U.S. patent application number 11/309808 was filed with the patent office on 2008-04-03 for loop heat pipe with flexible artery mesh.
This patent application is currently assigned to FOXCONN TECHNOLOGY CO., LTD.. Invention is credited to CHANG-SHEN CHANG, JUEI-KHAI LIU, HSIEN-SHENG PEI, CHAO-HAO WANG.
Application Number | 20080078530 11/309808 |
Document ID | / |
Family ID | 39259992 |
Filed Date | 2008-04-03 |
United States Patent
Application |
20080078530 |
Kind Code |
A1 |
CHANG; CHANG-SHEN ; et
al. |
April 3, 2008 |
LOOP HEAT PIPE WITH FLEXIBLE ARTERY MESH
Abstract
A loop heat pipe (10) includes an evaporator (11) thermally
connected with a heat generating electronic component and including
a wick structure (112) disposed therein, a condenser (12) thermally
connected with a heat dissipating component, a vapor line (13) and
a liquid line (14) connecting the evaporator with the condenser to
form a closed loop, a predetermined quantity of bi-phase working
medium contained in the closed loop, and an artery mesh (15)
located within the liquid line.
Inventors: |
CHANG; CHANG-SHEN;
(Tu-Cheng, TW) ; LIU; JUEI-KHAI; (Tu-Cheng,
TW) ; WANG; CHAO-HAO; (Tu-Cheng, TW) ; PEI;
HSIEN-SHENG; (Tu-Cheng, TW) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. CHENG-JU CHIANG JEFFREY T. KNAPP
458 E. LAMBERT ROAD
FULLERTON
CA
92835
US
|
Assignee: |
FOXCONN TECHNOLOGY CO.,
LTD.
Tu-Cheng
TW
|
Family ID: |
39259992 |
Appl. No.: |
11/309808 |
Filed: |
October 2, 2006 |
Current U.S.
Class: |
165/104.26 ;
165/104.21; 257/E23.088 |
Current CPC
Class: |
H01L 23/427 20130101;
F28D 15/043 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/104.26 ;
165/104.21 |
International
Class: |
F28D 15/04 20060101
F28D015/04 |
Claims
1. A loop heat pipe comprising: an evaporator configured for
thermally connecting with a heat generating electronic component
and comprising a wick structure disposed therein; a condenser
configured for thermally connecting with a heat dissipating
component; a vapor line and a liquid line connecting the evaporator
with the condenser to form a closed loop; a predetermined quantity
of bi-phase working medium filled in the closed loop; and an artery
mesh positioned within the liquid line.
2. The loop heat pipe of claim 1, wherein the artery mesh has a
linear contact with an inner wall of the liquid line.
3. The loop heat pipe of claim 1, wherein a diameter of a cross
section of the artery mesh is smaller than that of the liquid
line.
4. The loop heat pipe of claim 1, wherein the artery mesh is a
flexible hollow tube woven from a plurality of metal wires.
5. The loop heat pipe of claim 4, wherein the material of the metal
wires is selected from a group consisting of copper wires and
stainless steel wires.
6. The loop heat pipe of claim 1, wherein the artery mesh is formed
by weaving a plurality of fiber together.
7. The loop heat pipe of claim 1, wherein the wick structure is
selected from the group consisting of grooves, sintered powder,
fiber and screen mesh.
8. The loop heat pipe of claim 1, wherein the wick structure is
tubular shaped in profile and disposed in an inner wall of the
evaporator.
9. The loop heat pipe of claim 1, wherein the wick structure has a
closed end contacting with the liquid line and an open end
communicating with the vapor line, a vapor channel being defined in
a middle portion of the open end.
10. A loop heat pipe comprising: an evaporator configured for
thermally connecting with a heat generating electronic component
and comprising a wick structure disposed therein; a condenser
configured for thermally connecting with a heat dissipating
component; a vapor line connecting an open end of the wick
structure with the condenser; a liquid line connecting a closed end
of the wick structure with the condenser; a vapor channel defined
in a middle portion of the open end of the wick structure and
communicating with the vapor line; an artery mesh positioned within
the liquid line; and a predetermined quantity of bi-phase working
medium contained in the loop heat pipe.
11. The loop heat pipe of claim 10, wherein the artery mesh is a
hollow tube in contact with an inner wall of the liquid line.
12. The loop heat pipe of claim 10, wherein a diameter of a cross
section of the artery mesh is smaller than that of the liquid
line.
13. The loop heat pipe of claim 10, wherein the artery mesh is
woven from a plurality of metal wires selected from a group
consisting of copper and stainless steel wires.
14. The loop heat pipe of claim 10, wherein the artery mesh is
tightly attached to inner walls of the liquid line.
15. The loop heat pipe of claim 10, wherein the wick structure has
a column shaped outer wall contacting with an inner wall of the
evaporator.
16. The loop heat pipe of claim 10, wherein a diameter of the vapor
channel is larger than a diameter of an inner wall of the vapor
line.
Description
1. FIELD OF THE INVENTION
[0001] The present invention relates generally to a loop heat pipe
for transfer or dissipation of heat from heat-generating
components, and more particularly to a loop heat pipe with flexible
artery mesh disposed therein for improving heat dissipation for the
heat-generating components.
2. DESCRIPTION OF RELATED ART
[0002] Loop heat pipes have excellent heat transfer performance due
to their low thermal resistance, and are therefore an effective
means for transfer or dissipation of heat from heat-generating
components such as central processing units (CPUs) of
computers.
[0003] A conventionally loop heat pipe includes an evaporator
thermally connected with a CPU and disposing a wick structure
therein, a condenser thermally connected with a heat sink, a vapor
line and a liquid line disposed between and connecting the
evaporator with the condenser, a compensation disposed between the
wick structure and the liquid line, and a predetermined quantity of
bi-phase working medium contained in the evaporator and the liquid
line.
[0004] During operation of the loop heat pipe, the working medium
in the evaporator absorbs heat from the CPU and vaporizes, thus
generating a vapor pressure which propels vaporized working medium
towards the condenser via the vapor line. The vaporized working
medium dissipates the heat to the heat sink at the condenser and
condenses to liquid thereat. The condensed working medium is then
propelled through the liquid line, the compensation and the
evaporator in that order by the vapor pressure and by capillary
action generated by the wick structure. The condensed working
medium at the evaporator then evaporates and is condensed to liquid
thus perpetuating the cycle.
[0005] In the operation of the loop heat pipe, the working medium
at the evaporator needs to be heated to vaporize and generate
enough vapor pressure to conquer gravitational force acting on the
working medium in the liquid line so as to power the circulation of
the working fluid. Therefore, a start up temperature must first be
achieved before the heat pipe can operate, which troubles the loop
heat pipe to be operated in a lower temperature.
[0006] Therefore, it is desirable to provide a loop heat pipe which
has better gravity conquest capability and easily to be operated
under lower temperature.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a loop heat pipe for
removing heat from heat-generating components. The loop heat pipe
includes an evaporator with a wick structure disposed therein and
thermally connected with a heat generating electronic component, a
condenser thermally connected with a heat dissipating component, a
vapor line and a liquid line connecting the evaporator with the
condenser to form a closed loop, with a predetermined quantity of
bi-phase working medium contained in the closed loop, and an artery
mesh disposed within the liquid line.
[0008] Other advantages and novel features of the present invention
will become more apparent from the following detailed description
of preferred embodiment when taken in conjunction with the
accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Many aspects of the present invention can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily drawn to scale, the emphasis
instead being placed upon clearly illustrating the principles of
the present invention. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout the several
views:
[0010] FIG. 1 is a loop heat pipe in accordance with a preferred
embodiment of the present invention;
[0011] FIG. 2 is an enlarged transverse cross-sectional view of the
loop heat pipe of FIG. 1, taken along line II-II;
[0012] FIG. 3 is an enlarged transverse cross-sectional view of the
loop heat pipe of FIG. 1, taken along line III-III;
[0013] FIG. 4 is an enlarged view of a circled portion IV of the
loop heat pipe of FIG. 1;
[0014] FIG. 5 is an enlarged transverse cross-sectional view of the
loop heat pipe of FIG. 1, taken along line V-V;
[0015] FIG. 6 is a front view of an artery mesh of the loop heat
pipe of FIG. 1; and
[0016] FIG. 7 a transverse cross-sectional view of the artery mesh
of the FIG. 6, taken along line VII-VII.
DETAILED DESCRIPTION OF THE INVENTION
[0017] FIG. 1 illustrates a loop heat pipe 10 in accordance with a
first embodiment of the present invention. The loop heat pipe 10
includes an evaporator 11 thermally connected with a heat
generating electronic component such as a CPU (not shown), a
condenser 12 thermally connected with a heat dissipating component
such as a heat sink (not shown), vapor and liquid lines 13, 14
connecting the evaporator 11 with the condenser 12 to form a closed
loop, a predetermined quantity of bi-phase working medium (not
labeled) contained in the closed loop, and a flexible interwoven
artery mesh 15 disposed within the liquid line 14.
[0018] Referring particularly to FIGS. 2 and 3, the evaporator 11
is a hollow tube which contains a wick structure 112 coextensive
with a central longitudinal axis of the evaporator 11. The wick
structure 112 is tubular shaped in profile and has a column shaped
outer wall 113 contacting with an inner wall of the evaporator 11.
The wick structure 112 has a closed end 114 abutting against the
liquid line 14 and an open end 115 abutting against the vapor line
13. A column-shaped vapor channel 116 communicating with an inner
space of the vapor line 13 is defined in a middle portion along a
central longitudinal axis of the wick structure 112. A diameter of
the vapor channel 116 is larger than a diameter of an inner wall of
the vapor line 13, thus increasing the flow rate of vaporized
working medium entering into the inner space of the vapor line 13.
The wick structure 112 in the evaporator 11 of the loop heat pipe
10 can, for example, consist of porous structures, such as fine
grooves integrally formed at the inner wall of the evaporator 11,
screen mesh or fiber inserted into the evaporator 11 and held
against the inner wall thereof, or sintered powders combined to the
inner wall of the evaporator 11 using a sintering process.
[0019] The condenser 12 is disposed distant from the evaporator 11
and has a lower temperature than that of the evaporator 11, thus
causing the vaporized working medium to be condensed. The condenser
12 is a heat sink including a plurality of fins (not shown) for
increasing heat dissipation area thereof so as to benefit the
condensation of the vaporized working medium. An end of the liquid
line 14 extends into the condenser 12 and connects with the vapor
line 13 so that the vaporized working medium is condensed at the
condenser 12 and is directly propelled towards the evaporator 11.
Alternatively, the condenser 12 may be a cooling chamber, with the
liquid line 14 and the vapor line 13 separating from each other and
respectively connecting with two ends of the chamber. Under this
status, the vaporized working medium enters into the condenser 12
and is condensed thereat. The condenser working medium in the
condenser 12 enters into the liquid line 14 and is propelled
towards the evaporator 11.
[0020] The vapor and the liquid lines 13, 14 are made of deformable
materials compatible with the working medium, such as aluminum,
stainless steel, or plastics. Each of the vapor and liquid lines
13, 14 includes two parallel sections 13a and 13b/14a and 14b with
two corresponding ends thereof connecting with the respective ends
of the evaporator 11 and the condenser 12, and a perpendicular
section 13c/14c with two ends thereof connecting with the other two
ends of the parallel sections 13a and 13b/14a and 14b.
[0021] The working medium is usually selected from a liquid which
has a low boiling point such as water, methanol, or alcohol. Thus,
the working medium can easily evaporate to vapor when it receives
heat in the evaporator 11 and condense to liquid when it dissipates
heat in the condenser 12.
[0022] Referring to FIGS. 4 to 7, the artery mesh 15 is an
elongated hollow tube, which is attached to and extends along an
inner wall of the liquid line 14. The artery mesh 15 is woven from
a plurality of metal wires 151 (FIG. 6), such as copper, or
stainless steel wires. Alternatively, the artery mesh 15 can be
formed by weaving a plurality of non-metal threads such as fiber
together. A first channel 152 is defined in an inner space of the
artery mesh 15, whilst a second channel 153 is defined between an
outer wall of the artery mesh 15 and the inner wall of the liquid
line 14 for passage of the condensed working medium. A plurality of
pores (not shown) are formed in a peripheral wall of the artery
mesh 15, which provide capillary action to the working medium and
communicate the first channel 152 with the second channel 153. The
artery mesh 15 has a ring-like transverse cross section, a diameter
of which is smaller than a diameter of the liquid line 14. The
artery mesh 15 has a linear contact with the inner wall of the
liquid line 14 thereby defining an adjacent portion 154 contacting
with the inner wall of the liquid line 14 and a distal portion 155
spaced a distance from the inner wall of the liquid line 14 along a
radial direction of the loop heat pipe 10. In the present loop heat
pipe 10, the artery mesh 15 may be loosely inserted into the liquid
line 14 with some portions thereof isolated from the inner walls
thereof.
[0023] In operation of the loop heat pipe 10, the working medium in
the evaporator 11 absorbs heat from the heat generating electronic
component and evaporates. A vapor pressure is generated due to the
vaporization of the working medium and propels the vaporized
working medium into the vapor line 13 and towards the condenser 12.
The vaporized working medium looses its heat to the heat
dissipating component at the condenser 12 and condenses to liquid
to accumulate in the condenser 12 and the artery mesh 15 thereat.
The condensed working medium in the condenser 12 is propelled
towards the liquid line 14 and into the evaporator 11 via the vapor
pressure and the capillary force generated by the artery mesh 15
and the wick structure 112. The condensed working medium then
evaporates to vapor thus perpetuating a cycle in the loop heat pipe
and continuously absorbing heat from the heat generating electronic
component and dissipate the heat to the heat dissipating
component.
[0024] In the present loop heat pipe 10, the capillary force
generated by the artery mesh 15 conquers the gravity action of the
condensed working medium and helps to propel the condensed working
medium to enter into the evaporator 11 via the liquid line 14.
Therefore, the vapor pressure exerted on the condensed working
medium is decreased, and the start up temperature needed to
generate the vapor pressure is accordingly decreased. This results
in the dependence of the start up temperature of the loop heat pipe
10 not being limited by the gravity action of the condensed working
medium. Thus, the loop heat pipe 10 is easy to be operated under a
lower temperature and is preferably used for dissipating heat
generated by heat sensitive electronic components.
[0025] As compared to a conventional loop heat pipe with a
plurality of vapor channels defined between an inner wall of the
evaporator and an outer wall of the wick structure, the wick
structure 112 of the present loop heat pipe 10 has a larger
contacting area for the inner wall of the evaporator 11. The larger
contacting area of the inner wall of the evaporator enables the
heat generating electronic component to transfer more heat to the
working medium in the evaporator 11 and therefore increases the
heat dissipation efficiency of the present loop heat pipe 10.
Moreover, the wick structure 112 has a simpler structure than the
conventional loop heat pipe, which simplifies the manufacture
thereof. Furthermore, a part of the condensed working medium is
accommodated in the artery mesh of the present loop heat pipe 10,
which compensates for the working medium in the evaporator 11 which
evaporates to vapor, thus preventing the drying out of the
evaporator. Thus, there is no need to for additional compensation
in the evaporator 11 thus preventing the working medium therein
from drying out, which reduces the volume of the evaporator 11 of
the present loop heat pipe 10.
[0026] 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.
* * * * *