U.S. patent application number 12/549388 was filed with the patent office on 2011-01-06 for loop heat pipe.
This patent application is currently assigned to FOXCONN TECHNOLOGY CO., LTD.. Invention is credited to CHUEN-SHU HOU.
Application Number | 20110000647 12/549388 |
Document ID | / |
Family ID | 43411998 |
Filed Date | 2011-01-06 |
United States Patent
Application |
20110000647 |
Kind Code |
A1 |
HOU; CHUEN-SHU |
January 6, 2011 |
LOOP HEAT PIPE
Abstract
A loop heat pipe includes an evaporator and a tube hermetically
connecting with the evaporator. The evaporator includes a metallic
container and a first wick structure disposed on an inner surface
of the container. The container defines a vapor outlet and a liquid
inlet. The tube includes a vapor line connecting with the vapor
outlet and a liquid line connecting with the liquid inlet of the
evaporator. The vapor line and the liquid line of the tube
communicate with each other. A second wick structure is adhered on
a part of an inner surface of a wall of the tube and connects and
communicates with the first wick structure at two opposite ends of
the evaporator.
Inventors: |
HOU; CHUEN-SHU; (Tu-Cheng,
TW) |
Correspondence
Address: |
Altis Law Group, Inc.;ATTN: Steven Reiss
288 SOUTH MAYO AVENUE
CITY OF INDUSTRY
CA
91789
US
|
Assignee: |
FOXCONN TECHNOLOGY CO.,
LTD.
Tu-Cheng
TW
|
Family ID: |
43411998 |
Appl. No.: |
12/549388 |
Filed: |
August 28, 2009 |
Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
F28D 15/043 20130101;
F28D 15/046 20130101; H01L 23/427 20130101; F28F 2255/18 20130101;
H01L 2924/0002 20130101; H01L 2924/0002 20130101; H01L 2924/00
20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/04 20060101
F28D015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2009 |
CN |
200910303992.4 |
Claims
1. A loop heat pipe comprising: an evaporator comprising a metallic
container and a first wick structure disposed on an inner surface
of the container, the container defined a vapor outlet and a liquid
inlet; and a tube hermetically connecting with the vapor outlet and
the liquid inlet of the evaporator, the tube comprising a vapor
line connecting with the vapor outlet and a liquid line connecting
with the liquid inlet, the vapor line and the liquid line
communicating with each other; wherein a second wick structure is
disposed on an inner surface of a wall of the vapor line and
connects and communicates with the first wick structure.
2. The loop heat pipe as claimed in claim 1, wherein the second
wick structure is continuous and disposed on a part of the inner
surface of the wall of the vapor line.
3. The loop heat pipe as claimed in claim 2, wherein the second
wick structure is continuous and also disposed on a part of an
inner surface of a wall of the liquid line.
4. The loop heat pipe as claimed in claim 3, wherein opposite ends
of the second wick structure connect and communicate with the first
wick structure.
5. The loop heat pipe as claimed in claim 3, wherein each of the
first and second wick structures consists of one of screen mesh,
fiber and sintered powders.
6. The loop heat pipe as claimed in claim 1, wherein the container
of the evaporator comprises a heat absorbing portion and an
extending portion extending outwardly from a lateral end of the
heat absorbing portion, and the extending portion is larger than
the heat absorbing portion.
7. The loop heat pipe as claimed in claim 6, wherein the first wick
structure has a closed end abutting against the inner surface of
the container at which the vapor outlet is located, and an opening
end abutting against the inner surface of the container at which
the liquid inlet is located.
8. The loop heat pipe as claimed in claim 7, wherein a receiving
chamber is defined in the central portion of the first wick portion
along a longitudinal direction of the central portion to receive
liquid working medium therein.
9. The loop heat pipe as claimed in claim 1 further comprising a
heat sink contacting with the vapor line of the tube.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to heat pipes and, more
particularly, to a loop heat pipe having a good heat dissipation
efficiency and a stable and reliable performance.
[0003] 2. Description of Related Art
[0004] 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 form heat-generating
components such as central processing units (CPUs) of
computers.
[0005] A conventional loop heat pipe comprises an evaporator
thermally connected with a heat-generating component 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 predetermined
quantity of bi-phase working medium is contained in the evaporator
and the liquid line.
[0006] During operation of the loop heat pipe, the working medium
in the wick structure of the evaporator absorbs heat from the
heat-generated component and vaporizes. Thus, the vaporized working
medium generates a vapor pressure which propels vaporized working
medium towards the condenser via the vapor line. The vaporized
working medium dissipates heat to the heat sink at the condenser
and condenses to liquid thereat. The condensed working medium is
then propelled through the liquid line and the evaporator in that
order by the vapor pressure and by capillary action generated by
the wick structure. Generally, each of the liquid line and the
vapor line has a smooth, cylindrical configuration. When a little
vaporized working medium condenses to liquid in the vapor line, the
condensed working medium obstructs the vaporized working medium
flows to the liquid line. Thus, a speed of the working medium flows
back to the evaporator decreases. The evaporator is prone to be
drying.
[0007] What is needed, therefore, is a loop heat pipe having a good
heat dissipation efficiency and a stable and reliable
performance.
BRIEF DESCRIPTION OF THE DRAWING
[0008] The sole drawing shows a cross-sectional view of a loop heat
pipe in accordance with the present disclosure.
DETAILED DESCRIPTION
[0009] Referring to the sole drawing, it illustrates a loop heat
pipe in accordance with the present disclosure. The loop heat pipe
comprises an evaporator 10 and a tube 20 hermetically connects with
the evaporator 10. A predetermined quantity of working medium (not
labeled) is contained in the evaporator 10 and the tube 20. The
working medium is a liquid which has a low boiling point such as
water, methanol, or alcohol. Thus, the working medium can be easily
evaporated to vapor when it absorbs heat transferred to the
evaporator 10 and condensed to liquid when it dissipates heat to
atmosphere.
[0010] The evaporator 10 comprises a container 11 and a porous
elongated first wick structure 13 adhered on an inner surface of
the container 11. The container 11 may be constructed from any
suitable metallic, such as aluminum or stainless steel. In this
embodiment, the first wick structure 13 and the container 11 each
are preferably in a cylindrical shape.
[0011] The container 11 comprises a heat absorbing portion 112 and
an extending portion 114 extending forwardly from a front end of
the heat absorbing portion 112 along a central longitudinal axis of
the heat absorbing portion 112. The heat absorbing portion 112 is
used to thermally contact with a heat-generating component (not
shown), such as a CPU (central processing unit) of a computer. A
diameter of the extending portion 114 is larger than that of the
heat absorbing portion 112. A vapor outlet 1121 is defined at a
central portion of a rear end of the heat absorbing portion 112. A
liquid inlet 1141 is defined at a central portion of a front end of
the extending portion 114.
[0012] The first wick structure 13 consists of porous structure,
such as screen mesh, or fiber inserted into the container 11 and
held against the inner surface of the container 11, or sintered
powders combined to the inner surface of the container 11 using a
sintering process. The first wick structure 13 has a central
longitudinal axis, which is coextensive with the central
longitudinal axis of the heat absorbing portion 112 of the
container 11. A receiving chamber 137 extends partially along the
axis from an open end 134 to a closed end 132 of the first wick
structure 13. The closed end 132 abuts against an inner surface of
the rear end of the absorbing portion 112 of the container 11. The
open end 134 abuts against an inner surface of the front end of the
extending portion 114 of the container 11. The receiving chamber
137 comprises a first chamber 1371 and a second chamber 1373
communicating with the first chamber 1371. The first chamber 1371
is near to the closed end 132 of the first wick structure 13. The
second chamber 1373 is near to the opening end 134 of the first
wick structure 13. A diameter of the second chamber 1373 is larger
than that of the first chamber 1371. The second chamber 1373 is a
compensation chamber for supplying liquid working medium to the
first chamber 1371.
[0013] Opposite ends of the tube 20 connect with the vapor outlet
1121 and the liquid inlet 1141 of the evaporator 11, respectively.
The tube 20 is made of metallic materials compatible with the
working medium, such as aluminum, stainless steel. The tube 20 can
be easily bent and deformed to a desired configuration. A
continuous second wick structure 24 is adhered on a part of an
inner face of a wall of the tube 20. Opposite ends of the second
wick structure 24 connect and communicate with the close end 132
and the open end 134 of the first wick structure 13 of the
evaporator 11. The tube 20 comprises a vapor line 21 and a liquid
line 22 communicating with the vapor line 21. Opposite ends of the
vapor line 21 connect with the vapor outlet 1121 and the liquid
line 22, respectively. The vaporized working medium flows through
the vapor line 21 towards the liquid line 22. Opposite ends of the
liquid line 22 connect with the liquid inlet 1141 and the vapor
line 21, respectively. The liquid working medium flows through the
liquid line 22 toward the liquid inlet 1141 of the evaporator 10.
The second wick structure 24 absorbs condensed working medium in
the vapor line 21 and guides the condensed working medium into the
evaporator 11 from the liquid inlet 1141 of the evaporator 11.
[0014] During operation of the loop heat pipe, the working medium
in the first wick structure 13 absorbs heat from the
heat-generating component and vaporizes. The vapor pressure of the
vaporized working medium expels the vaporized working medium to
flow through the vapor line 21 via the vapor outlet 1121. The
second wick structure 24 absorbs condensed working medium, if any,
in the vapor line 21 to prevent the obstruction of flowing of the
vaporized working medium in the vapor line 21 by the condensed
working medium. The vaporized working medium dissipates the heat
via the tube 20 and condenses to liquid thereat. The condensed
working medium is then propelled through the liquid line 22, the
second chamber 1373 and the first chamber 1371 of the receiving
chamber 137 in that order by the capillary action generated by the
second and first wick structures 24, 13. The condensed working
medium at the evaporator 10 then evaporates into vapor again to
start another heat transfer cycle. A heat absorbing plate 30
thermally contacts with the vapor line 21 to absorb heat of the
vaporized working medium thereby dissipating heat of the
heat-generating component to the atmosphere. The heat absorbing
plate 30 functions as a heat sink. Although it is not shown, it is
readily appreciated by those skilled in the art that the heat
absorbing plate 30 can be provided with fins for increasing the
heat dissipation efficiency.
[0015] It is to be understood, however, that even though numerous
characteristics and advantages of the disclosure have been set
forth in the foregoing description, together with details of the
structure and function of the disclosure, 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 disclosure to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *