U.S. patent application number 12/903510 was filed with the patent office on 2011-08-11 for heating pipe.
This patent application is currently assigned to TSINGHUA UNIVERSITY. Invention is credited to SHOU-SHAN FAN, KAI-LI JIANG, JIA-PING WANG, RUI XIE.
Application Number | 20110194845 12/903510 |
Document ID | / |
Family ID | 44353809 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110194845 |
Kind Code |
A1 |
WANG; JIA-PING ; et
al. |
August 11, 2011 |
HEATING PIPE
Abstract
A heating pipe includes a guide pipe, a connector and an outer
pipe. A connector is disposed at one end of the guide pipe. The
outer pipe surrounds the guide pipe and is positioned apart from
the guide pipe. The heating pipe further includes two sealed
elements positioned apart from each other and between the guide
pipe and the outer pipe. The guide pipe, the outer pipe and the two
sealed elements define a sealed room. A heating module is disposed
in the sealed room.
Inventors: |
WANG; JIA-PING; (Beijing,
CN) ; XIE; RUI; (Beijing, CN) ; JIANG;
KAI-LI; (Beijing, CN) ; FAN; SHOU-SHAN;
(Beijing, CN) |
Assignee: |
TSINGHUA UNIVERSITY
Beijing
CN
HON HAI PRECISION INDUSTRY CO., LTD.
Tu-Cheng
TW
|
Family ID: |
44353809 |
Appl. No.: |
12/903510 |
Filed: |
October 13, 2010 |
Current U.S.
Class: |
392/468 |
Current CPC
Class: |
F24H 1/142 20130101;
H05B 3/42 20130101 |
Class at
Publication: |
392/468 |
International
Class: |
F24H 1/10 20060101
F24H001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2010 |
CN |
201010111802.1 |
Claims
1. A heating pipe comprising: a guiding pipe; an outer pipe
surrounding the guiding pipe and apart from the guiding pipe; a
connector disposed at one end of the guiding pipe and extending
beyond the outer pipe; two sealed elements apart from each other
and sealed between an outer surface of the guiding pipe and an
inner surface of the outer pipe, wherein the guiding pipe, the
outer pipe, and the two sealed elements cooperatively define a
sealed room; and a heating module positioned in the sealed
room.
2. The heating pipe of claim 1, wherein the connector is an end
portion of the guiding pipe 100 extending beyond the outer pipe,
and an inner diameter of the connector is substantially the same as
an inner diameter of the guiding pipe.
3. The heating pipe of claim 1, wherein the connector is a separate
pipe connected with the guiding pipe.
4. The heating pipe of claim 1, wherein the sealed room is in a
vacuum-like state.
5. The heating pipe of claim 1, further comprising a
heat-reflective layer located between the heating module and the
outer pipe.
6. The heating pipe of claim 5, wherein the heat-reflective layer
is located on the inner surface of the outer pipe.
7. The heating pipe of claim 6, wherein the heating module is
positioned on the outer surface of the guiding pipe and apart from
the heat-reflective layer.
8. The heating pipe of claim 5, wherein the heat-reflective layer
is made of insulative material and positioned on a surface of the
heating module.
9. The heating pipe of claim 1, wherein the heating module
comprises a heating element, a first electrode, and a second
electrode, the first electrode and the second electrode being
electrically connected with the heating element.
10. The heating pipe of claim 9, wherein the heating element
comprises a freestanding carbon nanotube structure comprising a
plurality of carbon nanotubes joined by Van der Waals attractive
force.
11. The heating pipe of claim 10, wherein the carbon nanotube
structure comprises at least one carbon nanotube film wrapping the
outer surface of the guiding pipe.
12. The heating pipe of claim 11, wherein the at least one carbon
nanotube film comprises a plurality of carbon nanotubes joined
end-to-end with each other and oriented in a substantially same
direction.
13. The heating pipe of claim 12, wherein the first electrode and
the second electrode each have a wire structure and are
substantially parallel with an axial direction of the guiding pipe,
and the carbon nanotubes in the carbon nanotube film are oriented
from the first electrode to the second electrode.
14. The heating pipe of claim 12, wherein the first electrode and
the second electrode each have a ring structure and are wound
around two opposite ends of the guiding pipe; the carbon nanotubes
in the carbon nanotube film are oriented from the first electrode
to the second electrode.
15. The heating pipe of claim 9, wherein the carbon nanotube
structure comprises at least one linear carbon nanotube structure
disposed on the outer surface of the guiding pipe.
16. A heating pipe comprising: a guiding pipe; an outer pipe
surrounding the guiding pipe and apart from the guiding pipe; a
connector disposed at one end of the guiding pipe and extending
beyond the outer pipe for connecting another pipe and allowing a
passage of fluid; two sealed elements apart from each other and
located between the guiding pipe and the outer pipe, wherein a
sealed room is cooperatively defined by the guiding pipe, the outer
pipe and the two sealed elements; and a heating module disposed in
the sealed room, the heating module comprising a heating element
comprising a carbon nanotube structure positioned on an outer
surface of the guiding pipe.
17. The heating pipe of claim 16, wherein a heat capacity per unit
area of the carbon nanotube structure is less than
2.times.10.sup.-4 J/m.sup.2*K.
18. The heating pipe of claim 16, wherein the carbon nanotube
structure comprises one linear carbon nanotube structure twisted
around the outer surface of the guiding pipe.
19. The heating pipe of claim 16, wherein the carbon nanotube
structure comprises a plurality of linear carbon nanotube
structures disposed side by side and substantially parallel with
each other on an outer surface of guiding pipe.
20. The heating pipe of claim 16, wherein the carbon nanotube
structure comprises a plurality of linear carbon nanotube
structures knitted to obtain a net structure disposed on an outer
surface of the guiding pipe.
Description
RELATED APPLICATIONS
[0001] This application claims all benefits accruing under 35
U.S.C. .sctn.119 from China Patent Application No. 201010111802.1,
filed on Feb. 8, 2010 in the China Intellectual Property Office,
the contents of which are hereby incorporated by reference. The
application is also related to copending application entitled,
"FLUID HEATER", filed ______ (Atty. Docket No. US30480).
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure generally relates to a heating
pipe.
[0004] 2. Description of Related Art
[0005] In everyday life, industry or science research, a heated
fluid is needed. Heating pipes are often used to guide and heat
fluid, such as liquid or gas.
[0006] A conventional heating pipe includes an inner pipe and an
outer pipe surrounding the inner pipe. The inner pipe and the outer
pipe define a cavity. Heat wires are disposed in the inner pipe. In
use of the conventional heating pipe, a fluid is guided in the
cavity and heated by the heating wires in the inner pipe. However,
because the fluid flowing in the cavity is disposed between the
inner pipe and the outer pipe, the outer pipe conducts heat from
the fluid to outside the heating pipe, and the heating efficiency
of the heating pipe will be adversely affected. As such, the
heating pipe has a low heating efficiency.
[0007] What is needed, therefore, is a heating pipe that can
overcome the above-described shortcomings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Many aspects of the embodiments 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
embodiments. Moreover, in the drawings, like reference numerals
designate corresponding parts throughout the several views.
[0009] FIG. 1 is an isometric view of one embodiment of a heating
pipe.
[0010] FIG. 2 is a cross-sectional view, along line II-II of FIG.
1.
[0011] FIG. 3 is an Scanning Electron Microscope (SEM) image of a
drawn carbon nanotube film.
[0012] FIG. 4 is a schematic view of carbon nanotube segments in
FIG. 3.
[0013] FIG. 5 is an SEM image of an untwisted carbon nanotube
wire.
[0014] FIG. 6 is an SEM image of a twisted carbon nanotube
wire.
[0015] FIG. 7 is an isometric view of the heating pipe of FIG. 1
with electrodes winding around an outer surface of a guide
pipe.
[0016] FIG. 8 is a schematic view of a system for testing the
heating pipe.
[0017] FIG. 9 is a relationship chart between a heating power of
the heating pipe in FIG. 1 and a temperature of a liquid flowing in
the heating pipe.
[0018] FIG. 10 is a cross-sectional view of another embodiment of a
heating pipe.
DETAILED DESCRIPTION
[0019] The disclosure is illustrated by way of example and not by
way of limitation in the figures of the accompanying drawings in
which like references indicate similar elements. It should be noted
that references to "an" or "one" embodiment in this disclosure are
not necessarily to the same embodiment, and such references mean at
least one.
[0020] Referring to FIGS. 1 and 2, a heating pipe 10 of one
embodiment is shown. The heating pipe 10 includes a guide pipe 100,
an outer pipe 102 surrounding the guide pipe 100, two sealed
elements 110 disposed on an outer surface of the guide pipe 100,
and a heating module 104 disposed between the guide pipe 100 and
the outer pipe 102. The two sealed elements 110 contact two ends of
the outer pipe 102, and are located between the guide pipe 100 and
the outer pipe 102. The guide pipe 100, the two sealed elements
110, and the outer pipe 102 define a sealed room 120. The heating
pipe 10 further includes a connector 1002 extending beyond the
outer pipe 102 for connecting to another pipe and allowing a
passage of fluid, such as a liquid or a gas.
[0021] The connector 1002 can extend beyond the outer pipe 102, and
have the same inner diameter as the guide pipe 100. In another
embodiment, the connector 1002 can be another pipe connected with
the guide pipe 100, and have a different inner diameter than the
inner diameter of the guide pipe 100. The connector 1002 can be an
extended portion of the guide pipe 100 extending outside the outer
pipe 102. The extended portion of the guide pipe 100 can be
mechanically treated to form the connector 1002. For example, the
connector 1002 can include a plurality of screw threads. Further, a
fixed element 14 can be positioned on the connector 1002. The fixed
element 14 can be used to fix the connector 1002 onto a
conventional pipe. In this embodiment, the connector 1002 includes
a plurality of screw threads, the fixed element 14 is a nut
including a plurality of screw threads to mate with the screw
threads of the connector 1002, until the connector 1002 is inserted
and fixed into the fixed element 14. As such, the heating pipe 10
and the conventional pipe are connected by the connector 1002 and
fixed by the fixed element 14.
[0022] The guide pipe 100 guides fluid flowing in the heating pipe
10. A cross sectional shape of the guide pipe 100 can be round,
square, triangular, or elliptical. A material of the guide pipe 100
can be dielectric materials, such as glass, ceramic, polymer,
resin, or quartz. The guide pipe 100 can also be made of conductive
materials coated with dielectric materials. The length and the
diameter of the guide pipe 100 are not limited, and can be
determined according to the conventional pipe to which the heating
pipe 10 will be connected. In one embodiment, the guide pipe 100
has a cylindrical shape with an outer diameter of about 5.12
millimeters, and a wall thickness of about 1.15 millimeters.
[0023] The heating module 104 can be located on an outer surface of
the guide pipe 100 or on an inner surface of the outer pipe 102. In
this embodiment, the heating module 104 is positioned on the outer
surface of the guide pipe 100 and is separated from the inner
surface of the outer pipe 102. The heating module 104 includes a
heating element 1046, a first electrode 1042, and a second
electrode 1044. The first electrode 1042 and the second electrode
1044 are electrically connected with the heating element 1046. The
heating element 1046 is positioned on the outer surface of the
guide pipe 100, with adhesive or by a mechanical method. The first
electrode 1042 and the second electrode 1044 can be located on the
same surface or different surfaces of the heating element 1046. In
one embodiment according to FIG. 1, the first electrode 1042 and
the second electrode 1044 are located on the same surface of the
heating element 1046. The first electrode 1042 and the second
electrode 1044 can be electrically connected with the circuit
system with at least two lead wires (not shown).
[0024] The heating element 1046 can be metal wires, metal alloy
wires, carbon fibers, or carbon nanotube structures. The carbon
nanotube structure can be formed by screen printing method. The
carbon nanotube structure can be a freestanding structure, namely,
the carbon nanotube structure can support itself without a
substrate. For example, if at least one point of the carbon
nanotube structure is held, the entire carbon nanotube structure
can be lifted without being destroyed. The carbon nanotube
structure includes a plurality of carbon nanotubes joined by Van
der Waals attractive force therebetween. The carbon nanotube
structure can be a substantially pure structure of the carbon
nanotubes, with few impurities. The carbon nanotubes can be used to
form many different structures and provide a large specific surface
area. The heat capacity per unit area of the carbon nanotube
structure can be less than 2.times.10.sup.-4 J/m.sup.2*K. In one
embodiment, the heat capacity per unit area of the carbon nanotube
structure is less than or equal to 1.7.times.10.sup.-6 J/m.sup.2*K.
Because the heat capacity of the carbon nanotube structure is very
low, the temperature of the heating element 1046 can rise and fall
quickly, and has a high response heating speed. Thus, the heating
element 1046 has a high heating efficiency and accuracy. In
addition, because the carbon nanotube structure can be
substantially pure, the carbon nanotubes are not easily oxidized
and the lifespan of the heating element 1046 will be relatively
long. Furthermore, the carbon nanotube structure can have a small
size, and the sealed room 120 can be small. As such, the heating
pipe 10 will have an equally small size. Additionally, because the
carbon nanotubes have a low density, about 1.35 g/cm.sup.3, the
heating element 1046 is light. Because the carbon nanotube has a
large specific surface area, the carbon nanotube structure with a
plurality of carbon nanotubes has a larger specific surface area.
If the specific surface of the carbon nanotube structure is large
enough, the carbon nanotube structure is adhesive and can be
directly applied to a surface.
[0025] The carbon nanotubes in the carbon nanotube structure can be
orderly or disorderly arranged. The term `disorderly carbon
nanotube structure` refers to a structure where the carbon
nanotubes are arranged along different directions, and the aligning
directions of the carbon nanotubes are random. The number of the
carbon nanotubes arranged along each different direction can be
almost the same (e.g. uniformly disordered). The disorderly carbon
nanotube structure can be isotropic, namely the carbon nanotube
structure has properties identical in all directions of the carbon
nanotube structure. The carbon nanotubes in the disorderly carbon
nanotube structure can be entangled with each other.
[0026] The term `ordered carbon nanotube structure` refers to a
structure where the carbon nanotubes are arranged in a consistently
systematic manner, e.g., the carbon nanotubes are arranged
approximately along a same direction and/or have two or more
sections within each of which the carbon nanotubes are arranged
approximately along a same direction (different sections can have
different directions). The carbon nanotubes in the carbon nanotube
structure can be selected from single-walled, double-walled, and/or
multi-walled carbon nanotubes.
[0027] The carbon nanotube structure can be a layered carbon
nanotube structure, a linear carbon nanotube structure or
combinations thereof. If the carbon nanotube structure is a layered
structure, the carbon nanotube structure can wrap the outer surface
of the guide pipe 100. If the carbon nanotube structure includes a
single linear carbon nanotube structure, the single linear carbon
nanotube structure can spirally twist about the guide pipe 100. If
the heating element 1046 includes two or more linear carbon
nanotube structures, the linear carbon nanotube structures can be
disposed on the outer surface of the guide pipe 100 and be
substantially parallel with each other. The linear carbon nanotube
structures can be disposed side by side or separately. If the
carbon nanotube structure includes a plurality of linear carbon
nanotube structures, the linear carbon nanotube structures can be
knitted to obtain a net structure disposed on the outer surface of
the guide pipe 100.
[0028] The carbon nanotube structure with layer structure includes
at least one carbon nanotube film. In one embodiment, the carbon
nanotube film is a drawn carbon nanotube film. A film can be drawn
from a carbon nanotube array, to obtain a drawn carbon nanotube
film. The drawn carbon nanotube film includes a plurality of
successive and oriented carbon nanotubes joined end-to-end by Van
der Waals attractive force therebetween. The drawn carbon nanotube
film is a free-standing film. Each drawn carbon nanotube film
includes a plurality of successively oriented carbon nanotube
segments joined end-to-end by Van der Waals attractive force
therebetween. Each carbon nanotube segment includes a plurality of
carbon nanotubes substantially parallel to each other, and joined
by Van der Waals attractive force therebetween. Some variations can
occur in the drawn carbon nanotube film. The carbon nanotubes in
the drawn carbon nanotube film are oriented along a preferred
orientation. The carbon nanotube film can be treated with an
organic solvent to increase the mechanical strength and toughness
of the carbon nanotube film and reduce the coefficient of friction
of the carbon nanotube film. The thickness of the carbon nanotube
film can range from about 0.5 nm to about 100 .mu.m.
[0029] The carbon nanotube structure of the heating element 1046
can include at least two stacked carbon nanotube films. In other
embodiments, the carbon nanotube structure can include two or more
coplanar carbon nanotube films, and can include layers of coplanar
carbon nanotube films. Additionally, if the carbon nanotubes in the
carbon nanotube film are aligned along one preferred orientation
(e.g., the drawn carbon nanotube film) an angle can exist between
the orientations of carbon nanotubes in adjacent films, whether
stacked or adjacent. Adjacent carbon nanotube films can be joined
by only the Van der Waals attractive force therebetween. The number
of the layers of the carbon nanotube films is not limited. However,
the thicker the carbon nanotube structure is, the smaller the
specific surface area. An angle between the aligned directions of
the carbon nanotubes in two adjacent carbon nanotube films can
range from about 0 degrees to about 90 degrees. The carbon
nanotubes in the heating element 1046 define a microporous
structure. The carbon nanotube structure in an embodiment employing
these films will have a plurality of micropores. Stacking the
carbon nanotube films will also add to the structural integrity of
the carbon nanotube structure.
[0030] In other embodiments, the carbon nanotube film can be a
flocculated carbon nanotube film. The flocculated carbon nanotube
film can include a plurality of long, curved, disordered carbon
nanotubes entangled with each other. Furthermore, the flocculated
carbon nanotube film can be isotropic. The carbon nanotubes can be
substantially uniformly dispersed in the carbon nanotube film.
Adjacent carbon nanotubes are acted upon by Van der Waals
attractive force to obtain an entangled structure with micropores
defined therein. It is noteworthy that the flocculated carbon
nanotube film is very porous. Sizes of the micropores can be less
than 10 .mu.m. The porous nature of the flocculated carbon nanotube
film will increase the specific surface area of the carbon nanotube
structure. Further, due to the carbon nanotubes in the carbon
nanotube structure being entangled with each other, the carbon
nanotube structure employing the flocculated carbon nanotube film
has excellent durability, and can be fashioned into desired shapes
with a low risk to the integrity of the carbon nanotube structure.
The thickness of the flocculated carbon nanotube film can range
from about 0.5 nm to about 1 mm.
[0031] In other embodiments, the carbon nanotube film can be a
pressed carbon nanotube film. The pressed carbon nanotube film can
be a free-standing carbon nanotube film. The carbon nanotubes in
the pressed carbon nanotube film are arranged along a same
direction or along different directions. The carbon nanotubes in
the pressed carbon nanotube film can rest upon each other. Adjacent
carbon nanotubes are attracted to each other and are joined by Van
der Waals attractive force. An angle between a primary alignment
direction of the carbon nanotubes and a surface of the pressed
carbon nanotube film is about 0 degrees to approximately about 15
degrees. The greater the pressure applied, the smaller the angle
obtained. If the carbon nanotubes in the pressed carbon nanotube
film are arranged along different directions, the carbon nanotube
structure can be isotropic. Here, "isotropic" means the carbon
nanotube film has properties identical in all directions
substantially parallel to a surface of the carbon nanotube film.
The thickness of the pressed carbon nanotube film ranges from about
0.5 nm to about 1 mm.
[0032] The linear carbon nanotube structure includes at least one
carbon nanotube wire. The carbon nanotube wire can be untwisted or
twisted. Treating the drawn carbon nanotube film with a volatile
organic solvent can obtain the untwisted carbon nanotube wire. In
one embodiment, the organic solvent is applied to soak the entire
surface of the drawn carbon nanotube film. During the soaking
process, adjacent parallel carbon nanotubes in the drawn carbon
nanotube film will bundle together, due to the surface tension of
the organic solvent as it volatilizes, and thus, the drawn carbon
nanotube film will be shrunk into an untwisted carbon nanotube
wire. Referring to FIG. 5, the untwisted carbon nanotube wire
includes a plurality of carbon nanotubes substantially oriented
along a same direction (i.e., a direction along the length
direction of the untwisted carbon nanotube wire). The carbon
nanotubes are substantially parallel to the axis of the untwisted
carbon nanotube wire. In one embodiment, the untwisted carbon
nanotube wire includes a plurality of successive carbon nanotube
segments joined end to end by Van der Waals attractive force
therebetween. Each carbon nanotube segment includes a plurality of
carbon nanotubes substantially parallel to each other, and combined
by Van der Waals attractive force therebetween. The carbon nanotube
segments can vary in width, thickness, uniformity, and shape. The
length of the untwisted carbon nanotube wire can be arbitrarily set
as desired. A diameter of the untwisted carbon nanotube wire ranges
from about 0.5 nm to about 100 .mu.m.
[0033] The twisted carbon nanotube wire can be obtained by twisting
a drawn carbon nanotube film using a mechanical force to turn the
two ends of the drawn carbon nanotube film in opposite directions.
Referring to FIG. 6, the twisted carbon nanotube wire includes a
plurality of carbon nanotubes helically oriented around an axial
direction of the twisted carbon nanotube wire. In one embodiment,
the twisted carbon nanotube wire includes a plurality of successive
carbon nanotube segments joined end to end by Van der Waals
attractive force therebetween. Each carbon nanotube segment
includes a plurality of carbon nanotubes substantially parallel to
each other, and combined by Van der Waals attractive force
therebetween. The length of the carbon nanotube wire can be set as
desired. A diameter of the twisted carbon nanotube wire can be from
about 0.5 nm to about 100 .mu.m. Further, the twisted carbon
nanotube wire can be treated with a volatile organic solvent after
being twisted. After being soaked by the organic solvent, the
adjacent substantially parallel carbon nanotubes in the twisted
carbon nanotube wire will bundle together, due to the surface
tension of the organic solvent when the organic solvent
volatilizes. The specific surface area of the twisted carbon
nanotube wire will decrease, while the density and strength of the
twisted carbon nanotube wire will increase.
[0034] The heating element 1046 can be a carbon nanotube composite
structure. The carbon nanotube composite structure includes the
carbon nanotube structure disclosed above and matrix materials. The
matrix materials are filled in the carbon nanotube structure or are
disposed on at least one surface of the carbon nanotube structure.
In other embodiments, the matrix material can surround the carbon
nanotube structure. The matrix materials can be metal, resin,
ceramic, glass, or fiber.
[0035] The first electrode 1042 and the second electrode 1044 can
be fixed on the surface of the heating element 1046 by conductive
adhesive (not shown). The first electrode 1042 and the second
electrode 1044 are made of conductive material. The shapes of the
first electrode 1042 and the second electrode 1044 are not limited
and can be lamellar, rod, or wire shaped. The cross sectional shape
of the first electrode 1042 and the second electrode 1044 can be
round, square, trapezium, triangular, or polygonal. The thickness
of the first electrode 1042 and the second electrode 1044 can be
any size, depending on the design, and can be about 1 micrometer to
about 1 centimeter. In the present embodiment as shown in FIG. 1,
the first electrode 1042 and the second electrode 1044 both have a
linear shape, and are positioned on the surface of the heating
element 1046, and substantially parallel with an axial direction of
the guiding pipe 100. The first electrode 1042 and the second
electrode 1044 are substantially parallel with each other. In one
embodiment, if the heating element 1046 includes the carbon
nanotube structure having a plurality of carbon nanotubes arranged
in substantially the same direction, the carbon nanotubes are
oriented from the first electrode 1042 to the second electrode
1044.
[0036] In another embodiment according to FIG. 7, the first
electrode 1042 and the second electrode 1044 are separately
positioned on two opposite ends of the guide pipe 100. The first
electrode 1042 and the second electrode 1044 wind around the guide
pipe 100 to form two ring structures. If the heating element 1046
includes the carbon nanotube structure having a plurality of carbon
nanotubes arranged in a same direction, the carbon nanotubes are
oriented from the first electrode 1042 to the second electrode
1044.
[0037] In other embodiments, the heating module 104 can include a
plurality of first electrodes 1042 and a plurality of second
electrodes 1044. The number of the first electrodes 1042 and the
number of the second electrodes 1044 can be the same. The first
electrodes 1042 and the second electrodes 1044 are alternatively
positioned on a surface of the heating element 1046. The carbon
nanotube structure disposed between every adjacent first electrode
1042 and second electrode 1044 can be electrically connected in
parallel with each other.
[0038] In one embodiment, the heating element 1046 includes a
single linear carbon nanotube structure spirally twisted about the
guide pipe 100, with the first electrode 1042 and the second
electrode 1044 can be omitted.
[0039] The outer pipe 102 covers the heating module 104. The outer
pipe 102 is configured for keeping the heating module 104 away from
contamination from the environmental surroundings, and can protect
the user from getting an electric shock when touching the heating
pipe 10. An inner diameter of the outer pipe 102 is larger than an
outer diameter of the guide pipe 100. In this embodiment, the outer
pipe 102 and the guide pipe 100 are coaxial. The sealed room 120
defined by the outer pipe 102, the guide pipe 100, and the two
sealed elements 110 can be in a vacuum-like state. The sealed room
120 can be used to reduce the less of the heat produced by the
heating element 1046. The material of the outer pipe 102 can be
conductive or insulated. The electrically conductive material can
be metal or alloy. The metal can be copper, aluminum, or titanium.
The insulated material can be resin, ceramic, plastic, or wood. The
resin can be acrylic, polypropylene, polycarbonate, polyethylene,
epoxy resin, or PTFE. The material of the outer pipe 102 can be
flexible. If the materials of the guide pipe 100 and the outer pipe
102 are both flexible, the heating pipe 10 can be flexible
according to determination. The thickness of the outer pipe 102 can
range from about 0.5 .mu.m to about 2 mm. If the material of the
outer pipe 102 is insulative, the outer pipe 102 can be directly
disposed on a surface of the heating module 104. If the outer pipe
102 is conductive, the outer pipe 102 should be insulated from the
heating module 104.
[0040] The heating pipe 10 can further include a heat-reflective
layer 112 positioned on the inner surface of the outer pipe 102.
The heat-reflective layer 112 is apart from the heating module 104.
The heat-reflective layer 112 is configured to reflect back the
heat emitted by the heating module 104, and control the direction
of the heat emitted by the heating module 104. The material of the
heat-reflective layer 112 can be selected from conductive material
or insulative material. The insulative material can be metal
oxides, metal salts, or ceramics. The conductive material can be
silver, aluminum, gold or alloy. A thickness of the heat-reflective
layer 112 can be in a range from about 100 micrometers to about 0.5
millimeters.
[0041] The heating pipe 10 can alternatively include a
heat-insulated layer 130 positioned on an outer surface of the
outer pipe 102. A material of the heat-insulated layer 130 can be
asbestos, diatomite, perlite, glass fiber, or combination thereof.
The heat-insulated layer 130 reduces the loss of the heat produced
by the heating module 104.
[0042] In use, if a voltage is applied to the first electrode 1042
and the second electrode 1044 of the heating pipe 10 by a power
wire 106, the carbon nanotube structure can radiate heat at a
certain wavelength. The heating pipe 10 can further include a
temperature-controlling element 108 to detect and control the
temperature of the heating pipe 10. The temperature of the heating
pipe 10 detected by the temperature-controlling element 108 can be
changed by changing some parameters of the heating pipe 10 and the
fluid guided into the heating pipe 10, such as a voltage between
the first electrode 1042 and the second electrode 1044 and/or a
flow rate of the fluid. In one embodiment, the
temperature-controlling element 108 is electrically connected in
series with the heating pipe 10.
[0043] The heating pipe 10 can be used as a fluid pipe directly or
be connected with one end of a fluid pipe. The heating pipe 10 can
heat the fluid flowing through the guiding pipe 100 of the heating
pipe 10. If the voltage between the first electrode 1042 and the
second electrode 1044 is kept unchanged, a temperature of the
liquid will be uniform when it reaches a steady state. The
temperature-controlling element 108 can also be used to control the
temperature of the fluid.
[0044] In one embodiment, the heating effect of the heating pipe 10
is tested in test equipment as shown in FIG. 8. The test equipment
includes a first container 60, a pump 30, the heating pipe 10, and
a second container 40. The guide pipe 100 has a larger length than
the heating pipe 10 and connects the first container 60 and the
second container 40. The guide pipe 100 is able to move liquid 50
from the first container 60 to the second container 40 by the pump
30. The liquid 50 is heated by the heating pipe 10 when it flows
from the guide pipe 100 of the heating pipe 10. In one embodiment,
the liquid 50 is water, and the guide pipe 100 is a cylindrical
rubber pipe having an outer diameter of about 5.12 millimeters and
a thickness of the wall of about 1.15 millimeters. The outer pipe
102 is made of polytetrafluoroethylene (PTFE), an inner diameter of
the outer pipe 102 is about 6.36 millimeters, and a thickness of
the wall of the outer pipe 102 is about 1.35 millimeters. The
sealed elements 110 are made of plastic. The first electrode 1042
and the second electrode 1044 are copper wires. The first electrode
1042 and the second electrode 1044 are oriented along the axis
direction of the guide pipe 100. The heating element 1046 is the
drawn carbon nanotube film with a width of about 5 centimeters. The
drawn carbon nanotube film wraps an outer surface of the guide pipe
100. The first electrode 1042 and the second electrode 1044 are
positioned on an outer surface of the heating element 1046. The
carbon nanotubes in the drawn carbon nanotube film are oriented
from the first electrode 1042 to the second electrode 1044.
[0045] In the embodiment according to FIG. 8, a flow rate of the
liquid 50 is about 3.53 ml/min. A temperature of the liquid 50 in
the first container 60, which is not heated by the heating pipe 10
is about 24 centigrades. The liquid 50 in the second container 40,
which is heated by the heating pipe 10 when it passes the heating
pipe 10, has a temperature determined by a heating power of the
heating pipe 10. A voltage between the first electrode 1042 and the
second electrode 1044 and the current of the heating element 1046
determines the heating power. The relationship of the voltage, the
current, the heating power and the temperature of the liquid 50 in
the second container 40 is tested. The test result is shown in
Table 1.
TABLE-US-00001 TABLE 1 Testing result of the heating pipe 10
Voltage Current heating temperature of (V) (A) power (W) the liquid
(.degree. C.) 3.1 0.3 0.93 30 4.5 0.4 1.80 34 6.0 0.6 3.60 41 7.5
0.9 6.75 53 9.0 1.2 10.8 72
[0046] It can be seen from Table 1 that the liquid 50 passing
through the heating pipe 10 can be sufficiently heated at a low
voltage. In the test process, the liquid 50 can reach a
predetermined temperature in 30 minutes, and the heating effect is
stable and uniform.
[0047] Referring to FIG. 9, a temperature difference between the
liquid 50 in the first container 60 and the liquid 50 in the second
container 40 has a linear relationship with the heating power. The
heating pipe 10 can uniformly heat the flowing liquid 50.
[0048] Referring to FIG. 10, a heating pipe 20 according to another
embodiment is provided. The heating pipe 20 includes a guide pipe
200, an outer pipe 202 surrounding the periphery of the guide pipe
200, two sealed elements 210 positioned on an outer surface of the
guide pipe 200 and a heating module 204 positioned between the
guide pipe 200 and the outer pipe 202. The two sealed elements 210
contact with two ends of the outer pipe 202, and are located
between the guide pipe 200 and the outer pipe 202. A sealed room
220 is defined by the guide pipe 200, the two sealed elements 210,
and the outer pipe 202. The heating module 204 includes a heating
element 2046, a first electrode 2042 and a second electrode 2044.
The heating element 2046 is attached to an inner surface of the
outer pipe 202, and is spaced from the guide pipe 200. In some
embodiments, the heating element 2046 can also be clamped between
the outer pipe 202 and the guide pipe 200, and the first electrode
2042 and the second electrode 2044 can each be a layer of
conductive material coated on the heating element 2046.
[0049] The heating pipe 20 further includes a heat-reflective layer
212 disposed on an outer surface of the heating element 2046. The
material of the heat-reflective layer 212 is an insulative
material.
[0050] Other characteristics of the heating pipe 20 are the same as
the heating pipe 10 disclosed above.
[0051] The heating pipe disclosed in the present disclosure can be
used to heat the fluid flowing through the heating pipe. The
heating pipe can be used in many fields, such as pre-heating air in
a boiler of power station to improve production efficiency, heating
a pipe in different sections in a laboratory to control catalytic
effect of enzyme, heating liquid medicine before it is injected
into a patient to make the patient comfortable or improve the
medical effect, and heating running water for everyday life or for
industry.
[0052] It is to be understood that the above-described embodiments
are intended to illustrate rather than limit the present
disclosure. Variations may be made to the embodiments without
departing from the spirit of the disclosure as claimed. It is
understood that any element of any one embodiment is considered to
be disclosed to be incorporated with any other embodiment. The
above-described embodiments illustrate the scope of the disclosure
but do not restrict the scope of the disclosure.
* * * * *