U.S. patent application number 14/076589 was filed with the patent office on 2015-05-14 for component reachable expandable heat plate.
The applicant listed for this patent is Kent Katterheinrich, Yung-Cheng Lee, Robert J. Monson. Invention is credited to Kent Katterheinrich, Yung-Cheng Lee, Robert J. Monson.
Application Number | 20150129174 14/076589 |
Document ID | / |
Family ID | 53042685 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150129174 |
Kind Code |
A1 |
Monson; Robert J. ; et
al. |
May 14, 2015 |
COMPONENT REACHABLE EXPANDABLE HEAT PLATE
Abstract
Some embodiments of the invention provide a heat plate system
that includes a closed vessel having at least one flexible surface.
The flexible surface allows the vessel to come into intimate
contact with heat-generating components (e.g., integrated circuits)
residing at varying heights above the floor of a module (e.g., an
avionics module). In some embodiments, the material may allow the
heat plate to expand in response to absorbing heat, so that it may
mold itself around the contours of different heat-generating
components, increasing the surface area contact between the heat
plate and the components, and increasing the heat plate's ability
to conduct heat away from the components.
Inventors: |
Monson; Robert J.; (St.
Paul, MN) ; Katterheinrich; Kent; (Coon Rapids,
MN) ; Lee; Yung-Cheng; (Boulder, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Monson; Robert J.
Katterheinrich; Kent
Lee; Yung-Cheng |
St. Paul
Coon Rapids
Boulder |
MN
MN
CO |
US
US
US |
|
|
Family ID: |
53042685 |
Appl. No.: |
14/076589 |
Filed: |
November 11, 2013 |
Current U.S.
Class: |
165/104.21 |
Current CPC
Class: |
F28F 2265/26 20130101;
H01L 2924/0002 20130101; H01L 2924/0002 20130101; H01L 23/427
20130101; F28D 15/02 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/104.21 |
International
Class: |
F28D 15/02 20060101
F28D015/02 |
Claims
1. An apparatus for use with a module comprising components which
generate heat during operation, each of the components having a
component surface, the apparatus comprising: a closed vessel
adapted for installation within the module to conduct heat away
from the components, the closed vessel storing a fluid in a liquid
state and a gaseous state, the vessel comprising at least one
vessel surface adapted to contact the component surface of each
component, the at least one vessel surface being at least partially
formed of a material exhibiting a Young's modulus of at least 120
MPa and a tensile strength of at least 231 MPa at room
temperature.
2. The apparatus of claim 1, wherein the material exhibits a
Young's modulus of approximately 2.5 GPa at room temperature.
3. The apparatus of claim 2, wherein the material is a polyimide
film.
4. The apparatus of claim 1, wherein the material is non-conductive
or dielectric.
5. The apparatus of claim 1, wherein the material exhibits a
tensile strength of approximately 330 MPa at room temperature.
6. The apparatus of claim 5, wherein the material comprises at
least one of an aluminum foil and a gold foil.
7. The apparatus of claim 1, wherein the component surface of each
of the components resides at a different height above a floor of
the module, and wherein the vessel surface comes into contact with
substantially the entirety of each component surface when installed
in the module.
8. The apparatus of claim 1, wherein the material accommodates
expansion of the fluid in response to absorbing heat generated by
the plurality of components.
9. The apparatus of claim 1, wherein the module comprises side
walls extending orthogonally from a floor of the module, and
wherein the closed vessel is adapted to conduct heat generated by
the components to at least one of the side walls.
10. The apparatus of claim 1, wherein the fluid comprises one or
more of water, alcohol and paraffin.
11. The apparatus of claim 1, in combination with the module.
12. The apparatus of claim 1, wherein the module is an avionics
module.
13. The apparatus of claim 1, wherein the plurality of components
comprise at least one integrated circuit.
14. A method for use in a system comprising a module having
components which generate heat during operation, each of the
components having a component surface, the method comprising an act
of: (A) employing a closed vessel to conduct heat away from the
components, the vessel being adapted for installation within the
module and storing a fluid in a liquid state and a gaseous state,
the vessel comprising at least one vessel surface adapted to
contact the component surface of each component, the at least one
vessel surface being at least partially formed of a material
exhibiting a Young's modulus of at least 120 MPa and a tensile
strength of at least 231 MPa at room temperature.
15. The method of claim 14, wherein the material exhibits a Young's
modulus of approximately 2.5 GPa at room temperature.
16. The method of claim 15, wherein the material is a polyimide
film.
17. The method of claim 14, wherein the material is non-conductive
or dielectric.
18. The method of claim 14, wherein the component surface of each
of the components resides at a different height above a floor of
the module, and wherein the act (A) comprises causing the vessel
surface to come into contact with substantially the entirety of
each component surface.
19. The method of claim 14, wherein the module comprises side walls
extending orthogonally from a floor of the module, and wherein the
act (A) comprises conducting heat generated by the components to at
least one of the side walls.
20. The method of claim 14, wherein the plurality of components
comprise at least one integrated circuit.
Description
FIELD OF INVENTION
[0001] This invention deals generally with heat transfer, and more
particularly with heat plates and/or heat pipes used in
transferring heat away from one or more heat-generating
components.
BACKGROUND
[0002] Proper thermal management is critical to the successful
operation of many types of devices. In this respect, modern jet
aircraft include numerous types of devices which generate
significant heat during operation, including avionic electronics,
radar and directed-energy systems. As an example, avionics
components commonly use integrated circuits (hereinafter called
"chips" for convenience) for computing applications which can
generate significant heat during operation.
[0003] Various techniques are known for transferring heat away from
devices and/or their components during operation, to keep the
devices functioning properly. For example, heat plates are commonly
used to transfer heat away from the tops of the chip(s) in an
avionics module toward the module's edge (e.g. to one or more side
walls). Often a thermal interface transfers heat from the edge to a
chassis, which is often a cooled component in which the module
resides.
[0004] Heat plates commonly employ heat pipe technology. A heat
pipe is a closed vessel which stores fluid in two states, or phases
(i.e., liquid and gas), and which makes use of changes between the
states to transfer heat. In some heat pipes, a volume of liquid is
stored in the heat pipe at a given temperature, and then a vacuum
is imposed in the vessel. The vessel is then sealed, so that the
pressure level within the vessel causes some of the liquid to
change to a gaseous state. The two-phase system inside the vessel
remains at equilibrium, meaning that the boiling point and
condensation point of the fluid in the vessel are at approximately
the system's temperature. If heat is then absorbed at a particular
location on the vessel, the heat causes liquid stored at that
location to boil and be converted to gas, the heat being
transferred to the gas, and pressure in the system increasing. A
pressure increase causes the condensation point to increase as
well, so that condensation begins occurring almost immediately at a
different location in the heat pipe, typically where it is coolest,
so that heat is transferred from the gas within the vessel to the
external environment near the cool location. The liquid which
results from this condensation transfers from the cool location
back to the heated region (e.g., via a wick, one or more
micro-grooves, and/or other mechanism(s)) so that the
evaporation-and-condensation cycle can begin again.
[0005] Within a heat pipe, heat is transferred at approximately
sonic speed from a heated location to a cooled location. As such,
if a heat pipe is long enough to transfer heat a sufficient
distance away from a heated location of a component, the heat pipe
can effectively cool the component, without the need for any
auxiliary pumping or moving parts.
[0006] FIG. 1 depicts the operation of an example conventional heat
pipe 100. In this example, water is the fluid within the closed
vessel that is used to transfer heat, although any of numerous
materials could alternatively be used. In the example of FIG. 1,
evaporator region 105 is heated, such as by a component (e.g., a
chip, not shown in FIG. 1) which generates heat during operation.
This heat causes water near evaporator region 105 to be turned to
vapor. The heat transfers through the vapor to condenser region
110, which is a cooled location in heat pipe 100. Heat is then
transferred to the external environment, causing the water at to be
converted back to liquid, and this liquid is transferred by wick
115 (e.g., via capillary action) to evaporator region 105.
SUMMARY
[0007] The inventors have appreciated that employing heat plates to
cool the numerous types of devices and components used in modern
applications can present challenges. Components on modern jet
aircraft serve as an illustrative example. On a modern jet
aircraft, there may be dozens of different avionics modules, each
having chips disposed at different locations within the module. In
modules in which chips are attached to the module floor, different
chips may be at different heights. To provide proper thermal
management for all types of modules, a different heat plate may
need to be separately configured to properly accommodate the
location and height of the chips therein. In this respect, a heat
plate is generally designed to come into intimate contact with the
chips in a module so as to effectively transfer heat away, without
applying so much pressure that any chip's operation is affected. As
such, preparing a heat plate for use with a module usually involves
configuring the plate to reach each of its chips at a particular
height with great specificity. This is difficult to accomplish
using conventional fabrication techniques.
[0008] One conventional approach to overcoming these difficulties
is to employ a conformable, compressible thermal interface layer
between each chip and the heat plate. In this approach, a thermal
interface typically sits atop each chip, and contacts the heat
plate when the heat plate is lowered into the module in which the
chip resides. Because the thermal interface is conformable, the
heat plate need not be configured to accommodate varying chip
heights with great specificity. However, thermal interfaces are
notoriously poor at conducting heat away from a chip, because they
are typically made from materials which are highly conformable but
not very thermally conductive. For example, many thermal interfaces
cause about a 50% loss in thermal conductivity when compared with
direct contact between a chip and a heat plate.
[0009] The inventors have recognized that other conformable
materials which are more thermally conductive could be used in a
thermal interface layer. For example, silver or copper pastes are
both conformable and thermally conductive. However, the use of
pastes can make module assembly problematic, because applying a
paste on a set of chips having varying heights so that the paste
atop each chip reaches the same height can be difficult. In
addition, pastes are messy, and can therefore make module
maintenance difficult.
[0010] In contrast to conventional approaches, some embodiments of
the invention provide a heat plate system which includes a closed
vessel having at least one flexible surface. The flexible surface
allows the vessel to come into intimate contact with
heat-generating components of varying heights. In some embodiments,
the heat plate may be expandable during use (e.g., in response to
being heated). As such, the heat plate may mold itself around the
contours of different heat-generating components, increasing the
surface area contact between the heat plate and the components, and
increasing the heat plate's ability to conduct heat away from the
components. In some embodiments of the invention, a heat plate may
interface directly with one or more of the module's side walls,
and/or a cooling mechanism. As a result, heat is transferred to the
external environment via the module's periphery rather than through
its cover, which may provide greater control and effectiveness with
respect to thermal management than conventional approaches
allow.
[0011] The foregoing is a non-limiting summary of the invention,
some embodiments of which are defined by the attached claims.
BRIEF DESCRIPTION OF DRAWINGS
[0012] The accompanying drawings are not intended to be drawn to
scale. In the drawings, each identical or nearly identical
component that is illustrated in various figures is represented by
a like numeral. For purposes of clarity, not every component may be
labeled in every drawing. In the drawings:
[0013] FIG. 1 is a symbolic representation of the operation of a
conventional heat pipe or heat plate, according to the prior
art;
[0014] FIG. 2 is a perspective view of a heat plate, implemented in
accordance with some embodiments of the invention, for use with an
example module;
[0015] FIG. 3 is a side view showing a heat plate, implemented in
accordance with some embodiments of the invention, installed in a
module; and
[0016] FIG. 4 is a side view of a heat plate, implemented in
accordance with some embodiments of the invention, illustrating the
heat plate's flexibility and expandability.
DETAILED DESCRIPTION
[0017] Some embodiments of the invention provide a heat plate
system which includes a closed vessel having at least one surface
that is pliable and/or flexible, allowing the vessel to come into
close contact with contoured surfaces of heat-generating components
of varying heights, and enabling effective heat transfer away from
those components. In some embodiments of the invention, a heat
plate may be expandable, such as upon the absorption of heat, so as
to increase the component surface area with which the heat plate
system comes into contact, and thereby improving thermal
conductivity. In addition, some embodiments of the invention may
provide a heat plate system for use with heat-generating components
residing in a module housing which is designed to conduct heat to
the housing's peripheral walls and/or a cooling mechanism, rather
than to the housing's cover, to provide greater control and
effectiveness with respect to heat transfer than conventional
systems provide.
[0018] FIG. 2 depicts an example heat plate system 205 that is
designed for use with module 220. Module 220 includes components
which generate heat during operation, and may be an avionics
module, or any other suitable type of module. In the example shown
in FIG. 2, module 220 includes four heat-generating components,
namely integrated circuits 210A, 210B, 210C and 210D. It should be
appreciated, however, that embodiments of the invention may be
employed with modules having any suitable number of heat-generating
components, which may or may not include integrated circuits.
[0019] In module 220, components 210A-210D reside on module floor
225. It should be appreciated, however, that embodiments of the
invention are not limited to being used with components residing on
the floor of a module, and may be used with components in any
suitable location. For example, components may be elevated above a
module floor, reside within a recess within a module's floor, be
attached to one or more of the module's side walls, and/or reside
in any other suitable location(s).
[0020] In module 220, periphery walls 215 define a cavity in which
components 210A-210D reside. As explained further below, in some
embodiments of the invention, one or more of walls 215 may contact,
or otherwise be thermally coupled to, one or more external cooling
components. For example, one or more of walls 215 may contact
components through or over which cooling fluid (which may comprise
any suitable gas and/or liquid) flows. It should be appreciated,
however, that embodiments of the invention are not limited to being
used in conjunction with modules having walls which contact
external cooling components.
[0021] Arrow 230 in FIG. 2 indicates that example heat plate 205 is
designed to be introduced into the cavity defined by walls 215 from
above. However, it should be appreciated that the invention is not
limited to being implemented in this manner, and that heat plate
205 may be introduced in to or on to a module in any suitable
manner. For example, heat plate 205 may be injected, fed or
introduced into a cavity in any other suitable way.
[0022] FIG. 3 is a side view (specifically, viewed along line 301
in FIG. 2) which shows heat plate 205 having been introduced into
the cavity defined by walls 215. In the example shown in FIG. 3,
the dimensions of heat plate 205 approximate those of the cavity
into which it is introduced, such that it contacts walls 215 when
in use. However, it should be appreciated that the invention is not
limited to such an implementation, and that a heat plate may take
any suitable shape, which may or may not coincide with the shape of
a cavity into which it is introduced. As one example, heat plate
205 could alternatively be designed to come into contact with one
or more of side walls 215 (e.g., one or more walls in contact with
a cooling element) but not all of the side walls.
[0023] In the example shown in FIG. 3, bottom surface 315 of heat
plate 205 comes into contact with the top surfaces 310B, 310C of
components 210B, 210C, respectively, when introduced, although
component 210B is taller than component 210C. In this respect, in
some embodiments of the invention, heat plate 205 is at least
partially formed of a flexible, pliable material which allows
bottom surface 315 to come into intimate contact with components of
varying heights. Any of numerous materials may be used. In some
embodiments, it may be desirable to employ a material or materials
which exhibit sufficient flexibility to allow the heat plate to
come into intimate contact with components at varying heights
within a module, a tensile strength and/or tensile modulus that is
sufficient to allow for stretching with minimal risk of rupture
during operation, and good heat transfer capability. Materials
having suitable physical properties include Kapton.RTM. polyimide
film (which exhibits a tensile strength of approximately 231 Mpa
and Young's modulus of approximately 2.5 GPa at room temperature),
aluminum foil (which exhibits a tensile strength of 330 Mpa and
Young's modulus of 70 GPa at room temperature), and gold foil
(which exhibits a tensile strength of 330 Mpa and Young's modulus
of 120 MPa at room temperature), although the inventors have
recognized that in certain applications it may be advantageous to
employ materials having dielectric or non-conductive properties so
that the surface of the heat plate which contacts electrical
components (e.g., circuits) does not interfere with their
operation. Thus, in certain applications, Kapton.RTM. polyimide
film may exhibit more suitable physical properties than aluminum or
gold foil. A moisture barrier layer (not shown in FIG. 3), which
may be formed of, for example, rubber, flexible glass, and/or any
other suitable material(s)), may be used to prevent vapor from
transmitting through the bottom surface of the heat plate if
Kapton.RTM. polyimide film is used.
[0024] In the example shown in FIG. 3, heat plate 205 conducts heat
from the top surfaces 310B and 310C of components 210B and 210C,
respectively, to cooled regions 305 which contact walls 215. More
specifically, fluid within heat plate 205 proximate top surfaces
310B and 310C is heated and converts to a vapor state, and the heat
transfers through the vapor to cooled regions 305 and then through
walls 215 to the external environment. The fluid then converts back
to a liquid state, and is transferred back to locations proximate
top surfaces 310B and 310C (e.g., by a wick, not shown), so that it
may transfer additional heat generated by components 210B and 210C
away from the components.
[0025] In some embodiments, the material(s) from which heat plate
205 is formed may allow it to expand as it absorbs heat generated
by module components, so that as heat is generated, bottom surface
315 is forced into more intimate contact with the components,
increasing the surface area of heat plate 205 across which heat may
be conducted. FIG. 4 illustrates this capability. In FIG. 4, heated
generated by component 210A causes heat plate 205 to expand,
forcing regions 415 and 420 of heat plate 205 to bend along the
edges of component 210, in contrast to FIG. 3, in which a lack of
heat generated by component 210 leaves regions 315 and 320 of heat
plate 205 largely undeformed. By expanding when heat is absorbed,
heat plate 205 forces regions into intimate contact with
heat-generating components and provides an efficient heat transfer
mechanism.
[0026] Heat plate 205 may employ any of numerous types of fluids to
perform heat transfer. The inventors have observed that fluids
which transition without difficulty between liquid and vapor
phases, and which expand when entering the vapor phase, may prove
advantageous in certain applications. Examples of fluids exhibiting
these characteristics include water, alcohol and paraffin. However,
it should be appreciated that any suitable fluid(s) may be used, as
embodiments of the invention are not limited in this respect.
[0027] It should also be appreciated that numerous advantages may
flow from the example arrangements shown in FIGS. 2-4. For example,
a heat plate formed of one or more materials that enable the heat
plate to expand as heat is absorbed enables the heat plate to
expand to a volume at which heat transfer may be more effectively
performed than in conventional arrangements. In addition, a heat
plate designed to transfer heat to one or more side walls of a
module, where cooling components may be located, may provide a more
effective mechanism than conventional arrangements which rely on
transfer or heat to the module's cover.
[0028] It should further be appreciated that the implementation
examples described above are intended to be illustrative rather
than limiting, and that numerous variations on these examples are
possible. For example, embodiments of the invention may be used to
transfer heat away from any suitable component(s), which may or may
not include an integrated circuit. In addition, embodiments of the
invention may be used in conjunction with any suitable collection
of components, which may or may not include or comprise a
functional module such as an avionics module. The collection of
components may be of any suitable size and include any suitable
quantity of components. Embodiments of the invention are not
limited in this respect.
[0029] Having thus described several aspects of at least one
embodiment of this invention, it is to be appreciated that various
alterations, modifications, and improvements will readily occur to
those skilled in the art. Such alterations, modifications, and
improvements are intended to be part of this disclosure, and are
intended to be within the spirit and scope of the invention.
Accordingly, the foregoing description and drawings are by way of
example only.
[0030] Various aspects of the present invention may be used alone,
in combination, or in a variety of arrangements not specifically
discussed in the embodiments described in the foregoing and is
therefore not limited in this application to the details and
arrangement of components set forth in the foregoing description or
illustrated in the drawings. For example, aspects described in one
embodiment may be combined in any manner with aspects described in
other embodiments.
[0031] Also, the invention may be embodied as a method, of which an
example has been provided. The acts performed as part of the method
may be ordered in any suitable way. Accordingly, embodiments may be
constructed in which acts are performed in an order different than
illustrated, which may include performing some acts simultaneously,
even though shown as sequential acts in illustrative
embodiments.
[0032] Use of ordinal terms such as "first," "second," "third,"
etc. in the claims to modify a claim element does not by itself
connote any priority, precedence or order of one claim element over
another or the temporal order in which acts of a method are
performed, but are used merely as labels to distinguish one claimed
element having a certain name from another element having a same
name (but for use of the ordinal term) to distinguish the claim
elements.
[0033] Also, the phraseology and terminology used herein is used
for the purpose of description and should not be regarded as
limiting. The use of "including," "comprising," or "having,"
"containing," "involving," and variations thereof herein, is meant
to encompass the items listed thereafter and equivalents thereof as
well as additional items.
* * * * *