Electrostatically actuated pump with elastic restoring forces

• US 20030129064A1
• Filed: 02/25/2003
• Published: 07/10/2003
• Est. Priority Date: 10/09/2001
• Status: Active Grant

• Current Assignee: Cleopatra Cabuz, Eugen I. Cabuz
• Original Assignee: Cleopatra Cabuz, Eugen I. Cabuz
• Inventors: Cabuz, Cleopatra, Cabuz, Eugen I.
• Granted Patent: US 6,767,190 B2
• Time in Patent Office: Days
• US Class Current: 417/53
• CPC Class Codes: F04B 43/025 two or more plate-like pumping members in parallel
• CPC Class Codes: F04B 43/043 Micropumps

Abstract

Methods and apparatus for electrostatically pumping fluids without passing the fluids through the electric field of the pump are contemplated. Electrostatic forces are preferably used to move the diaphragms in one direction, while elastic and/or other restorative forces are used to move the diaphragms back to their original un-activated positions. In some embodiments, this may allow fluid to be pumped without passing the fluid between actuating electrodes. This may be particularly useful when the fluids have dielectric, conductive, polar or other qualities that may affect traditional electrostatic pump performance. Pumps having various elementary cells are contemplated, including two-celled pumps disposed within a single chamber and pumps having greater numbers of cells wherein each cell is disposed within a different chamber.

Claims

1. An electrostatic pump comprising:

a body forming a chamber;

the chamber having a first opposing wall and a second opposing wall;

a diaphragm mounted between said first opposing wall and the second opposing wall, the diaphragm assuming a first position that extends adjacent the first opposing wall when no external force is applied;

a first electrode secured relative to the second opposing wall;

a second electrode secured relative to the diaphragm; and

wherein the diaphragm is electrostatically pulled and elastically deformed toward the second opposing wall when a voltage is applied between the first electrode and the second electrode, and returns substantially to the first position under elastic restoring forces when the voltage is removed.

2. An electrostatic pump according to claim 1 wherein the first opposing wall and the second opposing wall are configured such that the spacing between the first opposing wall and the second opposing wall is smaller near the edge of the chamber than near the center of the chamber.

3. An electrostatic pump according to claim 1 wherein the diaphragm is mounted under tension.

4. An electrostatic pump according to claim 1 further comprising:

an input port in fluid communication with the space between the diaphragm and the first opposing wall; and

an output port in fluid communication with the space between the diaphragm and the first opposing wall.

5. An electrostatic pump according to claim 4 wherein the input port comprises a lateral conduit that extends between the first opposing wall and the second opposing wall.

6. An electrostatic pump according to claim 4 wherein the input port is adapted to be opened and closed by movement of said diaphragm.

7. An electrostatic pump according to claim 1 further comprising a vertical conduit that extends through the second opposing wall.

8. A pump having at least one elementary cell, said cell comprising:

an electrode; and

a diaphragm, said diaphragm being adapted to deflect toward and away from said electrode;

wherein a material being pumped by said pump does not pass between said diaphragm and said electrode.

9. A pump having at least one elementary cell, said cell comprising:

a body forming a chamber having at least two opposing walls, a first opposing wall being generally flat and a second opposing wall having a curved surface to define said chamber;

a diaphragm mounted in the body under tension, the diaphragm being adapted to deflect toward and away from the first opposing wall;

wherein a material being pumped by said pump does not pass between said diaphragm and said second opposing wall.

10. An electrostatic pump comprising:

a body forming a first chamber having a first opposing wall and a second opposing wall and a second chamber having a third opposing wall and a fourth opposing wall;

a first diaphragm mounted between the first opposing wall and the second opposing wall, the first diaphragm assuming a first position that extends adjacent the first opposing wall when no external force is applied;

a second diaphragm mounted between the third opposing wall and the fourth opposing wall, the second diaphragm assuming a second position that extends adjacent the third opposing wall when no external force is applied;

a first electrode secured relative to the second opposing wall;

a second electrode secured relative to the first diaphragm;

a third electrode secured relative to the fourth opposing wall;

a fourth electrode secured relative to the second diaphragm;

wherein the first diaphragm is electrostatically pulled and elastically deformed toward the second opposing wall when a first voltage is applied between the first electrode and the second electrode, and returns substantially to the first position under elastic restoring forces when the first voltage is removed; and

wherein the second diaphragm is electrostatically pulled and elastically deformed toward the fourth opposing wall when a second voltage is applied between the third electrode and the fourth electrode, and returns substantially to the second position under elastic restoring forces when the second voltage is removed.

11. An electrostatic pump according to claim 10 further comprising:

an interconnecting conduit in fluid communication with the space between the first diaphragm and the first opposing wall and the space between the second diaphragm and the third opposing wall;

an input port in fluid communication with the space between the first diaphragm and the first opposing wall; and

an output port in fluid communication with the space between the second diaphragm and the third opposing wall.

12. An electrostatic pump according to claim 11 wherein the input port comprises a first lateral conduit that extends between the first opposing wall and the second opposing wall.

13. An electrostatic pump according to claim 12 wherein the first lateral conduit is adapted to be opened and closed by movement of said first diaphragm.

14. An electrostatic pump according to claim 11 wherein the output port. comprises a second lateral conduit that extends between the third opposing wall and the fourth opposing wall.

15. An electrostatic pump according to claim 14 wherein the second lateral conduit is adapted to be opened and closed by movement of said second diaphragm.

16. An electrostatic pump according to claim 10 wherein the first opposing wall and the second opposing wall are configured such that the spacing between the first opposing wall and the second opposing wall is smaller near the edge of the first chamber than near the center of the first chamber.

18. An electrostatic pump according to claim 10 wherein the first diaphragm is mounted under tension.

19. An electrostatic pump according to claim 10 wherein the second diaphragm is mounted under tension.

17. An electrostatic pump according to cjaim 10 wherein the third opposing wall and the fourth opposing wall are configured such that the spacing between the third opposing wall and the fourth opposing wall is smaller near the edge of the second chamber than near the center of the second chamber.

20. A pump comprising:

a chamber;

a first electrode;

a second electrode;

a first diaphragm, said first diaphragm being mounted and adapted to deflect toward and away from said first electrode;

a second diaphragm, said second diaphragm being mounted and adapted to deflect toward and away from said second electrode;

a wall situated across said chamber defining an upper portion and a lower portion of said chamber, said wall having a channel creating fluid communication between said lower portion to said upper portion, said first diaphragm being situated in said upper portion, said second diaphragm being situated in said lower portion;

an inlet in fluid communication with said upper portion; and

an outlet in fluid communication with said lower portion.

21. A pump according to claim 20, further comprising a third electrode secured relative the first diaphragm and a fourth electrode secured relative the second diaphragm.

22. A pump according to claim 21 wherein application of a voltage between said first electrode and said third electrode causes movement of said first diaphragm.

23. A pump according to claim 21 wherein application of a voltage between said second electrode and said fourth electrode causes movement of said second diaphragm.

24. A pump according to claim 21 wherein application of a voltage between said third electrode and said fourth electrode causes movement of said diaphragms.

25. A pump according to claim 20, wherein fluid being moved by said pump does not pass between said first diaphragm and said first electrode.

26. A pump according to claim 20, wherein fluid being moved by said pump does not pass between said second diaphragm and said second electrode.

27. A method of pumping a fluid in a pump comprising a body forming at least one chamber having a volume, wherein each chamber includes a diaphragm mounted in said chamber, said diaphragm having a major portion located in said chamber, wherein said diaphragm is mounted and adapted to move within said chamber;

the method comprising the steps of;

selecting a diaphragm;

using an electrostatic force to move the selected diaphragm; and

using an elastic force to move the selected diaphragm.

28. A method according to claim 27 wherein each step is repeated until every diaphragm in the body has been selected once.

29. A method according to claim 27 further comprising the step of using an elastic force to prevent movement of all non-selected diaphragms.

30. A method according to claim 27 further comprising the step of using an electrostatic force to prevent movement of all non-selected diaphragms.

31. A method of pumping a fluid in a pump comprising a body forming at least one chamber having a volume wherein at least one chamber includes a diaphragm and an electrode mounted relative a wall of the chamber, the method comprising the steps of:

using an electrostatic force to move the diaphragm to a first position;

using an elastic force to move the diaphragm to a second position.

32. A method according to claim 31 wherein the fluid being pumped does not pass between the diaphragm and the electrode.

33. A method according to claim 31 wherein the elastic force is generated by a tension applied to the diaphragm.

34. A method according to claim 31 wherein the elastic force is generated by using a diaphragm having a predefined shape and wherein the first position represents a position in which the diaphragm is deformed from the predefined shape.

35. A method of pumping a fluid in a pump comprising a body forming a chamber having a volume wherein the chamber is divided into first and second portions by a center wall, the center wall having a conduit placing the first portion and second portion in fluid communication with each other, a first diaphragm being mounted in said first portion and a second diaphragm being mounted in said second portion, a first electrode fixed relative a wall of the chamber defining part of said first portion, a second electrode fixed relative a wall of the chamber defining part of said second portion, said chamber having an inlet in fluid communication with said first portion and an outlet in fluid communication with said second portion, the method comprising:

drawing fluid into said first portion through said inlet;

drawing fluid into said second portion from said first portion through said conduit; and

pushing fluid out of said second portion through said outlet.

36. A method according to claim 35 wherein the fluid does not pass between the first electrode and the first diaphragm.

37. A method according to claim 35 wherein the step of drawing fluid into said first portion through said inlet includes:

applying an electrostatic force to the first diaphragm to pull said first diaphragm towards the first electrode while applying an elastic force to keep said second diaphragm adjacent said center wall to prevent fluid from passing through said conduit.

38. A method according to claim 35 wherein the step of drawing fluid into said second portion from said first portion through said conduit includes:

applying an electrostatic force to the second diaphragm to pull said second diaphragm towards the second electrode while applying an elastic force to pull the first diaphragm towards the center wall until the first diaphragm covers the inlet, preventing fluid flow through said inlet; and

applying an electrostatic force to the second diaphragm and an elastic force to the first diaphragm until said first diaphragm lies adjacent to the center wall and prevents fluid from flowing through the conduit.

39. A method according to claim 35 wherein the step of pushing fluid out of the second portion through the outlet includes:

applying an elastic force to the first diaphragm to keep said first diaphragm adjacent the center wall to prevent fluid from flowing through the conduit while applying an elastic force to the second diaphragm to force the fluid through the outlet.

40. A method of pumping a fluid in a pump having at least a first elementary cell and a second elementary cell, each cell including a diaphragm, the method comprising:

drawing an amount of fluid into the first elementary cell;

drawing the amount of fluid from the first elementary cell into the second elementary cell;

using the diaphragm from the first elementary cell to limit backflow from the second elementary cell into the first elementary cell; and

forcing the amount of fluid out of the second elementary cell.