U.S. patent application number 11/611885 was filed with the patent office on 2008-06-19 for heat pipe with advanced capillary structure.
Invention is credited to Jian-Dih Jeng.
Application Number | 20080142196 11/611885 |
Document ID | / |
Family ID | 39525742 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080142196 |
Kind Code |
A1 |
Jeng; Jian-Dih |
June 19, 2008 |
Heat Pipe with Advanced Capillary Structure
Abstract
A heat pipe has a wick of capillary structure formed on the
inner wall of the heat pipe so as to form a working fluid path in
the heat pipe, wherein the wick of the capillary structure is
un-ringlike or various radially. The cross-section of the working
fluid path in the heat pipe is in various shapes, such as in a
shape of polygon, poly-petal, poly-serration, arc or semicircle.
Thus, the thickness of the capillary wick structure on the inner
wall of the heat pipe is various due to the shape of the working
fluid path.
Inventors: |
Jeng; Jian-Dih; (Linkou
Township, TW) |
Correspondence
Address: |
HDSL
4331 STEVENS BATTLE LANE
FAIRFAX
VA
22033
US
|
Family ID: |
39525742 |
Appl. No.: |
11/611885 |
Filed: |
December 17, 2006 |
Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
F28D 15/0233 20130101;
F28D 15/046 20130101; F28D 15/0266 20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/02 20060101
F28D015/02 |
Claims
1. A heat pipe with a wick of capillary structure, in which a
capillary structure is formed on the inner wall of the heat pipe so
as to form a working fluid path, wherein of the capillary wick
structure is un-ringlike or various radially.
2. The heat pipe as claimed in claim 1, wherein the cross-sectional
of working fluid path in the heat pipe is a shape of polygon.
3. The heat pipe as claimed in claim 1, wherein the cross-sectional
of working fluid path in the heat pipe is a shape of
poly-petal.
4. The heat pipe as claimed in claim 1, wherein the cross-sectional
of working fluid path in the heat pipe is a shape of
poly-serration.
5. The heat pipe as claimed in claim 1, wherein the capillary wick
structure is formed at the part of the semicircle, or arc of the
heat pipe, or gradually increases the thickness of wick, or
increases by step.
6. The heat pipe as claimed in claim 1, wherein the working fluid
path of the present heat pipe is a combination of sections with
different radius, such as two sections respectively, or
multi-sections with different radius.
7. The heat pipe as claimed in claim 1, wherein a reinforced layer
is provided to be formed at the inner wall of the heat pipe to
incorporate into the capillary wick structure for reinforcing the
capillary wick structure and enhancing the capillary transfer
function thereof.
8. The heat pipe as claimed in claim 7, wherein a reinforced layer
is a mesh layer.
9. The heat pipe as claimed in claim 1, wherein a reinforced layer
is fibers.
10. The heat pipe as claimed in claim 1, wherein a reinforced layer
is a porous material.
11. The heat pipe as claimed in claim 1, wherein a reinforced layer
is a plurality of slots on the inner wall of the heat pipe.
12. The heat pipe as claimed in claim 1, wherein the heat pipe is
further pressed in to a flat tube.
13. The heat pipe as claimed in claim 1, wherein heat pipe is
further bended into a continuous U-shape tube.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a heat pipe with a capillary
structure, and in particular, relates to a heat pipe with a wick of
a capillary structure at the inner wall of the pipe, in which the
thickness of the wick is un-ringlike or various radially.
[0003] 2. Description of the Related Art
[0004] A conventional method for manufacturing a heat pipe
comprises the steps of positioning a mandrel in a tube, filling
metal powder into the space between the mandrel and inner wall of
the tube, sintering the metal powder and removing out the mandrel.
A heat pipe 10 with a capillary structure is thus formed with a
concentric and ringlike wick 16, as shown in FIG. 1. The heat pipe
is performed further processes for the specific uses, such as
cutting, bending, or pressing processes. The capillary wick
structure is unavoidably damaged during the processes and the
properties thereof is thus adversely affected, for example, the
capillarity of the heat pipe is decreased, which results in a
decrease of the performance of the vapor and working fluid in the
heat pipe. Thus, the application of the heat pipe is limited.
[0005] Therefore, a heat pipe is demanded, in which the damage to
the capillary wick of a heat pipe is limited during the
manufacturing processes.
SUMMARY OF THE INVENTION
[0006] The present invention is to provide a heat pipe with a wick
of capillary structure, in which the thickness of the capillary
wick structure is various radially. The cross-sectional of working
fluid path in the heat pipe is in various shapes, such as in a
shape of polygon, poly-petal, poly-serration, arc, or semicircle.
Thus, the thickness of the capillary wick structure on the inner
wall of the heat pipe is various due to the shape of the working
fluid path.
[0007] In one embodiment of the present invention, the capillary
wick structure is at part of the axial semicircle or arc of the
heat pipe. In another one embodiment of present invention, the
working fluid path of the present heat pipe is a combination of
sections with different radius, such as two sections respectively
with different radius.
[0008] A reinforced layer, such as mesh, fibers, a porous material,
is provided to be formed at the inner wall of the heat pipe to
incorporate into the capillary wick structure for reinforcing the
capillary wick structure and enhancing the capillary transferring
function thereof.
DESCRIPTION OF THE DRAWINGS
[0009] The invention can be more fully understood by reading the
subsequent detailed description in conjunction with the examples
and references made to the accompanying drawings, wherein:
[0010] FIG. 1 is a perspective view of a conventional heat pipe
with a capillary wick;
[0011] FIG. 2 is a perspective view of an embodiment of a heat pipe
with a capillary wick according to the present invention;
[0012] FIG. 3 is a perspective view of another embodiment of a heat
pipe with a capillary wick according to the present invention;
[0013] FIG. 4 is a perspective view of another embodiment of a heat
pipe with a capillary wick according to the present invention;
[0014] FIG. 5 is a perspective view of another embodiment of a heat
pipe with a capillary wick according to the present invention;
[0015] FIG. 6 is a perspective view of another embodiment of a heat
pipe with a capillary wick according to the present invention;
[0016] FIG. 7A is a perspective view of an embodiment of a mandrel
for using in manufacturing of a capillary wick according to the
present invention;
[0017] FIG. 7B is a perspective view of another embodiment of a
mandrel for using in manufacturing of a capillary wick according to
the present invention;
[0018] FIG. 8 is a perspective view of another embodiment of a heat
pipe with a capillary wick according to the present invention;
[0019] FIG. 8A is a perspective view of another embodiment of a
heat pipe with a capillary wick according to the present
invention;
[0020] FIG. 8B is a perspective view of another embodiment of a
heat pipe with a capillary wick according to the present
invention;
[0021] FIG. 9 is a perspective view of another embodiment of a heat
pipe with a capillary wick according to the present invention;
[0022] FIG. 10 is a perspective view of another embodiment of a
heat pipe with a capillary wick according to the present
invention;
[0023] FIG. 11 is a perspective view of a continuous U-shape tube
made from the heat pipe of FIG. 8 according to the present
invention;
DETAILED DESCRIPTION OF THE INVENTION
[0024] The present invention is to provide a heat pipe 20 with a
capillary wick structure 26. Referring to FIG. 2, a mandrel of
rectangular shape (not shown in the drawings) is inserted into a
tube 22 for forming a working fluid path 24 in the heat pipe. A
metal powder is filled into the space between the mandrel and the
inner wall of the tube. After sintering process is complete, the
metal powder is sintered to form a capillary wick structure 26 on
the inner wall of the tube. Thus, a heat pipe 20 with a working
fluid path 24 of rectangular shape in cross section is constructed.
This heat pipe 20 with rectangular working fluid path 24 is able to
be pressed into a flat tube without damaging the capillary
structure during the pressing process because the thickness of the
capillary wick 26 is radially various.
[0025] As shown in FIG. 3, a heat pipe 30 with a penta-petalous
working fluid path 34 is constructed by the above described method.
A capillary wick 36 is formed on the tube wall with a radially
various thickness. When the heat pipe 30 is pressed into a flat
tube, the thinner portion of the wick 36 is born with the stress
damage. However, the thicker portion of the wick 36 is not damaged
and keeps the original axial capillarity for the application of the
heat pipe 30, such as used as a heat pipe for vaporization.
[0026] A heat pipe 40 with an octagonal working fluid path 44, as
shown in FIG. 4, is constructed by the above described method. The
thickness of the wick 46 is various according to the shape of the
octagonal mandrel. Thus, when the heat pipe 40 is pressed into a
flat tube, the working fluid path 44 is deformed into a
poly-serration shape in cross section, as shown in FIG. 5. Due to
the octagonal shape of the working fluid path, the damage to the
capillary wick structure is limited during the pressing
process.
[0027] As described above, the non-circle mandrel is provided to
form a capillary wick with different thickness radially. The
different thickness of wicks is provided to meet the different
requirements in different application of the present heat pipes.
However, when a heat pipe is pressed for forming a specific shape,
the capillary wick is stressed and thus is damaged. To minimize
this possible defect to the capillary wick, the present invention
is to provide a reinforced capillary structure, as shown in FIG. 6.
A reinforce material 67 is applied to the inner wall of the tube
60. The reinforced material is a mesh, fibers, a porous material
and the likes, which are well known to the skilled in the art.
Optionally, a plurality of slots can be formed on the inner wall
for strengthening the capillary wick structure. The reinforced
material or the plurality of the slots are able to reinforce the
capillary wicks 66, especially in the case that the working fluid
path 64 is non-circle shape in cross-section. Particularly, when
the thickness of the capillary wick 66 is various radially, the
reinforced means is able to compliment the thinner portion of the
capillary wick 66 to be against the pressing stress.
[0028] For a various requirements of heat pipes, the mandrel can be
in various shapes, such as described above, in rectangular,
penta-petalous, octagonal and the likes. Optionally, the mandrel is
able to be a combination of sections with different radius, as
shown in FIG. 7. In one embodiment of the FIG. 7A, one end 71a of
the mandrel 71 is smaller than the other end 71b, wherein the end
71a is in a conical shape and gradually extends toward the end 71b.
The other embodiment as shown in FIG. 7B, the mandrel 73 is a
combination of two sections, or multi-sections with different
radius. When the mandrel of FIGS. 7A and 7B are used to manufacture
heat pipes, the thickness of capillary structure on the inner wall
of the tube is axially various at the ends thereof. Thus, this heat
pipe is able to be used for specific applications.
[0029] In general, heat pipes contact a heat source at one side
only. Thus, the capillary wick structure can be sintered at one
side of the tube for meeting the high heat transfer efficiency
request. As shown in FIG. 8, the capillary structure 86 is at the
half side of the heat pipe 80 for concentrating the capillary
function. The working fluid path 84 is at the other half side for
the vapor of working fluid in the heat pipe 80. A reinforced layer
87, such as in mesh, fibers, a porous material, is formed at all
over the inner wall of the heat pipe 80. The reinforced layer 87 is
performed as a secondary capillary structure for enhancing the
radial capillary function in heat pipe 80. The heat pipe 80 can be
further conducted to be pressed into a flat tube, as shown in FIGS.
8a and 8b. In FIG. 8a, the pressed capillary structure 86a is thus
at the horizontal side of the heat pipe 80a. In FIG. 8b, the
pressed capillary structure 86b is thus at the longitudinal side.
The pressed secondary capillary layers 87a, 87b still cover the
inner wall the heat pipe 80a and 80b.
[0030] Referring to FIG. 9, the curve heat pipe 90 is shown. Since
the capillary structure will be significantly damaged if a tube
with capillary sintering layer is bended. In such a situation, the
tube is conducted a bending process and then, is sintering a wick
of capillary structure 96.
[0031] In another one embodiment of the present invention, a
capillary structure of a heat pipe 100 is manufactured as an
axially various thickness. As shown in FIG. 10, the thickness of
the capillary structure is gradually increased from the end 111
toward the end 112. Due to the space variation between the end 111
to end 112, the working fluid path 140 and the capillary wick 160
can effectively transfer the heat via the capillary wick 160 and
the working fluid path 140.
[0032] FIG. 11 shows a continuous U-shape tube 110 made from a heat
pipe 80 of the embodiment of FIG. 8 according to the present
invention. In conventional, when a heat pipe is subjected to a
180.degree. bending process, the capillary structure is damaged and
the thermal resistance is very high. Thus, the continuous U-shape
tube made from a conventional heat pipe is unable to perform the
desired heat transfer function. The present invention is to provide
a method to avoid the defeat to the capillary structure of heat
pipe. In present invention, a tube is bended to form a continuous
180.degree. U-shape tube and then, is sintered to form a wick of
capillary structure, such as mesh, fibers, porous layer, as shown
in FIG. 8, so as to afford the capillary function to the tube.
[0033] Accordingly, the present invention provides a novel mandrel
for using in the sintering of the capillary structure of a heat
pipe. Due to the various shape of the mandrel, the capillary wick
sintering thereby is in various thicknesses. Thus, the pressing
damage to the capillary structure will be minimized
[0034] As is understood by a person skilled in the art, the
foregoing preferred embodiments of the present invention are
illustrative of the present invention rather than limiting of the
present invention. It is intended that various modifications and
similar arrangements be included within the spirit and scope of the
appended claims, the scope of which should be accorded the broadest
interpretation so as to encompass all such modifications and
similar structures.
* * * * *