U.S. patent application number 11/059545 was filed with the patent office on 2006-08-17 for heat pipe.
This patent application is currently assigned to Yuh-Cheng Chemical Ltd.. Invention is credited to Ying-Chieh Liu.
Application Number | 20060180296 11/059545 |
Document ID | / |
Family ID | 36814477 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060180296 |
Kind Code |
A1 |
Liu; Ying-Chieh |
August 17, 2006 |
Heat pipe
Abstract
A heat pipe includes a hollow envelope, a wick bonded to an
inner wall of the envelope, and a working fluid contained in a
chamber inside the envelope. The wick is formed of sintering a
plurality of first particles, which are made from copper, and a
plurality of second particles, which are made from a material
selected from the group consisting of silver, bismuth, indium, tin,
and alloys thereof, together.
Inventors: |
Liu; Ying-Chieh; (Taoyuan
County, TW) |
Correspondence
Address: |
BROWDY AND NEIMARK, P.L.L.C.;624 NINTH STREET, NW
SUITE 300
WASHINGTON
DC
20001-5303
US
|
Assignee: |
Yuh-Cheng Chemical Ltd.
Taipei City
TW
|
Family ID: |
36814477 |
Appl. No.: |
11/059545 |
Filed: |
February 17, 2005 |
Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
B22F 5/106 20130101;
B22F 3/10 20130101; B22F 1/0003 20130101; B22F 2998/10 20130101;
F28F 2255/18 20130101; F28D 15/046 20130101; B22F 2998/10
20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Claims
1. A heat pipe comprising: a hollow envelope having an inside wall
and a chamber; a wick containing a plurality of first particles and
a plurality of second particles sintered together, said wick being
provided at the inside wall of said envelope; wherein said first
particles are substantially made from copper and said second
particles are made from a material selected from the group
consisting of silver, bismuth, indium, tin, and alloys thereof; and
a working fluid contained in the chamber of said envelope.
2. The heat pipe as claimed in claim 1, wherein said second
particles have a particle size ranging from 0.01 .mu.m to 15
.mu.m.
3. The heat pipe as claimed in claim 1, further comprising an
intermediate layer arranged between the inside wall of said
envelope and said wick, said intermediate layer being made from a
material selected from the group consisting of silver, bismuth,
indium, tin, and alloys thereof.
4. The heat pipe as claimed in claim 1, wherein said wick has a
tubular shape; the heat pipe further comprises a netting provided
at an inner side of said wick.
5. The heat pipe as claimed in claim 4, wherein said netting has a
mesh size ranging from 100 meshes to 325 meshes.
6. The heat pipe as claimed in claim 4, wherein said netting is
made from copper-silver-phosphorus alloy.
7. The heat pipe as claimed in claim 4, wherein said netting is
coated with a layer of coating made from a material selected from
the group consisting of bismuth, indium, tin, and alloys
thereof.
8. The heat pipe as claimed in claim 1, wherein said envelope is
made from a material selected from the group consisting of copper
and copper-silver alloy.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates a heat pipe and more
particularly, to such a heat pipe, which is easy and inexpensive to
manufacture.
[0003] 2. Description of the Related Art
[0004] A regular heat pipe is generally comprised of a pipe body, a
wick, and a working fluid. The pipe body is made from copper or
copper alloy. The wick is sintered from copper powder and provided
at the inside wall of the pipe body. Because the wick is a porous
member having crevices, the working fluid can flow in the wick to
achieve heat transfer by means of a capillary effect.
[0005] However, because the melting point of copper is as high as
1083.degree. C., it is necessary to increase the temperature to
about 900-1000 .degree. C. when sintering copper powder. This
manufacturing process requires much working time, resulting in a
high manufacturing cost.
SUMMARY OF THE INVENTION
[0006] The present invention has been accomplished under the
circumstances in view. It is one object of the present invention to
provide a heat pipe, which is easy to fabricate, thereby
effectively shorting the working time and reducing the
manufacturing cost.
[0007] To achieve this object of the present invention, the heat
pipe comprises a hollow envelope having an inside wall and a
chamber, a wick containing a plurality of first particles and a
plurality of second particles sintered together, and a working
fluid contained in the chamber of the envelope. The wick is bonded
to the inside wall of the envelope. The first particles are
substantially made from copper and the second particles are made
from a material selected from the group consisting of silver,
bismuth, indium, tin, and alloys thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. I is a perspective view of a heat pipe according to the
present invention.
[0009] FIG. 2 is a cross-sectional view taken in an enlarged scale
along line 2-2 of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Referring to FIGS. 1 and 2, a heat pipe 10 is shown
comprised of a hollow envelope 20, an intermediate layer 30, a wick
40, a netting 50, and a working fluid 60.
[0011] The hollow envelope 20 has a tubular shape, and is made from
copper or its alloy, for example copper-silver alloy. The envelope
20 defines a chamber 22 therein. The intermediate layer 30, the
wick 40 and the netting 50 are provided in proper order at the
inside wall of the envelope 20.
[0012] The intermediate layer 30 is formed of silver on the inside
wall of the envelope 20 by electroplating. The intermediate layer
30 has a tubular shape. Alternatively, the intermediate layer 30
can be made from bismuth, indium, tin, or their alloy.
[0013] The wick 40 comprises a plurality of first particles 41 and
a plurality of second particles 42. The first particles 41 and the
second particles 42 are sintered together. The wick 40 has a
tubular shape. The first particles 41 are substantially made from
copper or its alloy. The second particles 42 are made from silver
or its alloy. Actually, the second particles 42 can be made from
silver, bismuth, indium, tin, or their alloy. The first particles
41 and the second particles 42 have particle size within about 0.01
.mu.m to 15 .mu.m.
[0014] The netting 50 is provided at the inner side of the wick 40.
The netting 50 is made from copper-silver-phosphorus alloy in the
shape of a tube. The mesh size of the netting 50 can be within
about 100-325 meshes.
[0015] The working fluid 60 can be pure water or any of a variety
of other solutions.
[0016] The working fluid 60 is received inside the envelope 20. By
means of a capillary effect, the working fluid 60 is adhered to
crevices in the wick 40 and the netting 50.
[0017] Because the melting point of silver is 960.5 .degree. C., it
simply needs to increase the temperature to about 700-900 .degree.
C. when sintering the mixture of the first particles 41 and the
second particles 42. When sintered, the second particles 42 are
bonded to the first particles 41. The second particles 42 act as a
bonding agent. Further, silver content lowers the melting point of
the netting 50, allowing quick bonding of the wick 40 and the
netting 50 during sintering. Silver in the intermediate layer 30
acts as a bonding agent, for enabling the wick 40 to be bonded to
the envelope 20 at a low temperature (700-900.degree. C.).
[0018] In other words, the wick 40 contains a certain amount of the
second particles 42 that lowers the working temperature of
sintering. Silver in the intermediate layer 30 enables the wick 40
to be positively bonded to the envelope 20 below 900.degree. C. The
silver-contained netting 50 can also be positively bonded to the
wick 40 below 900.degree. C.
[0019] Therefore, the heat pipe according to the present invention
can be made at a relatively lower working temperature. The
fabrication procedure of the heat pipe according to the present
invention is simple. Further, the invention saves much time in
raising and lowering the temperature, thereby reducing the
manufacturing cost. Further, the invention also saves much
sintering time.
[0020] Further, the intermediate layer 30 is not imperative, and
can be eliminated.
[0021] The wick 40, which contains the second particles 42, can be
bonded to the envelope 20 by itself at a relatively lower
temperature (700-900.degree. C.). The netting 50 enhances the
flowing and capillary action of the working fluid 60. However, the
netting 50 can also be eliminated subject to different
requirements.
[0022] Further, the melting point of bismuth is 271.3.degree. C.,
the melting point of tin is 231.8.degree. C., and the melting point
of indium is 156.6.degree. C. These melting points are all lower
than copper's melting point 1083.degree. C. Therefore, these
materials can be used to replace the role of silver in the wick or
the intermediate layer to lower the working temperature during
sintering and to achieve the effects of the present invention.
Further, phosphorus stabilizes the chemical properties of the
netting. In addition, the netting 50 can be covered with a layer of
coating material, which can be prepared from bismuth, indium, tin,
or their alloy, for enabling the wick 40 and the netting 50 to be
easily bonded together at a low temperature.
* * * * *