U.S. patent application number 12/854637 was filed with the patent office on 2012-02-16 for flat heat pipe having swirl core.
This patent application is currently assigned to CELSIA TECHNOLOGIES TAIWAN, I. Invention is credited to Chieh-Ping Chen, Ming-Kuei Hsieh, George Anthony Meyer, IV, Chien-Hung Sun.
Application Number | 20120037344 12/854637 |
Document ID | / |
Family ID | 45563951 |
Filed Date | 2012-02-16 |
United States Patent
Application |
20120037344 |
Kind Code |
A1 |
Meyer, IV; George Anthony ;
et al. |
February 16, 2012 |
FLAT HEAT PIPE HAVING SWIRL CORE
Abstract
A flat heat pipe having a swirl core includes a flat sealed
casing having smooth inner walls, a working fluid filled within the
flat sealed casing, and a swirl core disposed along a central axis
of the flat sealed casing to support upper and lower inner walls of
the flat sealed casing. Two airflow channels are formed between the
swirl core and left and right inner walls of the flat sealed casing
for allowing vapors of the working fluid to flow through. The swirl
core is made by winding a metallic woven mesh in at least two
circles for allowing the working fluid to flow through. A center of
the swirl core is formed with a reflow channel. By this
arrangement, the swirl core is used as a wick structure for
allowing the working fluid to flow through, thereby saving the cost
and time for manufacturing the wick structure.
Inventors: |
Meyer, IV; George Anthony;
(Morgan Hill, CA) ; Sun; Chien-Hung; (Zhongli
City, TW) ; Chen; Chieh-Ping; (Zhongli City, TW)
; Hsieh; Ming-Kuei; (Zhongli City, TW) |
Assignee: |
CELSIA TECHNOLOGIES TAIWAN,
I
|
Family ID: |
45563951 |
Appl. No.: |
12/854637 |
Filed: |
August 11, 2010 |
Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
F28D 15/0233 20130101;
H01L 23/427 20130101; F28F 13/12 20130101; F28D 15/046 20130101;
H01L 2924/0002 20130101; H01L 2924/00 20130101; H01L 2924/0002
20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/04 20060101
F28D015/04 |
Claims
1. A flat heat pipe having a swirl core, including: a flat sealed
casing having smooth inner walls; a working fluid filled within the
flat sealed casing; and a swirl core disposed along a central axis
of the flat sealed casing to support upper and lower inner walls of
the flat sealed casing, two airflow channels being formed between
the swirl core and left and right inner walls of the flat sealed
casing for allowing vapors of the working fluid to flow through,
the swirl core being made by winding a metallic woven mesh in at
least two circles for allowing the working fluid to flow through, a
center of the swirl core being formed with a reflow channel.
2. The flat heat pipe having a swirl core according to claim 1,
wherein the flat heat pipe has an evaporating section and a
condensing section away from the evaporating section, the vapors of
the working fluid flow from the evaporating section to the
condensing section through the two airflow channels and the smooth
inner walls of the flat sealed casing.
3. The flat heat pipe having a swirl core according to claim 2,
wherein a small portion of the vapors of the working fluid flow
from the condensing section back to the evaporating section through
the reflow channel.
4. The flat heat pipe having a swirl core according to claim 3,
wherein a gap is formed between adjacent two circles of the
metallic woven mesh.
5. The flat heat pipe having a swirl core according to claim 4,
wherein the working fluid flows from the condensing section back to
the evaporating section along the swirl core.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat pipe, in particular
to a flat heat pipe having a swirl core.
[0003] 2. Description of Prior Art
[0004] With the advancement of science and technology, the power
and performance of electronic elements have increased to a greater
extent, resulting in the generation of a huge amount heat during
the operation of electronic elements. If the heat is not dissipated
to the outside immediately and accumulated in the electronic
elements, the working temperature of the electronic elements will
be raised to such a high extent as to deteriorate the performance.
In view of this, the manufacturers in this art continuously propose
various heat-dissipating devices for electronic elements. Heat pipe
is one of the common heat-dissipating devices.
[0005] The conventional heat pipe is substantially formed into a
hollow pipe. The inner walls of the heat pipe are arranged with a
wick structure made of a metallic woven mesh or metallic sintered
power. The internal space of the heat pipe is filled with a working
fluid. After being subjected to a vacuum-pumping process and a
sealing process, a finished heat pipe can be obtained. The heat
pipe is divided into an evaporating section brought into thermal
contact with an electronic heat-generating element and a condensing
section away from the evaporating section. The working fluid
located in the evaporating section absorbs the heat of the
electronic heat-generating element and is vaporized. The vapors of
the working fluid flow toward the condensing section. After being
heat-exchanged with the outside of the condensing section, the
vapors of the working fluid condense into liquid and flows back to
the evaporating section. With the circulation and phase change of
the working fluid in the heat pipe, the heat of the electronic
heat-generating element can be conducted to other place.
[0006] Since the modern electronic devices are made more and more
compact, the conventional heat pipe may occupy a relatively larger
height and space in such a compact electronic device. In view of
this, a flat heat pipe is proposed. The interior of the flat heat
pipe is substantially the same as that of the conventional tubular
heat pipe. The only difference between the flat heat pipe and the
conventional tubular heat pipe lies in that: the casing of the flat
heat pipe is pressed to be flattened in order to reduce its height
and space occupied in the height-wise direction. In this way, the
requirements for compact design of the heat pipe can be
conformed.
[0007] However, the above conventional flat heat pipe has the
following problems. When the casing is pressed to be flattened, the
wick structure arranged on the inner walls of the casing may be
cracked or broken due to external forces, especially when the wick
structure is made of sintered metallic powder. As a result, the
flowing path of the working fluid in the wick structure becomes
discontinuous, so that the reflow rate of the working fluid is
affected. On the other hand, since the wick structure is arranged
on the inner walls of the casing and the vapors of the working
fluid flow to the condensing section through the space between the
casing and the wick structure, the speed of the vapors flowing on a
rugged porous surface of the wick structure is certainly lower than
that flowing on a smooth surface. Thus, the arrangement of the wick
structure inevitably makes the flowing speed of the vapors unable
to be optimized. Further, in order to manufacture the wick
structure, it is necessary to arrange a metallic woven mesh or
metallic powder on the inner walls of the casing and perform a
sintering process to make the wick structure to be adhered to the
inner walls, which needs more materials and a longer procedure.
[0008] Therefore, it is an important issue for the present Inventor
to solve the aforesaid problems in prior art.
SUMMARY OF THE INVENTION
[0009] The present invention is to provide a flat heat pipe having
a swirl core, in which the swirl core made by winding a metallic
woven mesh serves as a wick structure for allowing a working fluid
to flow through. Thus, the cost and time for manufacturing the flat
heat pie are saved while maintaining a good heat-conducting effect
and confirming to the requirements for compact design.
[0010] The present invention provides a flat heat pipe having a
swirl core, including: a flat sealed casing having smooth inner
walls; a working fluid filled within the flat sealed casing; and a
swirl core disposed along a central axis of the flat sealed casing
to support upper and lower inner walls of the flat sealed casing,
two airflow channels being formed between the swirl core and left
and right inner walls of the flat sealed casing for allowing vapors
of the working fluid to flow through, the swirl core being made by
winding a metallic woven mesh in at least two circles for allowing
the working fluid to flow through, a center of the swirl core being
formed with a reflow channel.
[0011] In comparison with prior art, the present invention has
advantageous features as follows:
[0012] Since the swirl core of the present invention is made by
winding the metallic woven mesh in at least two circles for
allowing the working fluid to flow through, the material and time
for manufacturing the wick structure by a sintering process in
prior art can be saved.
[0013] Since two airflow channels are formed between the swirl core
and left and right inner walls of the flat sealed casing for
allowing vapors of the working fluid to flow through, the vapors of
the working fluid flow on the smooth inner walls of the flat sealed
casing. Thus, the speed of vapor flowing on the smooth surface is
greater than that flowing on a rugged porous surface of the
traditional wick structure. In this way, the heat-conducting effect
of the flat heat pipe can be increased.
[0014] On the other hand, in the conventional heat pipe, the vapors
of the working fluid flow from the evaporating section to the
condensing section in only one direction. The amount of vapors in
the evaporating section is often greater than that in the
condensing section, so that a vapor pressure difference is
generated between the evaporating section and the condensing
section. If the vapors are accumulated in the condensing section
due to the insufficient condensing rate, the flowability of the
vapors in the heat pipe will be deteriorated and in turn the
heat-conducting effect of the heat pipe will be affected. In view
of this, according to the present invention, the swirl core is made
by winding the metallic woven mesh in at least two circles and a
reflow channel is formed in the center of the swirl core. Such a
reflow channel allows a small portion of the vapors accumulated in
the condensing section to flow back to the evaporating section if
necessary. In this way, the flowability of the vapors flowing from
the evaporating section toward the condensing section may not be
deteriorated.
BRIEF DESCRIPTION OF DRAWING
[0015] FIG. 1 is an exploded perspective view of the present
invention;
[0016] FIG. 2 is an assembled perspective view of the present
invention;
[0017] FIG. 3 is an axial cross-sectional view of the present
invention;
[0018] FIG. 4 is a side cross-sectional view of the present
invention; and
[0019] FIG. 5 is a schematic view showing the operation of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The detailed description and technical contents of the
present invention will become apparent with the following detailed
description accompanied with related drawings. It is noteworthy to
point out that the drawings is provided for the illustration
purpose only, but not intended for limiting the scope of the
present invention.
[0021] Please refer to FIGS. 1 to 4. The present invention provides
a flat heat pipe 1 having a swirl core for conducting the heat of
an electronic heat-generating element 100 (as shown in FIG. 5). It
can be seen from FIG. 4 that the flat heat pipe 1 includes a flat
sealed casing 10, a working fluid 20 (indicated by dotted lines),
and a swirl core 30. Based on the functionality in heat conduction,
as shown in FIG. 5, the flat heat pipe 1 is divided into an
evaporating section 2 brought into thermal contact with the
electronic heat-generating element 100 and a condensing section 3
away from the evaporating section 2.
[0022] The flat sealed casing 10 is made of metallic materials
having good heat conductivity. The flat sealed casing 10 has smooth
inner walls and no grooves are provided on the inner walls. For
better illustration, the inner walls of the flat sealed casing 10
are divided into an upper inner wall 11, a lower inner wall 12, a
left inner wall 13 and a right inner wall 14 based on a central
axis of the flat heat pipe 1.
[0023] The working fluid 20 is filled within the flat sealed casing
10. With the circulation and phase change of the working fluid 20
in the flat sealed casing 10, the flat heat pipe 1 can continuously
conduct the heat of the electronic heat-generating element 100 to
the outside. As for the heat-conducting mechanism of the working
fluid 20 by means of its phase change, it will be described in more
detail later.
[0024] As shown in FIG. 3, the swirl core 30 is disposed along the
central axis of the flat sealed casing 10 for supporting the upper
inner wall 11 and the lower inner wall 12 (as shown in FIG. 4)
because the strength of the flat heat pipe 1 is lowest along the
central axis. Thus, the arrangement of the swirl core 30 in the
central axis generates a portion of supporting effect to prevent
the central portion of the flat heat pipe 1 to be sunken due to
external forces.
[0025] Two airflow channels 15 and 16 are respectively formed
between the swirl core 30 and the left inner wall 13 and the right
inner wall 14 for allowing the vapors of the working fluid 20 to
flow from the evaporating section 2 to the condensing section 3 (as
shown in dotted arrows in FIG. 5). Since the vapors flow on the
smooth inner walls of the flat sealed casing 10, the flowing speed
of the vapors is greater than that on a rugged porous surface of
the traditional wick structure. Thus, the heat-conducting
efficiency of the flat heat pipe 1 is enhanced greatly.
[0026] The swirl core 30 is made by winding a metallic woven mesh
31 in at least two circles for allowing the working fluid 30 to
flow through. It can be seen from FIG. 4 that the swirl core 30 is
made by winding the metallic woven mesh 31 in three circles. A gap
G is formed between adjacent two circles of the metallic woven mesh
31. In other word, adjacent two circles of the metallic woven mesh
31 are not tightly adhered to each other. The gap G allows a small
portion of the vapors of the working fluid 20 to flow from the
condensing section 3 back to the evaporating section 2.
[0027] It should be noted that, according to the present invention,
the center of the swirl core 30 is formed with a reflow channel 32,
so that the center of the swirl core 30 is not solid. The reflow
channel 32 also allows a small portion of the vapors to flow from
the condensing section 3 back to the evaporating section 2 (as
shown in the arrows in FIG. 5), thereby preventing the accumulation
of excess vapors in the condensing section 3 to deteriorate the
flowability of the vapors in the flat heat pipe 1.
[0028] With reference to FIG. 5, the operating principle of the
flat heat pipe 1 of the present invention will be described as
follows. The evaporating section 2 is brought into thermal contact
with the electronic heat-generating element 100. The working fluid
near the evaporating section 2 absorbs the heat generated by the
electronic heat-generating element 100 and is vaporized. The
thus-formed vapors rapidly flow to the condensing section 3 through
the airflow channels 15 and 16 formed between the swirl core 30 and
the left inner wall 13 and the right inner wall 14 of the flat
sealed casing 10. Since the vapors flow on the smooth inner walls
of the flat sealed casing 10 toward the condensing section 3, the
flowing speed of the vapors of the working fluid 20 is increased
greatly, thereby generating a better heat-conducting effect.
[0029] A heat-dissipating fin asset 200 may be further connected to
the outer surface of the condensing section 3 of the flat heat pipe
1, thereby dissipating the heat of the condensing section 3 to the
outside. If the vapors are accumulated in the condensing section 3
because of the insufficient condensing rate of the vapors, the
vapor pressure between the evaporating section 2 and the condensing
section 3 will force a portion of the vapors in the condensing
section 3 to flow back to the evaporating section 2 through the
reflow channel 32, thereby preventing the accumulation of excess
vapors in the condensing section 3 to deteriorate the flowability
of the vapors in the flat heat pipe 1.
[0030] In comparison with prior art, the present invention has
advantageous features as follows:
[0031] Since the swirl core 30 of the present invention is made by
winding the metallic woven mesh 31 in at least two circles for
allowing the working fluid 20 to flow through, the material and
time for manufacturing the wick structure by a sintering process in
prior art can be saved.
[0032] Since the two airflow channels 15 and 16 are formed between
the swirl core 30 and left and right inner walls 13 and 14 of the
flat sealed casing 10 for allowing vapors of the working fluid 20
to flow through, the vapors of the working fluid 20 flow on the
smooth inner walls of the flat sealed casing 10. Thus, the speed of
vapor flowing on the smooth surface is greater than that flowing on
a rugged porous surface of the traditional wick structure. In this
way, the heat-conducting effect of the flat heat pipe 1 can be
increased.
[0033] On the other hand, in the conventional heat pipe, the vapors
of the working fluid flow from the evaporating section to the
condensing section in only one direction. The amount of vapors in
the evaporating section is often greater than that in the
condensing section, so that a vapor pressure difference is
generated between the evaporating section and the condensing
section. If the vapors are accumulated in the condensing section
due to the insufficient condensing rate, the flowability of the
vapors in the heat pipe will be deteriorated and in turn the
heat-conducting effect of the heat pipe will be affected. In view
of this, according to the present invention, the swirl core 30 is
made by winding the metallic woven mesh 31 in at least two circles
and a reflow channel 32 is formed in the center of the swirl core
30. Such a reflow channel 32 allows a small portion of the vapors
accumulated in the condensing section 3 to flow back to the
evaporating section 2. In this way, the flowability of the vapors
flowing from the evaporating section 2 toward the condensing
section 3 may not be deteriorated.
[0034] Although the present invention has been described with
reference to the foregoing preferred embodiments, it will be
understood that the invention is not limited to the details
thereof. Various equivalent variations and modifications can still
occur to those skilled in this art in view of the teachings of the
present invention. Thus, all such variations and equivalent
modifications are also embraced within the scope of the invention
as defined in the appended claims.
* * * * *