Active valve and active valving for pump
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.
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.
BACKGROUND1. Field of the Invention
The present invention pertains to an active valve for a pump.
2. Related Art and Other Considerations
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.
What is needed, and an object of the present invention, is apparatus, method, and/or technique for providing effective valving for a pump.
BRIEF SUMMARYA 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.
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).
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 DRAWINGSThe 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.
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.
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.
Pump 20 of
It just so happens that the form of the actuator illustrated in
The pump body 22 of the example pump 20 of
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.
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
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”.
As illustrated in
The piezoelectric element 40 can be mounted to, affixed to or on, or incorporated into the valve in various ways.
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.
Further, as shown in the variation depicted in
In one mode of operation of a pump such as pump 320 of
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.
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).
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.
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”.
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.
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
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.
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.
Although the foregoing description of the magnet 60 and the electrical conductor has been illustrated in
In the embodiment of
In the embodiment of
In the embodiment of
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.
Moreover, it is also possible essentially to reverse the positioning of the elements in the embodiments of
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.
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.
Type: Application
Filed: Dec 30, 2004
Publication Date: Jul 6, 2006
Inventor: Edward Tanner (Williamsburg, VA)
Application Number: 11/024,937
International Classification: F04B 7/00 (20060101);