U.S. patent application number 13/197886 was filed with the patent office on 2012-03-01 for micropump and driving method thereof.
This patent application is currently assigned to POSTECH ACADEMY-INDUSTRY FOUNDATION. Invention is credited to BOHEUM KIM, SANG JOON LEE.
Application Number | 20120051946 13/197886 |
Document ID | / |
Family ID | 44922588 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120051946 |
Kind Code |
A1 |
LEE; SANG JOON ; et
al. |
March 1, 2012 |
MICROPUMP AND DRIVING METHOD THEREOF
Abstract
Provided are a micropump that makes it possible to reduce the
entire size and improve pumping performance of fluid, and a method
of operating the micropump. The micropump includes a case that
forms a first space and a second space that are connected through a
connection channel, a fluid intake pipe that is connected to the
first space, a fluid discharge pipe that is connected to the second
space, a first deforming member that is disposed on the case to
cover the first space, and a second deforming member that is
disposed on the case to cover the second space. The second
deforming member is formed larger than the first deforming member
and the maximum displacement of the second deforming member is
larger than the maximum displacement of the first deforming
member.
Inventors: |
LEE; SANG JOON; (Pohang-si,
KR) ; KIM; BOHEUM; (Pohang-si, KR) |
Assignee: |
POSTECH ACADEMY-INDUSTRY
FOUNDATION
Pohang-city
KR
|
Family ID: |
44922588 |
Appl. No.: |
13/197886 |
Filed: |
August 4, 2011 |
Current U.S.
Class: |
417/53 ;
417/413.2 |
Current CPC
Class: |
F04B 43/043 20130101;
F04B 43/046 20130101 |
Class at
Publication: |
417/53 ;
417/413.2 |
International
Class: |
F04B 43/04 20060101
F04B043/04; F04B 49/06 20060101 F04B049/06 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 25, 2010 |
KR |
10-2010-0082546 |
Claims
1. A micropump comprising: a case that forms a first space and a
second space that are connected through a connection channel; a
fluid intake pipe that is positioned at a side of the case and
connected with the first space; a fluid discharge pipe that is
positioned at the other side of the case and connected with the
second space; a first deforming member that is disposed on the case
to cover the first space and deformed by an electric signal; and a
second deforming member that is disposed on the case to cover the
second space and deformed by an electric signal, wherein the second
deforming member is formed larger than the first deforming member,
and the maximum displacement of the second deforming member is
larger than the maximum displacement of the first deforming
member.
2. The micrcopump of claim 1, wherein: the first deforming member
and the second deforming member are implemented by piezoelectric
actuators.
3. The micropump of claim 2, wherein: the first deforming plate
includes a first conductive elastic plate and a first piezoelectric
device, and the second deforming member includes a second
conductive elastic plate and a second piezoelectric device.
4. The micropump of claim 3, further comprising: a plurality of
lead wires that is connected to the first conductive elastic plate,
the first piezoelectric device, the second conductive elastic
plate, and the second piezoelectric device, respectively; and a
controller that is electrically connected with the plurality of
lead wires.
5. The micropump of claim 1, wherein: the first deforming member
and the second deforming member are made of artificial muscles.
6. The micropump of claim 5, wherein: the first deforming member
includes a first imitative muscle and a first electrode, and the
second deforming member includes a second imitative muscle and a
second electrode.
7. The micropump of claim 6, wherein: the first imitative muscle
and the second imitative muscle include nanofiber made of electric
active hydrogel.
8. The micropump of claim 6, further comprising: a pair of lead
wires that is connected to the first electrode and the second
electrode, respectively; and a controller that is electrically
connected with the pair of lead wires.
9. The micropump of claim 1, wherein: the volume of the second
space is larger than the volume of the first space.
10. The micropump of claim 1, further comprising: an on/off valve
that is disposed in the connection channel; and an anti-backflow
member that is disposed in the fluid intake pipe and the fluid
discharge pipe.
11. The micropump of claim 10, wherein: the on/off valve is a
piezoelectric valve that includes a first piezoelectric disk and a
second piezoelectric disk that are disposed in parallel with the
connection channel.
12. The micropump of claim 10, wherein: the anti-backflow member is
formed in a cone shape of which the inner diameter gradually
increases from a side facing the fluid intake pipe to the opposite
side facing the fluid discharge pipe.
13. The micropump of claim 10, wherein: the anti-backflow member
includes: a deforming plate that is formed of a thin layer and has
a fixed end and a free end; and a fixing protrusion that is
positioned ahead of the free end of the deforming plate in a
forward direction toward the fluid discharge pipe from the fluid
intake pipe.
14. The micropump of claim 1, further comprising: an anti-backflow
member that is disposed in the fluid intake pipe, the connection
channel, and the fluid discharge pipe.
15. The micropump of claim 14, wherein: the anti-backflow member is
formed in a cone shape of which the inner diameter gradually
increases from a side facing the fluid intake pipe to the opposite
side facing the fluid discharge pipe.
16. The micropump of claim 14, wherein: the anti-backflow member
includes: a deforming plate that is formed of a thin layer and has
a fixed end and a free end; and a fixing protrusion that is
positioned ahead of the free end of the deforming plate in a
forward direction toward the fluid discharge pipe from the fluid
intake pipe.
17. A method of operating the micropump of claim 1, comprising: a
first section where the first deforming member expands from the
minimum displacement to the maximum displacement and the second
deforming member initially expands from the minimum displacement; a
second section where the first deforming member retracts from the
maximum displacement and the second deforming member expands to the
maximum displacement; and a third section where the first deforming
member retracts to the minimum displacement and the second
deforming member retracts from the maximum displacement.
18. The method of claim 17, wherein: the second deforming member
starts to expand from the minimum displacement with a time
difference from the maximum displacement position of the first
deforming member in the first section.
19. The method of claim 17, wherein: the minimum displacement
position of the first deforming member has a time difference from
the maximum displacement position of the second deforming member in
the third section.
20. The method of claim 17, wherein: an on/off valve is disposed in
a connection channel of the micropump, and the on/off valve opens
the connection channel by operating simultaneously with the
expansion of the second deforming member and closes the connection
channel by operating simultaneously with that the second deforming
member reaches the maximum displacement.
21. A method of operating the micropump of claim 1, comprising: a
first section where the first deforming member expands from the
minimum displacement to the maximum displacement and the second
deforming member initially expands from the minimum displacement; a
second section where the first deforming member retracts from the
maximum displacement to the minimum displacement and the second
deforming member expands to the maximum displacement; and a third
section where the first deforming member initially expands from the
minimum displacement and the second deforming member retracts to
the minimum displacement.
22. The method of claim 21, wherein: the second deforming member
starts to expand from the minimum displacement with a time
difference from the maximum displacement position of the first
deforming member in the first section.
23. The method of claim 21, wherein: the maximum displacement
position of the first deforming member agrees with the maximum
displacement position of the second deforming member in the second
section.
24. The method of claim 21, wherein: an on/off valve is disposed in
a connection channel of the micropump, and the on/off valve opens
the connection channel by operating simultaneously with the
expansion of the second deforming member and closes the connection
channel by operating simultaneously with that the second deforming
member reaches the maximum displacement.
25. A method of operating the micropump of claim 1, comprising: a
first section where fluid is sucked into the first space by
expanding the first deforming member from the minimum displacement
to the maximum displacement; a second section where fluid is sucked
into the first space and the second space by retracting the first
deforming member from the maximum displacement to the minimum
displacement and expanding the second deforming member from the
minimum displacement to the maximum displacement; and a third
section where the fluid in the first space and the second space is
discharged by retracting the second deforming member from the
maximum displacement to the minimum displacement.
26. The method of claim 25, wherein: the maximum displacement
position of the first deforming member agrees with the minimum
displacement position of the second deforming member.
27. The method of claim 25, wherein: an on/off valve is disposed in
a connection channel of the micropump, and the on/off valve opens
the connection channel by operating simultaneously with the
expansion of the second deforming member and closes the connection
channel by operating simultaneously with that the second deforming
member reaches the maximum displacement.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of
Korean Patent Application No. 10-2010-0082546 filed in the Korean
Intellectual Property Office on Aug. 25, 2010, the entire contents
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] (a) Field of the Invention
[0003] The present invention relates to a micropump for delivering
fluid. More particularly, the present invention relates to a
micropump that sucks fluid by generating a strong suction force in
a channel and delivers the sucked fluid to the downstream, and a
driving method thereof.
[0004] (b) Description of the Related Art
[0005] With the development in the micromachining technology,
researches on microdevices, such as MEMS (Micro-Electro Mechanical
System), have been actively conducted. In the devices, a micropump,
a device that manipulates a very small amount of fluid, using fluid
mechanics, is applied to various fields, including medical
chemistry systems and medical equipment, such as chemical analyzing
systems and medicine delivery systems, and inkjet heads.
[0006] The micropump may be implemented by a piezoelectric
micropump using a piezoelectric actuator. A typical piezoelectric
micropump has a configuration in which three or more piezoelectric
actuators are disposed in parallel in one pump case and
electrically connected to a control device.
[0007] According to the piezoelectric micropump, when an
electromotive force is applied to the piezoelectric actuators from
the control device, the piezoelectric actuators sequentially
operate and make a pumping action that sucks and discharges fluid.
The micropump equipped with a plurality of piezoelectric actuators,
as described above, can easily control the flow of fluid, but has a
defect in that the pumping performance is low and the size is
large.
[0008] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
invention and therefore it may contain information that does not
form the prior art that is already known in this country to a
person of ordinary skill in the art.
SUMMARY OF THE INVENTION
[0009] The present invention has been made in an effort to provide
a micropump that can improve pumping performance while decreasing
the entire size, and a driving method thereof.
[0010] An exemplary embodiment of the present invention provides a
micropump including: a case that forms a first space and a second
space that are connected through a connection channel; a fluid
intake pipe that is positioned at a side of the case and connected
to the first space; a fluid discharge pipe that is positioned at
the other side of the case and connected to the second space; a
first deforming member that is disposed on the case to cover the
first space and deforms in response to an electric signal; and a
second deforming member that is disposed on the case to cover the
second space and deforms in response to an electric signal. The
second deforming member is formed larger than the first deforming
member and the maximum displacement of the second deforming member
is larger than the maximum displacement of the first deforming
member.
[0011] The first deforming member and the second deforming member
may be implemented by piezoelectric actuators. The first deforming
plate may include a first conductive elastic plate and a first
piezoelectric device and the second deforming member may include a
second conductive elastic plate and a second piezoelectric
device.
[0012] The micropump may further include: a plurality of lead wires
that is connected to the first conductive elastic plate, the first
piezoelectric device, the second conductive elastic plate, and the
second piezoelectric device, respectively; and a controller that is
electrically connected with the plurality of lead wires.
[0013] On the other hand, the first deforming member and the second
deforming member may be made of artificial muscles. The first
deforming member may include a first imitative muscle and a first
electrode and the second deforming member may include a second
imitative muscle and a second electrode.
[0014] The first imitative muscle and the second imitative muscle
may include nanofiber made of electric active hydrogel. The
micropump may include: a pair of lead wires that is connected to
the first electrode and the second electrode, respectively; and a
controller that is electrically connected with the pair of lead
wires.
[0015] The volume of the second space may be larger than the volume
of the first space.
[0016] The micropump may further include: an on/off valve that is
disposed in the connection channel; and an anti-backflow member
that is disposed in the fluid intake pipe and the fluid discharge
pipe. On the other hand, the micropump may further include an
anti-backflow member disposed in the fluid intake pipe, the
connection channel, and the fluid discharge pipe.
[0017] The on/off valve may be a piezoelectric valve that includes
a first piezoelectric disk and a second piezoelectric disk that are
disposed in parallel with the connection channel.
[0018] The anti-backflow member may be formed in a cone shape of
which the inner diameter gradually increases from a side facing the
fluid intake pipe to the opposite side facing the fluid discharge
pipe.
[0019] On the other hand, the anti-backflow member may include: a
deforming plate that is formed of a thin layer and has a fixed end
and a free end; and a fixing protrusion that is positioned ahead of
the free end of the deforming plate in a forward direction toward
the fluid discharge pipe from the fluid intake pipe.
[0020] Another exemplary embodiment of the present invention
provides a method of operating a micropump, including: a first
section where the first deforming member expands from the minimum
displacement to the maximum displacement and the second deforming
member initially expands from the minimum displacement; a second
section where the first deforming member retracts from the maximum
displacement and the second deforming member expands to the maximum
displacement; and a third section where the first deforming member
retracts to the minimum displacement and the second deforming
member retracts from the maximum displacement.
[0021] The second deforming member may start to expand from the
minimum displacement with a time difference from the maximum
displacement position of the first deforming member in the first
section. The minimum displacement position of the first deforming
member may have a time difference from the maximum displacement
position of the second deforming member in the third section.
[0022] Yet another exemplary embodiment of the present invention
provides a method of operating a micropump, including: a first
section where the first deforming member expands from the minimum
displacement to the maximum displacement and the second deforming
member initially expands from the minimum displacement; a second
section where the first deforming member retracts from the maximum
displacement to the minimum displacement and the second deforming
member expands to the maximum displacement; and a third section
where the first deforming member initially expands from the minimum
displacement and the second deforming member retracts to the
minimum displacement.
[0023] The second deforming member may start to expand from the
minimum displacement with a time difference from the maximum
displacement position of the first deforming member in the first
section. The minimum displacement position of the first deforming
member may agree with the maximum displacement position of the
second deforming member in the second section.
[0024] Still another exemplary embodiment of the present invention
a method of operating a micropump, including: a first section where
fluid is sucked into the first space by expanding the first
deforming member from the minimum displacement to the maximum
displacement; a second section where fluid is sucked into the first
space and the second space by retracting the first deforming member
from the maximum displacement to the minimum displacement and
expanding the second deforming member from the minimum displacement
to the maximum displacement; and a third section where the fluid in
the first space and the second space is discharged by retracting
the second deforming member from the maximum displacement to the
minimum displacement.
[0025] The maximum displacement position of the first deforming
member may agree with the minimum displacement position of the
second deforming member.
[0026] In all of the methods of operating a micropump, the on/off
valve may be positioned in the connection channel of the micropump
and the on/off valve may open the connection channel by operating
simultaneously with the expansion of the second deforming member
and may close the connection channel by operation simultaneously
with that the second deforming member reaches the maximum
displacement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a top plan view of a micropump according to a
first exemplary embodiment of the present invention.
[0028] FIG. 2 is a cross-sectional view of the micropump according
to the first exemplary embodiment of the present invention.
[0029] FIG. 3 is a schematic diagram showing an on/off valve in the
micropump shown in FIG. 1.
[0030] FIG. 4 is a schematic diagram showing an exemplary variation
of an anti-backflow member in the micropump shown in FIG. 1.
[0031] FIG. 5 is a cross-sectional view of a micropump according to
a second exemplary embodiment of the present invention.
[0032] FIG. 6 is a cross-sectional view of a micropump according to
a third exemplary embodiment of the present invention.
[0033] FIG. 7 is a cross-sectional view of a micropump according to
a fourth exemplary embodiment of the present invention.
[0034] FIG. 8 is a waveform diagram showing applied signals of a
first deforming member and a second deforming member shown to
illustrate a first operation method of a micropump.
[0035] FIG. 9 is a waveform diagram showing applied signals of a
first deforming member and a second deforming member shown to
illustrate a second operation method of a micropump.
[0036] FIG. 10 is a waveform diagram showing applied signals of a
first deforming member and a second deforming member shown to
illustrate a third operation method of a micropump.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0037] The present invention will be described more fully
hereinafter with reference to the accompanying drawings, in which
exemplary embodiments of the invention are shown. As those skilled
in the art would realize, the described embodiments may be modified
in various different ways, all without departing from the spirit or
scope of the present invention.
[0038] FIG. 1 and FIG. 2 are a plan view and a cross-sectional view
of a micropump according to a first exemplary embodiment of the
present invention.
[0039] Referring to FIG. 1 and FIG. 2, a micropump 100 according to
the first exemplary embodiment includes a case 10, a fluid intake
pipe 12, a fluid discharge pipe 14, a first deforming member 16, a
second deforming member 18 and a controller 20.
[0040] The case 10 has a first space 101, a connection channel 103,
and a second space 102, sequentially formed in one direction
therein. The first space 101 and the second space 102 are
separately positioned at a predetermined distance from each other
and the connection channel 103 smaller in size than the two spaces
101 and 102 is formed between the two spaces 102 and 103 and
connects the two spaces 101 and 102.
[0041] The fluid intake pipe 12 is fixed to a side of the case 10
that is in contact with the first space 101 and connected with the
first space 101. The fluid discharge pipe 14 is fixed to the other
side of the case 10 that is in contact with the second space 102
and connected with the second space 102. FIG. 1 and FIG. 2 show
when the fluid intake pipe 12 is positioned at the left of the case
10 and the fluid discharge pipe 14 is positioned at the right of
the case 10, as an example.
[0042] The first deforming member 16 is disposed on the case 10 to
cover the first space 101 and the second deforming member 102 is
disposed on the case 10 to cover the second space 102. The first
deforming member 16 and the second deforming member 18 are
positioned at a predetermined distance from each other. In the
exemplary embodiment, the first deforming member 16 and the second
deforming member 18 are implemented by piezoelectric actuators.
[0043] The first deforming member 16 has a stacking structure
composed of a first conductive elastic plate 161 and a first
piezoelectric element 162 while the second deforming member 18 has
a stacking structure composed of a second conductive elastic plate
181 and a second piezoelectric element 182. A lead wire 22 is
connected to the first conductive elastic plate 161, the first
piezoelectric element 162, the second conductive elastic plate 181,
and the second piezoelectric element 182, respectively, and the
lead wires 22 are connected to the controller 20.
[0044] The first deforming member 16 and the second deforming
member 18 make an expanding or retracting displacement in
accordance with the polarity when an electromotive force is applied
from the controller 20. The maximum displacement (second
displacement) of the second deforming member 18 close to the fluid
discharge pipe 14 is larger than the maximum displacement (first
displacement) of the first deforming member 16 close to the fluid
intake pipe 12. As a result, the second deforming member 18
generates a pressure inclination larger than the first deforming
member 16, such that it is possible to effectively control the flow
of fluid in the operation process of the micropump 100, which is
described below.
[0045] The second deforming member 18 is formed larger than the
first deforming member 16 to increase the maximum displacement of
the second deforming member 18. That is, the second conductive
elastic plate 181 is formed larger than the first conductive
elastic plate 161 and the second piezoelectric device 182 is formed
larger than the first piezoelectric device 162. Further, the volume
of the second space 102 that is in contact with the second
deforming member 18 is defined larger than the volume of the first
space 101 that is in contact with the first deforming member
16.
[0046] Further, the micropump 100 includes an on/off valve 24
disposed in the connection channel 103 and an anti-backflow member
26 disposed in the fluid discharge pipe 14. The anti-backflow
member 26 may also be disposed in the fluid intake pipe 12. The
on/off valve 24 is an active valve and opens or closes the
connection channel 103 while the operation is controlled by the
controller 20. The on/off valve 24 may be implemented by a common
mechanical valve or a piezoelectric valve using a piezoelectric
device.
[0047] FIG. 3 is a schematic diagram showing an on/off valve in the
mircropump shown in FIG. 1.
[0048] Referring to FIG. 3, the piezoelectric valve 240 includes a
first piezoelectric disk 241 and a second piezoelectric disk 242
that are disposed in parallel with the connection channel 103. The
first piezoelectric disk 241 may have a stacking structure of a
conductive elastic plate and a piezoelectric device and the second
piezoelectric disk 242 may also have a stacking structure of a
conductive elastic plate and a piezoelectric device. The first
piezoelectric disk 241 and the second piezoelectric disk 242 are
connected with the controller 20 through the lead wires 243,
respectively.
[0049] The first piezoelectric disk 242 and the second
piezoelectric disk 242 close the connection channel 103 by coming
in contact with each other when an electromotive force is not
applied from the controller 20, and opens the connection channel
103 by expanding away from each other when an electromotive force
is applied from the controller 20. The piezoelectric valve 240 can
open/close the connection channel 103 fast by these operations.
[0050] As shown in FIG. 3, the piezoelectric valve 240 is shown to
described an example of the on/off valve 24, and the on/off valve
24 of the present invention is not limited to the piezoelectric
valve 240 and all valves that can open/close the connection channel
103 can be used.
[0051] Referring to FIG. 1 and FIG. 2, the anti-backflow member 26
is a passive valve, which allows the fluid to smoothly flow in the
forward direction toward the fluid discharge pipe 14 from the fluid
intake pipe 12, while preventing the fluid from flowing in the
opposite direction.
[0052] The anti-backflow member 26 may be formed in a cone shape of
which the inner diameter gradually increases from a side facing the
fluid intake pipe 12 to the opposite side facing the fluid
discharge pipe 14. In this case, the fluid cannot pass through the
anti-backflow member 26 by pressure that increases when flowing in
the backward direction, such that the anti-backflow member 26 can
effectively stop the backward flow of the fluid.
[0053] FIG. 4 is a schematic diagram showing an exemplary variation
of an anti-backflow member in the micropump shown in FIG. 1.
[0054] Referring to FIG. 4, the anti-backflow member 260 may have a
structure composed of a deforming plate 28 and a fixing protrusion
30, instead of the cone shape. The deforming plate 28 may be made
of a thin layer that can easily deform. The deforming plate 28 has
a fixed end 281 that is partially fixed in the fluid intake pipe 12
and the fluid discharge pipe 14 and a free end 282 that is
separated, not fixed, at the other portion. Further, the fixing
protrusion 30 is positioned ahead of the free end 282 of the
deforming plate 28 in the forward direction toward the fluid
discharge pipe 14 from the fluid intake pipe 12.
[0055] Accordingly, the anti-backflow member 260 opens the channel
while the free end 282 of the deforming plate 28 moves away from
the fixing protrusion 30 when the fluid flows in the forward
direction, whereas it closes the channel while the free end 282 of
the deforming plate 28 is blocked by the fixing protrusion 30 when
the fluid flows in the backward direction. As a result, the
anti-backflow member 260 can effectively stop the backward flow of
the fluid.
[0056] Referring to FIG. 1 and FIG. 2, the micropump 100 according
to the first exemplary embodiment can effectively control the fluid
flow even being equipped with the two deforming members 16 and 18
by setting the maximum displacement of the second deforming member
18 larger than the maximum displacement of the first deforming
member 16. Therefore, it is possible to reduce the size of the
micropump 100 by decreasing the number of deforming members 16 and
18.
[0057] Further, the micropump 100 according to the first exemplary
embodiment can pump fast the viscous fluid in the forward direction
by using the on/off valve 24 and the anti-backflow member 26, in
addition to the first and second deforming members 16 and 18, such
that pumping performance can be improved.
[0058] FIG. 5 is a cross-sectional view of a micropump according to
a second exemplary embodiment of the present invention.
[0059] Referring to FIG. 5, a micropump 200 according to the second
exemplary embodiment has the same configuration as the micropump
100 of the first exemplary embodiment, except that the
anti-backflow member 26 is disposed in the connection channel 103.
The same members as those in the first exemplary embodiment are
indicated by the same reference numerals.
[0060] The micropump 200 according to the second exemplary
embodiment is not provided with an on/off valve, and an
anti-backflow member 26 is disposed in a connection channel 103 and
a fluid discharge pipe 14. The anti-backflow member 26 may also be
disposed in a fluid intake pipe 12.
[0061] The anti-backflow member 26 may be formed in a cone shape of
which the inner diameter gradually increases from a side facing the
fluid intake pipe 12 to the opposite side facing the fluid
discharge pipe 14. On the other hand, as shown in FIG. 4, the
anti-backflow member 260 may have a structure composed of a
deforming plate 28 and a fixing protrusion 30.
[0062] FIG. 6 is a cross-sectional view of a micropump according to
a third exemplary embodiment of the present invention.
[0063] Referring to FIG. 6, a micropump 300 according to the third
exemplary embodiment has the same configuration as the micropump
100 according to the first exemplary embodiment, except that a
first deforming member 160 and a second deforming member 180 are
made of artificial muscles. The same members as those in the first
exemplary embodiment are indicated by the same reference
numerals.
[0064] The first deforming member 160 is composed of a first
imitative muscle 163 and a first electrode 164 and the first
electrode 164 is electrically connected with a controller 20
through the corresponding lead wire 22. The second deforming member
180 is composed of a second imitative muscle 183 and a second
electrode 184 and the second electrode 184 is electrically
connected with a controller 20 through the corresponding lead wire
22. The second imitative muscle 183 is formed larger than the first
imitative muscle 163 such that the maximum displacement of the
second deforming member 180 is larger than the maximum displacement
of the first deforming member 160.
[0065] The first and the second imitative muscles 163 and 183 may
be made of nanofiber that can react to electric stimulation, and
are physically retracted or expanded by electric stimulation
received through the first and the second electrodes 164 and 184.
The first and the second imitative muscles 163 and 183 may be
manufactured by composing nanofiber with electric active hydrogel.
The material and manufacturing method of the first and the second
imitative muscles 163 and 183 are not limited to the exemplary
embodiment and may be variously changed.
[0066] FIG. 7 is a cross-sectional view of a micropump according to
a fourth exemplary embodiment of the present invention.
[0067] Referring to FIG. 7, a micropump 400 according to the fourth
exemplary embodiment has the same configuration as the micropump
200 according to the second exemplary embodiment, except that the
first deforming member 160 and the second deforming member 180 are
made of artificial muscles. The same members as those in the second
exemplary embodiment are indicated by the same reference numerals.
The configurations of the first deforming member 160 and the second
deforming member 180 are the same as those in the third exemplary
embodiment, such that the detailed description is not provided.
[0068] FIG. 8 is a waveform diagram showing applied signals of a
first deforming member and a second deforming member shown to
illustrate a first operation method of the micropumps according to
the first to fourth exemplary embodiments. One cycle waveform is
shown in (a) of FIG. 8 and a continuous waveform is shown in (b) of
FIG. 8. In (a) of FIG. 8, the vertical axis shows the displacement
of the first deforming member and the second deforming member,
which shows the amount of maximum upward displacement, assuming
that the flat state is 0.
[0069] Referring to FIG. 8, the operation method of the micropump
includes a first section, a second section, and a third section.
The first section is a section where an electric signal is applied
to the first deforming member such that the first deforming member
expands to the maximum displacement (first displacement) while an
electric signal is applied to the second deforming member, with a
time difference from the first deforming member, such that the
second deforming member initially expands. The second section is a
section where the first deforming member retracts from the maximum
displacement while the second deforming member expands to the
maximum displacement (second displacement). The third section is a
section where the first deforming member retracts to the minimum
displacement while the second deforming member retracts.
[0070] Referring to FIG. 2 and FIG. 8, the first deforming member
16 expands from the minimum displacement to the maximum
displacement in the first section. Therefore, an intake force is
generated in the first space 101 and the fluid is sucked from the
first intake pipe 12 into the first space 101. In the exemplary
embodiment, the minimum displacement implies zero displacement.
[0071] In the first section, the second deforming member 18 starts
to expand from the minimum displacement with a time difference "a"
shown in FIG. 8, before the first deforming member 16 reaches the
maximum displacement. Accordingly, the fluid in the first space 101
can be sucked into the second space 102 when the fluid in the first
space 101 keeps the inertia in the forward direction, by opening
the second space 102, such that energy efficiency of the micropump
100 can be increased.
[0072] In the second section, the first deforming member 16 starts
to retracts from the maximum displacement and the second deforming
member 18 expands to the maximum displacement. Accordingly, the
maximum intake force is generated in the second space 102, such
that the fluid is sucked into the second space 102 through the
first space 101 and the connection channel 103. Since the maximum
displacement of the second deforming member 18 is larger than the
maximum displacement of the first deforming member 16, the second
deforming member 18 makes a pressure inclination larger than the
first deforming member 16.
[0073] In the third section, the first deforming member 16 retracts
to the minimum displacement and the second deforming member 18 also
retracts. The minimum displacement of the second deforming member
18 may exists in the first section of the next cycle. As the first
deforming member 16 and the second deforming member 18 retract, the
fluid in the first space 101 and the second space 102 is discharged
to the fluid discharge pipe 14. The first deforming member 16 has a
function of preventing backward discharge through the fluid intake
pipe 12, when the first deforming member 16 keeps the minimum
displacement in the third section.
[0074] When the on/off valve 24 is disposed in the connection
channel 103, the on/off valve 24 opens the connection channel 103
by operating simultaneously with the expansion of the second
deforming member 18 in the first section. Further, the on/off valve
24 closes the connection channel 103 by operating simultaneously
with that the second deforming member 18 reaches the maximum
displacement between the second section and the third section.
[0075] The on/off valve 24 actively controls the time when the
fluid flows into the second space 102 from the first space 101. In
particular, when the on/off valve 24 is implemented by the
piezoelectric valve 240, as shown in FIG. 3, the piezoelectric
valve 240 has a structure than can expand by itself, such that the
piezoelectric valve 240 can contribute to increasing the pumping
performance and the energy efficiency of the micropump 100 by
generating an intake force by itself.
[0076] Further, the anti-backflow member 26 disposed in the fluid
intake pipe 12 and the fluid discharge pipe 14 prevents backward
flow of the fluid in the operation of the micropump 100.
[0077] As described above, the first, second, and third sections
constitute one pumping cycle while the second deforming member 18
makes a displacement larger than the first deforming member 16 and
accordingly makes a pressure inclination larger than the first
deforming member 16. Therefore, the micropump 100 according to the
present exemplary embodiment can effectively send the fluid in the
forward direction from the fluid intake pipe 12 to the fluid
discharge pipe 14 by increasing the pumping performance, and it is
possible to reduce the entire size by decreasing the number of
deforming members 16 and 18.
[0078] In the operation method of the micropump shown in FIG. 8,
the maximum displacement position of the second deforming member 18
and the minimum displacement position of the first deforming member
16 do not agree with each other. That is, the second deforming
member 18 expands to the maximum displacement and then the first
deforming member 16 retracts to the minimum displacement. Further,
a time difference as much as the second section is maintained
between the maximum displacement position of the first deforming
member 16 and the maximum displacement position of the second
deforming member 18.
[0079] FIG. 9 is a waveform diagram showing applied signals of a
first deforming member and a second deforming member shown to
illustrate a second operation method of the micropumps according to
the first exemplary embodiment to the fourth exemplary embodiment.
One cycle waveform is shown in (a) of FIG. 9 and a continuous
waveform is shown in (b) of FIG. 9.
[0080] Referring to FIG. 9, the operation method of the micropump
includes a first section, a second section, and a third section.
The first section is a section where an electric signal is applied
to the first deforming member such that the first deforming member
expands to the maximum displacement (first displacement) while an
electric signal is applied to the second deforming member, with a
time difference from the first deforming member, such that the
second deforming member initially expands. The second section is a
section where the first deforming member retracts from the maximum
displacement to the minimum displacement while the second deforming
member expands to the maximum displacement (second displacement).
The third section is a section where the first deforming member
initially expands from the minimum displacement while the second
deforming member retracts to the minimum displacement.
[0081] The second operation method of the micropump includes the
same processes as those in the first operation method, except that
the minimum displacement position of the first deforming member
agrees with the maximum displacement position of the second
deforming member and the first deforming member initially expands
in the third section.
[0082] As described above, as the minimum displacement position of
the first deforming member agrees with the maximum displacement
position of the second deforming member, the first deforming member
completely functions as a valve when the second deforming member
retracts in the third section, such that it is possible to prevent
the backward flow of the fluid and increase the pumping
performance. Further, according to the second operation method, the
flow rate from the first deforming member to the second deforming
member is larger than that in the first operation method, such that
it is possible to increase the available flow rate of the micropump
without increasing the size of the micropump.
[0083] FIG. 10 is a waveform diagram showing applied signals of a
first deforming member and a second deforming member shown to
illustrate a third operation method of the micropumps according to
the first exemplary embodiment to the fourth exemplary embodiment.
One cycle waveform is shown in (a) of FIG. 10 and a continuous
waveform is shown in (b) of FIG. 10.
[0084] Referring to FIG. 10, the operation method of the micropump
includes a first section, a second section, and a third section.
The first section is a section where an electric signal is applied
to the first deforming member such that the first deforming member
expands to the maximum displacement (first displacement). The
second section is a section where the first deforming member
retracts from the maximum displacement to the minimum displacement
while an electric signal is applied to the second deforming member
such that the second deforming member expands to the maximum
displacement (second displacement). The third section is a section
where the first deforming member is maintained at the minimum
displacement while the second deformation member retracts to the
minimum displacement.
[0085] The third operation method of the micropump includes the
same processes as those in the second operation method except that
the maximum displacement position of the first deforming member
agrees with the minimum displacement position of the second
deforming member.
[0086] While this invention has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
* * * * *