U.S. patent application number 11/024937 was filed with the patent office on 2006-07-06 for active valve and active valving for pump.
Invention is credited to Edward T. Tanner.
Application Number | 20060147329 11/024937 |
Document ID | / |
Family ID | 36640605 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060147329 |
Kind Code |
A1 |
Tanner; Edward T. |
July 6, 2006 |
Active valve and active valving for pump
Abstract
A pump (20, 120, 320, 420) comprises a pump body (22); an
actuator (26); and, one or more active valves (30, 32). The pump
body at least partially defines a pumping chamber (28) which has an
inlet port (29) and an outlet port (31). The actuator (26) is
situated at least partially in the pumping chamber for acting upon
a fluid in the pumping chamber. The active valve (30, 32)
selectively opens and closes a port with which it is aligned, e.g.,
either the inlet port (20) or the outlet port (31). In some
embodiments, the active valve (30, 32) comprises a piezoelectric
element (40) which responds to voltage for the selective opening
and closing of its aligned port. In an illustrated embodiment, the
piezoelectric element is a piezoceramic film (42). In one
implementation of the pump, both the inlet valve (30) and the
outlet valves (32) are active valves. In another implementation of
the pump, the inlet valve (30) is an active valve but the outlet
valve (323) is a passive valve (e.g., is influenced by flow of
fluid in the pump). In other embodiments, active valves operate in
accordance with magnetic forces and have electric conductors (64)
or wiring embedded or otherwise formed therein in a coil shape to
form a magnetic field. In addition, the ports which host the
magnetically activated active valves have a magnet (60) formed
therearound. In some embodiments, when an electric current is
applied to the circuit in the valve, the direction of electric flow
in the conductors in the flexible valve is such that the magnetic
field created thereby attracts the magnetic field extant at the
port opening to close the valve.
Inventors: |
Tanner; Edward T.;
(Williamsburg, VA) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Family ID: |
36640605 |
Appl. No.: |
11/024937 |
Filed: |
December 30, 2004 |
Current U.S.
Class: |
417/505 |
Current CPC
Class: |
F04B 43/046 20130101;
F16K 99/0048 20130101; F16K 99/0057 20130101; F16K 99/0046
20130101; F04B 7/0076 20130101; F16K 99/0001 20130101; F16K 99/0034
20130101; F04B 7/00 20130101; F16K 99/0007 20130101; F16K 2099/0094
20130101 |
Class at
Publication: |
417/505 |
International
Class: |
F04B 7/00 20060101
F04B007/00 |
Claims
1. A pump comprising: a pump body for at least partially defining a
pumping chamber, the pump body having an inlet port and an outlet
port; an actuator situated at least partially in the pumping
chamber for acting upon a fluid in the pumping chamber; a valve for
selectively opening and closing an aligned one of the ports, the
valve comprising a piezoelectric element which responds to a
voltage for the selective opening and closing of the aligned
port.
2. The pump of claim 1, wherein the piezoelectric element is a
piezoceramic film.
3. The pump of claim 1, wherein the valve is an inlet valve for
admitting the fluid into the pumping chamber.
4. The pump of claim 1, wherein the valve is an outlet valve for
discharging the fluid into the pumping chamber.
5. The pump of claim 1, wherein the valve is an inlet valve aligned
with the inlet port; and further comprising an outlet valve for
selectively opening and closing the outlet port, the outlet valve
comprising a piezoelectric element which responds to a voltage for
the selective opening and closing of the outlet port.
6. The pump of claim 1, wherein the valve is an inlet valve aligned
with the inlet port; and further comprising an outlet valve for
selectively opening and closing the outlet port, the outlet valve
being a passive valve having motion primarily influenced by flow of
fluid in the pump.
7. A pump comprising: a pump body for at least partially defining a
pumping chamber, the pump body having an inlet port and an outlet
port, at least one of the inlet port and the outlet port having a
magnet positioned proximate thereto; an actuator situated at least
partially in the pumping chamber for acting upon a fluid in the
pumping chamber; a valve for selectively opening and closing an
aligned one of the ports, the valve which selectively opens and
closes the port having the magnet proximate thereto comprising a
flexible member through which an electrical conductor is configured
for creating a magnetic field which either causes the valve to
attract or to repulse the magnet for respectively either closing or
opening the port having the magnet proximate thereto.
8. The pump of claim 7, wherein the valve which comprises the
flexible member having the electrical conductor is an inlet valve
for admitting the fluid into the pumping chamber.
9. The pump of claim 7, wherein the valve which comprises the
flexible member having the electrical conductor is an outlet valve
for discharging the fluid into the pumping chamber.
10. The pump of claim 7, wherein both the inlet port and the outlet
port have a magnet proximate thereto, and wherein both an inlet
valve which is aligned with the inlet port and an outlet valve
which is aligned with the outlet port comprise the flexible member
having the electrical conductor.
11. The pump of claim 7, wherein the flexible member comprises a
flex circuit.
12. The pump of claim 7, wherein the valve which selectively opens
and closes the port having the magnet proximate thereto is
connected so that, in a first stroke of pump operation electrical
current runs through the conductor to create a magnetic field which
attracts the valve to the magnet, and so that, in a second stroke
of pump operation electrical current runs through the conductor to
create a magnetic field which causes the valve to repel the
magnet.
13. A pump comprising: a pump body for at least partially defining
a pumping chamber, the pump body having an inlet port and an outlet
port, at least one of the inlet port and the outlet port having
means for generating a first magnetic field positioned proximate
thereto; an actuator situated at least partially in the pumping
chamber for acting upon a fluid in the pumping chamber; a valve for
selectively opening and closing an aligned one of the ports, the
valve which selectively opens and closes the port having the means
for generating the first magnetic field proximate thereto
comprising a flexible member which carries means for generating a
second magnetic field, and wherein the first magnetic field and the
second magnetic field serve to attract or to repulse the valve for
respectively either closing or opening the port having the means
for generating the first magnetic field proximate thereto.
14. The pump of claim 13, wherein the means for generating the
second magnetic field comprises an electrical conductor carried by
the flexible member.
15. The pump of claim 14, wherein the valve which selectively opens
and closes the port having the means for generating the first
magnetic field proximate thereto is connected so that, in a first
stroke of pump operation electrical current runs through the
conductor to generate the second magnetic field to cause attraction
of the valve to the magnet, and so that, in a second stroke of pump
operation electrical current runs through the conductor to generate
the second magnetic field to cause the valve to repel the
magnet.
16. The pump of claim 13, wherein the means for generating the
first magnetic field comprises a permanent magnet.
17. The pump of claim 13, wherein the flexible member comprises a
flex circuit.
18. A method of operating a pump, the pump comprising a pump body
for at least partially defining a pumping chamber, the pump body
having an inlet port and an outlet port, and an actuator situated
at least partially in the pumping chamber for acting upon a fluid
in the pumping chamber, the method comprising: providing an active
valve for selectively closing and opening an aligned one of the
ports; applying a signal to a piezoelectric member which comprises
the active valve for suitably orienting the active valve for the
selective opening and closing of the aligned port.
19. The method of claim 18, further comprising controlling duration
of application of the signal to the active valve.
20. The method of claim 18, wherein the active valve is an inlet
valve aligned with the inlet port, wherein the pump further
comprises a passive outlet valve aligned with the outlet port, and
wherein the method further comprises: applying the signal to a
piezoelectric member which comprises the active valve for suitably
orienting the active valve for the opening of the inlet port; and,
once the pump chamber is self-primed, maintaining the inlet port
essentially open while allowing the outlet valve to move in
response to phenomena occurring in the pump chamber.
21. A method of operating a pump, the pump comprising a pump body
for at least partially defining a pumping chamber, the pump body
having an inlet port and an outlet port, and an actuator situated
at least partially in the pumping chamber for acting upon a fluid
in the pumping chamber, the method comprising: providing a magnet
proximate at least one of the inlet port and the outlet port;
providing an active valve for selectively closing and opening the
magnet-proximate port; applying a signal to an electrical conductor
provided in a flexible member of the active valve for creating a
magnetic field at the active valve, the magnetic field at the
active valve either causing the active valve to attract the magnet
and thereby close the magnet-proximate port, or causing the active
valve to repel the magnet and thereby open the magnet-proximate
port.
22. The method of claim 21, further comprising: applying electrical
current in a manner so that, in a first stroke of pump operation,
the electrical current runs through the conductor to create a
magnetic field which attracts the valve to the magnet to close the
magnet-proximate port; and applying electrical current in a manner
so that, in a second stroke of pump operation, the electrical
current runs through the conductor to create a magnetic field which
repels the valve relative to the magnet to open the
magnet-proximate port.
23. A method of operating a pump, the pump comprising a pump body
for at least partially defining a pumping chamber, the pump body
having an inlet port and an outlet port, and an actuator situated
at least partially in the pumping chamber for acting upon a fluid
in the pumping chamber, the method comprising: providing a first
magnetic field proximate at least one of the inlet port and the
outlet port; providing an active valve having a flexible member for
selectively closing and opening the port which is proximate the
means for generating the first magnetic field; providing a second
magnetic field by means carried at the active valve, the second
magnetic field either causing the active valve to attract the first
magnetic field and thereby close the port, or causing the active
valve to repel the first magnetic field and thereby open the port.
Description
[0001] This application is related to simultaneously-filed U.S.
patent application Ser. No. 10/______ (attorney docket: 4209-52),
entitled "METHOD AND APPARATUS FOR SCAVENGING ENERGY DURING PUMP
OPERATION", which is incorporated herein by reference in its
entirety.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention pertains to an active valve for a
pump.
[0004] 2. Related Art and Other Considerations
[0005] Many types of pumps have been devised for pumping fluid,
such as (for example) piston pumps, diaphragm pumps, peristaltic
pumps, just to name a few. These pumps have different types of
actuators and moving parts which act upon fluid in a pumping
chamber. Typically the pumping chamber is defined by a pump body
which has an inlet port and an outlet port. Communication of fluid
through the inlet port and into the chamber, and out of the output
port, is usually gated by one or more valves.
[0006] What is needed, and an object of the present invention, is
apparatus, method, and/or technique for providing effective valving
for a pump.
BRIEF SUMMARY
[0007] A pump comprises a pump body; an actuator; and, one or more
active valves. The pump body at least partially defines a pumping
chamber which has an inlet port and an outlet port. The actuator is
situated at least partially in the pumping chamber for acting upon
a fluid in the pumping chamber. The active valve selectively opens
and closes a port with which it is aligned, e.g., either the inlet
port or the outlet port.
[0008] In some embodiments the active valve comprises a
piezoelectric element which responds to voltage for the selective
opening and closing of its aligned port. In an illustrated
embodiment, the piezoelectric element is a piezoceramic film. In
one implementation of the pump, both the inlet valve and the outlet
valves are active valves. In another implementation of the pump,
only one of the valves is an active valve and the other is a
passive valve, e.g., the inlet valve is an active valve but the
outlet valve is a passive valve (e.g., is influenced by flow of
fluid in the pump).
[0009] In other active valve embodiments, active valves operate in
accordance with magnetic forces. In various implementations of the
magnetically activated active valve embodiments, one or more of the
inlet valve and the outlet valve are formed from a flexible
material and have electric conductors or wiring embedded or
otherwise formed therein in a coil shape to form a magnetic field.
In addition, the ports which host the magnetically activated active
valves have a magnet (e.g., permanent magnet) formed therearound.
In some embodiments, when an electric current is applied to the
circuit in the valve, the direction of electric flow in the
conductors in the flexible valve is such that the magnetic field
created thereby attracts the magnetic field extant at the port
opening to close the valve. When the electric field is not applied,
the valve can open (e.g., by fluidic conditions created in the
pumping chamber by the diaphragm). In other embodiments, when an
electric current is applied to the circuit in the valve, the
direction of electric flow in the conductors in the flexible valve
is such that the magnetic field created thereby repels the magnetic
field extant at the port opening to open the valve. When the
electric field is not applied, the valve can close. In yet other
embodiments, the direction of electric current can be switched to
selective create attracting and repelling fields for closing and
opening of the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing and other objects, features, and advantages of
the invention will be apparent from the following more particular
description of preferred embodiments as illustrated in the
accompanying drawings in which reference characters refer to the
same parts throughout the various views. The drawings are not
necessarily to scale, emphasis instead being placed upon
illustrating the principles of the invention.
[0011] FIG. 1A and FIG. 1B are sectioned side views of a first
example embodiment of a pump having active valves, FIG. 1A showing
a displaced state of an active inlet valve and a non-displaced
state of an active outlet valve; and FIG. 1B showing a
non-displaced state of the active inlet valve and a displaced state
of the active outlet valve.
[0012] FIG. 2 is a sectioned side view of an example, non-limiting
embodiment of a piezoelectric wafer which can comprise an active
valve for a pump.
[0013] FIG. 3 is a plan view taken along line 3-3 of FIG. 1B.
[0014] FIG. 4 is a sectioned side view of another example
embodiment of a pump having active valves and a timer for
controlling duration of valve operation.
[0015] FIG. 5A and FIG. 5B are sectioned side views of yet another
example embodiment of a pump having an active valve, FIG. 5A
showing a displaced state of an active inlet valve and a
non-displaced state of a passive outlet valve; and FIG. 5B showing
a non-displaced state of the active inlet valve and an opened state
of the passive outlet valve.
[0016] FIG. 6 is a sectioned side view of the example pump
embodiment of FIG. 5A and FIG. 5B but having a timer for
controlling duration of valve operation.
[0017] FIG. 7 is a sectioned side view of the example pump
embodiment of FIG. 5A and FIG. 5B showing a mode of operation in
which an active inlet valve is kept open after self-priming of the
pump, and wherein a passive outlet valve opens an outlet port.
[0018] FIG. 8A and FIG. 8B are sectioned side views of an example
embodiment of a pump having magnetically activated active valves,
FIG. 8A showing a displaced state of an active inlet valve and a
non-displaced state of an active outlet valve; and FIG. 8B showing
a non-displaced state of the active inlet valve and an opened state
of the active outlet valve.
[0019] FIG. 8A1 and FIG. 8A2 are enlargements of an inlet port
region and an outlet port region, respectively, of FIG. 8A.
[0020] FIG. 9A and FIG. 9B are sectioned side views of another
example embodiment of a pump having magnetically activated active
valves, FIG. 9A showing a displaced state of an active inlet valve
and a non-displaced state of an active outlet valve; and FIG. 9B
showing a non-displaced state of the active inlet valve and an
opened state of the active outlet valve.
[0021] FIG. 10 is a plan view taken along line 10-10 of FIG.
8A.
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] In the following description, for purposes of explanation
and not limitation, specific details are set forth such as
particular architectures, interfaces, techniques, etc. in order to
provide a thorough understanding of the present invention. However,
it will be apparent to those skilled in the art that the present
invention may be practiced in other embodiments that depart from
these specific details. In other instances, detailed descriptions
of well-known devices, circuits, and methods are omitted so as not
to obscure the description of the present invention with
unnecessary detail.
[0023] The pumps described herein comprise a pump body for at least
partially defining a pumping chamber; an actuator which acts upon a
fluid in the pumping chamber; and at least one active valve for the
pump. In some embodiments, the active valve has a piezoelectric
element which is selectively responsive to voltage for opening and
closing a port of the pump body with which the active valve is
aligned. In other embodiments, the active valve is a
magnetically-activated active valve.
[0024] Pump 20 of FIG. 1A and FIG. 1B is described generally, and
as such is meant to be representative of many different pump
configurations which can host the inventive advancement described
herein. Pump 20 comprises a body which includes a pump body base 22
and a pump body lid or cover 24. For the particular geometry shown
in FIG. 1A and FIG. 1B, the pump body, including both its pump body
base 22 and a pump body cover 24, are essentially cylindrical
(e.g., circular as seen from the top). A pumping chamber 28 is
formed in the pump body, and an actuator is provided for drawing
fluid into pumping chamber 28 and pumping fluid out of pumping
chamber 28.
[0025] It just so happens that the form of the actuator illustrated
in FIG. 1A and FIG. 1B is a diaphragm 26. However, it should be
understood that, for this and subsequently described embodiments,
the actuator need not be a diaphragm but could take other forms
such as, for example, a piston-type actuator or even a peristaltic
type actuator, for example. In the particular case that the
actuator is actually a diaphragm, the diaphragm 26 can be clamped,
adhered, fastened, or welded, preferably about its periphery, to a
seat or other surface of the pump body.
[0026] The pump body 22 of the example pump 20 of FIG. 1A and FIG.
1B has an inlet port 29 which is selectively opened and closed by
inlet valve 30 with which it is aligned. Similarly, pump body 22
has an outlet port 31 which is selectively opened and closed by
outlet valve 32, the outlet valve 32 being aligned or situated for
opening and closing of outlet port 31. The inlet valve 30 admits
the fluid into the pumping chamber 28, whereas the outlet valve 32
permits fluid to be discharged from the pumping chamber 28. In the
embodiment of FIG. 1A and FIG. 1B, both of the valves 30 and 32 are
active valves in that they are actively driven, e.g., by an
external signal or circuit, and are not merely passively responsive
to phenomena (e.g., fluidic phenomena) occurring in the pumping
chamber 28.
[0027] The valves of pump 20 (e.g., either inlet valve 30 or outlet
valve 32) comprise a deformable or flexible member which is a
piezoelectric member (e.g., piezoceramic film). That is, one or
both of valves 30, 32 comprise a piezoelectric element 40 that
preferably constitutes a working portion of the valve. As explained
subsequently, the piezoelectric member comprising the valve
preferably has electrodes sputtered or otherwise formed on its
opposing major surfaces.
[0028] In whatever form it takes, application of a voltage to
piezoelectric element 40 causes a flexure, stress, or compression
in a piezoelectric wafer 42 which comprises piezoelectric element
40. The flexure, stress, or compression in piezoelectric wafer 42
causes the piezoelectric element 40 to deflect or displace, thereby
moving the valve which it comprises, either to a port closing
position or to a port opening position. In the particular
implementation shown in FIG. 1A and FIG. 1B, application of a
non-zero voltage to the valve causes flexure of the piezoelectric
element 40 and thus an opening of the port that otherwise would be
covered by the valve.
[0029] The piezoelectric element 40 preferably comprises a
multi-layered laminate 42. The multi-layered laminate can comprise
a piezoelectric wafer which is laminated by an adhesive between an
unillustrated metallic substrate layer and an unillustrated outer
metal layer. The structure of the multi-layered laminate and a
process for fabricating the same are described in one or more of
the following (all of which are incorporated herein by reference in
their entirety): PCT Patent Application PCT/US01/28947, filed 14
Sep. 2001; U.S. patent application Ser. No. 10/380,547, filed Mar.
17, 2003, entitled "Piezoelectric Actuator and Pump Using Same";
U.S. patent application Ser. No. 10/380,589, filed Mar. 17, 2003,
entitled "Piezoelectric Actuator and Pump Using Same".
[0030] As illustrated in FIG. 2, the piezoelectric element 42
(which can be included in inlet valve 30 and/or outlet valve 32)
has thin electrodes 44 sputtered or otherwise is formed on its two
opposing major surfaces. The electrodes 44 can be formed of Nickel
or Silver, or other appropriate conductive metal. One of the
electrodes 44 is a positive electrode; the other electrode 44 is a
negative electrode. The positive and negative electrodes 44 are
engaged by respective positive and negative leads 46.
[0031] The piezoelectric element 40 can be mounted to, affixed to
or on, or incorporated into the valve in various ways. FIG. 3 shows
the inlet port 29 from the perspective of the pumping chamber 25.
In the example illustration of FIG. 3, the valve 30 has a shoulder
portion 47 which is proximate a sidewall of pump body 22, and a
distal portion 48 which flexibly extends over inlet port 29. At its
shoulder portion 47 valve 30 may be secured to the floor of pump
body 22 by an adhesive, by spot welding (as indicated by dotted
lines 49), or by mechanical clamping, for example. Other geometric
configurations of the valve and other mounting techniques are also
possible. The foregoing discussion of inlet valve 30 is also
applicable, at least in some embodiments, to outlet valve 32.
[0032] The positive and negative leads 46 are connected to control
circuit 50. The control circuit 50 includes a power supply 51
(e.g., battery) or other type of charge storage device (e.g.,
capacitance). In one example implementation, the control circuit 50
has a switch 52 which is selectively closed to provide voltage to
the inlet valve 30, and a switch 53 which is selectively closed to
provide voltage to the outlet valve 32.
[0033] FIG. 1A shows inlet valve 30 being flexed in response to
application of non-zero voltage to the piezoelectric element 40 of
inlet valve 30 for permitting fluid to enter into pumping chamber
28. In FIG. 1A the outlet valve 32 remains unflexed for covering
outlet port 31. FIG. 1B, on the other hand, shows inlet valve 30
remaining unflexed for covering inlet port 29 while also showing
movement of outlet valve 32 in response to application of voltage
to the piezoelectric element 40 of outlet valve 32 for permitting
expulsion of fluid from pumping chamber 28 through outlet port
31.
[0034] FIG. 4 shows a variation of the pump of 20 of the embodiment
of FIG. 1A and FIG. 1B, i.e., pump 120. In the variation of FIG. 4,
control circuit 50 includes a timer 54 which times or controls the
duration of opening and/or closure of switch 52 and/or switch 53,
and thus the opening and closing of inlet valve 30 and/or outlet
valve 32. The timer 54 can take any suitable form, from a simple
circuit or delay line to a microprocessor, and is operated,
sequenced, or programmed in accordance with a desired operation of
the pump 120, e.g., to match the frequency of operation of pump
120. In one mode of operation, the timer 54 likely operates the two
switches 52 and 53 with differing signals and thus differing
timings, so that the inlet valve 30 and outlet valve 32 are not
necessarily open at the same time. FIG. 4 basically corresponds to
FIG. 1A in showing opening of active inlet valve 30. Those skilled
in the art will appreciate that the active outlet valve 32 of the
FIG. 4 embodiment can be opened or activated by appropriate signal
or voltage as aforediscussed in conjunction with FIG. 1B. Moreover,
the opening and controlling of switches 53 can be accomplished via
any suitable means, such as (for example) solenoids, Hall Effect
devices, relays, or transistors, bearing in mind that switches do
not necessarily need to be mechanical but can be partially or
entirely electrical.
[0035] FIG. 5A and FIG. 5B show another embodiment of a pump having
one valve which is an active valve and another valve which is a
passive valve. In the particular example implementation of FIG. 5A
and FIG. 5B, pump 320 has an active inlet valve 30 but a passive
outlet valve 332. In another implementation, the outlet valve may
be active and the inlet valve may be passive.
[0036] FIG. 5A shows a displaced state of the active inlet valve 30
and a non-displaced state of the passive outlet valve 332. FIG. 5B
shows a non-displaced state of the active inlet valve 30 and an
opened state of the passive outlet valve 332. The active inlet
valve 30 is driven by a signal or voltage to selectively cover and
open inlet port 29. The passive outlet valve 332 opens and closes
over outlet port 31 in response to phenomena occurring (e.g.
fluidic phenomena) in pumping chamber 28. In essentially all other
respects except the valving and the circuitry 350 for driving the
inlet valve 30, the pump structure is illustrated as being
substantially the same as the generic, representative embodiment of
FIG. 1.
[0037] Further, as shown in the variation depicted in FIG. 6, the
circuitry 250 can include a timer 354 which times or controls the
duration of opening and/or closure of switch 52, and thus the
opening and closing of active inlet valve 30.
[0038] In one mode of operation of a pump such as pump 320 of FIG.
5A and FIG. 5B, the active inlet valve 30 may be activated to open
inlet port 29 while passive outlet valve 332 remains closed. Then,
after the pump 320 has been self-primed by sufficient admission of
fluid through inlet port 29, the active inlet valve 30 is kept open
(in view of the self-priming) and passive outlet valve 323 operates
(e.g., opens and closes) in accordance with phenomena occurring in
the pumping chamber 28. For example, FIG. 7 shows the active inlet
valve 30 being kept open (in view of completion of the
self-priming) and passive outlet valve 323 being open in response
to phenomena in the pumping chamber 28. At a subsequent moment in
time as dependent upon conditions in the pumping chamber, the
passive outlet valve 323 closes outlet port 31 (not illustrated).
Then, yet subsequently, when conditions again favor opening of
outlet port 31, the passive outlet valve 323 does again open outlet
port 31.
[0039] As one example way of implementing pumps of any of the
foregoing example embodiments, the actuator 26 can be a diaphragm
and/or include a piezoelectric layer, with the piezoelectric layer
causing the displacement of diaphragm 26 when an electric field is
applied to the piezoelectric layer. The electric field is supplied
to the piezoelectric layer of diaphragm 26 by a power supply such
as power supply 54.
[0040] Most of the structural features of the pumps are described
above merely for providing an example context for explaining how
active valves operate. As such, no particular emphasis or
criticality should be assigned to any of the structural elements or
position of elements of pump 20. For example, the structure and
positioning of the inlet valves and outlet valves are not
necessarily germane. The person skilled in the art will appreciate
that one or more of the inlet valve and outlet valve can be
oriented so that the direction of fluid flow through the valve(s)
is parallel to the displacement direction arrow 36 (e.g., one or
more of inlet valve and outlet valve are formed in a bottom wall of
pump body base 22). Alternatively, one or more of the inlet valve
and the outlet valve can be oriented so that the direction of fluid
flow through the valve(s) is perpendicular to the displacement
direction arrow 36 (e.g., one or more of inlet valve and outlet
valve is formed in a sidewall of pump body base 22).
[0041] Moreover, the shape, size, or other configuration of the
pump body and its pump body base 22 and pump body lid 24 are
variable. Variously shaped pump bodies, with or without myriad
auxiliary or surface features, could be utilized.
[0042] Examples of diaphragm type structures which include a
piezoelectric layer, and methods of fabricating the such diaphragms
and pumps incorporating the same, as well as various example pump
configurations with which the present invention is compatible, are
illustrated in the following (all of which are incorporated herein
by reference in their entirety): PCT Patent Application
PCT/US01/28947, filed 14 Sep. 2001; U.S. patent application Ser.
No. 10/380,547, filed Mar. 17, 2003, entitled "Piezoelectric
Actuator and Pump Using Same"; U.S. patent application Ser. No.
10/380,589, filed Mar. 17, 2003, entitled "Piezoelectric Actuator
and Pump Using Same".
[0043] It will be further appreciated that it is possible to
control the voltage amplitude applied to the active valves
described herein for controlling an opening distance by which the
valve displaces relative to the respective port. Thus, a degree of
opening effected by the valve is controllable or adjustable, and
thus also the flow of fluid through the valve and the pump is
adjustable and controllable.
[0044] In other active valve embodiments, active valves operate in
accordance with magnetic forces. Two illustrative examples of
differing embodiments of magnetically activated active valves are
illustrated, such as a first embodiment shown in FIG. 8A and FIG.
8B and a second embodiment shown in FIG. 9A and FIG. 9B.
[0045] For sake of simplicity, valve bodies 22 and diaphragms 26
are shown in similar manner as previous embodiments, although it
will be understood from previous explanations that such features
are not limited. The magnetically activated active valve
embodiments differ from previous embodiments in that the active
valves do not necessarily include a piezoelectric layer or member.
Rather, the active valves of the magnetically activated active
valve embodiments are formed from a flexible material and have
electric conductors or wiring embedded or otherwise formed therein
in a coil shape to form a magnetic field. In addition, the ports
which host the magnetically activated active valves have a magnet
(e.g., permanent magnet) formed therearound. In some embodiments,
when an electric current is applied to the circuit in the valve,
the direction of electric flow in the conductors in the flexible
valve is such that the magnetic field created thereby attracts the
magnetic field extant at the port opening to close the valve. When
the electric field is not applied, the valve can open (e.g., by
fluidic conditions created in the pumping chamber by the
diaphragm). In other embodiments, when an electric current is
applied to the circuit in the valve, the direction of electric flow
in the conductors in the flexible valve is such that the magnetic
field created thereby repels the magnetic field extant at the port
opening to open the valve. When the electric field is not applied,
the valve can close. In yet other embodiments, the direction of
electric current can be switched to selective create attracting and
repelling fields for closing and opening of the valve.
[0046] FIG. 8A and FIG. 8B illustrate inlet port 29(8) as having a
magnet 60 positioned around at least a portion thereof. If inlet
port 29(8) is circular, then magnet 60 is annular in shape and
substantially surrounds inlet port 29(8). A similar magnet 62 can
be provided at outlet port 31(8).
[0047] FIG. 10 shows, from the perspective of the pumping chamber,
inlet valve 30(8) which selectively opens and closes inlet port
29(8) of FIG. 8A. FIG. 10 illustrates the electrical conductor 64
which is formed or embedded in inlet valve 30(8). The electrical
conductor 64 comprises two parallel segments 66, 68 which extend
from respective attachment points 70 and 72 toward a distal end of
valve 30(8). An intermediate coiled segment 74 connects parallel
segments 66, 68. The coiled segment 74 extends over and around the
mouth of inlet port 29(8), and is preferably aligned over the
magnet 60.
[0048] In an example implementation, valves such as inlet valve
30(8) described above can be realized by a flex circuit which has
the embedded conductor. Such a flex circuit needs to flexible
enough to displace sufficiently to accommodate fluid flow, and yet
sufficiently non-permeable so that fluid does not flow or seep
therethrough when the valve is closed.
[0049] Although the foregoing description of the magnet 60 and the
electrical conductor has been illustrated in FIG. 10 and
specifically described with regard to the inlet valve 30(8), it
will be appreciated that the outlet valve 32(8) of the same
embodiment can be similarly formed, as well as one or both of the
inlet valves and outlet valves of the ensuing embodiments (e.g.,
the embodiment of FIG. 9A and FIG. 9B).
[0050] In the embodiment of FIG. 8A and FIG. 8B, a power supply is
connected so that a closed electric circuit results in electric
current flow through conductor 64 in inlet valve 30(8) and outlet
valve 32(8) in a direction which causes magnetic attraction of the
valve to the magnet 60 in the respective port 29(8) and 31(8). In
particular, FIG. 8A shows an intake stroke of the pump in which the
electrical circuit for conductor 64 of inlet valve 30(8) is open so
that valve 30(8) is not magnetically attracted to magnet 60 of
inlet port 29(8), with the result that fluid can enter through
inlet port 29(8), e.g., under action of the diaphragm in the
pumping chamber. At outlet port 31(8), on the other hand, in the
intake stroke the electrical circuit for conductor 64 of outlet
valve 32(8) is closed so that electrical current does flow through
the conductor 64 of valve 32(8), whereby outlet valve 32(8) is
magnetically attracted to magnet 60 of outlet port 31(8), with the
result that the valve 32(8) closes outlet port 31(8) so that fluid
is not permitted to leave.
[0051] FIG. 8B shows an exhaust stroke which follows the intake
stroke of FIG. 8A. In the exhaust stroke, the electrical circuit
for conductor 64 of inlet valve 30(8) is closed so that electrical
current does flow through the conductor 64 of valve 30(8), whereby
inlet valve 30(8) is magnetically attracted to magnet 60 of inlet
port 29(8), with~the result that the valve 30(8) closes inlet port
29(8) so that fluid is not permitted to enter. At outlet port
31(8), on the other hand, in the exhaust stroke the electrical
circuit for conductor 64 of outlet valve 32(8) is open so that
valve 32(8) is not magnetically attracted to magnet 60 of outlet
port 31(8), with the result that fluid can exit through outlet port
31(8).
[0052] In the embodiment of FIG. 8A and FIG. 8B, as well as in
ensuing embodiments, a separate power supply is depicted for each
of the inlet valve and the outlet valve. It will be appreciate that
other power supply arrangements can alternatively be provided, such
as utilizing a same power supply for both the inlet valve and the
outlet valve. Further, the closing and opening of the electrical
circuit for the inlet valve is depicted by a simple switch S.sub.i
and the closing and opening of the electrical circuit for the
outlet valve is depicted by a simple switch S.sub.o. It will be
appreciated that such switches can take the forms of one or more
switches as described in conjunction with previous embodiments, and
even include an electronic controller or the like which either
times or is coordinated with the timing of the pumping action of
the pump.
[0053] In the embodiment of FIG. 9A and FIG. 9B, direction of flow
of electrical current for each of inlet valve 30(9) and outlet
valve 32(9) is selectable so that, for differing pump strokes, each
valve can either experience magnetic attraction for closing a port
or magnetic repulsion for opening a port. For example, during the
intake stroke shown in FIG. 9A, the conductor 64 in inlet valve
30(9) is connected to a power supply such that the electrical
current flowing through conductor 64 is in a direction to create a
repulsive magnetic field for inlet valve 30(9), thereby opening
inlet port 29(9) for fluid to enter the pumping chamber during the
intake stroke. During the intake stroke at the outlet port 31(9),
on the other hand, the conductor 64 in outlet valve 32(9) is
connected to a power supply such that the electrical current
flowing through conductor 64 is in a direction to create an
attractive magnetic field for outlet valve 32(9), thereby closing
outlet port 31(9) for precluding fluid from leaving the pumping
chamber during the intake stroke.
[0054] FIG. 9B shows the exhaust stroke which follows the intake
stroke of FIG. 9A. In the exhaust stroke shown in FIG. 9B, the
conductor 64 in inlet valve 30(9) is connected (e.g., to another
power supply) such that the electrical current flowing through
conductor 64 is in an opposite direction relative to the intake
stroke to create an attractive magnetic field for inlet valve
30(9), thereby closing inlet port 29(9) to preclude fluid from
entering the pumping chamber during the intake stroke. During the
exhaust stroke at the outlet port 31(9), on the other hand, the
conductor 64 in outlet valve 32(9) is connected (e.g., to another
power supply) such that the electrical current flowing through
conductor 64 is in an opposite direction relative to the intake
stroke to create a repulsive magnetic field for outlet valve 32(9),
thereby opening outlet port 31(9) for permitting fluid to leave the
pumping chamber during the intake stroke.
[0055] In the embodiments which feature the magnetically-activated
active valves, the magnets at the ports need not necessarily
surround the ports, but may merely be positioned proximate thereto.
The magnet provided at the port need not necessarily be a permanent
magnet, although provision of a permanent magnet simplifies the
electronics design. The flexible material comprising the flexible
valves can be any suitable material for forming flex circuits, for
example, so long as the material is essentially
fluid-impervious.
[0056] Moreover, it is also possible essentially to reverse the
positioning of the elements in the embodiments of FIG. 8A, FIG. 8B
and FIG. 9A, FIG. 9B by providing, for example, a magnetic material
in the valve and a electrical coil about the port covered by the
valve.
[0057] While embodiments of the invention have been described in
connection with what is presently considered to be the most
practical and preferred embodiment, it is to be understood that the
invention is not to be limited to the disclosed embodiment, but on
the contrary, is intended to cover various modifications and
equivalent arrangements included within the spirit and scope of the
appended claims.
* * * * *