Note: Descriptions are shown in the official language in which they were submitted.
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HEAT PIPE ASSEMBLY WITH BONDED FINS ON THE BASEPLATE HYBRID
FIELD OF THE INVENTION
[0001] The following disclosure is directed generally to hybrid heat pipe
assemblies.
BACKGROUND OF THE INVENTION
[0002] A device usually generates heat as a result of losses in
efficiency. A heat sink is a
passive heat exchanger that can cool a device by transferring heat generated
by the device into a
surrounding cooling medium, such as air. A heat sink may have a baseplate that
can extract heat
from a device that is in contact with the baseplate. A heat sink may also
include an assembly of
fins bonded to the baseplate that can transfer the extracted heat from the
baseplate to the
surrounding cooling medium. Thus, there is a flow of heat from the device
through the baseplate
and the fins to the surrounding cooling medium, thereby serving to cool the
device in contact
with the baseplate.
[0003] Since the heat sink is a passive heat transfer mechanism, there
may be situations
in which the heat sink is not able to adequately cool a device in contact
therewith. In such cases,
a heat pipe apparatus might be applied. A heat pipe apparatus is also a heat
exchanger than can
cool a device by transferring heat generated by the device into a surrounding
cooling medium.
The heat pipe apparatus may include an evaporator plate that can extract heat
from a device that
is in contact with the evaporator plate. The apparatus may also include a
plurality of heat pipes
in contact with the evaporator plate that can transfer heat from the
evaporator plate to another
location using liquid-to-vapor phase changes.
[0004] Each of the heat pipes includes a working fluid, such as water,
sealed in a long
thin walled cavity under vacuum. The cavity may be cylindrical or rectangular,
but is not limited
thereto. When heat is applied to a portion of the heat pipe, the working fluid
boils and is
converted into vapor. The vapor moves from the heated portion, or an
evaporating area, of the
pipe to a lower temperature area, or a condensing area, of the heat pipe via
an adiabatic portion
of the pipe where no phase change takes place. The lower temperature area of
the heat pipe is at
an opposite end of the heat pipe from the end of the heat pipe in contact with
the evaporator
plate. In the lower temperature area of the heat pipe, the vapor will condense
back into a liquid.
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The liquid will move back to the heated area of the heat pipe via the
adiabatic portion of the pipe
to be heated and evaporated again. Thus, a two-phase flow cycle is created.
[0005] The condensed liquid moves from the lower temperature area of the
heat pipe to
the heated area of the heat pipe using gravity or a wicking structure. If the
liquid moves back to
the heated area as a result of gravity, the heat pipe has been oriented in
such a way that gravity
can draw the condensed liquid down toward the heated portion of the heat pipe.
For example,
such an orientation may include a heat pipe being angled downwardly from the
lower
temperature area of the heat pipe to the heated area of the heated pipe. This
allows gravity to
draw the condensed liquid from the higher, condensing area of the heat pipe
toward the lower,
evaporating area of the heat pipe.
[0006] A large fin stack is positioned around the lower temperature area,
and possibly the
adiabatic portion, of the heat pipe. The fin stack can transfer the heat away
from the heat pipes
into the air through forced or natural convection.
[0007] However, even such a heat pipe apparatus may not be effective to
dissipate heat
from certain devices that are either exceedingly inefficient or of a size
significant enough to
require a greater cooling capacity than such a heat pipe apparatus can provide
on its own.
SUMMARY OF THE INVENTION
[0008] Described herein are multiple example embodiments related to
hybrid heat pipe
assemblies.
[0009] In an aspect, a hybrid heat pipe is provided. The assembly
includes a baseplate
dimensioned to be placed in surface contact with a device, the baseplate being
configured to
extract heat from the device. The assembly additionally includes a plurality
of fins bonded to the
baseplate, the fins being configured to transfer a first portion of the
extracted heat from the
baseplate to air surrounding the fins. The assembly further includes a complex
heat pipe
extending from the baseplate and having an end positioned within the
baseplate, the complex
heat pipe being configured to receive and transfer a second portion of the
extracted heat
transferred from the baseplate. Moreover, the assembly includes a heat pipe
fin stack to which
the complex heat pipe is configured to transfer the second portion of heat,
the heat pipe fin stack
being joined to the complex heat pipe and configured to transfer the second
portion of the
extracted heat received from the complex heat pipe to air surrounding the
stack.
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[0010] In an example of the aspect, the complex heat pipe extends from
the baseplate and
through the fins and the heat pipe fin stack. In another example of the
aspect, the fins are bonded
to the baseplate in a plurality of groups. The groups are separated from each
other by the
complex heat pipe. In a further example of the aspect, the complex heat pipe
extends from the
baseplate and through two of the fin groups and the heat pipe fin stack. In an
additional example
of the aspect, each of the complex heat pipes extends through the heat pipe
fin stack.
100111 In a further example of the aspect, the heat pipe fin stack
includes a heat pipe
protective fin into which the complex heat pipe extends. The heat pipe
protective fin is
positioned on an opposite side of the heat pipe fin stack from the fins. In an
example of the
aspect, the heat pipe protective fin is positioned adjacent to one end of the
complex heat pipe. In
yet another example of the aspect, another end of the complex heat pipe is
embedded in the
baseplate.
[0012] In an additional example of the aspect, the fins are mounted to an
opposite side of
the baseplate from a side of the baseplate in contact with the device. In
still another example of
the aspect, the complex heat pipe is embedded in the baseplate. In a further
example of the
aspect, the complex heat pipe extends at an angle from the baseplate to an end
of the complex
heat pipe.
[0013] In a second aspect, a hybrid heat pipe assembly for cooling a
device in contact is
provided. The assembly includes a baseplate dimensioned to be placed in
surface contact with a
device, the baseplate being configured to extract heat from the device. The
assembly also
includes a plurality of fins bonded to the baseplate, the fins being
configured to transfer a first
portion of the extracted heat from the baseplate to air surrounding the fins.
The assembly further
includes a complex heat pipe apparatus positioned within the baseplate, the
apparatus including a
chamber positioned within the baseplate and a plurality of complex heat pipes
secured within the
chamber, the complex heat pipes extending from the baseplate and having ends
positioned within
the baseplate, the chamber being configured to receive a second portion of the
extracted heat
transferred from the baseplate and transfer the second heat portion to the
complex heat pipes, the
complex heat pipes being configured to receive and transfer the second heat
portion from the
chamber. The assembly additionally includes a heat pipe fin stack to which the
complex heat
pipes are configured to transfer the second portion of heat, the heat pipe fin
stack being joined to
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the complex heat pipes and configured to transfer the second portion of the
extracted heat
received from the complex heat pipes to air surrounding the stack.
[0014] In an example of the aspect, the complex heat pipes extend from
the chamber
through the fins and the heat pipe fin stack. In an additional example of the
aspect, the fins are
bonded to the baseplate in a plurality of groups, and the groups are separated
from each other by
the complex heat pipes. In a further example of the aspect, the complex heat
pipes extend from
the chamber through two of the fin groups and the heat pipe fin stack. In yet
another example of
the aspect, the chamber is mounted horizontally in the baseplate. In another
example of the
aspect, the chamber is embedded in the baseplate. In a still further example
of the aspect, the
chamber is positioned in a baseplate channel comprising walls defining the
baseplate channel,
the chamber being secured to the walls.
[0015] Other features and aspects may be apparent from the following
detailed
description, the drawings and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view illustrating an example of a hybrid
heat pipe
assembly.
[0017] FIG. 2 is front view illustrating an example of the hybrid heat
pipe assembly
shown in FIG. 1.
[0018] FIG. 3 is a side cross-sectional view taken along lines 3-3 of
FIG. 2 illustrating an
example of the hybrid heat pipe assembly shown in FIG. 1.
[0019] FIG. 4 is a close-up view of area 4 of FIG. 3 illustrating an
example of an
interface of a baseplate and a complex heat pipe of the hybrid heat pipe
assembly shown in FIG.
1.
[0020] FIG. 5 is a perspective view illustrating an example of a complex
heat pipe of the
hybrid heat pipe assembly shown in FIG. 1.
[0021] FIG. 6 is a perspective view illustrating an example of the hybrid
heat pipe
assembly shown in FIG. 1 with devices in contact therewith.
[0022] Throughout the drawings and the detailed description, unless
otherwise described,
the same drawing reference numerals will be understood to refer to the same
elements, features
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and structures. The relative size and depiction of these elements may be
exaggerated for clarity,
illustration and convenience.
DETAILED DESCRIPTION
[0023] Examples incorporating one or more embodiments are described and
illustrated in
the drawings. These illustrated examples are not intended to be limiting. For
example, one or
more aspects of an embodiment may be utilized in other embodiments and even
other types of
devices.
[0024] FIGS. 1-6 illustrate an example hybrid heat pipe assembly in
surface contact with
a plurality of devices 4. While the devices 4 illustrated in FIG. 6 bear a
common resemblance
with electronic modules, embodiments described herein are not limited thereto.
In fact, one
having ordinary skill in the art may use the hybrid heat pipe assembly 2 to
cool any applicable
heat-generating device having the ability to be in contact with the hybrid
heat pipe assembly 2.
[0025] While the devices 4 illustrated in FIG. 6 are mounted to the
hybrid heat pipe
assembly 2 using fasteners 6, embodiments described herein are not limited
thereto. For
example, the devices 4 may merely be in contact with the hybrid heat pipe
assembly 2 without
being fixed or mounted thereto. In addition, the devices 4 contacting the
hybrid heat pipe
assembly 2 may be related or unrelated to each other. Moreover, the devices 4
may be in contact
with or isolated from each other. Whatever the case, the devices 4 to be
cooled by the hybrid heat
pipe assembly 2 are positioned with respect to the hybrid heat pipe assembly
in such a way as to
maximize surface contact with the hybrid heat pipe assembly 2, thereby serving
to increase an
amount of heat extracted from the devices 4 by the hybrid heat pipe assembly
2.
[0026] The illustrated hybrid heat pipe assembly 2 may combine various
aspects and
elements of a bonded fin heat sink and a heat pipe apparatus. However, the
hybrid heat pipe
assembly 2 is not limited thereto and can be further supplemented by other
heat transfer means
known by those of ordinary skill in the art.
[0027] The example hybrid heat pipe assembly 2 described and illustrated
herein
includes a baseplate 8 in contact with the devices 4, baseplate fins 10 bonded
to the baseplate 8, a
complex heat pipe 12 extending from the baseplate 8 and having an end
positioned within the
baseplate 8, and a heat pipe fin stack 14 joined to the complex heat pipe 12.
[0028] The baseplate 8 is configured to extract heat from the devices 4
in contact with
the baseplate 8. As was previously noted with respect to the hybrid heat pipe
assembly 2, while
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the devices 4 illustrated in FIG. 6 are mounted to the baseplate 8 using
fasteners 6, embodiments
described herein are not limited thereto. For example, the devices 4 may be in
contact with the
baseplate 8 without being fixed or mounted thereto. In addition, the devices 4
may be related or
unrelated to each other or other items contacting the baseplate 8.
[0029] The baseplate 8 may have a shape consistent with that of a
rectangular block.
However, embodiments disclosed herein are not limited thereto as the baseplate
8 can have any
shape or structure that is effective in cooling devices in contact therewith.
Further, while the
baseplate 8 is illustrated in the example herein as being flat or planar,
embodiments described
here are not limited thereto, as the baseplate 8 may be curved or otherwise to
maximize surface
contact with the devices 4 and extract heat from the devices 4 as efficiently
as possible. Thus, the
shape and design of the baseplate 8 may be adjusted for effective extraction
of heat from
whatever device might be in surface contact therewith.
[0030] The baseplate 8 may be mounted on a corresponding structure such
that an edge
line 20 of the baseplate 8 is parallel with gravity. However, embodiments
disclosed herein are
not limited thereto, as the baseplate 8 can be mounted in any plane
particularly suited for cooling
the devices 4 in contact therewith, as long as requirements for cooling the
heat-generating
devices 4 are met and acceptable support is provided for the baseplate 8.
[0031] The heat extracted from the devices 4 by the baseplate 8 may be
transferred
therefrom to the baseplate fins 10 bonded to the baseplate 8. The heat
received by the baseplate
fins 10 may be directly transferred to the air surrounding the baseplate fins
10.
[0032] The baseplate fins 10 may be mounted directly on the baseplate 8
or on a fin plate
30 that is subsequently mounted on the baseplate 8. If mounted directly on the
baseplate 8, each
of the baseplate fins 10 may include a flange (not shown) via which the
baseplate fin 10 is
fastened to the baseplate 8. The flange may extend from an edge of a body 32
of the baseplate
fin 10 in a substantially perpendicular manner that is additionally
substantially parallel with the
sides 16, 18 of the baseplate 8. The baseplate fins 10 may be bonded to the
baseplate 8 in a
plurality of groups. In addition, the baseplate fins 10 may be mounted to an
opposite side 16 of
the baseplate 8 from a side 18 of the baseplate 8 in contact with the devices
4.
[0033] In some cases, when cooling requirements for the devices 4 are
great, the heat
generated by the devices 4 may be too substantial to be effectively dissipated
solely by the
baseplate fins 10. When this occurs, the excess heat may be dissipated from
the baseplate 8
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through the complex heat pipe 12. The complex heat pipe 12 may transfer the
received excess
heat from the baseplate 8 to the heat pipe fin stack 14 for subsequent
dissipation to air
surrounding the heat pipe fin stack 14.
[0034] As is the case with the baseplate fins 10, the complex heat pipe
12 may also be
positioned on the opposite side 16 of the baseplate 8 from the side 18 of the
baseplate 8 in
contact with the devices 4. In addition, the complex heat pipe 12 may be
mounted on the
complex heat pipe side of the baseplate 8 in a location that corresponds with
a location of the
devices 4 positioned on the opposite side 18 of the baseplate 8. When the
complex heat pipe 12
is mounted on the baseplate 8 in such a location, the heat extraction from the
devices 4 may be
more efficient.
[0035] The complex heat pipe 12 may be similar in design to a clarinet
heat pipe or a
tube that has been fabricated to seal a working fluid under vacuum pressure.
Several complex
heat pipes 12 may be mounted in the baseplate 8 to extend therefrom. Ends of
the complex heat
pipes 12 may also be embedded in the baseplate 8.
[0036] As such, a complex heat pipe 12 may separate one group of the
baseplate fins 10
from another group of the baseplate fins 10. The complex heat pipe 12 may
extend from the
baseplate 8 and through the baseplate fins 10 and the heat pipe fin stack 14.
The baseplate fins
may be mounted to and arranged on the baseplate 8 in a plurality of separated
groups. In such
cases, the groups of the baseplate fins 10 may be separated from each other by
a complex heat
pipe 12 extending from the baseplate 8, between the groups of the baseplate
fins 10, and through
the heat pipe fin stack 14. For example, two groups of baseplate fins 10 may
be separated by a
complex heat pipe 12 mounted to the baseplate 8 in an area between the two
groups of the
baseplate fins 10. The complex heat pipe 12 may extend between and past the
baseplate fins 10
and into the heat pipe fin stack 14. The heat pipe fin stack 14 may be
separated from the
baseplate 8 by the baseplate fins 10.
[0037] Further, a complex heat pipe apparatus 22 may include a plurality
of the complex
heat pipes 12 secured within a closed chamber 24 that is positioned within the
baseplate 8. The
complex heat pipes 12 may be secured within respective recesses in the closed
chamber 24 by
brazing the heat pipes 12 to respective walls that define the recesses. The
chamber 24 may be
embedded in a baseplate channel 26 formed within the baseplate 8 such that
chamber 24 can fit
therein. For example, the chamber 24 may be welded to walls that define the
baseplate channel
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26. The closed chamber 24 may act as a fluid reservoir within the baseplate 8
to expedite the
transfer of heat from the baseplate 8 using a two-phase flow cycle created
within the complex
heat pipes 12.
100381 Moreover, the closed chamber 24 may be mounted at a location in
the baseplate 8
that enhances or maximizes heat extraction from the devices 4. For example,
the chamber 24
may be placed within a baseplate channel 26 at a location on the side 18 at
which the devices 4
make surface contact with the baseplate 8. The baseplate channel 26 location
on the side 16 may
be essentially opposite a location on the side 18 at which the devices 4 are
in surface contact
therewith.
100391 Further, the chamber 24 and the channel 26 may be correspondingly
oriented to
maximize exposure to devices 4 in surface contact with the baseplate 8 in
order to enhance or
maximize extraction of heat therefrom. For example, while both the chamber 24
and the channel
26 are illustrated herein as being straight, embodiments disclosed herein are
not limited thereto,
as the channel 24 can be correspondingly curved to a curved channel 26 and of
the baseplate 8 in
order to maximize heat extraction from a correspondingly positioned and/or
shaped group of
devices 4 making surface contact with the baseplate 8.
[0040] The heat pipe fin stack 14 may include a heat pipe protective fin
28 to provide
protection for a complex heat pipe 12 extending therethrough. The heat pipe
protective fin 28
may be positioned on an opposite side of the heat pipe fin stack 14 from the
baseplate fins 10 and
adjacent to one end 36 of the complex heat pipe 12. The pipe end 36 may extend
through the
heat pipe protective fin 28, such that the pipe end 36 is separated from a
remainder of the
complex heat pipe 12 by the heat pipe protective fin 28. Further, an end cap
34 may be
positioned on the pipe end 36 of the complex heat pipe 12 to provide
additional protection to the
complex heat pipe 12.
[0041] In the examples described herein, the complex heat pipe 12 is
positioned to absorb
excess heat from the baseplate 8 when cooling requirements are high enough
that the baseplate
fins 10 are unable to effectively cool the devices 4 contacting the baseplate
8. As a result,
melting of a devices 4 due to insufficient cooling may be inhibited.
[0042] A number of examples have been described above. Nevertheless, it
will be
understood that various modifications may be made. For example, suitable
results may be
achieved if the described elements are combined in a different manner and/or
replaced or
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supplemented by other elements or their equivalents. Accordingly, other
implementations are
within the scope of the following claims.
