are fixed onto a cylindrical motor holder which is located at the center of the main frame, and is hollow for receiving therein a motor used for driving the rotor blades to revolve. Especially preferred, at least one reinforcing ring connecting all of the guard blades is provided for strengthening the far guard. In general, the guard blades are made of plastic. Nevertheless, the guard blades can also be made of a material other than plastic for a desired purpose. For example, they can be made of a metal which is advantageous for heat dissipation.
To assemble the fan, the main frame of the fan guard is coupled to the frame of the rotor device. Alternatively, the main frame of the fan guard is integrally formed with the frame of the rotor device so that the fan can be assembled by installing the non-integrally formed parts into the common frame. The fan guard can be arranged either upstream or downstream of the rotor device. Preferably, the fan guard includes two sets of frame and guard blades respectively arranged by both sides of the rotor device. By properly designing the shapes and the position arrangement of the guard blades relative to the rotor blades, the upstream guard blades can guide air into the rotor device at an angle to make an air inflow to the rotor device have an additional tangential velocity which increases the work of the rotor blades on air, and on the other hand, the downstream guard blades can transform a tangential velocity of an air outflow from the rotor device into a static pressure, both advantageous for supercharging the fan. For example, all of the guard blades are made to have a shape identical to the shape of the rotor blades. As for the position arrangement of the downstream guard blades relative to the upstream rotor blades, one of the guard blades and one of the rotor blades constitute a near letter C configuration in a cross-sectional view instantaneously. Contrarily, the position arrangement of the upstream guard blades relative to the downstream rotor blades makes one of the guard blades and one of the rotor blades constitute a near letter S configuration in a cross-sectional view instantaneously.
Furthermore, by taking the combination of a fan guard according to the present invention and a rotor device as a fan unit, a fan can be designed to include a plurality of such fan units to enhance efficiency.
The present invention may best be understood through the following description with reference to the accompanying drawings, in which:
The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed. On the other hand, all arrows shown in the drawings are used for schematically illustrating the directions of airflows and velocities, and the length of the arrows does not indicate the measure of the corresponding items.
Please refer to
The assembled fan is shown on
Please refer to FIG. 3. In order to concretely illustrate the arrangement of the guard blades, an upstream rotor blade 313 which can be any one of the rotor blades and a downstream guard blade 303 which can be any one of the guard blades, are shown in a cross-sectional view, and a specific moment that a leading point A of the guard blade 303 is moved to be axially aligned with the trailing point B of the rotor blade 313 is taken to facilitate to describe the position relationship between the selected rotor blade and guard blade. As shown, the rotor and the guard blades 313 and 303 constitute a near letter C configuration.
When the rotor device operates to have the rotor blade 313 revolve at a tangential velocity Vr, the airflow arriving at the guard blade 303 has an axial velocity and a tangential velocity. Due to conservation of mass, the axial velocity will not change through the entire guard blade 303, and is represented by a reference symbol Va in FIG. 3. The tangential velocity, however, varies from a relatively high value Vt approximating the velocity Vr of the rotor blade to a relatively low value Vt′ down to zero. According to the Bernoulli's Law, the pressure will increase with the decrease of velocity. The tangential velocity of the airflow Fm will be transformed into a static pressure. Accordingly, the blast pressure further rises through the fan guard, and the fan is thus supercharged.
Although such a near C configuration is exemplified as above to describe a preferred embodiment, other configurations are acceptable as long as the purpose of transforming a tangential velocity into a static pressure can be achieved.
In another embodiment according to the present invention, the guard blades are arranged upstream of the rotor blades. As shown in
When the rotor device operates to have the rotor blade 413 revolve at a tangential velocity Vr, the guard blade 403 guide air into the rotor blade 413 at an angle. Consequently, the air outflow from the guard blade 403 has an axial velocity Va and a tangential velocity Vt, and thus the airflow arriving at the rotor blade 413 has a tangential velocity of Vr+Vt. As known, the increase of the tangential velocity enhances the work of the rotor blades on air, so in this way, the fan is supercharged.
Although such a near S configuration is exemplified as above to describe a preferred embodiment, other configurations are acceptable as long as the purpose of providing an additional tangential velocity can be achieved.
Please now refer to
The composite fan shown in
A further embodiment of a composite fan is shown on
On the basis of the above fan guard skeletons, at least one reinforcing ring connecting the guard blades are preferably arranged for strengthening the fan guard. Referring to
Although the guard blades in the above embodiments are exemplified to have a shape identical to the shape of the rotor blades, they can be plane plates or any other suitable shapes as long as the efficiency of the fan can be enhanced thereby.
The number of the guard blades need not be particularly limited, but one to two times of the count of the rotor blades will result in satisfactory performance.
The guard blades can be made of plastic. Nevertheless, the guard blades can also be made of a material other than plastic for a desired purpose. For example, when they are made of metal, the guard blades can serve as efficient heat-dissipating plates to further enhance the heat-dissipating efficiency.
To sum up, according to the present invention, the performance of a fan can be easily improved by changing the structure of the fan guard conventionally only used for supporting the fan. On the other hand, it is even advantageous because for the application to compact products, the high performance of the fan according to the present invention allows the fan size to be reduced so as to be installed properly.
While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1062258||Jul 7, 1911||May 20, 1913||Georg Arthur Schlotter||Propeller.|
|US1747627 *||Apr 1, 1929||Feb 18, 1930||Guth Edwin F||Fan guard|
|US2154313||Apr 1, 1938||Apr 11, 1939||Gen Electric||Directing vane|
|US2208615 *||Jul 27, 1939||Jul 23, 1940||Frank L Wattendorf||Axial flow type fan or pump|
|US2592471 *||Aug 22, 1946||Apr 8, 1952||Sawyer James G||Axial flow fan|
|US2952403 *||Apr 22, 1954||Sep 13, 1960||Stalker Edward A||Elastic fluid machine for increasing the pressure of a fluid|
|US3168235||Dec 30, 1960||Feb 2, 1965||Lyonnaise Ventilation||Helicoidal fans|
|US3342254||Sep 1, 1965||Sep 19, 1967||Hitachi Ltd||Ventilating machine of supply-exhaust type with heat exchanger|
|US3883264||Apr 8, 1971||May 13, 1975||Gadicherla V R Rao||Quiet fan with non-radial elements|
|US3924964||Dec 23, 1974||Dec 9, 1975||Trane Co||Axial flow fan apparatus|
|US3995970 *||Sep 3, 1975||Dec 7, 1976||Mitsubishi Jukogyo Kabushiki Kaisha||Axial-flow fan|
|US4483624 *||Aug 25, 1982||Nov 20, 1984||Freeport Kaolin Company||High intensity conditioning mill and method|
|US4603271 *||Aug 14, 1985||Jul 29, 1986||Nippon Keiki Works, Ltd.||Fan motor|
|US4724747||May 7, 1986||Feb 16, 1988||Ebm Elektrobau Mulfingen Gmbh & Co.||Ventilator housing with a protective screen|
|US4968216||Oct 12, 1984||Nov 6, 1990||The Boeing Company||Two-stage fluid driven turbine|
|US4971143||May 22, 1989||Nov 20, 1990||Carrier Corporation||Fan stator assembly for heat exchanger|
|US5295811 *||Dec 2, 1991||Mar 22, 1994||Duracraft Corporation||Portable fan with electrical control retaining stand|
|US5342167 *||Oct 9, 1992||Aug 30, 1994||Airflow Research And Manufacturing Corporation||Low noise fan|
|US5393197||Nov 9, 1993||Feb 28, 1995||Lemont Aircraft Corporation||Propulsive thrust ring system|
|US5546272 *||Jan 18, 1995||Aug 13, 1996||Dell Usa, L.P.||Serial fan cooling subsystem for computer systems|
|US5839205||Sep 8, 1997||Nov 24, 1998||Hung; Fred L.||Electric fan using multiple fan blades to raise air output pressure|
|US6024536||Nov 21, 1997||Feb 15, 2000||Zexel Corporation||Device for introducing and discharging cooling air|
|US6092988 *||Jul 6, 1998||Jul 25, 2000||Ford Motor Company||Centrifugal blower assembly with a pre-swirler for an automotive vehicle|
|US6142733 *||Dec 30, 1998||Nov 7, 2000||Valeo Thermique Moteur||Stator for fan|
|US6547540 *||Sep 28, 2001||Apr 15, 2003||Sunonwealth Electric Machine Industry Co., Ltd.||Supercharging structure for a fan|
|US6663342 *||Feb 1, 2002||Dec 16, 2003||Delta Electronics Inc.||Composite heat-dissipating system and its used fan guard with additional supercharging function|
|GB2156007A||Title not available|
|JP2823657B2||Title not available|
|JP33018660A||Title not available|
|JPH0226799A||Title not available|
|JPH0323700A||Title not available|
|JPH1066305A||Title not available|
|JPH02103198A||Title not available|
|JPH03206398A||Title not available|
|JPH10205497A||Title not available|
|JPS5524399A||Title not available|
|JPS6141886A||Title not available|
|JPS57186097A||Title not available|
|JPS57186098A||Title not available|
|JPS61104116A||Title not available|
|1||"Aircraft Gas Turbine Engine Technology," Chapter 5, 1994.|
|2||"Axial Flow Fans and Ducts," 1997.|
|3||"Design of Ventilator and Pump," 1971, Taiwan, with concise statement of relevance in English.|
|4||"Design of Ventilator and Pump," 1971, Taiwan.|
|5||"Fan Handbook Selection, Application, and Design," Frank P. Bleier, 1997.|
|6||"Fluid Mechanics," 1993, Taiwan, with concise statement of relevance in English.|
|7||"Ventilator Handbook," 1994, China, with concise statement of relevance in English.|
|8||"Ventilator Handbook," 1994, China.|
|9||*||Encyclopedia Britannica Online. http://www.britannica.com/eb/article?tocId=9005219. Accessed May 25, 2005.|
|10||Fluid Mechanics, 1993, Taiwan.|
|11||*||Merium-Webster Online Dictionary.|
|12||*||Merriam-Webster's Collegiate Dictionary, Tenth Edition, 1998, p. 25.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8225623 *||Feb 19, 2008||Jul 24, 2012||Mitsubishi Electric Corporation||Centrifugal fan, air conditioner|
|US20090263238 *||Apr 17, 2008||Oct 22, 2009||Minebea Co., Ltd.||Ducted fan with inlet vanes and deswirl vanes|
|US20100115983 *||Feb 19, 2008||May 13, 2010||Mitsubishi Electric Corporation||Centrifugal fan, air conditioner|
|US20120213650 *||Aug 23, 2012||Don-Cheng Lee||Cooling Fan with Dual Rotation Directions|
|CN101776090B||Dec 29, 2009||Feb 20, 2013||林钧浩||Circular current pressure boosting ventilation gas compressor|
|DE102008042712A1 *||Oct 9, 2008||Apr 15, 2010||BSH Bosch und Siemens Hausgeräte GmbH||Ventilation grid for household appliance, has multiple faces, which are fixed at frame, where one face is curved in section wise manner|
|U.S. Classification||415/208.2, 415/193, 415/209.1, 415/223, 415/199.4, 416/247.00R|
|International Classification||F04D29/54, F01D25/24, F02C7/055, H05K7/20, F04D29/70, G06F1/20, F04D29/44, F01D9/00|
|Cooperative Classification||F05D2240/14, F05D2240/12, F05D2240/40, F04D29/542, H05K7/20172, F02C7/055, F04D29/703, G06F1/20, F05B2240/13, F01D25/24|
|European Classification||H05K7/20B10F, F04D29/54C2, F02C7/055, F04D29/70C2, F01D25/24, G06F1/20|
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|Jan 2, 2009||FPAY||Fee payment|
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|Dec 12, 2012||FPAY||Fee payment|
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