U.S. patent application number 11/901533 was filed with the patent office on 2008-10-02 for heat-removal device.
This patent application is currently assigned to DK Innovations Inc.. Invention is credited to Daniel Mark St. Louis.
Application Number | 20080236794 11/901533 |
Document ID | / |
Family ID | 39788840 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080236794 |
Kind Code |
A1 |
St. Louis; Daniel Mark |
October 2, 2008 |
Heat-removal device
Abstract
A heat-removal device for removing heat from a hot surface
includes a housing containing a cooling fluid. The housing has a
heat-absorption section, which is in contact with the hot surface.
The housing also has a heat-dissipation section, which is cooled by
natural or forced convection with ambient air. An internal impeller
circulates the cooling fluid in a closed loop between the
heat-absorption section and the heat-dissipation section to
transport heat away from the hot surface to the ambient air.
Inventors: |
St. Louis; Daniel Mark;
(Wichita, KS) |
Correspondence
Address: |
MELANIUS D'SOUZA
1718 AVENIDA ENTRADA
SAN DIMAS
CA
91773-4314
US
|
Assignee: |
DK Innovations Inc.
|
Family ID: |
39788840 |
Appl. No.: |
11/901533 |
Filed: |
September 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60920203 |
Mar 27, 2007 |
|
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Current U.S.
Class: |
165/104.19 ;
165/104.21; 165/104.28; 165/122; 257/E23.098 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/00 20130101; H01L 23/473 20130101; H01L 2924/0002
20130101 |
Class at
Publication: |
165/104.19 ;
165/104.21; 165/104.28; 165/122 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Claims
1) A device for removing heat from a hot-surface, the device
comprising: a generally closed chamber, the chamber having a first
end-closure member, a second end-closure member, and an
intermediate-member connecting the first end-closure member to the
second end-closure member, the first end-closure member having a
heat-absorbing section, the heat-absorbing section having an
external surface in contact with the hot-surface and an internal
surface, the second end-closure member and intermediate-member
together or individually functioning as a heat-dissipation section
which is exposed to the external environment; and a heat-conducting
fluid located within the chamber, the heat-conducting fluid
generally contacting both the internal surface of the
heat-absorbing section and the internal surface of the
heat-dissipation section.
2) The device of claim 1, further including a fluid-circulation
means for circulating the heat-conducting fluid past the internal
surface of the heat-absorbing section and the internal surface of
the heat-dissipation section of the chamber.
3) The device of claim 1, further including an open
fluid-flow-passage having a first open end submerged in the
heat-conducting fluid adjacent to the internal surface of the
heat-absorbing section of the chamber and having a second open end
submerged in the heat-conducting fluid adjacent to the internal
surface of the heat-dissipation of the chamber.
4) The device of claim 2, wherein the fluid-circulation means is an
impeller, which is submerged within the heat-conducting fluid.
5) The device of claim 3, further including a fluid-circulation
means for circulating the heat-conducting fluid through the
fluid-flow-passage.
6) The device of claim 5, wherein the fluid-circulation means is an
impeller which is located between the first and second open ends of
the fluid-flow-passage.
7) The device of claim 6, wherein the impeller draws the
heat-conducting fluid into its second open end and impels it
through the first open end against the internal-surface of the
heat-absorbing section.
8) The device of claim 7, wherein the impeller impels the
heat-conducting fluid at a generally perpendicular orientation
against the internal-surface of the heat-absorbing section.
9) The device of claim 6, wherein the impeller draws the
heat-conducting fluid into its first open end and expels it through
the second open end.
10) The device of claim 6, further comprising a rotating-movement
generating device which has a rotating element which is
rotationally-coupled to the impeller.
11) The device of claim 10, wherein the rotating-movement
generating device is located outside the chamber and the
rotational-coupling is effected by a shaft which is connected
through the chamber-wall at its first end to the rotating element
and at its second end to the impeller.
12) The device of claim 10, wherein the rotating-movement
generating device is located outside the chamber and the rotating
element and the impeller are magnets and the rotational-coupling is
effected by a magnetic force connecting the rotating element to the
impeller.
13) The device of claim 12, wherein the rotating element is an
electromagnet.
14) The device of claim 1, wherein the external surface of the
heat-dissipation section has heat-transfer fins.
15) The device of claim 1, wherein the internal surface of the
heat-dissipation section is heat-transfer enhanced.
16) The device of claim 1, wherein the internal surface of the
heat-dissipation section has heat-transfer fins.
17) The device of claim 1, wherein the internal surface of the
heat-absorption section is heat-transfer enhanced.
18) The device of claim 1, wherein the internal surface of the
heat-absorption section has heat-transfer fins.
19) The device of claim 1, wherein the heat-conducting fluid
comprises water.
20) The device of claim 1, wherein the heat-conducting fluid
comprises ethylene-glycol.
21) The device of claim 6, further comprising a rotating-magnetic
field generating device which has a rotating magnetic field which
is magnetically-coupled to the impeller.
22) The device of claim 1, wherein heat is transferred from the
external surface of the heat-dissipation section to the external
environment by natural convection.
23) The device of claim 1, wherein heat is transferred from the
external surface of the heat-dissipation section to the external
environment by forced convection.
24) The device of claim 1, wherein the heat-conducting fluid
undergoes a thermodynamic phase-change.
25) The device of claim 1, wherein the heat-conducting fluid stays
in the same thermodynamic phase
26) A device for removing heat from a hot-surface, the device
comprising: a generally closed housing, the housing having a
heat-absorbing section and a heat-dissipation section, the
heat-absorbing section having an external surface in contact with
the hot-surface and an internal surface, the heat-dissipation
section having an external surface which is exposed to the external
environment and an internal surface; and a heat-conducting fluid
located within the housing, the heat-conducting fluid generally
contacting both the internal surface of the heat-absorbing section
and the internal surface of the heat-dissipation section.
27) A device for removing heat from a hot-surface, the device
comprising: a generally closed liquid-filled chamber, a first
external surface of which is in contact with the hot-surface to
receive heat therefrom, a second external surface of which is
exposed to the external environment to transfer heat thereto.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Serial No. 60/920,203, filed Mar. 27, 2007
FIELD OF THE INVENTION
[0002] This invention relates to a device for efficiently removing
large quantities of heat generated within a relatively small area
such as Electronic Devices, Integrated Circuits, Bearings, etc.
BACKGROUND OF THE INVENTION
[0003] The problem of efficiently removing heat generated within
relatively small areas such as Integrated Circuits, Bearings, etc.
has long plagued engineers. If generated heat is not removed
efficiently from such parts, the performance or longevity of the
part can be adversely affected.
[0004] A common problem is heat removal from integrated circuits
(ICs). As ICs get smaller, they generate more heat within smaller
volumes. If this heat is not removed, the IC overheats causing loss
of performance and malfunction. A specific example is the common
problem of reduction of performance of a computer due to
overheating of its Central Processing Unit (CPU).
[0005] Typically a finned aluminum or copper block, with or without
reticulated metallic foam, such as that described in U.S. Pat. Nos.
6,424,529, 6,424,531, and others is used to transfer heat generated
within an Integrated Circuit (IC) to the external environment by
natural or forced convection with ambient air. However such IC
Coolers are relatively inefficient at transferring the heat,
especially from modern computer chips which generate tremendous
amounts of heat. The overheating of the computer chips reduces the
processing ability of the chips. Furthermore, reticulated
metallic-foam is relatively expensive.
[0006] Other designs, which incorporate heat-pipes, are also used
to attempt to remove the generated heat from ICs. However, they are
complicated and expensive to manufacture. U.S. Pat. No. 5,949,648
to Liao describes such a heat-pipe design.
[0007] Other designs, which are similar to automotive radiator
systems, use circulated water and a remote heat-exchanger and
cooling-fan. These designs, while able to provide good cooling, are
very large, are assembled from a number of parts, and are expensive
to produce.
[0008] Similarly, as rotating equipment gets miniaturized, it
generates large quantities of heat from miniaturized bearings. If
the heat is not removed from these bearings, they are liable to
overheat and seize. The higher operating temperature of these
bearings reduces their operating life. There is therefore also a
great need for a heat-removal device that will efficiently transfer
the generated heat away from a bearing or other small machine
part.
[0009] Many other mechanical, electrical and chemical devices
generate large amounts of heat in a small area and would benefit
from a high efficiency heat-removal device described in this
invention.
SUMMARY OF THE INVENTION
[0010] In one aspect of the present invention a device for removing
heat from a hot-surface comprises a generally closed housing, the
housing having a heat-absorbing section and a heat-dissipation
section, the heat-absorbing section having an external surface in
contact with the hot-surface and an internal surface, the
heat-dissipation section having an external surface which is
exposed to the external environment and an internal surface and a
heat-conducting fluid located within the housing, the
heat-conducting fluid generally contacting both the internal
surface of the heat-absorbing section and the internal surface of
the heat-dissipation section.
[0011] In another aspect of the present invention, the Heat Removal
Device further includes a fluid-circulation means (FCM) for
circulating the heat-conducting fluid past the internal surface of
the heat-absorbing section and the internal surface of the
heat-dissipation section of the housing.
[0012] In yet another aspect of the present invention, the Heat
Removal Device further includes an open fluid-flow-passage (FFP)
which has a first open end submerged in the heat-conducting fluid
adjacent to the internal surface of the heat-absorbing section of
the housing and a second open end submerged in the heat-conducting
fluid adjacent to the internal surface of the heat-dissipation
section of the housing.
[0013] In another aspect of the present invention, the
fluid-circulation means is an impeller, which is submerged within
the heat-conducting fluid.
[0014] In another aspect of the present invention, the Heat Removal
Device further includes a fluid-circulation means (FCM) for
circulating the heat-conducting fluid through the
fluid-flow-passage.
[0015] In another aspect of the present invention, the
fluid-circulation means is an impeller, which is located between
the first and second open ends of the fluid-flow-passage.
[0016] In another aspect of the present invention, the impeller
draws the heat-conducting fluid (HCF) into its second open end and
impels it through the first open end against the internal-surface
of the heat-absorbing section.
[0017] In another aspect of the present invention, the impeller
impels the heat-conducting fluid (HCF) at a generally perpendicular
orientation against the internal-surface of the heat-absorbing
section.
[0018] In another aspect of the present invention, the impeller
draws the heat-conducting fluid (HCF) into its first open end and
expels it through the second open end.
[0019] In another aspect of the present invention, the Heat Removal
Device further includes a rotating-movement-generating device
(RMGD) which has a rotating element, which is rotationally coupled
to the impeller.
[0020] In another aspect of the present invention, the RMGD is
located outside the housing and the rotational-coupling is effected
by a shaft which is connected through the housing at its first end
to the rotating element and at its second end to the impeller.
[0021] In another aspect of the present invention, the RMGD is
located outside the housing and the rotating element and the
impeller are magnets and the rotational-coupling is effected by a
magnetic force connecting the rotating element to the impeller.
[0022] In another aspect of the present invention, the rotating
element is an electromagnet.
[0023] In another aspect of the present invention, the external
surface of the heat-dissipation section has heat-transfer fins.
[0024] In another aspect of the present invention, the internal
surface of the heat-dissipation section is heat-transfer
enhanced.
[0025] In another aspect of the present invention, the internal
surface of the heat-dissipation section has heat-transfer fins.
[0026] In another aspect of the present invention, the internal
surface of the heat-absorption section is heat-transfer
enhanced.
[0027] In another aspect of the present invention, the internal
surface of the heat-absorption section has heat-transfer fins. In
another aspect of the present invention, the heat-conducting fluid
comprises water.
[0028] In another aspect of the present invention, the
heat-conducting fluid comprises ethylene-glycol.
[0029] In another aspect of the present invention, the Heat Removal
Device further includes a rotating-magnetic field-generating device
(RMFGD) which has a rotating magnetic field, which is magnetically
coupled to the impeller.
[0030] In another aspect of the present invention, heat is
transferred from the external surface of the heat-dissipation
section to the external environment by natural convection.
[0031] In another aspect of the present invention, heat is
transferred from the external surface of the heat-dissipation
section to the external environment by forced convection.
[0032] In another aspect of the present invention, the
heat-conducting fluid undergoes a thermodynamic phase. In another
aspect of the present invention, the heat-conducting fluid stays in
the same thermodynamic phase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1a is a cross-sectional elevation-view representation
of the Heat Removal Device of the present invention as used to
remove heat from the CPU of a computer.
[0034] FIG. 1b is a sectional plan-view representation of the Heat
Removal Device of FIG. 1a.
[0035] FIG. 2 is a cross-sectional elevation-view representation of
another embodiment of the Heat Removal Device of the present
invention, which uses a direct-driven impeller.
[0036] FIG. 3 is a cross-sectional elevation-view representation of
another embodiment of the Heat Removal Device of the present
invention which uses a magnetic field generating device to rotate
the impeller shown in FIG. 1a.
[0037] FIG. 4 is a cross-sectional elevation-view representation of
another embodiment of the Heat Removal Device of the present
invention, which has a flattened or pancake elevational
profile.
DESCRIPTION OF THE INVENTION
[0038] The present invention is directed to a Heat-Removal Device,
which combines conductive and convective heat-transfer in a simple
and inexpensive design to rapidly transfer large amounts of heat
from a small area or a point source to the external
environment.
[0039] Referring to FIGS. 1a and 1b, Heat Removal Device 12
comprises a closed housing 12h, which contains a cooling fluid, and
a cooling-air circulation fan 15. The cold and hot states of the
cooling fluid are represented as 14c and 14h in FIGS. 1a and 1b. In
one embodiment of the invention shown in FIG. 1a, housing 12h is
configured as a chamber which comprises a first end-closure floor
member 12c, a second end-closure roof member 12p, and an
intermediate vertical walled hollow member 12w, to define a closed,
internal, hollow space 12v. As shown in FIGS. 1a and 1b, vertical
member 12w is configured from a short piece of extruded, circular
cross-sectioned tube made of a metal, such as aluminum or copper or
aluminum plated with copper or other such heat-conductive material.
Other design refinements could include plating the inside of an
extruded aluminum tube with a non-corroding, highly-conductive
surface such as copper, silver, gold, diamond, or other suitable
highly conductive non-corroding material to provide high
heat-transfer at an economical price.
[0040] To dissipate heat efficiently, a plurality of fins 12f is
provided on the exterior surface of vertical member 12w. Such fins
can also be provided on the exterior surface of roof member 12p if
additional heat-transfer area is desired. While only 12 fins have
been shown in FIG. 1b, it will be obvious that the maximum possible
number of fins that can be physically accommodated on the external
surface of vertical member 12w will be advantageous to provide the
maximum heat-dissipation from vertical member 12w. Vertical member
12w and roof member 12p therefore comprise the heat-dissipation
section of Heat Removal Device 12.
[0041] Located within internal volume 12v is a volume displacement
member (VDM) 12s, which is configured as a short length of a
thick-walled tube made of Styrofoam or other such material. VDM 12s
has an outside diameter which is less than the inside diameter of
vertical member 12w to provide an annular flow passage 12a between
the outside diameter of VDM 12s and the inside diameter of vertical
member 12w. While a thick walled tube is shown, VDM 12s could also
be fabricated of a thin-walled tube depending on the required
dimensions for housing 12h. Also VDM 12s has a vertical length that
is less than the vertical length of vertical member 12w. The
outside diameter and vertical length of VDM 12s are chosen to
provide a top flow passage 12t which is connected to an outer
annular flow passage 12a which in turn is connected to a bottom
flow passage 12b. It will be obvious to one of ordinary skill in
the art that these flow-passages have to have adequate dimensions
to allow the cooling fluid to flow there-through without excessive
pressure drop. The dimensions are also selected to provide an
optimum heat-transfer coefficient between the liquid and the
internal wall of vertical member 12w. The optimum value of these
dimensions can be chosen through theoretical calculations, or
experimental trial-and-error, or computer-aided computational fluid
dynamic calculations. Such methods are considered to be within the
knowledge base of one of ordinary skill in the art.
[0042] Further VDM 12s has an inside diameter, which is chosen to
accommodate a fluid-circulation means (FCM), such as cooling-fluid
pump impeller 16i, described below, therein. The inside diameter of
VDM 12s is also chosen to provide a concentric, circular fluid
flow-passage 12cf connecting upper flow channel 12t to lower flow
channel 12b. It will be obvious that fluid flow-passage 12cf has to
have a suitable diameter to allow the cooling fluid to flow
there-through without excessive pressure drop while providing an
optimum impinging jet on floor 12c to transfer heat away from the
hot surface.
[0043] Thus the placement of VDM 12s within internal volume 12v
creates a toroidal flow-path for the cooling fluid within housing
12h. In this flow-path, the cooling fluid is impelled downwards
through the central flow passage 12cf and impinges the internal
surface 12ci of floor 12c, and is then deflected outwards radially
into lower flow passage 12b towards the internal surface 12wi of
vertical member 12w. It will be obvious that some stand-off means
(not shown for clarity), such as legs or supports, for raising VDM
12s away from bottom floor plate 12c needs to be provided to create
the lower flow passage 12b. The cooling fluid then passes upwards
within annular flow passage 12a and then radially inwards in top
flow passage 12t from where it is inducted into central flow
passage 12cf by the suction action of impeller 16i.
[0044] During operation of Heat Removal Device 12, cooling air fan
15 is activated to create forced convection by blowing cold cooling
air 15c through flow channels 12fc between adjacent fins 12f of
vertical member 12w. While not shown, flow directing means, such as
a cowl, can be provided around the periphery of fan 15 to direct
the maximum amount of air over fins 12f. The cooling-air fan has
blades 15b, which are connected to a rotating movement generating
device, such as electric motor 15z. In FIG. 1a, blades 15b are
shown connected to rotating shaft 15s of motor 15z. At its free
end, shaft 15s is also connected to a magnetic coupling member 15m.
Magnetic coupling member 15m is located so that its magnetic
surface can rotate freely over the upper surface of top plate 12p
of housing 12h. Ideally, to reduce friction, a small gap is
provided between the magnetic surface of magnetic coupling member
15m and the upper surface of top plate 12p of housing 12h. As will
be described below, magnetic coupling 15m non-contactingly rotates
cooling fluid impeller 16i.
[0045] During operation of Heat Removal Device 12, the heat,
(represented by "Q" in FIG. 1a), generated by the hot-surface is
transferred to the cold cooling fluid 14c through its contact with
internal surface 12ci of heat-conductive floor plate 12c of housing
12h. Heat-conductive floor plate 12c therefore comprises the
heat-absorption section of Heat Removal Device 12. The heated
cooling fluid 14h then passes upwards through annular flow channel
12a and transfers its heat through its contact with cooler internal
surface 12wi of vertical wall 12w. The heat is then conducted away
from wall 12w by fins 12f, which transfer the heat to the ambient
air of the external environment, either by natural or forced
convection. If cooling-air fan 15 is in operation, the cold air 15c
absorbs the heat from hot fins 12f by forced convection, as shown
in FIG. 1a. If cooling-air fan 15 is not in operation, the ambient
air surrounding hot fins 12f absorbs the heat from hot fins 12f by
natural convection, as shown in FIG. 3. The cooled cooling fluid
14c is then recirculated back to central fluid flow passage 12cf
for removing additional heat from the hot surface as previously
described.
[0046] To rotate impeller 16i, a magnetic coupling 16m is provided
within volume 12v. Magnetic coupling 16m is attached to impeller
16i by shaft 16s. While a fan-propeller type of impeller is shown,
other impeller forms such as an Archimedes Screw can also be used
to move the cooling fluid. Coupling 16m is non-contactingly coupled
to mating magnetic coupling 15m, which was described above. Thus
the rotational motion of external mating magnetic coupling 15m is
non-contactingly transferred to internal mating magnetic coupling
16m by magnetic forces that pass through roof member 12p. This
arrangement provides a hermetically sealed housing 12h and prevents
leakage of the cooling fluid.
[0047] Roof member 12p is plastic or non-ferrous metal or other
material, which will not substantially obstruct the magnetic force
linkage between coupling members 15m and 16m.
[0048] While impeller 16i is shown as magnetically driven by
cooling fan motor 15z, it could also be direct coupled to shaft 15s
of motor 15z, as shown in FIG. 2. In this situation, a liquid-tight
shaft-seal (not shown) will be needed in roof member 12p for the
through-insertion of shaft 15s into central flow passage 12cf to
attach to impeller 16i. Alternatively, impeller 16i can be rotated
by its own dedicated, hermetically sealed motor that is located
within housing 12h. The dedicated motor could be connected to the
external electrical power source by wires that penetrate housing
12h in a liquid-tight manner. All of these modifications for
rotating impeller 16i will be obvious to one of ordinary skill in
the art and are considered to fall within the scope of the present
invention.
[0049] The cooling fluid 14c can be a gas such as Freon or it can
be a liquid such as water or ethylene-glycol, or other such liquid.
Any other fluid or mixture of fluids that can meet the required
heat-transfer, non-corrosiveness, non-toxicity, and other desired
characteristics of the application can also be used. Further, the
fluid may or may not undergo a thermodynamic phase-change. Yet
other configurations and modification of Heat Removal Device 12
disclosed herein will be obvious to persons skilled in the art.
These configurations are considered to fall within the scope of the
present invention.
[0050] While the above disclosure relates to the use of the Heat
Removal Device of the present invention for cooling ICs, it could
also have other applications for removal of spot heat. For example,
it could be used for cooling bearings or other machine parts.
[0051] Yet further refinements can be provided to enhance the
performance of Heat Removal Device 12 of the present invention.
[0052] For example, liquid flow straighteners can be used to
maintain the toroidal flow-path within housing 12h and thereby
enhance the pumping efficiency of impeller 16i.
[0053] Further, housing 12h may have other cross-sections besides
the circular cross-section shown in FIG. 1b. Vertical section 12w
of housing 12h could take on other geometric or non-geometric
shapes. For example, the vertical section 12w could be hexagonal
and the fins could create a square profile if desired.
[0054] Yet further, as shown in FIG. 1a, heat-transfer enhanced
surfaces 12ce on internal surface 12ci of bottom plate 12b and 12we
on internal surface 12wi of vertical member 12w can be provided to
increase the heat-transfer from the hot surface to the cooling
fluid and cooling air. Such means to enhance the heat-transfer from
between a surface and a fluid includes dimples, etchings, grooves,
fins, pins or any other means of disturbing the laminar flow
boundary of the fluid to create turbulent flow, which is known to
enhance heat-transfer. Such an enhanced heat-transfer surface can
be provided on the internal side of floor plate 12c, where floor
plate 12c contacts the hot surface, to increase heat-transfer from
floor plate 12c to cooling fluid 14c.
[0055] Similar, heat-transfer enhancement means 12we can be
provided on the internal side of vertical section 12w, opposite the
location of fins 12f, to enhance heat-transfer from hot
cooling-fluid 14h to fins 12f.
[0056] Yet further, additional means of creating and maintaining
turbulent flow of cooling-fluid 14c to enhance heat transfer can be
provided. For example, the internal wall of vertical section 12w or
the surfaces of internal fluid displacer 12s can be roughened to
create turbulent flow. Alternately, protrusions can be provided on
these surfaces to create turbulent flow in cooling-fluid 14c.
[0057] Similarly, the heat-transferring surfaces of fins 12f could
be roughened by methods such as sand-blasting or other such
processes, to create a turbulent flow of cold air 15c over fins 12f
to enhance heat transfer. All such heat-transfer enhanced surfaces
are considered to fall within the scope of the present
invention.
[0058] While the preferred embodiment of the invention has been
shown and described with the internal volume displacement device
12s, there could be other means of creating largely toroidal flow
to achieve substantially the same results. All such means of
creating toroidal flow are considered to fall within the spirit of
this invention. The invention may even be practiced without volume
displacement means 12s as it is highly likely that even random or
uncontrolled flow pattern pumping of cooling-fluid 14c within
housing 12h would produce at least some of the heat-transfer
effects described above.
[0059] In the preferred embodiment, the toroidal flow is directed
through central fluid flow passage 12cf of VDM 12s to impinge on
internal surface 12ci of Heat Removal Device 12. However, in
another embodiment of the present invention shown in FIG. 2, the
flow is reversed with cooling fluid 14c moving upwards in central
flow passage 12cf, away from heated absorption section 12c. As
shown in FIG. 2, to maintain the counter-current flow between the
cooling fluid 14c and the cooling air 15c, the rotation of cooling
air fan blades 15b can also be reversed. Alternately, though less
efficient from a heat-transfer point of view, a co-current flow can
be maintained between cooling fluid 14c and cooling air 15c.
[0060] In the description of the Heat Removal Device of the present
invention, a propeller type pump is depicted. However, other
arrangements may also be conceived to incorporate other types of
pumps such as centrifugal pumps, mixed flow pumps, etc. It is also
not necessary that the pump be located in central flow passage
12cf. The pump could be located anywhere in the fluid circulation
flow-path to circulate the fluid past the heat-absorption and
heat-dissipation sections. A further refinement to the design would
be a nozzle, which could be fitted to the bottom flow-opening 12cx
of fluid flow-passage 12cf to enhance the impingement of cooling
fluid 14c on floor plate section 12c of Heat Removal Device 12.
[0061] The pump, pump housing, magnetic drive and bearings may be
manufactured as a complete sub-assembly that will easily be fitted
into VDM 12s. For example, for lower cost and ease of assembly, a
centrifugal pump with an integrated magnetic coupling could be
provided in upper flow opening 12cy.
[0062] Yet other modifications can be made to Heat Removal Device
12 of the present invention to suit specific applications. For
example, the vertical height of Heat Removal Device 12 could be
shortened to suit headroom constraints, such as in laptop
computers. Thus, in this design represented by FIG. 4, Heat Removal
Device 12 would have a flattened or pancake elevational profile.
The location and orientation of fins 12f can also be adjusted to
fit specific design constraints. All of these modifications are
considered to fall within the scope of the present invention.
[0063] Yet further, as shown in FIG. 3, magnetic coupling 16m could
be rotated by a rotating magnetic field generating device 15zm,
which would include a plurality of stationary electromagnetic poles
15zp. For example, a stator of an electric motor could be used to
create a rotating magnetic field to rotate magnetic coupling
16m.
[0064] Further, as shown in FIG. 4, impeller 16im could itself be
magnetized to eliminate the magnetic coupling member and connecting
shaft. Thus impeller 16im would be directly magnetically coupled to
the rotating magnetic field created by rotating magnetic field
generating device 15zm.
[0065] Further, the heat recovery device of the present invention
can be used with more than one heat-source. For example, FIG. 4
shows the pancake version of Heat Removal Device 12 being used with
a plurality of Liquid Crystal Display (LCD) elements. Heat Removal
Device 12 can also used with a plurality of Light Emitting Diode
(LED) elements.
[0066] All of these design alternatives and refinements are
considered to fall within the scope of the present invention, which
should be limited, only by the scope of the following claims.
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