U.S. patent application number 09/877321 was filed with the patent office on 2001-10-11 for heatsink with integrated blower for improved heat transfer.
Invention is credited to Budelman, Gerald A..
Application Number | 20010027855 09/877321 |
Document ID | / |
Family ID | 23687416 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010027855 |
Kind Code |
A1 |
Budelman, Gerald A. |
October 11, 2001 |
Heatsink with integrated blower for improved heat transfer
Abstract
A device that efficiently transfers heat from a heat source. The
device includes a heat sink, the heat sink comprising a thermally
conductive base, and a plurality of thermally conductive pin fins
coupled to the thermally conductive base. A gas source, such as a
blower, proximate to the pin fins, directs a gas, such as ambient
air, axially along at least a portion of the pin fins, and then in
a direction radial to the pin fins and substantially parallel to
the heat source, to transfer heat away from the heat source. The
heat transfer device may be utilized in any application that
requires efficient removal of heat from a heat source, for example,
an electronic device such as an integrated circuit or
microprocessor.
Inventors: |
Budelman, Gerald A.;
(Olympia, WA) |
Correspondence
Address: |
JOSEPH A. TWAROWSKI
BLAKELY, SOKOLOFF, TAYLOR & ZAFMAN LLP
Seventh Floor
12400 Wilshire Boulevard
Los Angeles
CA
90025-1026
US
|
Family ID: |
23687416 |
Appl. No.: |
09/877321 |
Filed: |
June 7, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09877321 |
Jun 7, 2001 |
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09425639 |
Oct 22, 1999 |
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6244331 |
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Current U.S.
Class: |
165/80.3 ;
165/121; 165/185; 174/16.3; 257/E23.088; 257/E23.099; 361/697 |
Current CPC
Class: |
H01L 23/427 20130101;
F28F 2250/08 20130101; F28F 3/022 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101; H01L 23/467 20130101; H01L
2924/0002 20130101; F28D 15/0233 20130101 |
Class at
Publication: |
165/80.3 ;
165/121; 165/185; 174/16.3; 361/697 |
International
Class: |
H05K 007/20; H01L
023/26; F28F 007/00; F28F 001/00; F24H 003/02 |
Claims
What is claimed is:
1. An apparatus that transfers heat from a heat source, comprising:
a thermally conductive base; a plurality of thermally conductive
pins coupled to the thermally conductive base; and a gas source
that encompasses the plurality of pins and directs gas over the
pins in a direction substantially axial to the pins.
2. The apparatus of claim 1 wherein the gas source comprises a
blower.
3. The apparatus of claim 1, wherein the pins have an irregular
cross section to increase surface area available for
convection.
4. The apparatus of claim 1, wherein the pins have a star shape to
increase surface area available for convection.
5. A heat removal system, comprising: a heat sink coupled to a heat
source, said heat source comprising a first plurality of pin fins
and a second plurality of pin fins each coupled to a base; a gas
source coupled to said heat sink for directing gas over said first
and second plurality of pin fins, said gas source encompassing said
first plurality of pin fins.
6. The heat removal system of claim 5, wherein said gas source
comprises a blower.
7. The heat removal system of claim 5, wherein the gas is air
8. The heat removal system of claim 5, wherein the heat source is
an electronic device.
9. The heat removal system of claim 8, wherein the electronic
device is an integrated circuit.
10. The heat removal system of claim 9, wherein the integrated
circuit is a microprocessor.
11. The heat removal system of claim 5, wherein the gas source for
directing gas over said first and second plurality of pin fins
directs gas over said first plurality of pins in a direction
substantially axial with said first plurality of pin fins and over
said second plurality of pin fins in a direction substantially
radial with said second plurality of pin fins.
12. The heat removal system of claim 11, wherein said gas comprises
air.
13. The heat removal system of claim 5 wherein the heat sink base
and pin fins are comprised of metal.
14. The heat removal system of claim 6 wherein the first and second
plurality of pin fins are distributed over a top surface of the
base in a substantially regular pattern.
15. A heat dissipating apparatus comprising: a body; a plurality of
pin fins coupled to the body within a circular area; a blower
coupled to the body and having an open first face adjacent the body
about the circular area and having a second face adjacent ends of
the plurality of pins, the blower capable of directing a gas over
the plurality of pin fins within the circular area in a direction
substantially axial with the pin fins.
16. The apparatus of claim 15 further comprising: a second
plurality of pins coupled to the body outside the circular
area.
17. The apparatus of claim 16 wherein the circular area of the body
is substantially non-planar and the plurality of pins are of
varying lengths such that the ends of the pins are substantially
planar.
18. The apparatus of claim 15 further comprising: metallic wool
dispersed among the plurality of pins and in thermal contact with
at least a subset of the pins.
19. A heat-dissipating apparatus comprising: a body; a plurality of
rods coupled to the body; a blower coupled to the body such that
the plurality of rods are substantially enclosed within the
blower.
20. The apparatus of claim 19 wherein the plurality of rods are
coupled to the body generally in alignment with a rotational axis
of the blower.
21. The apparatus of claim 20 wherein the blower further comprises:
a motor having an axle and mounted to the body with the axle
substantially normal to a plane of the body; and wherein the blower
is coupled to body via the axle.
22. The apparatus of claim 21 further comprising: a constriction
ring coupled to the heat dissipating apparatus near an inner
perimeter of the blower, to prevent intake of a cooling fluid near
the interior perimeter.
23. The apparatus of claim 22 wherein the constriction ring is
coupled to the blower.
24. The apparatus of claim 21 further comprising: a deflector
coupled to the apparatus near an outer perimeter of the blower, to
prevent recirculation of a cooling fluid near the outer
perimeter.
25. An apparatus that transfers heat from a heat source,
comprising: a vessel having a housing and a vapor chamber; a
plurality of thermally conductive pins coupled to the vessel
housing, the plurality of pins having a first portion extending
outside the vessel housing and a second portion penetrating the
vapor chamber to transfer heat from the vessel to the second
portion of the plurality of pins; and a gas source that encompasses
the second portion of the plurality of pins and directs gas over
the second portion of the pins in a direction substantially axial
to the pins.
26. The apparatus of claim 25, wherein the vessel is a rectangular
shaped heat pipe.
27. An apparatus that transfers heat from a heat source,
comprising: a vessel having a housing and a vapor chamber; a
plurality of thermally conductive pins coupled to the vessel
housing, the plurality of pins each having a base coupled to the
vessel housing and a portion extending from the base; and a gas
source that directs gas through the vapor chamber of the vessel to
transfer heat from the vessel to the plurality of pins
28. The apparatus of claim 27, wherein the vessel is a rectangular
shaped heat pipe.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a thermal dissipation
device having improved surface area and fluid flow characteristics
resulting in high thermal transfer efficiency.
[0003] 2. Description of the Related Art
[0004] Thermal dissipation devices are present in a wide variety of
applications, including electronic apparatus such as computers,
stereos, televisions, or any other device that produces unwanted
heat by inefficiencies in electronic circuits, such as integrated
circuit chips (ICs), including microprocessors.
[0005] Among the factors that influence the design of a thermal
dissipation device are the principles that: 1) increasing surface
area of the thermal dissipation device generally improves thermal
transfer, and 2) increasing fluid flow over the device generally
improves thermal transfer. A heat sink is a thermal dissipation
device, typically comprising a mass of material (generally metal)
that is thermally coupled to a heat source and draws heat energy
away from the heat source by conduction of the energy from a
high-temperature region to a low-temperature region of the metal.
The heat energy can then be dissipated from a surface of the heat
sink to the atmosphere primarily by convection. A well known
technique of improving the efficiency of a conductive heat sink is
to provide a greater surface area on the heat sink, typically
provided by fins that are formed on a base portion of the heat
sink, so that more heat can dissipate from the heat sink into the
atmosphere by natural (or free) convection. The thermal efficiency
of a heat sink can be further increased by employing forced
convection wherein a flow or stream of fluid, typically a gas such
as air, is forced over and around the surface of the heat sink.
[0006] Current heat sinks increase surface area by including a
number of raised, rectangular cross-section beams, or fins. If a
heat source produces enough heat that forced convection is required
to maintain the heat source within an appropriate operating
temperature range, a fan is mounted to provide air flow over the
fins to dissipate a greater amount of heat energy. For purposes of
explanation, the heat source described herein is an integrated
circuit (IC). However, it should be understood that the heat source
may be any device that generates heat.
[0007] Some thermal dissipation devices use rod-shaped pins ("pin
fins"), as illustrated in the cross sectional side view in FIG. 1.
Pin fins 102 are in thermal contact with and extend from the top of
base 101 of heatsink 100. The pins may be integrally formed or
later affixed to the base 101. Each pin has a diameter D, an
overall length L, and if applicable, a depth B of insertion into
the base 101. While the pins are illustrated as being of circular
cross-section, any suitable cross section may be employed, with the
understanding that a smooth, circular cross section minimizes air
flow resistance, while rough, square, complex (e.g., star shaped)
or irregular cross section will increase airflow resistance and
surface area available for convection.
[0008] The base, or plate, of the heat sink device may have a flat
surface or curved surface in different embodiments. The bottom
surface of base 101 generally is coupled directly, or indirectly,
to the IC to dissipate heat from the IC. The heat travels through
the heat sink base 101 and then through pins 102 by conduction. At
the top surface of base 101 and the surface of pins 102, the heat
is dissipated into the atmosphere by natural or forced convection.
A fan commonly is utilized to generate additional airflow across
heat sink 100 to dissipate a greater amount of heat energy. FIG. 2
provides a top view in which a number of pins rise from base 101,
spaced and aligned to form a grid on the top surface of the base
101 of heat sink 100.
[0009] Presently, pin fins are limited by a relatively low
length:width ratio. Reasonably inexpensive pin fins generally are
limited to a length:width ratio of approximately 8:1, in part due
to their being fabricated by casting. More expensive pin fins might
reach a length:width ratio as high as 15:1. Due to limitations of
known manufacturing methods, there is a trade off between
length:width ratio and occupancy ratio.
[0010] With reference to FIG. 3, occupancy ratio is measured as the
percentage of surface area of the body of a heat sink that is
occupied by the cumulative cross sectional area of the pin fins. In
the case of a square or rectangular area on the surface of the heat
sink, the pins, of radius R, are arranged in rows on dimension X
centers and in columns on dimension Y centers. The combination of
pins in rows and columns forms a grid pattern. In this case, the
occupancy of the overall grid is measured by taking the occupancy
of one X-by-Y area:
[0011] overall area=XY
[0012] rod area=.pi.R.sup.2
[0013] and thus occupancy ratio is .pi.R.sup.2/XY. In the case of a
square grid, where X and Y are equal and the rows and columns are
at right angles, occupancy can be stated more simply as an
occupancy ratio .pi.D/4X where D is the diameter of the pins and X
is the on-center distance between the pins. Given small geometries
and large pin heights in relation thereto, existing pin fin
architectures are limited to a fairly low occupancy ratio,
principally governed by existing manufacturing methods. Prior
thermal dissipation systems rely on natural, or forced convection
generated by a fan or other inefficient air flow device. The heat
sinks employ fins and generally mount the fan or blower adjacent or
above the heat sink fins. In these and other prior art systems, the
challenge is generating sufficient airflow past a maximum amount of
surface area of the heat sink, while minimizing manufacturing cost
and space requirements.
BRIEF SUMMARY OF THE INVENTION
[0014] An embodiment of the present invention transfers heat from a
heat source. A heat sink, having a thermally conductive base, and a
plurality of thermally conductive pin fins coupled to the thermally
conductive base, is integrated with a device that directs a gas
axially along the pin fins to transfer heat away from the heat
source.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0015] The present invention is illustrated by way of example and
not limitation in the following figures. Like references indicate
similar elements, in which:
[0016] FIG. 1 shows a cross-section of the body of a prior art
thermal dissipation device.
[0017] FIG. 2 show a top view of the body of a prior art thermal
dissipation device.
[0018] FIG. 3 shows a grid array of pin fins for a prior art
thermal dissipation device.
[0019] FIG. 4 illustrates a grid array of pin fins as may be
utilized by an embodiment of the present invention.
[0020] FIG. 5A illustrates an embodiment of the present
invention.
[0021] FIG. 5B illustrates an embodiment of the present
invention.
[0022] FIG. 6 shows a cross-section of one embodiment of a pin
fin.
[0023] FIG. 7 shows one exemplary pin fin pattern arrangement.
[0024] FIG. 8 shows another exemplary pin fin pattern
arrangement.
[0025] FIG. 9 illustrates another embodiment of the present
invention.
[0026] FIG. 10 illustrates another embodiment of the present
invention.
[0027] FIG. 11 illustrates another embodiment of the present
invention.
[0028] FIG. 12 illustrates another embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] A method and an apparatus for improving the thermal
efficiency of heat sinks is described. In the following
description, for purposes of explanation, numerous details are set
forth in order to provide a thorough understanding of the present
invention. However, it will be apparent to one skilled in the art
that these specific details are not required in order to practice
the present invention.
[0030] An embodiment of the invention is now described with
reference to FIGS. 4 and 5. FIG. 4 illustrates a thermal
dissipation device 410, and particularly illustrates the
distribution of the pins 414, i.e., the overall manner in which the
pins 414 are organized about the base 412. FIG. 4 shows a
distribution in which there are spaces 416 and 418 within the grid
of pins where there are no pins, and a space 420 outside the grid
where there also are no pins. Other distributions are, of course,
capable of being implemented, according to the design requirements
of the particular application. An inner plurality 428 of pins 414
is defined by the region of base 412 between spaces 418 and 416. An
outer plurality 430 of pins 414 is defined by the region of base
412 between spaces 416 and 420.
[0031] FIG. 5A illustrates an application in which the distribution
of pins 414 illustrated in FIG. 4 is particularly useful. The
thermal dissipation device 410 in this embodiment includes a blower
522. The blower includes a motor 524 that is affixed (by any
conventional means) to the base 412 of heat sink 410 within space
418. In another embodiment of the present invention, the motor 524
is in contact with the perimeter of the blower. In the latter
configuration, bearings or the like support the blower, providing
sufficient support to prevent wobble, within the tolerances of the
bearings.
[0032] The vanes 526 of the blower are positioned to operate in
space 416. Space 416 permits the blower to substantially enclose a
plurality 428 of the pins. This is desirable because, as shown, the
plurality of pins 428 that is within the blower is subjected to
airflow 538 that is substantially axial, for at least a portion of
the length of those pins. This axial airflow has a significant
beneficial effect on the thermal efficiency of the heat sink 410.
Moreover, the axial airflow exposes more of the surface area of the
pins to airflow.
[0033] The axial airflow also allows for a greater occupancy ratio
for plurality 428 of pins 414, without significantly increasing air
resistance, due to the axial direction of air flow over the
plurality 428. This greater occupancy ratio increases the heat
transfer efficiency of the heat sink by increasing the surface area
available for dissipation of heat.
[0034] Furthermore, although the plurality 430 of pins 414 that are
not enclosed will not necessarily have a significant axial
component to the airflow 536 about them, they still contribute to
the total thermal capacity of the device 410.
[0035] FIG. 5A also illustrates that the vanes 526 are coupled to
an axle 532 of the blower's motor 524 by a face element 534. Face
element 534 may be substantially planar, in one embodiment, and
lies generally in a plane that is perpendicular to the axis about
which the blower rotates. With reference to FIG. 5B, in one
embodiment, the face comprises a plurality of spokes 540 that
couple the vanes to the motor, and a plurality of openings 550
through which air flows onto the pin. This is a conventional blower
design. In another embodiment, the blower does not have an axially
mounted motor nor spokes. Rather, the blower 522 is supported at
its perimeter by a bearing means that may support the blower at its
perimeter, or from the bottom. In such a case, the rotational force
needs to be applied to the blower at its perimeter.
[0036] The vanes 526 are the functional elements that cause air to
flow, and are disposed about the perimeter of the blower. The
illustration in FIG. 5 shows the blower drawing air axially down
through face element 534 and out across vanes 526.
[0037] FIG. 5A further illustrates an application of the thermal
dissipation device 410 for cooling an integrated circuit (IC)
package 540.
[0038] While FIG. 5A illustrates the use of a blower to provide
axial airflow 534 about the pins 428, in some applications, it may
be acceptable or even required to use an air moving device other
than a blower. In some applications, a propeller or screw may be
most suitable. In other cases, an impeller or a pump may be most
suitable. In these cases, it is still desirable to achieve axial
airflow about the pins, to the extent possible. Note that radial
airflow is beneficial, and that at the inside periphery of the
blower wheel, airflow is almost entirely radial.
[0039] It is further understood that the base and the pins may be
constructed of any suitable materials, according to the
requirements of the particular application. It is well known that
metals provide good thermal transfer, as well as durability.
However, other materials may certainly be utilized, within the
scope of this invention. Preferably, a metal such as copper is used
because of its high thermal conductivity. Other materials such as
aluminum, steel, metal filled plastic, or various alloys of metal
such as aluminum, zinc, or other thermally conductive metals can
also be used for heat sink 410.
[0040] FIG. 6 illustrates one embodiment of the materials of a pin
fin. In this embodiment, the pin 600 includes an alloy clad with
heterogeneous materials to provide sufficient rigidity, strength
and thermal conductivity to allow for desired height to width pin
ratios. For example, pin 600 may include a steel core 610
surrounded by a copper jacket 620. In such an embodiment, the pin
provides good thermal conductivity from the copper sheath and high
strength from the steel core. This configuration gives the pin
increased axial strength, and, in many applications, is better
suited to insertion into a body which does not have pre-drilled
holes.
[0041] FIG. 6 further illustrates another, independent principle
which may optionally be used in an embodiment of the invention. The
pins and/or the base of the heat sink (not shown) may be formed
with a microporous surface 630 to increase the effective surface
area. The degree to which the pins are textured is determined by
trading off increased surface area against increased resistance to
air flow, according to the application's demands.
[0042] FIG. 7 illustrates an axial grid, in which the pins may be
distributed over the base of heat sink. A plurality of
substantially linear rows 736 of pins extend axially outward from
the center, such as o from an opening 418 as discussed above. As
the rows extend outward, the distance between adjacent rows
increases. If the rows are sufficiently long that the empty space
in this increased distance becomes wasteful or less than thermally
optimal, the device may further include optional shorter,
substantially linear rows 738 which do not extend as far inward as
the other rows 736. As will be understood, there may be more than
two lengths of such rows, extending to more than two distances from
the center, as needed.
[0043] FIG. 8 illustrates an alternative configuration, in which
the grid is a spiral. In the spiral grid configuration, there is a
plurality of curved rows 836 of pins. The rows may have arc
curvature, elliptical curvature, or other suitable curvature,
according to the application's requirements. As with the axial
grid, there can be rows of varying lengths, to maintain the
occupancy ratio across the device. In some applications, the amount
and direction of curvature of the rows may be selected according to
the air flow desired. For example, if the air exiting the blower
(not shown) tends to curve rather than simply radiate directly,
radially outward, it may be desirable to use a spiral grid to
maximize airflow over the pins that lie outside the blower.
[0044] In any type of configuration, whether it is a rectangular
grid, axial grid, spiral grid, or other, e.g., an interstitial grid
wherein the pins are situated near one another but not necessarily
aligned in accordance with any particular grid or pattern, the
principles taught above with reference to FIGS. 4 and 5 may be
utilized.
[0045] FIG. 9 illustrates another aspect of the pin fin
configuration. In some applications, it may be desirable to enclose
the maximum possible total pin length within the blower. In such
cases, it is desirable that all the pins extend as close as
possible to the face 534 of the blower. If the underlying base 912
has a surface which is significantly non-planar, then pins 414 of
varying lengths will need to be used, as will be understood from
FIG. 9.
[0046] FIG. 10 illustrates a hybrid embodiment, in which the rods
414 are supplemented with another thermal dissipation means 1040.
In one embodiment, this may be a metallic wool which is
interspersed within, and in thermal contact with, the array of
pins. Consideration should be paid to the tradeoff between
increased surface area and decreased air flow, as the application
dictates. For example, in some applications, where the dimensions
of the device are limited by external constraints to a very small
size, an extremely high air pressure may be available. In such a
case, because thermal transfer does not increase forever as air
velocity increases, it may be impossible to achieve sufficient
thermal transfer using only the pins, and the addition of metallic
wool 1040 may provide enough added surface area to accomplish the
necessary thermal transfer.
[0047] FIG. 11 illustrates yet another enhancement that can be made
to improve the thermal transfer of the heat sink device of the
present invention. In the embodiment shown, the blower 522 is
improved with the addition of a constriction ring 1142, which is a
thin, substantially ring-shaped member attached to, very near to,
or integral with the face of the blower, generally near the
blower's outer perimeter. The constriction ring serves to prevent
air from being drawn in near the perimeter. Air being drawn in near
the perimeter tends to provide little cooling as it passes over
only a very small number of pins before being expelled through the
vanes of the blower. In the worst case, the air may pass over only
a small fraction of the length of the outermost pins. The
dimensions of the constriction ring, and specifically the distance
that the constriction ring extends inward from the vanes 526,
depends on the demands of the particular application.
[0048] FIG. 11 also illustrates another, similar improvement, with
the addition of a deflector 1144. Unlike the constriction ring, the
deflector is positioned outside the perimeter of the vanes 526.
Like the constriction ring, the purpose of the deflector is to
control air circulation to improve thermal performance. The
deflector prevents hot air from looping from the output of the
blowers to the input of the face 534.
[0049] The constriction ring and the deflector may, independently,
be coupled to the blower to rotate with the vanes, or to the base
of the heat sink device to remain stationary. If coupled to the
blower, they increase the rotating mass. If coupled to the body,
they should not interfere with the blower's rotation. Either of
these issues should be taken into consideration, according to the
design requirements of the blower or the overall system. A design
may include a constriction ring, a deflector, both, or neither.
[0050] With reference to FIG. 12, another embodiment 1200 of the
present invention is described in which a vessel, commonly referred
to as a heat pipe, is utilized to further spread heat generated by
the heat source. The blower 522 encompasses the pins 414 as in
previously described embodiments, and rotates in the direction
illustrated by arrow 1201. The blower sits on a heat pipe, more
specifically, on a heat pipe housing 1210. The heat pipe comprises
a wick 1220, a working fluid 1240 and a vapor chamber 1230, and
provides lateral heat transfer via a vapor transported through the
vapor chamber. While the heat pipe as illustrated is rectangular in
shape, it is understood that other heat pipe dimensions may be
utilized, such as square or cylindrical. If the heat source is
relatively small, e.g., a microprocessor die, then a significant
portion of the heat that needs to be dissipated from the heat
source has to migrate laterally along the base of the heat sink. In
the embodiment illustrated in FIG. 12, a flat heatpipe efficiently
spreads the heat to the entire top surface of the heat sink. The
combination of the flat heatpipe and the blower encompassed heat
sink improves the rate of heat dissipation.
[0051] The heat pipe, in one embodiment, is formed of copper or
aluminum sheet metal that encloses the working fluid 1240 (e.g.,
water under a vacuum) and the wicking substance 1220. The pin fins
414 are illustrated in this embodiment as penetrating at 1260 the
top portion of the heatpipe and protruding into the vapor chamber
1230 to subject the pins to the vaporized working fluid. However,
it is understood that the pins need not penetrate the top surface
of the heat pipe, but affixed to the top surface of the heatpipe.
The working fluid evaporates in the region of high temperature and
rapidly flows to the cooler areas, yielding its heat to the pins
coupled to the top plate, or coupled to and protruding through the
top plate of the heat pipe, depending on the embodiment. The blower
then dissipates the heat in the manner described above. Having the
pins protruding directly into the fluid vapor permits the use of
the relatively large surface area inherent in the pin fins for
thermal transfer, at only a marginal increase in the manufacturing
process to press the pins into the heat pipe's metal housing.
[0052] For the sake of simplicity, this patent discusses the
cooling fluid as though it were air, but this is not a necessary
limitation, and the invention may be utilized in the presence of
any suitable fluid, liquid, gas, or other environment. In some
cases, the existing fluid is not sufficient, and the performance of
the thermal dissipation device can be improved by augmenting or
replacing the fluid with another fluid.
[0053] The invention has been discussed in the context of a
separate cooling device that is placed into thermal contact with a
heat generating device such as an engine or a computer chip.
However, in some cases, it may be desirable to utilize the base or
surface of the heat generating device itself as the base of the
cooling device, as is done with air cooled motorcycle engines. In
this case, the pins 414 are coupled directly to the surface of the
engine or other heat source. In the case of an internal combustion
engine, the pins may be coupled to a variety of members, such as
the cylinder wall, the head, the exhaust header, and so forth. And,
of course, they may also be used with the radiator, oil cooler,
transmission fluid cooler, air conditioning heat exchanger, and so
forth.
[0054] While the invention has been described with reference to
specific modes and embodiments, for ease of explanation and
understanding, those skilled in the art will appreciate that the
invention is not necessarily limited to the particular features
shown herein, and that the invention may be practiced in a variety
of ways that fall under the scope and spirit of this disclosure.
The invention is, therefore, to be afforded the fullest allowable
scope of the claims that follow.
* * * * *