U.S. patent application number 11/686939 was filed with the patent office on 2008-05-01 for flexible heat pipe.
This patent application is currently assigned to FOXCONN TECHNOLOGY CO., LTD.. Invention is credited to Yeu-Lih Lin, Fang-Xiang Yu.
Application Number | 20080099186 11/686939 |
Document ID | / |
Family ID | 39328743 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080099186 |
Kind Code |
A1 |
Yu; Fang-Xiang ; et
al. |
May 1, 2008 |
FLEXIBLE HEAT PIPE
Abstract
A flexible heat pipe (10) includes a casing (12), a wick
structure (20) arranged in the casing, and a working medium
saturated in the wick structure. The casing includes an evaporation
section (122), a condensation section (126), and a flexible
adiabatic section (124) connecting the evaporation section with the
condensation section. The wick structure includes a first portion
(21), a second portion (23) and a third portion respectively
disposed in the evaporation, the condensation and the adiabatic
sections of the casing. The adiabatic section of the casing further
accommodates a supporting member (30) therein for supporting the
third portion of the wick structure to have an intimate contact
with an inner surface of the adiabatic section.
Inventors: |
Yu; Fang-Xiang; (Shenzhen,
CN) ; Lin; Yeu-Lih; (Tu-Cheng, TW) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. CHENG-JU CHIANG J
458 E. LAMBERT ROAD
FULLERTON
CA
92835
US
|
Assignee: |
FOXCONN TECHNOLOGY CO.,
LTD.
Tu-Cheng
TW
|
Family ID: |
39328743 |
Appl. No.: |
11/686939 |
Filed: |
March 15, 2007 |
Current U.S.
Class: |
165/104.11 |
Current CPC
Class: |
F28D 15/0241 20130101;
F28D 15/0266 20130101; F28D 15/046 20130101; H01L 2924/0002
20130101; H01L 2924/0002 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/104.11 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 1, 2006 |
CN |
200610063418.2 |
Claims
1. A flexible heat pipe comprising: a casing comprising an
evaporation section, a condensation section, and a flexible
adiabatic section connecting the evaporation section with the
condensation section; a wick structure arranged in the casing and
comprising first, second and third portions respectively disposed
in the evaporation, the condensation and the adiabatic sections of
the casing, the adiabatic section of the casing further
accommodating a supporting member therein configured for supporting
the third portion of the wick structure to have an intimate contact
with an inner surface of the adiabatic section; and a working
medium contained in the wick structure.
2. The flexible heat pipe as described in claim 1, wherein the
supporting member is a coil spring.
3. The flexible heat pipe as described in claim 1, wherein the
supporting member is a tube lining an inner surface of the third
portion of the wick structure, the supporting member defines a
plurality of pores therein allowing flowing of the working medium
through the supporting member.
4. The flexible heat pipe as described in claim I, wherein a
diameter of an outer surface of the supporting member is a bit
greater than that of an inner surface of the third portion of the
wick structure.
5. The flexible heat pipe as described in claim 1, wherein the
third portion of the wick structure is a mesh wick woven from a
plurality of wires.
6. The flexible heat pipe as described in claim 1, wherein the
third portion of the wick structure is a fibrous wick comprising a
plurality of wires distributed around the inner surface of the
adiabatic section of the casing.
7. The flexible heat pipe as described in claim I, wherein the
first, the second and the third portions of the wick structure are
integrally formed as a single piece.
8. The flexible heat pipe as described in claim 1, wherein the
first and second portions of the wick structure are formed
separately from the third section of the wick structure.
9. The flexible heat pipe as described in claim 8, wherein the
first and second portions of the wick structure are sintered
wick.
10. The flexible heat pipe as described in claim 9, wherein the
first and second portions of the wick structure have different pore
sizes.
11. The flexible heat pipe as described in claim 10, wherein an
average capillary pore size of the first portion of the wick
structure is greater than that of the second portion of the wick
structure.
12. The flexible heat pipe as described in claim 1, wherein the
adiabatic section of the heat pipe is made of materials selected
from plastics, rubber and soft metal.
13. The flexible heat pipe as described in claim 1, wherein the
working medium is selected from the group consisting of water,
alcohol, kerosene, and paraffin.
14. A flexible heat pipe comprising: a casing comprising rigid
evaporation and condensation sections at two end portions of the
casing and a flexible adiabatic section interconnecting the
evaporation and condensation sections; a wick structure attached to
an inner surface of the casing; a supporting member received in the
flexible adiabatic section of the casing and pushing the wick
structure against the inner surface of the casing; and working
fluid received in the casing and saturated in the wick
structure.
15. The flexible heat pipe as described in claim 14, wherein the
supporting member comprises a coil spring.
16. The flexible heat pipe as described in claim 14, wherein the
supporting member comprises a tube with a plurality of pores
defined in a wall thereof.
17. The flexible heat pipe as described in claim 14, wherein the
wick structure comprises a plurality of axially extended wires.
18. The flexible heat pipe as described in claim 14, wherein the
wick structure comprises a mesh.
19. The flexible heat pipe as described in claim 14, wherein the
wick structure has a first wick portion at the evaporation section,
a second wick portion at the condensation section and a third wick
portion at the adiabatic section, the first wick portion and the
second wick portions being made of one of sintered wick and groove
wick.
20. The flexible heat pipe as described in claim 19, where the
first wick portion has a pore size larger than that of the second
wick portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat pipe, and more
particularly to a flexible heat pipe having a high heat transfer
capability when it is bent.
[0003] 2. Description of Related Art
[0004] Flexible heat pipes are traditionally used in
micro-electronics to help transfer heat from heat producing
products. The typical flexible heat pipe includes a casing and a
wick structure contacting with an inner surface of the casing. The
wick structure contains a working medium. The casing includes an
evaporation section connected with a heat generating electronic
component such as a CPU, a condensation section connected with a
heat dissipating apparatus such as a heat sink, and a flexible
adiabatic section connecting the evaporation section with the
condensation section for transferring heat. The wick structure is
selected from mesh wick, or fibrous wick which provides capillary
force to help circulation of the working medium between the
evaporation section and the condensation section of the casing.
[0005] In ordinary use, the adiabatic section of the flexible heat
pipe needs to be bent to achieve miniaturization of the electronic
products. However, the wick structure may separate from the inner
surface of the casing since the wick structure has a different
flexibility coefficient to that of the casing. This decreases heat
exchange between the casing and the wick structure and liquid
transportation capability of the wick structure, which further
decreases heat transfer through the flexible heat pipe. Therefore,
there is a need for a flexible heat pipe which can be bent without
overly decreasing its heat transfer capability.
SUMMARY OF THE INVENTION
[0006] The present invention relates to a flexible heat pipe. The
flexible heat pipe includes a casing and a wick structure arranged
in the casing. The wick structure contains a working medium. The
casing includes an evaporation section, a condensation section, and
a flexible adiabatic section connecting the evaporation section
with the condensation section. The wick structure includes first,
second and third portions respectively disposed in the evaporation,
the condensation and the adiabatic sections of the casing. The
adiabatic section of the casing further accommodates a supporting
member therein for supporting the third portion of the wick
structure to have an intimate contact with an inner surface of the
adiabatic section.
[0007] Other advantages and novel features of the present invention
will become more apparent from the following detailed description
of preferred embodiments when taken in conjunction with the
accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic view of a flexible heat pipe in
accordance with a first embodiment of the present invention;
[0009] FIG. 2 is a partly sectional view of an adiabatic section of
the flexible heat pipe of FIG. 1;
[0010] FIG. 3 is a cross-sectional view of the flexible heat pipe
of FIG. 1, taken along line III-III thereof;
[0011] FIG. 4 is similar to FIG. 3, but shown a flexible heat pipe
in accordance with a second embodiment of the present
invention;
[0012] FIG. 5 is a longitudinal sectional view of an adiabatic
section of a flexible heat pipe in accordance with a third
embodiment of the present invention;
[0013] FIG. 6 is a schematic view of a flexible heat pipe in
accordance with a fourth embodiment of the present invention;
[0014] FIG. 7 is a cross-sectional view of the flexible heat pipe
of FIG. 6, taken along line VII-VII thereof; and
[0015] FIG. 8 is a cross-sectional view of the flexible heat pipe
of FIG. 6, taken along line VIII-VIII thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring to FIGS. 1 and 2, a flexible heat pipe 10
according to a first embodiment of the present invention is shown.
The heat pipe 10 includes a casing 12, and a wick structure 20
disposed in the casing 12. The wick structure 20 contains working
medium (not shown).
[0017] The casing 12 includes an evaporation section 122 for
connecting with a heat generating electronic component (not shown)
such as a CPU, a condensation section 126 for connecting with a
heat dissipating apparatus (not shown) such as a heat sink, and an
adiabatic section 124 connecting the evaporation section 122 with
the condensation section 126 for transferring heat therebetween.
The adiabatic section 124 connects with the evaporation and the
condensation sections 122, 126 via two connecting members 127. Both
the evaporation and the condensation sections 122, 126 of the
casing 12 are made of high thermally conductive material such as
copper, stainless steel or aluminum. The adiabatic section 124 is
made of flexible material such as plastics, rubber or soft
metal.
[0018] Particularly referring to FIG. 3, the wick structure 20 is a
fibrous wick including a plurality of wires 22. The wires 22 are
evenly distributed around an inner surface and parallel to an axis
of the casing 12. The wires 22 are made of flexible material such
as copper, stainless steel, or fiber. The wires 22 are each
separated by a small distance from the wires adjacent to them along
a circumference of the casing 12 so as to provide a capillary force
therebetween. The working medium is a fluid having a lower boiling
point and being compatible with the casing 12 and the wick
structure 20, such as water, alcohol, kerosene, or paraffin. The
heat pipe 10 further includes a supporting member 30 for holding
the wick structure 20 in intimate contact with the inner surface of
the casing 12.
[0019] The supporting member 30 is a coil spring, and is inserted
into an inner surface of the wick structure 20. A diameter of an
outer surface of the supporting member 30 is marginally greater
than or equal to that of the inner surface of the wick structure 20
so as to push the wick structure 20 towards the inner surface of
the casing 12. The supporting member 30 is made of a flexible
material such as copper, stainless steel, or polyamide so that the
supporting member 30 provides a radial resilient force which pushes
the wick structure 20 into intimate contact with the inner surface
of the casing 12.
[0020] In the present flexible heat pipe 10, the supporting member
30 is inserted into the inner surface of the wick structure 20 and
holds the wick structure 20 in intimate contact with the inner
surface of the casing 12. When the flexible adiabatic section 124
of the heat pipe 10 is bent, the wick structure 20 and the
supporting member 30 at this section accordingly bends. Meanwhile,
the supporting member 30 generates a resilient force which urges
the wick structure 20 towards the inner surface of the casing 12.
Therefore, the wick structure 20 of the heat pipe 10 remains in
intimate contact with the inner surface of the casing 12 when it is
bent. In this way significant reduction of the heat transfer
capability of the flexible heat pipe 10 caused by bending of the
adiabatic section 124 of the casing 12 is avoided.
[0021] Referring to FIG. 4, a flexible heat pipe 10a according to a
second embodiment of the present invention is shown. The wick
structure 20a in the second embodiment of the present flexible heat
pipe 10a is different from the wick structure 20 in the first
embodiment of the present flexible heat pipe 10. In the second
embodiment, the wick structure 20a of the heat pipe 10a is a mesh
wick woven from a plurality of metal wires such as copper wires, or
stainless steel wires. Alternatively, the mesh wick may also be
woven from a plurality of fiber wires. The mesh wick is urged to
have an intimate contact with the inner surface of the casing 12
via the supporting member 30.
[0022] Referring to FIG. 5, a flexible heat pipe 10b according to a
third embodiment of the present invention is shown. In the third
embodiment, the supporting member 30b of the heat pipe 10b is a
column shaped tube, where a diameter of an outer surface of the
tube is a bit greater than or equal to that of the inner surface of
the wick structure 20b. As a result of the difference in diameter
between the outer surface of the tube and the inner surface of the
wick structure 20b, the wick structure 20b is pushed towards the
inner surface of the casing 12. The tube defines a plurality of
pores 31 in a periphery wall thereof, so that the working medium
can flow through these pores 31. Preferably, the porosity of the
supporting member 30b should be about 70%.
[0023] Referring to FIGS. 6 to 8, a flexible heat pipe 10c
according to a fourth embodiment of the present invention is shown.
In the fourth embodiment, the wick structure of the flexible heat
pipe 10c is divided into a first portion 21, a second portion 23
and a third portion (not shown) along a main axis of the casing 12.
The first portion 21, the second portion 23 and the third portion
of the wick structure are respectively disposed in the evaporation,
the condensation and the adiabatic sections 122, 126, 124 of the
casing 12. Both the first and the second portion 21, 23 of the wick
structure are sintered wicks, whilst the third portion of the wick
structure is a mesh wick or a fibrous wick. Alternatively, the
first and second portions 21, 23 of the wick structure may be of
types differing from each other, e.g. the first portion 21 of the
wick structure may be a grooved wick, whilst the second portion 23
of the wick structure may be a sintered wick. An average capillary
pore size of the first portion 21 of the wick structure is greater
than that of the second portion 21 of the wick structure, thus
allowing the small-sized second portion 23 of the wick structure to
develop a large capillary force to rapidly absorb the condensed
working medium. In this way the working medium can be caused to
rapidly enter into the second portion 23 of the wick structure at
the condensation section 126 of the casing 12. Meanwhile, the
large-sized first portion 21 of the wick structure provides a
reduced amount of resistance to the working medium flowing through
the adiabatic section 124 towards the evaporation section 122 of
the casing 12. As a consequence, the circulation speed of the
working medium in the casing 12 is increased, which further
improves the heat transfer capability of the flexible heat pipe
10c.
[0024] It is to be understood, however, that even though numerous
characteristics and advantages of the present invention have been
set forth in the foregoing description, together with details of
the structure and function of the invention, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the
principles of the invention to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *