Electrostatically actuated pump with elastic restoring forces

• US 6,729,856 B2
• Filed: 10/09/2001
• Issued: 05/04/2004
• Est. Priority Date: 10/09/2001
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cabuz, Eugen I., Cabuz, Cleopatra
• Primary Examiner(s): Yu, Justine R.
• Assistant Examiner(s): Sayoc, Emmanuel
• Application Number:
  US09/974,413
• Publication Number:
  US 20030068231A1
• Time in Patent Office: 938 Days
• Field of Search: 417/322, 417/413.1, 417/413.2, 417/413.3, 417/349, 417/479
• US Class Current: 417/322
• CPC Class Codes: F04B 43/025 two or more plate-like pumping members in parallel
• CPC Class Codes: F04B 43/043 Micropumps

Abstract

An apparatus for electrostatically pumping fluids without passing the fluids through the electric field of the pump is 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 on the first opposing wall when no external force is applied;

a first electrode secured to the second opposing wall;

a second electrode secured 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:

one or more first electrodes fixed to a first opposing wall that has a curved surface;

a diaphragm having one or more second electrodes and being adapted to selectively and electrostatically deflect toward said one or more first electrodes at some time during operation of the cell;

wherein the material being pumped by said pump does not pass between said one or more first electrodes and said one or more second electrodes.

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 on 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 on the third opposing wall when no external force is applied;

a first electrode secured to the second opposing wall;

a second electrode secured to the first diaphragm;

a third electrode secured to the fourth opposing wall;

a fourth electrode secured 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.

17. An electrostatic pump according to claim 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.

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.