US 20080130222 A1
A fan sink that includes a dual impeller push-pull axial fan and a heat sink to cool a hot electronic device is presented. The axial fan has a hub motor, a first impeller that is radially proximate to the hub motor, and a second impeller that is radially distal to the hub motor, wherein the first impeller pushes air in a first direction and the second impeller pulls air in a second direction. The heat sink is oriented between the axial fan and the hot electronic device such that the hot electronic device, the heat sink, and the axial fan are axially oriented, wherein cool air is forced onto the heat sink by one impeller in the axial fan, and wherein heated air from the heat sink is removed by an other impeller in the axial fan.
1. A method comprising:
mounting a heat sink between a heat generating unit and an axial fan, wherein the axial fan is composed of:
a first impeller that is radially proximate to the hub, and
a second impeller that is radially distal to the hub, wherein the first impeller
pushes air in a first direction and the second impeller pulls air in a second direction, wherein the heat generating unit, the heat sink, and the axial fan are axially oriented, and wherein cool air is forced onto the heat sink by one impeller in the axial fan, and wherein heated air from the heat sink is removed by an other impeller in the axial fan, and wherein a top surface of the heat sink has a concave surface that aids a direction of airflow direction between the first and second impellers, wherein the axial fan is mounted to the heat sink without any ductwork surrounding the axial fan, and wherein ambient air flows freely through the second impeller from an interior of a housing that holds the hot device, and wherein the first impeller has only large fan blades, and wherein the second impeller has only small fan blades, and wherein the large fan blades are larger than the small fan blades, and wherein the first impeller has fewer large fan blades compared to a quantity of small fan blades in the second impeller;
a first interior duct that is aligned axially with the first impeller to bring the cool air in from outside a housing of the system; and
a second interior duct that circumscribes the first interior duct, wherein the second interior duct is aligned axially with the second impeller to exhaust hot air outside the housing of the system, wherein the first and second impellers are only supported by the hub, and wherein rotational force to the first and second impellers is supplied by a separate mechanical means.
2. The method of
3. The method of
a plurality of fins, wherein air moving from the first impeller towards the second impeller moves across the fins.
The present application is a continuation of U.S. patent application Ser. No. 11/314,707 (Atty. Docket No. RPS920050164US1), filed on Dec. 21, 2005, and entitled, “Dual Impeller Push-Pull Axial Fan Heat Sink,” which is incorporated herein by reference.
The present invention relates in general to the field of electronics, and in particular to electronic chips that generate extraneous heat during normal operation. More particularly, the present invention relates to a method and system for removing heat from an integrated circuit using a dual impeller push-pull axial fan.
2. Description of the Related Art
In a typical personal computer (PC), the main heat-generating component among the logic circuits is the processor, also referred to as the Central Processing Unit (CPU) or microprocessor (MP). As illustrated in
To remove heat from processor 102, a heat sink (HS) 110, having a HS base 112 and a plurality of fins 114, is secured to processor 102 by a strap 116 or other attachment means. Heat is conducted from the processor 102 to the HS base 112 and the fins 114, which dissipate heat by conduction and convection to ambient air surrounding fins 114. To provide thermal conduction between a top surface 120 of processor 102 and the HS base 112, thermal grease 118, typically a thermally conductive silicon or filled hydrocarbon grease doped with fillings such as metals, is used.
A major problem with the heat sink 110 shown in
A major problem with the system shown in
The present invention is therefore directed to a fan sink that includes a dual impeller push-pull axial fan and a heat sink to cool a hot electronic device. The axial fan has a hub, a first impeller that is radially proximate to the hub, and a second impeller that is radially distal to the hub, wherein the first impeller pushes air in a first direction and the second impeller pulls air in a second direction. The heat sink is oriented between the axial fan and the hot electronic device such that the hot electronic device, the heat sink, and the axial fan are axially oriented, wherein cool air is forced onto the heat sink by one impeller in the axial fan, and wherein heated air from the heat sink is removed by an other impeller in the axial fan.
The above, as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further purposes and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, where:
In accordance with a preferred embodiment of the present invention, and with reference now to
First impeller 206 is radially proximate to hub motor 204, while second impeller 208 is radially distal to hub motor 204. As depicted by the airflow arrows, air is pulled through an opening 224 a (in a housing 218) and down an inner duct 210 to reach first impeller 206. The airflow passes across fins 214 of heat sink 213 (which includes heat sink base 215 to which fins 214 are attached). This airflow across fins 214 removes heat from processor 102, which is an exemplary hot device that is in need of cooling.
After passing across fins 214 (and heat sink base 215), the airflow is pulled upwards by second impeller 208, which moves the heated air up an outer duct 212 (which surrounds inner duct 210) and out of opening 224 b in housing 218. Thus, the heated air is efficiently exhausted out of the housing 218 of the (e.g., computer) system, thus preventing additional hot air from being blown across nearby ICs 128. Note that in a preferred embodiment, opening 224 a and opening 224 b are separate plenums, such that there is adequate separation between inlet air and outlet air, such that mixing of the inlet air and outlet air is minimized or (preferably) eliminated even when the inlet air and outlet air are outside of housing 218. Thus, a plenum collar 219 outside housing 218 may be added to prevent such air mixing. Alternatively, inner duct 210 may be extended through opening 224 a to serve the same described function of plenum collar 219.
Note that while the duct bottom 220 is shown as being only slightly recessed, such that axial fan 202 is still surrounded by outer duct 212, alternatively duct bottom 220 can be more recessed such that axial fan 202 is completely exposed (not shown) outside of either inner duct 210 or outer duct 212. Such a configuration would increase the airflow across ICs 128, but would result in additional heat escaping into the interior of housing 218 due to the increased lack of control of air currents about axial fan 202.
Note also that, as shown in
Another embodiment of the presently presented fan sink 200 is presented in
Another less attractive embodiment is presented in
As thus depicted in
With reference now to
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. For example, while the present invention has been described in removing heat from a processor, the inventive fan heat sink (having a dual impeller push-pull axial fan) is useful in removing heat from any heat generating device, and particularly any heat generating integrated circuit package.
Note further that while terms such as “above” and “beneath,” “push” and “pull,” etc., may have been used herein to describe the spatial orientation and movement, such terms are used generically, and the present invention as described and claimed is to include orientations and movements so generally described, but not limited to such “up/down,” “top/bottom,” and “push/pull” descriptions.