U.S. patent application number 13/461192 was filed with the patent office on 2013-11-07 for segmented heat sink for natural-convection cooled systems.
This patent application is currently assigned to Alcatel-Lucent USA Inc.. The applicant listed for this patent is Todd Salamon, Maria E. Simon. Invention is credited to Todd Salamon, Maria E. Simon.
Application Number | 20130292105 13/461192 |
Document ID | / |
Family ID | 49511663 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130292105 |
Kind Code |
A1 |
Salamon; Todd ; et
al. |
November 7, 2013 |
SEGMENTED HEAT SINK FOR NATURAL-CONVECTION COOLED SYSTEMS
Abstract
Various exemplary embodiments relate to a heat sink system. The
heat sink system may include: a first heat sink segment including a
first fluid inlet and a first fluid outlet having an outlet flow
path; and a second heat sink segment including a second fluid inlet
having an inlet flow path and a second fluid outlet. The second
heat sink segment may be arranged in a placement position within
the heat sink system so that the second fluid inlet receives fluid
from substantially other sources than the first outlet flow path.
Various exemplary embodiments relate to a heat sink segment. The
heat sink segment may include: a base plate; a plurality of
vertical fins; a horizontal wall; a first fluid opening; and a
second fluid opening. The first fluid opening may face a different
direction than the second fluid opening.
Inventors: |
Salamon; Todd; (New
Providence, NJ) ; Simon; Maria E.; (New Providence,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Salamon; Todd
Simon; Maria E. |
New Providence
New Providence |
NJ
NJ |
US
US |
|
|
Assignee: |
Alcatel-Lucent USA Inc.
Murray Hill
NJ
|
Family ID: |
49511663 |
Appl. No.: |
13/461192 |
Filed: |
May 1, 2012 |
Current U.S.
Class: |
165/185 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/0002 20130101; H01L 23/3672 20130101; H01L 2924/00
20130101; H05K 7/20418 20130101; H01L 23/467 20130101 |
Class at
Publication: |
165/185 |
International
Class: |
F28F 7/00 20060101
F28F007/00 |
Claims
1. A heat sink system comprising: a first heat sink segment, the
first heat sink segment comprising a first heat sink base, a first
fluid inlet, and a first fluid outlet having an outlet flow path,
the first heat sink segment being positioned in a first placement
position within the heat sink system; and a second heat sink
segment, the second heat sink segment comprising a second heat sink
base, a second fluid inlet having an inlet flow path, and a second
fluid outlet, the second heat sink segment being positioned in a
second placement position within the heat sink system based on the
first placement position; wherein the second placement position is
arranged so that the second fluid inlet receives fluid from
substantially other sources than the first outlet flow path.
2. The heat sink system of claim 1, wherein the second placement
position is arranged vertically above and adjacent to the first
placement position.
3. The heat sink system of claim 1, wherein the first fluid outlet
is located on a first face of the heat sink system and the second
fluid inlet is located on a second face of the heat sink
system.
4. The heat sink system of claim 3, wherein the outlet flow path is
approximately perpendicular to the inlet flow path.
5. The heat sink system of claim 1, further comprising a cover
plate comprising a first opening that at least partially defines
the first fluid inlet and a second opening that at least partially
defines the first fluid outlet.
6. The heat sink of claim 5, wherein the cover plate comprises a
vertical baffle located between the first fluid outlet and the
second fluid inlet.
7. The heat sink segment of claim 1, wherein the first fluid outlet
comprises a plurality of pins projecting outwardly from the first
heat sink base.
8. The heat sink system of claim 1, wherein the second fluid inlet
comprises a plurality of pins projecting outwardly from the second
heat sink base.
9. The heat sink system of claim 1, further comprising a horizontal
wall separating the first heat sink segment and the second heat
sink segment.
10. The heat sink system of claim 1, wherein the first placement
position overlaps the second placement position and at least one of
the first heat sink segment and the second heat sink segment is
oriented at an angle.
11. The heat sink system of claim 10, wherein the first fluid
outlet is above the second fluid inlet.
12. The heat sink system of claim 10, wherein one of the first
fluid inlet and the first fluid outlet is located at an end face of
the first heat sink segment.
13. A heat sink comprising: a base plate; a first heat sink segment
comprising: a first plurality of vertical fins extending outwardly
from the base plate toward a front face, a first fluid inlet, and a
first fluid outlet; a second heat sink segment comprising: a second
plurality of vertical fins extending outwardly from the base plate
toward a front face, a second fluid inlet, and a second fluid
outlet, the second heat sink segment located vertically above the
first placement position; and a cover at least partially enclosing
the first plurality of vertical fins and the second plurality of
vertical fins and defining the first fluid outlet and the second
fluid inlet.
14. The heat sink of claim 13, wherein one of the first fluid
outlet and the second fluid inlet is located on a front face of the
heat sink system, and the other of the first fluid outlet and the
second fluid inlet is located on a side face of the heat sink
system.
15. The heat sink of claim 13, further comprising a plurality of
pins extending outwardly from the base plate toward the front
face.
16. The heat sink of claim 13, further comprising a horizontal wall
separating the first heat sink segment and the second heat sink
segment.
17. The heat sink of claim 13, wherein the cover comprises a
vertical baffle between the first fluid outlet and the second fluid
inlet.
18. The heat sink of claim 13 further comprising a duct adjacent
one of the first fluid outlet and the second fluid inlet.
19. A heat sink segment comprising: a base plate; a plurality of
vertical fins, each fin extending outward from the base plate
toward an edge located at a front face of the heat sink segment; a
horizontal wall extending outward from the base plate at a first
end of the plurality of vertical fins; a first fluid opening
located at the first end of the heat sink segment; and a second
fluid opening located at a second end of the heat sink segment,
wherein the first fluid opening faces a different direction than
the second fluid opening.
20. The heat sink segment of claim 19, further comprising: a cover
panel at least partially enclosing the plurality of vertical fins
and defining the first fluid opening and the second fluid
opening.
21. The heat sink segment of claim 20, further comprising a
plurality of spaced apart pins extending from the base plate toward
the cover panel, wherein the cover panel defines openings on two
side faces of the heat sink segment.
22. The heat sink segment of claim 20, wherein the first fluid
opening comprises a gap in the cover that exposes a portion of the
vertical fins along the edges of the fins.
23. The heat sink segment of claim 20, further comprising a
plurality of curved fins extending from the base plate toward the
cover panel, the curved fins extending from one of the first fluid
opening and the second fluid opening toward the plurality of
vertical fins.
24. The heat sink segment of claim 19, wherein the first fluid
opening is located on the front face of the of the heat sink
segment and the second fluid opening is located on a face opposite
the front face.
25. The heat sink segment of claim 19 further comprising a duct or
plenum.
Description
TECHNICAL FIELD
[0001] Various exemplary embodiments disclosed herein relate
generally to heat sinks for dissipating heat from a heat
source.
BACKGROUND
[0002] Many types of electronic components require cooling in order
to maintain a suitable working temperature. A heat sink is used to
draw heat away from an electronic component and dissipate the heat,
usually into a fluid. A heat sink increases the surface area in
contact with a surrounding cooling fluid such as air.
SUMMARY
[0003] A brief summary of various exemplary embodiments is
presented. Some simplifications and omissions may be made in the
following summary, which is intended to highlight and introduce
some aspects of the various exemplary embodiments, but not to limit
the scope of the invention. Detailed descriptions of a preferred
exemplary embodiment adequate to allow those of ordinary skill in
the art to make and use the inventive concepts will follow in later
sections.
[0004] Various exemplary embodiments relate to a heat sink system.
The heat sink system may include: a first heat sink segment, the
first heat sink segment including a first fluid inlet and a first
fluid outlet having an outlet flow path, the first heat sink
segment being positioned in a first placement position within the
heat sink system; and a second heat sink segment, the second heat
sink segment including a second fluid inlet having an inlet flow
path and a second fluid outlet, the second heat sink segment being
positioned in a second placement position within the heat sink
system based on the first placement position. The second placement
position may be arranged so that the second fluid inlet receives
fluid from substantially other sources than the first outlet flow
path.
[0005] In various alternative embodiments, the second placement
position is arranged vertically above and adjacent to the first
placement position.
[0006] In various alternative embodiments, the second fluid inlet
is located on a different face than the first fluid outlet. The
outlet flow path may be approximately perpendicular to the inlet
flow path.
[0007] In various alternative embodiments, the heat sink system
further includes a cover plate including a first opening that at
least partially defines the first fluid inlet and a second opening
that at least partially defines the first fluid outlet. The cover
plate may include a vertical baffle located between the first fluid
outlet and the second fluid inlet.
[0008] In various alternative embodiments, the first fluid outlet
includes a plurality of pins projecting outwardly from the heat
sink. In various alternative embodiments, the second fluid inlet
includes a plurality of pins projecting outwardly from the heat
sink.
[0009] In various alternative embodiments, the heat sink system may
further include a horizontal wall separating the first heat sink
segment and the second heat sink segment.
[0010] In various alternative embodiments, the first placement
position overlaps the second placement position and at least one of
the first heat sink segment and the second heat sink segment is
oriented at an angle. The first fluid outlet may be above the
second fluid inlet. One of the first fluid inlet and the first
fluid outlet may be located at an end face of the first heat sink
segment.
[0011] Various exemplary embodiments relate to a heat sink. The
heat sink may include: a base plate; a first heat sink segment
comprising: a first plurality of vertical fins extending outwardly
from the base plate toward a front face, a first fluid inlet, and a
first fluid outlet; a second heat sink segment comprising: a second
plurality of vertical fins extending outwardly from the base plate
toward a front face, a second fluid inlet, and a second fluid
outlet, the second heat sink segment located vertically above the
first placement position; and a cover at least partially enclosing
the first plurality of vertical fins and the second plurality of
vertical fins and defining the first fluid outlet and the second
fluid inlet.
[0012] In various alternative embodiments, one of the first fluid
outlet and the second fluid inlet is located on a front face of the
heat sink system, and the other of the first fluid outlet and the
second fluid inlet is located on a side face of the heat sink
system.
[0013] In various alternative embodiments, the heat sink further
includes a plurality of pins extending outwardly from the base
plate toward the front face.
[0014] In various alternative embodiments, the heat sink further
includes a horizontal wall separating the first heat sink segment
and the second heat sink segment.
[0015] In various alternative embodiments, the heat sink further
includes a duct adjacent one of the first fluid outlet and the
second fluid inlet.
[0016] Various exemplary embodiments relate to a heat sink segment.
The heat sink segment may include: a base plate; a plurality of
vertical fins, each fin extending outward from the base plate
toward a front face; a horizontal wall extending outward from the
base plate at a first end of the plurality of vertical fins; a
first fluid opening located at the first end of the heat sink
segment; and a second fluid opening located at a second end of the
heat sink segment. The first fluid opening may face a different
direction than the second fluid opening.
[0017] In various alternative embodiments, the heat sink segment
further includes a cover panel at least partially enclosing the
plurality of vertical fins and defining the first fluid opening and
the second fluid opening. The heat sink segment may also include a
plurality of spaced apart pins extending from the base plate toward
the cover panel, wherein the cover panel defines openings on two
side faces of the heat sink segment. One of the first fluid opening
and the second fluid opening may be a gap in the cover that exposes
a portion of the vertical fins along the edges of the fins.
[0018] In various alternative embodiments, the heat sink segment
further includes a plurality of curved fins extending from the base
plate toward the cover panel, the curved fins extending from one of
the first fluid opening and the second fluid opening toward the
plurality of vertical fins.
[0019] In various alternative embodiments, the first fluid opening
is located on the front face of the heat sink segment and the
second fluid opening is located on a face opposite the front
face.
[0020] In various alternative embodiments, the heat sink segment
further comprises a duct or plenum.
[0021] It should be apparent that, in this manner, various
exemplary embodiments enable a segmented heat sink. In particular,
by isolating an outlet air flow from an inlet air flow, the
segmented heat sink may reduce reentrance of heated air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to better understand various exemplary embodiments,
reference is made to the accompanying drawings, wherein:
[0023] FIG. 1A illustrates a perspective view of an electronics
unit with an exemplary segmented heat sink;
[0024] FIG. 1B illustrates a side view of the electronics unit and
exemplary segmented heat sink of FIG. 1A;
[0025] FIG. 1C illustrates a cross sectional view of FIG. 1A along
the line C;
[0026] FIG. 2 illustrates a side view of another embodiment of a
segmented heat sink;
[0027] FIG. 3 illustrates a side view another embodiment of a
segmented heat sink;
[0028] FIG. 4 illustrates another embodiment of a segmented heat
sink;
[0029] FIG. 5 illustrates another embodiment of a heat sink
segment; and
[0030] FIG. 6 illustrates another embodiment of a heat sink
segment.
DETAILED DESCRIPTION
[0031] Cooling systems for outdoor electronics components located
on top of a mast or tower may face several challenges. The location
may limit the size and weight of a heat sink. Moving parts such as
fans and motors may wear out leading to an expensive and dangerous
procedure to replace the part. Accordingly, an outdoor application
may use an air-cooled natural convection heat sink. Such a heat
sink may include a plurality of vertically oriented fins that
dissipate heat. It should be appreciated that air-cooled natural
convection heat sinks are not limited to cooling systems for
outdoor electronic components.
[0032] Some electronic's applications use vertically arranged
arrays of electronic components. Such arrays may include a heat
sink with vertically oriented fins. In such a heat sink, the fins
heat the surrounding air, causing it to rise in a natural
convection current. One problem faced by such heat sinks is that as
air is heated and moves upward, the fins are able to dissipate less
heat into the preheated air while maintaining the electronic
components at or below a desired temperature. Accordingly,
electronics components located at the top of an array may receive
less cooling than components located lower in the array. In order
to achieve sufficient cooling, the entire heat sink may be made
larger, increasing cost and weight.
[0033] A segmented heat sink may be used to prevent the increase in
temperature of a cooling medium such as air toward the top of a
heat sink. When a heat sink is divided into a plurality of
segments, cooler ambient air may be brought into each segment. Each
segment may act as an individual heat sink and provide greater
cooling. A segmented heat sink may not operate efficiently if the
exhausted heated air of one segment reenters another segment as
ambient air.
[0034] In view of the foregoing, it would be desirable to provide
effective cooling for vertically arrayed electronics components in
an outdoor application. In particular, it would be desirable to use
a segmented heat sink utilizing natural convection cooling that
minimizes reentrance of heated air into the heat sink.
[0035] Referring now to the drawings, in which like numerals refer
to like components or steps, there are disclosed broad aspects of
various exemplary embodiments.
[0036] FIG. 1A illustrates a perspective view of an electronics
unit with an exemplary heat sink 100. Reference will also be made
to FIG. 1B, which illustrates a side view of the electronics unit
and heat sink 100, and FIG. 1C, which illustrates a cross sectional
view of heat sink. 100 along line C. Heat sink 100 may include a
plurality of heat sink segments 120a-n. Heat sink segments 120a-n
may be mounted on a heat source 50, or on multiple distributed heat
sources. Although two heat sink segments are shown in FIG. 1A, any
number n of heat sink segments 120 a-n may be mounted to a heat
source 50. The exact size and shape of heat sink 100 and heat
source 50 may vary depending on the use of the electronics
unit.
[0037] Heat source 50 may include any electronics component or
other component that produces heat for which cooling is desirable.
Heat source 50 may include, for example, an active antenna array,
radio-on-chip, power amplifier, and other heat producing
components. In various exemplary embodiments, heat source 50 may
include multiple modular components. The components may be
interconnected or distributed elements that are not physically
connected. The components may be arrayed vertically. The components
may produce varying amounts of heat, or the heat may be distributed
evenly.
[0038] Heat sink segments 120a-n may form a heat sink 100 for
dissipating the heat produced by heat source 50. FIG. 1A
illustrates a heat sink with two heat sink segments 120a and 120n.
Additional heat sink segments 120 may be added above heat sink
segment 120n or below heat sink segment 120a. Heat sink segments
120 may be made in varying heights to meet cooling and space
requirements. Heat sink segments 120a-n may be made from a material
with high thermal conductivity such as, for example, aluminum
alloy, magnesium alloy, copper alloy, or other materials known by
those skilled in the art. Heat sink segments 120a-n may be placed
adjacent heat source 50. In various embodiments, thermal adhesive
or thermal grease may be used to improve the thermal performance
between the heat source 50 and heat sink segments 120a-n. In some
instances, the base 130n may be integral with the enclosure or
package containing the heat source. Heat sink segments 120a-n may
be positioned to correspond to locations of electronics components
of heat source 50. In various embodiments, the heat sink segments
120a-n may be adjacent each other.
[0039] Each heat sink segment 120a-n may include: base 130, cover
140, inlet 150, lower wall 155, pins 160, vertical fins 165, outlet
170, and upper wall 175.
[0040] Base 130 may be a flat plate of material adjacent to heat
source 50. Base 130 may extend horizontally and vertically across
the entire face of heat source 50. In various embodiments, multiple
heat sink segments 120a-n may be formed on the same base 130.
Alternatively, a heat sink segment 120 may have an individual base
130.
[0041] Cover 140 may be a piece of material that covers heat sink
segment 120. Cover 140 may be made from a material with a higher
thermal resistance, i.e., a lower thermal conductivity, such as,
for example, plastic. Cover 140 may include openings defining inlet
150 and outlet 170 of a heat sink segment 120. Cover 140 may also
include horizontal lower wall 155 and horizontal upper wall 175. As
shown in FIGS. 1a and 1B, cover 140 may include a front face 142a
and a side face 144a. In various embodiments, cover 140 may include
only front face 142a, and a vertical fin 165 may form the side face
of heat sink segment 120. Cover 140 may at least partially define
opening 150 by providing a gap in side face 144.a. Cover 140 may
define opening 170 by providing a gap in front face 142a. Cover 140
may, in conjunction with base 130 and vertical fins 165 may define
an opening 150 and/or an opening 170. Cover 140 may act as a solar
shield to reduce the absorption of solar radiation by the heat sink
segment 120. Cover 140 may also act as a protective shield to
prevent damage to heat sink segment 120. Cover 140 may also act to
direct the airflow through heat sink segment 120. The opening for
inlet 150 may allow ambient air to flow to the interior of heat
sink segment 120. The opening for outlet 170 may allow heated air
to flow out of heat sink segment 120.
[0042] Inlet 150 may be an opening in heat sink segment 120 and
cover 140 that allows ambient air to enter the interior of heat
sink segment 120. Inlet 150 may be located near the bottom end of
heat sink segment 120 to allow ambient air to enter near the
bottom. As the air is heated inside the heat sink segment 120,
buoyancy may cause the heated air to rise, and more ambient air may
be drawn in through inlet 150. In various exemplary embodiments, as
shown in FIG. 1A, inlet 150 may include an opening on each side of
heat sink segment 120. As shown, such openings may face the lateral
sides of heat sink segment 120 and draw ambient air from the
lateral sides. An inlet flow path may be directed from one or more
lateral sides toward the interior of the heat sink segment 120. A
path may be the direction along which the fluid is primarily
flowing at a particular location within the heat sink. To be more
specific, the path may correspond to the velocity vector associated
with the fluid motion at a particular location. For example,
between a set of long, vertically-oriented fins that are in contact
with a heat sink base that is in contact with a heat source, the
path may be primarily in the vertical direction. i.e., the velocity
vector associated with the fluid motion may be primarily vertical
as buoyancy forces are causing the fluid to rise vertically. As
will be described in further detail below, other embodiments may
have one or more inlets located in different positions at the
bottom end of heat sink segment 120.
[0043] Pins 160 may form a portion of heat sink segment 120. Pins
160 may be a plurality of pin fins. Pins 160 may extend from base
130 outward toward cover 140. Pins 160 may be integrally formed
with base 130 by processes such as, for example, extrusion, die
casting, skiving, press fitting or machining. Alternatively, pins
160 may be soldered or welded to base 130. Pins 160 may be arranged
in any pattern on base 130. Pins 160 may include any arrangement of
fins that allows air flow in two directions, e.g., horizontally and
vertically. The pins 160 may be square, round, triangular,
diamond-shaped, rectangular, or some other shape. The pins 160 may
be arranged in an array like fashion, such as a grid that has
regular spacing, like a lattice or in a less regular structure.
[0044] Pins 160 may dissipate heat from base 130 into the
surrounding air, while allowing air to flow in different directions
around pins 160. For example, in the embodiment shown in FIG. 1A,
ambient air entering heat sink segment 120 from inlet 150 may flow
horizontally from the lateral sides of heat sink segment 120 toward
the center. The entering air may also flow vertically upward as it
is heated. In various alternative embodiments, pins 160 may be
replaced with curved fins. The curved fins may extend from an
opening toward vertical fins 165. Curved fins may allow air to flow
in the desired direction while also providing heat dissipation.
Other types of fins, such as angled straight fins, may also be used
to allow air flow in the desired direction while also providing
heat dissipation. In various alternative embodiments, pins 160 may
be absent, leaving a finless portion. A finless portion may allow
optimal airflow but less surface area.
[0045] Vertical fins 165 may form a portion of heat sink segment
120. Vertical fins 165 may be a plurality of parallel vertical
fins. Vertical fins 165 may extend outward from base 130 toward
cover 140. Vertical fins 165 may be integrally formed in base 130
by processes such as, for example, machining, extrusion, die
casting, press fitting and skiving. Alternatively, vertical fins
165 may be soldered or welded to base 130. Vertical fins 165 may
dissipate heat from base 130. As shown in FIG. 1C, vertical fins
165 may be wider near base 130 than at the top edge. In various
exemplary embodiments, vertical fins 165 may be spaced
approximately 1 cm apart. In various embodiments, vertical fins 165
may be spaced anywhere from 5 mm to 15 mm apart. Vertical fins 165
may use natural convection cooling based on the buoyancy of heated
air. As the air between vertical fins 165 is heated, it may rise
upward toward the top of heat sink segment 120. In various
exemplary embodiments, as shown in FIG. 1A, a portion of vertical
fins 165 may be located beneath cover 140. Another portion of
vertical fins 165 may be exposed by an opening in cover 140. In
various exemplary embodiments, vertical fins 165 may extend
vertically to a horizontal wall of the heat sink segment. In
various embodiments, vertical fins 165 may not extend to a
horizontal wall of the heat sink segment, forming a gap that may at
least partially define an inlet or outlet.
[0046] Outlet 170 may be an opening in heat sink segment 120 and
cover 140 that allows heated air to exit the heat sink segment 120.
Outlet 170 may be located near the top of heat sink segment 120. In
various exemplary embodiments, as shown in FIG. 1A, outlet 170 may
be formed by an opening in cover 140 along the front face of heat
sink segment 120. Outlet 170 may exhaust heated air out the front
face of heat sink segment 120. An outlet flow path may be directed
from the interior of heat sink segment 120 toward the forward face
of heat sink segment 120. It may be noted, that outlet 170 may face
a different direction than inlet 150. For example, outlet 170 may
face the front of the heat sink segment, whereas inlet 150 may face
the lateral sides of the heat sink segment. In various embodiments,
inlet 150 and outlet 170 may be located on approximately orthogonal
faces of heat sink segment 120. The approximately orthogonal faces
may be oriented between 80 degrees and 100 degrees of each
other.
[0047] Lower wall 155 may be a horizontal barrier that prevents
fluid from entering via the bottom face of heat sink segment 120.
Lower wall 155 may be present when heat sink segment 120 is located
adjacent another heat sink segment. In particular, lower wall 155
may divide an upper heat sink segment from a lower heat sink
segment. If heat sink segment 120 is a bottom segment, lower wall
155 may be absent, allowing air to enter from the bottom surface of
heat sink segment 120. Lower wall 155 may be made from a thermally
resistant material, such as, for example, plastic. In various
embodiments, lower wall 155 may be formed as part of cover 140.
[0048] Upper wall 175 may be a horizontal barrier that prevents
fluid from exiting via the top edge of heat sink segment 120. Upper
wall 175 may be present when heat sink segment 120 is located
adjacent another heat sink segment. In particular, upper wall 175
may divide a lower heat sink segment from an upper heat sink
segment. If heat sink segment 120 is the top segment, upper wall
175 may be absent, allowing air to exit from the top surface of
heat sink segment 120. Upper wall 175 may be made from a thermally
resistant material, such as, for example, plastic. In various
embodiments, upper wall 175 may be formed as part of cover 140. In
various embodiments, upper wall 175 of one heat sink segment may
form the lower wall 155 of an adjacent heat sink segment.
Alternatively, upper wall 175 and lower wall 155 may be separate
adjacent walls.
[0049] A heat sink segment 120 may be oriented in the opposite
direction, that is, upside down. In such an embodiment, outlet 170
may be located at the bottom of the heat sink segment 120 and act
as an inlet. Inlet 150 may be located at the top of the heat sink
segment 120 and act as an outlet. Likewise the orientation of upper
wall 175 and lower wall 155 may be reversed.
[0050] Having described various structural components of a heat
sink segment 120 and heat sink 100, a brief overview of the
functionality of the heat sink 100 will be provided. It should be
apparent that the structural components of heat sink 100 or similar
components may be used to design heat sinks with similar
functionality.
[0051] Base 130 may be in thermal contact with heat source 50. Heat
from heat source 50 may spread across base 130 due to the thermal
conductivity of the base material. Heat may also spread into pins
160 and vertical fins 165 from base 130. Heat may also radiate away
from the base 130, pins 160, and vertical fins 165.
[0052] Cool ambient air may enter heat sink segment 120a via inlet
150a. In the first portion including pins 160a, the air may receive
heat from base 130a and pins 160a. The air may move upwards into
the portion including vertical fins 165. Vertical fins 165a and
base 130a may provide additional surface area for radiating heat.
The air may continue to move upward toward outlet 170. In the
portion near outlet 170, vertical fins 165a may be exposed. The
rising warm air may exit heat sink segment 120a via outlet 170a.
Upper wall 175a may prevent the warm air from entering heat sink
segment 120n. The warm air may continue to rise, primarily passing
in front of cover 140n. Heat sink segment 120n may draw ambient air
from the lateral faces of heat sink 100. Accordingly, heat sink
segment 120n may draw air from substantially other sources than the
outlet 170a. The substantially other sources may provide at least
fifty percent of the air, by volume, entering heat sink segment
120n.
[0053] FIG. 2 illustrates a side view of another embodiment of a
segmented heat sink 200. Segmented heat sink 200 may include a
plurality of heat sink segments 220a adjacent a heat source 52. In
various embodiments, heat source 52 may also be segmented into a
plurality of heat sources 52a-c. Segments of heat source 52 may
correspond to electronic components. As shown in FIG. 2, each heat
sink segment 220 may be positioned at an angle from a vertical
line. An angle may allow individual heat sink segments 220 to be
longer. Individual heat sink segments 220 may overlap. The angle
may also allow beneficial positioning of inlets 250 and outlets
270. An angle may reduce the buoyant effect of warmed air and
reduce air flow through a heat sink segment.
[0054] A middle heat sink segment 220b may illustrate
characteristics of this embodiment. Heat sink segment 220b may
include similar components to a heat sink segment 120 as discussed
above. Base 230b may be in thermal contact with heat source 52b. In
various embodiments, base 230b may extend along a bottom end of
heat sink segment 220b and be in thermal contact with heat source
52a. Cover 240b may cover the entire front surface of heat sink
segment 220b. In particular, cover 240b may separate inlet 250b
from outlet 270a. Cover 240b may include openings on the side faces
of heat sink 200 for inlet 250b. Alternatively, cover 240b and
openings in vertical fins (not shown) located along the edge of
base 230b may define the inlet 250b. Inlet 250b may be located
substantially below outlet 270a, such that at least fifty percent
of inlet 250b is below outlet 270a, to prevent warm air from outlet
270a from entering inlet 250b. Pins 260b may extend outward from
base 230b and dissipate heat in the portion near opening 250b.
Vertical fins (not shown) may be located inside cover 240b. The
vertical fins may extend from base 230b and dissipate heat as air
rises within heat sink segment 220b. Outlet 270b may be located at
the top end face of heat sink segment 220b. Outlet 270b may exhaust
warm air substantially vertically. Outlet 270b may be positioned
such that an outlet flow path from outlet 270b is within 20 degrees
of vertical. It may be noted that in this embodiment, outlet 270b
may be located on a different face than inlet 250b. Further, outlet
270a may be orthogonal to nearby inlet 250b.
[0055] FIG. 3 illustrates another embodiment of a segmented heat
sink 300. Segmented heat sink 300 may include a plurality of heat
sink segments 320. Heat sink segments 320 may be adjacent a heat
source 54. In various embodiments, heat source 54 may also be
segmented into a plurality of heat sources 54a-c. Segments of heat
source 54 may correspond to electronic components. As shown in FIG.
3, each heat sink segment 320 may be positioned at an angle from a
vertical line. An angle may allow individual heat sink segments 320
to be longer. Individual heat sink segments 320 may overlap. The
angle may also allow beneficial positioning of inlets 350 and
outlets 370. An angle may reduce the buoyant effect of warmed air
and reduce air flow through a heat sink segment.
[0056] A middle heat sink segment 320b may illustrate
characteristics of this embodiment. Heat sink segment 320b may
include similar components to a heat sink segment 120. Base 330b
may be in thermal contact with heat source 54b. Cover 340b may
cover the entire front surface of heat sink segment 320b. In
particular, cover 340b may separate inlet 350b from outlet 370a.
Cover 340b may leave the bottom end of heat sink segment 320b
exposed for inlet 350b. Inlet 350b may be located on the bottom end
face of heat sink segment 320b and draw air vertically into heat
sink segment 330b. Inlet 350b may be located substantially below
outlet 370a to prevent warm air from outlet 370a from entering
inlet 350b. Inlet 350b may be located such that at least fifty
percent of inlet 350b is below outlet 370a. Vertical fins (not
shown) may be located inside cover 240b. The vertical fins may
extend outward from base 330b and dissipate heat as air rises
within heat sink segment 320b. Outlet 370b may be located at the
lateral faces of heat sink segment 320b. Pins 360b may extend
outward from base 330b and dissipate heat in the portion near
outlet 370b. Outlet 370b may exhaust warm air substantially
horizontally. The outlet flow path at outlet 370b may be within 10
degrees of horizontal. It may be noted that in this embodiment,
outlet 370b may be located on a different face than inlet 350b.
Further, outlet 370a may be orthogonal to nearby inlet 350b.
[0057] FIG. 4 illustrates another embodiment of a segmented heat
sink. This embodiment may include a cover 440 including one or more
vertical baffles 445. The cover 440 may extend across a plurality
of heat sink segments. As shown in FIG. 4, two heat sink segments
420a and 420b may be divided by a horizontal wall 455. Horizontal
wall 455 may prevent fluid from flowing from heat sink segment 420a
to heat sink segment 420b. In the bottom heat sink segment 420a, an
outlet 470 may be formed in cover 440. In this embodiment, the
outlet 470 y be centrally located between two vertical baffles 445.
The portion of heat sink segment 420a below the outlet 470 may
include vertical fins 465. Vertical fins 465 may extend vertically
beneath cover 440 toward an inlet 450. The portion of the heat sink
segment 420a near outlet 470 may include pins 460, which may be
spaced apart horizontally across the upper portion of heat sink
segment 420a. The pins 460 may allow air to flow horizontally
toward the central outlet 470. Air exiting outlet 470 may be
confined between the vertical baffles 445.
[0058] On the other side of horizontal wall 455, heat sink segment
420b may include inlet 450. Cover 440 may define openings on the
side and/or front of heat sink segment 420b. The openings may be
separated from outlet 470 by vertical baffles 445. The portion of
heat sink segment 420b near inlet 450 may include pins 460. Pins
460 may be spaced apart horizontally to allow air to flow
horizontally inward and vertically upward. The portion of heat sink
segment 420b above the inlet 450 may include vertical fins 465.
Vertical fins 465 may extend vertically beneath cover 440 toward
the next outlet 470. The embodiment shown in FIG. 4 includes only
two heat sink segments. Other embodiments may include additional
heat sink segments. Cover 445 may be extended and define additional
inlets 450 and outlets 470.
[0059] FIG. 5 illustrates another embodiment of a heat sink segment
520. Heat sink segment 520 may include base plate 530, cover 540,
inlet 550, vertical fins 565, outlet 570, horizontal wall 575, and
curved fins 580. Heat sink segment 520 may be placed in a placement
position among other heat sink segments to form a heat sink. Heat
sink segment 520 may be oriented as shown with curved fins 580
located near the top end of the heat sink segment 520 or oriented
upside down such that the curved fins 580 are located near the
bottom end. Other types of fins besides curved fins, such as angled
straight fins, may also be used to allow air flow in the desired
direction while also providing heat dissipation.
[0060] Curved fins 580 may extend from an opening such as outlet
570 to vertical fins 565. Curved fins 580 may be integrally formed
with vertical fins 565. Alternatively, curved fins 580 may be
attached to vertical fins 565 using welding or soldering. As with
vertical fins 565, curved fins 580 may extend from base 530 toward
a front face of heat sink segment 520. Curved fins 580 may
dissipate heat from base 530. Curved fins 580 may direct a flow
path of a fluid within heat sink segment 520. For example, curved
fins 580 may direct air from the interior vertical fins 565 toward
outlet 570 located on a side face of heat sink segment 520. Curved
fins may direct a flow path so that an inlet flow path is
approximately perpendicular to an outlet flow path. The
approximately perpendicular flow paths may vary by up to 10
degrees.
[0061] FIG. 6 illustrates another embodiment of a heat sink segment
620. Heat sink segment 620 may include base plate 630, cover 640,
inlet 650, vertical fins 665, outlet 670 and horizontal wall 675.
Heat sink segment 620 may be placed in a placement position among
other heat sink segments to form a heat sink. Heat sink segment 620
may be constructed such that the inlet 650 is located on a face on
the back of the heat sink segment 620, and the outlet 670 is
located on a face on the front of the heat sink segment 620. This
arrangement may be advantageous as it allows the fins 665 to extend
into the inlet and outlet regions, i.e., pins are not required,
which can reduce fin surface area, and may also minimize the
potential for mixing of outlet air with inlet air. In various
embodiments, the inlet 650 may be located on a face on the front of
the heat sink segment 620 and the outlet 670 may be located on the
back of the heat sink segment 620. Also shown in FIG. 6, the side
face of the heat sink segment 620 may be formed by a vertical fin
670. In this embodiment, cover plate 640 may form only the front
face of heat sink segment 620.
[0062] FIG. 7 illustrates another embodiment of a heat sink 100
including ducts 190. Heat sink 700 may be similar to the heat sink
100 shown in FIGS. 1A-1C with like numerals indicating like parts.
Heat sink 700 may further include ducts or plenum 190. In various
embodiments, a heat sink segment may include inlet and outlet
plenums, or ducts, which may be cylindrical, rectangular, square,
etc., in shape. The plenum or ducts may be constructed of the same
material as cover 140 and be formed integrally with cover 140.
Alternatively, the plenum of ducts may be formed of a material with
a high thermal conductivity to assist in heat dissipation. The
plenums or ducts may be used to bring inlet air into the heat sink
segments and exhaust outlet air away from the heat sink segments.
The use of ducts may better ensure that outlet air does not mix
with inlet air by making the locations of the air inlets and air
outlets physically isolated. In the example embodiment shown in
FIG. 7, ducts 190 may extend outward from heat sink segment 120n
and have an inlet 150n located on the back face of heat sink 700.
The inlet 150n may face the opposite direction from outlet 170a.
The inlet flow path of inlet 150n may be in the opposite direction
of the outlet flow path of outlet 170a. It should be apparent that
plenum or ducts may be arranged in various configurations to
provide inlets and outlets in appropriate locations with
appropriate flow paths.
[0063] According to the foregoing, various exemplary embodiments
provide for a segmented heat sink. In particular, by isolating an
outlet air flow from an inlet air flow, the segmented heat sink may
reduce reentrance of heated air.
[0064] Although the various exemplary embodiments have been
described in detail with particular reference to certain exemplary
aspects thereof, it should be understood that the invention is
capable of other embodiments and its details are capable of
modifications in various obvious respects. As is readily apparent
to those skilled in the art, variations and modifications can be
affected while remaining within the spirit and scope of the
invention. Accordingly, the foregoing disclosure, description, and
figures are for illustrative purposes only and do not in any way
limit the invention, which is defined only by the claims.
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