U.S. patent application number 11/491896 was filed with the patent office on 2007-03-15 for heat dissipation module and heat pipe thereof.
This patent application is currently assigned to DELTA ELECTRONICS, INC.. Invention is credited to Chin-Ming Chen, Chi-Feng Lin, Horng-Jou Wang, Min-Hui Yu.
Application Number | 20070056712 11/491896 |
Document ID | / |
Family ID | 37853883 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070056712 |
Kind Code |
A1 |
Yu; Min-Hui ; et
al. |
March 15, 2007 |
Heat dissipation module and heat pipe thereof
Abstract
A heat dissipation module includes a heat pipe and at least one
fin, which is connected to and disposed on an external surface of
the heat pipe. The heat pipe includes a casing, a wick and a
working fluid. The casing has an accommodating space and a bottom
portion. The bottom portion has an uneven surface facing the
accommodating space. The wick is disposed over the uneven surface
of the bottom portion and the working fluid is filled within the
casing.
Inventors: |
Yu; Min-Hui; (Taoyuan Hsien,
TW) ; Wang; Horng-Jou; (Taoyuan Hsien, TW) ;
Lin; Chi-Feng; (Taoyuan Hsien, TW) ; Chen;
Chin-Ming; (Taoyuan Hsien, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
DELTA ELECTRONICS, INC.
|
Family ID: |
37853883 |
Appl. No.: |
11/491896 |
Filed: |
July 25, 2006 |
Current U.S.
Class: |
165/104.21 ;
165/104.26; 257/E23.088 |
Current CPC
Class: |
F28D 15/046 20130101;
H01L 2924/00 20130101; F28F 3/048 20130101; H01L 23/427 20130101;
H01L 2924/0002 20130101; F28D 15/0233 20130101; H01L 2924/0002
20130101 |
Class at
Publication: |
165/104.21 ;
165/104.26 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2005 |
TW |
094130972 |
Claims
1. A heat pipe, comprising: a casing having an accommodating space
and a bottom portion, the bottom portion having an uneven surface
facing the accommodating space; a wick disposed on the surface; and
a working fluid filled within the casing.
2. The heat pipe according to claim 1, wherein the casing comprises
copper, silver, aluminum or alloy thereof, or a material with high
thermal conductivity.
3. The heat pipe according to claim 1, wherein the casing is a
hollow plate-like casing or a hollow column-like casing.
4. The heat pipe according to claim 1, wherein the casing further
has a cover plate opposite to the bottom portion, and a sidewall
mounted around the bottom portion.
5. The heat pipe according to claim 1, wherein a cross section of
the bottom portion of the casing has a semi-spheral shape, an arc
shape, a triangular shape, a square shape, a rectangular shape or a
trapezoidal shape, and the bottom portion has a circular or
rectangular profile.
6. The heat pipe according to claim 1, wherein the surface is
formed with at least one protrusion or a plurality of protrusions
arranged in a checkerboard pattern, a pattern in a row, a
symmetrical pattern or an asymmetrical pattern.
7. The heat pipe according to claim l, wherein the wick is disposed
over the surface such that the wick faces the accommodating space
to form a plane.
8. The heat pipe according to claim 7, wherein the wick has a first
thickness and a second thickness in a direction perpendicular to
the bottom portion, and the first thickness is relatively greater
than the second thickness.
9. The heat pipe according to claim 1, wherein the wick is disposed
along a profile of the surface, and the wick on the surface has a
uniform thickness or a varied thickness.
10. A heat dissipation module, comprising: a heat pipe comprising a
casing, a wick and a working fluid, the casing having an
accommodating space and a bottom portion, the bottom portion having
an uneven surface facing the accommodating space, the wick being
disposed on the surface, and the working fluid being filled within
the casing; and at least one fin disposed on an external surface of
the heat pipe and connected to the heat pipe.
11. The heat dissipation module according to claim 10, wherein the
casing comprises copper, silver, aluminum or alloy thereof, or a
material with high thermal conductivity.
12. The heat dissipation module according to claim 10, wherein the
casing is a hollow plate-like casing or a hollow column-like
casing.
13. The heat dissipation module according to claim 10, wherein the
casing further has a cover plate opposite to the bottom portion,
and a sidewall mounted around the bottom portion.
14. The heat dissipation module according to claim 10, wherein a
cross section of the bottom portion of the casing has a
semi-spherical shape, an arc shape, a triangular shape, a square
shape, a rectangular shape or a trapezoidal shape, and the bottom
portion has a circular or rectangular profile.
15. The heat dissipation module according to claim 10, wherein the
surface is formed with at least one protrusion or a plurality of
protrusions arranged in a checkerboard pattern, a pattern in a row,
a symmetrical pattern or an asymmetrical pattern.
16. The heat dissipation module according to claim 10, wherein the
wick is disposed over the surface such that the wick faces the
accommodating space to form a plane.
17. The heat dissipation module according to claim 16, wherein the
wick has a first thickness and a second thickness in a direction
perpendicular to the bottom portion, and the first thickness is
relatively greater than the second thickness.
18. The heat dissipation module according to claim 10, wherein the
wick is disposed along a profile of the surface, and the wick on
the surface has a uniform thickness or a varied thickness.
19. The heat dissipation module according to claim 10, wherein the
heat pipe contacts a heat source via a base or contact the heat
source directly so as to transfer heat emitted by the heat source
to the fin.
Description
[0001] This Non-provisional application claims priority under 35
U.S.C. .sctn.119(a) on Patent Application Nos. 094130972 filed in
Taiwan, Republic of China on Sep. 9, 2005, the entire contents of
which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The invention relates to a heat dissipation module, and in
particular to a heat dissipation module having a heat pipe with
high dissipation efficiency.
[0004] 2. Related Art
[0005] With the continuous progress of the industrial technology,
various electronic products are developed toward small size, light
weight, and low power-consumption. Because the energy utilized
efficiency of the electronic element cannot reach 100 percent, some
power is wasted and thus converted into heat, which rises the
temperature in the system. When the temperature of the system
exceeds the allowable operating temperature, the physical property
of the electronic element changes and the system becomes abnormal
and the operation error or the function halt occurs. In addition,
when the temperature in the system is getting higher and higher,
the fault rate of the system also increases.
[0006] In order to make the system have a higher reliability, the
operating temperature of the system has to be kept within a proper
range. In order to enhance the heat dissipation efficiency of the
electronic element, the heat of the heat source is mostly conducted
out via a heat sink, and then transferred to the environment
through the fin of the heat sink by way of natural or forced
convection.
[0007] Because a heat pipe can transfer a lot of heat by a
considerable distance with a quite small cross section and a quite
small temperature difference, and the heat pipe can work without
exterior power supply, the heat pipe has become one of the most
widely used heat conducting elements in the electronic heat
dissipation product.
[0008] FIG. 1 is a schematically cross-sectional view showing a
conventional heat pipe 10. The heat pipe 10 has a tube wall 11, a
wick 12 disposed on the tube wall 11, and a working fluid filled
within the heat pipe 10. The heat pipe 10 has one end serving as an
evaporating end "A", and the other end serving as a condensing end
"B". The evaporating end "A" contacts the heat source (not shown).
The working fluid at the evaporating end "A" absorbs heat and
evaporates into vapor, which flows to the condensing end "B"
naturally under the influence of the pressure difference. Then, the
vapor releases the latent heat and condenses into liquid at the
condensing end "B". The condensed working fluid flows back to the
evaporating end "A" due to the capillary force of the wick 12. The
circulation is made repeatedly such that the heat dissipation
effect can be achieved.
[0009] FIG. 2 is a schematic illustration showing a dashed-line
portion C of the heat pipe of FIG. 1. Referring to FIGS. 1 and 2,
the wick 12 of the conventional heat pipe 10 has a uniform
thickness. If the wick 12 is thick, this can increase the
liquid-containing amount of the wick at the evaporating end "A" but
tends to make the vaporized bubble "G", which is produced during
the phase change procedure, be congested in the wick 12 and thus
influences the mechanism of re-filing the working fluid. As the
result, the performance of the heat pipe 10 is deteriorated. On the
contrary, if the wick 12 is thin, this prevents the vaporized
bubble G from being congested but decreases the liquid-containing
amount of the wick at the evaporating end "A". Thus, the heat that
can be dissipated by the heat pipe 10 is reduced, or the dry-out
phenomenon may occur.
[0010] Thus, it is an important subject of the invention to solve
the problem of congestion of the vaporized bubble caused by the
thickness of the wick, enlarge the heat exchanging area of the heat
pipe effectively, and thus enhance the overall heat dissipation
efficiency.
SUMMARY OF THE INVENTION
[0011] In view of the foregoing, the invention is to provide a heat
dissipation module and a heat pipe thereof capable of solving the
prior art problems of the congestion of the vaporized bubble,
effectively enlarging the heat exchanging area of the heat pipe and
enhancing the overall heat dissipation efficiency.
[0012] The invention achieves the above-identified object by
providing a heat pipe, which includes a casing, a wick and a
working fluid. The casing has an accommodating space and a bottom
portion. The bottom portion has an uneven surface facing the
accommodating space. The wick is disposed on the surface of the
bottom portion, and the working fluid is filled within the
casing.
[0013] The invention also achieves the above-identified object by
providing a heat dissipation module including a heat pipe and at
least one fin. The heat pipe includes a casing, a wick and a
working fluid. The casing has an accommodating space and a bottom
portion. The bottom portion has an uneven surface facing the
accommodating space. The wick is disposed on the surface, and the
working fluid is filled within the casing. The fins are disposed on
an external surface of the heat pipe and connected to the heat
pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will become more fully understood from the
detailed description given herein below illustration only, and thus
is not limitative of the present invention, and wherein:
[0015] FIG. 1 is a schematically cross-sectional view showing a
conventional heat pipe;
[0016] FIG. 2 is a schematic illustration showing a dashed-line
portion C of the heat pipe of FIG. 1;
[0017] FIG. 3A is a schematic illustration showing a heat pipe
according to a preferred embodiment of the invention;
[0018] FIG. 3B is a schematic illustration showing a dashed-line
portion D of FIG. 3A;
[0019] FIGS. 4 and 5 are schematic illustrations showing another
two wicks of FIG. 3B;
[0020] FIGS. 6 to 8 are schematic illustrations showing various
shapes of the cross section of a casing of the heat pipe;
[0021] FIG. 9 is a schematic illustration showing a column-like
heat pipe according to the preferred embodiment of the
invention;
[0022] FIG. 10 is a schematic illustration showing a heat
dissipation module according to the preferred embodiment of the
invention; and
[0023] FIGS. 11 and 12 are schematic illustrations showing another
two heat dissipation modules according to another two embodiments
of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The present invention will be apparent from the following
detailed description, which proceeds with reference to the
accompanying drawings, wherein the same references relate to the
same elements.
[0025] FIG. 3A is a schematic illustration showing a heat pipe
according to a preferred embodiment of the invention. FIG. 3B is a
schematic illustration showing a dashed-line portion D of FIG. 3A.
Referring to FIGS. 3A and 3B, a heat pipe 20 of the embodiment is a
plate-like heat pipe and includes a casing 21, a wick 22 and a
working fluid W. The casing 21 has an accommodating space 211 and a
bottom portion 212. In this embodiment, the casing 21 is a hollow
plate-like casing and is made of copper, silver, aluminum or the
alloy thereof, or a material with high thermal conductivity. Thus,
when the bottom portion 212 of the casing 21 contacts a heat source
(not shown, such as an electronic device generating heat), the heat
of the heat source can be transferred to other places quickly. The
bottom portion 212 has a surface 213 facing the accommodating space
211, and the accommodating space 211 of the casing 21 is a airtight
space.
[0026] The surface 213 of the bottom portion 212 is an uneven
surface. That is, the bottom portion 212 has a varied thickness.
The surface 213 is formed with at least one protrusion 214 or
multiple protrusions 214 arranged on the surface 213 to form a
checkerboard pattern, a pattern in a row, a symmetrical pattern or
an asymmetrical pattern. In FIG. 3B, the surface 213 shows a
checkerboard pattern composed of multiple rectangular column-like
protrusions 214, and the cross section of the surface 213 has a
square shape or a rectangular shape.
[0027] The wick 22 is disposed on the surface 213 of the bottom
portion 212. Take FIG. 3B as the example, the wick 22 is disposed
over the surface 213 of the bottom portion 212 such that the wick
22 faces the accommodating space 211 to form a plane. In other
words, the sum of the thickness of the bottom portion 212 of the
casing 21 and the thickness of the wick 22 is same. Consequently,
the wick 22 has a first thickness H1 and a second thickness H2 in a
direction perpendicular to the bottom portion 212. The first
thickness H1 is relatively greater than the second thickness H2.
Herein, it is to be noted that the designs of the wick 22 and the
bottom portion 212 are mainly aimed at the evaporating end "A" of
the heat pipe. The wick 22 is made of a material such as a plastic
material, a metal, an alloy, a porous non-metallic material or the
combination thereof, and the wick 22 is formed on the surface 213
by way of sintering, adhering, filling and/or depositing.
[0028] The working fluid W is filled within the casing 21 and the
working fluid W is an inorganic compound, pure water, alcohol,
ketone, a liquid metal, a refrigerant, an organic compound or a
mixture thereof. When the heat pipe 20 is disposed on the heat
source, the working fluid W at the end (i.e., the evaporating end
A) of the wick 22 close to the heat source absorbs the heat
generated by the heat source to evaporate, and the vaporized
working fluid further releases its latent heat and condenses back
to the liquid working fluid at the end (i.e., the condensing end B)
of the wick 22 away from the heat source. Then, the capillary force
provided by the wick 22 forces the fluid to flow back to the
evaporating end A. The circulation is made continuously such that
the heat is transferred away from the heat source continuously and
the heat dissipation can be achieved.
[0029] Because the bottom portion 212 of the casing 21 has the
uneven surface 213, the surface contact area between the casing 21
and the wick 22 is increased, which is advantageous to the
enhancement of the heat dissipation performance of the heat pipe
20. Furthermore, because the wick 22 has the uneven thickness, the
portion (i.e., the portion above the protrusion 214) having the
smaller thickness "H2" enables the working fluid to evaporate
easily and separate from the wick 22 so as to avoid the boiling of
the working fluid between the bottom portion 212 and the wick 22
and the problem of congestion caused by the vaporized bubble. On
the other hand, the sufficient liquid working fluid W can be
provided at the portion (i.e., the portion without the protrusion
214) having the larger thickness "H1" in order to supplement the
fluid to the portion having the smaller thickness "H2" and to avoid
the dry-out phenomenon.
[0030] However, the invention is not limited to the above-mentioned
embodiments, in which the wick 22 is disposed over the surface 213
of the bottom portion 212 such that the wick 22 faces the
accommodating space 211 to form a plane. Furthere, the wick 22 may
also be disposed along the profile of the surface 213 such that the
wick 22 also forms an uneven surface. That is to say, the wick 22
has the single uniform thickness on the surface 213. For example,
as shown in FIGS. 4 and 5, the wick 22' on the protrusion 214' has
a thickness H1', and the wick 22' on the bottom portion 212'
without the protrusion 214' has a thickness H2'. The thickness H1'
may be equal or unequal to the thickness H2' according to the
users' requirements.
[0031] Because the wick 22' is disposed along the profile of the
surface 213', the surface contact area of the wick 22' exposed to
the accommodating space is increased and thus the evaporating area
is enlarged, which is advantageous to the enhancement of the
overall efficiency of the heat pipe. In addition, the surface 213'
of the bottom portion 212' is an uneven surface such that the
surface contact area between the casing and the wick is enlarged
and the heat dissipation performance of the heat pipe can be
enhanced.
[0032] Furthermore, the shape of the cross section of the bottom
portion 212' of the casing is not particularly limited, and may be
a square shape or a rectangular shape as shown in FIGS. 3B and 4,
or a triangular shape (FIG. 5), a semi-spheral shape (FIG. 6), an
arc shape (FIG. 7) or a trapezoidal shape (FIG. 8). In addition,
the shape of the cross section may be a discontinuous pattern or a
curved surface.
[0033] In addition, the heat pipe 20 in FIG. 3A has the hollow
plate-like casing 21 as the example. However, the casing 21 may
also have other different shapes according to the shapes of the
to-be-used heat sources. So, the bottom portion 212 of the casing
21 may have a circular shape, a rectangular shape, or other
geometric shapes. FIG. 9 is a schematic illustration showing a
column-like heat pipe 30 according to the preferred embodiment of
the invention. Referring to FIG. 9, the heat pipe 30 of the
embodiment includes a casing 31, a wick 32 and a working fluid W.
The wick 32 and the working fluid have the same technological
features and functions as the wick 22 and the working fluid W of
the first embodiment, and detailed descriptions thereof will be
omitted.
[0034] The casing 31 has a hollow column-like casing and has an
accommodating space 311 and a bottom portion 312. The bottom
portion 312 has an uneven surface 313 facing the accommodating
space 311. The casing 31 further has a cover plate 314 and a
sidewall 315. The sidewall 315 is disposed around the bottom
portion 312, and the cover plate 314 is disposed opposite to the
bottom portion 312. In the hollow column-like casing 31, the
evaporating end of the heat pipe 30 is located at the bottom
portion 312 while the condensing end of the heat pipe 30 is located
at the sidewall 315. Because the bottom portion 312 of the casing
31 has the uneven surface 313, the surface contact area between the
bottom portion 312 and the wick 32 may be increased such that the
efficiency of the heat pipe 30 can be enhanced. In addition, if the
wick 32 disposed over the surface 313 of the bottom portion 312 is
also uneven, the surface contact of the wick 32 exposed to the
accommodating space 311 may be enlarged, and the efficiency of the
heat pipe 30 is enhanced.
[0035] FIG. 10 is a schematic illustration showing a heat
dissipation module 40 according to the preferred embodiment of the
invention. Referring to FIG. 10, the heat dissipation module 40
includes a heat pipe 50 and at least one fin 60. The heat pipe 50
includes a casing 51, a wick 52 and a working fluid W. The heat
pipe 50 may have the same technological features as the heat pipe
20 of FIG. 3A and the heat pipe 30 of FIG. 9, and detailed
descriptions thereof will be omitted.
[0036] In FIG. 10, the heat pipe 50 is a plate-like heat pipe. That
is to say, the casing 51 is a hollow plate-like casing. Of course,
the casing 51 may also be a column-like casing as shown in FIG. 11
or 12. The fins 60 are manufactured by way of aluminum extrusion
and are disposed on an external surface of the heat pipe 50 and
connected to the heat pipe 50. The fins 60 are connected to the
heat pipe 50 by way of welding, embedding, engaging or adhering.
The fins 60 may directly contact the heat pipe 50. Alternatively, a
soldering paste, a grease or a material capable of serving as a
heat sink interface may be coated between the fins 60 and the heat
pipe 50.
[0037] The fins 60 are disposed on the plate-like heat pipe 50.
Alternatively, the heat pipe 50' is mounted and fit within the fins
60' or 60'', as shown in FIG. 11 or 12, and the fins 60' or 60'',
are embedded in and/or engaged with the heat pipe by way of hot
mounting. The fins 60, 60' or 60'' may be disposed in a horizontal
interval distribution, a vertically interval distribution, a
slantingly interval distribution, a radial distribution, or other
distributions.
[0038] Referring again to FIG. 10, the heat dissipation module 40
may be applied to a heat source (not shown), and the heat pipe 50
contacts the heat source directly or indirectly via an external
base "S". As shown in FIG. 10, the base "S" is a solid metal block,
one side of the base "S" contacts the bottom portion 512 of the
casing 51 of the heat pipe 50, and the other side of the base "S"
contacts the heat source. The heat generated by the heat source can
be quickly conducted to the casing 51 of the heat pipe 50 and then
to the fins 60 according to the high conducting property of the
base "S". The heat source is an electronic element, such as a CPU
(Central Processing Unit), a transistor, a server, an advanced
graphics card, a hard disk, a power supply, a mobile control
system, a multimedia electronic mechanism, a wireless communication
transceiver station or an advanced game machine, which generates
the heat. In addition, the heat dissipation module 40 may further
be combined with a fan to dissipate heat, which facilitates heat
dissipation more quickly.
[0039] As mentioned in the heat dissipation module and the heat
pipe thereof according to the invention, the casing has the bottom
portion having the uneven surface such that the surface contact
area between the casing and the wick is increased, which is
advantageous to the enhancement of the heat dissipation performance
of the heat pipe. In addition, the wick disposed over the surface
to form a plane has a varied thickness. The portion with the
smaller thickness enables the working fluid to evaporate easily and
thus avoid the problem of congestion caused by the boiling and the
vaporized bubble between the bottom portion and the wick. The
portion with the larger thickness can provide the sufficient liquid
working fluid for supplementation to the portion with the smaller
thickness and avoid the occurrence of the dry-out phenomenon. In
addition, the wick disposed along the profile of the surface of the
bottom portion of the casing can enlarge the surface contact area
of the wick to expose to the accommodating space, and thus enlarges
the evaporating area, whereby the dissipation efficiency of the
heat pipe is improved.
[0040] Although the invention has been described with reference to
specific embodiments, this description is not meant to be construed
in a limiting sense. Various modifications of the disclosed
embodiments, as well as alternative embodiments, will be apparent
to persons skilled in the art. It is, therefore, contemplated that
the appended claims will cover all modifications that fall within
the true scope of the invention.
* * * * *