Methods of operating an electrostatically actuated pump

• US 6,767,190 B2
• Filed: 02/25/2003
• Issued: 07/27/2004
• Est. Priority Date: 10/09/2001
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cabuz, Cleopatra, Cabuz, Eugen I.
• Primary Examiner(s): Yu, Justine R.
• Assistant Examiner(s): Sayoc, Emmanuel
• Application Number:
  US10/374,294
• Publication Number:
  US 20030129064A1
• Time in Patent Office: 518 Days
• Field of Search: 417/322, 417/413.1, 417/413.2, 417/413.3, 417/349, 417/479, 417/53
• 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. 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, wherein said diaphragm is mounted and adapted to move within said chamber;

the method comprising the steps of;

selecting a diaphragm for actuation;

using an electrostatic force by applying a voltage between two or more electrodes to move the selected diaphragm across more than half of said chamber from a first position to a second position; and

using an elastic force to return the selected diaphragm to substantially the first position in said chamber.

2. A method according to claim 1 wherein each step is repeated until every diaphragm in the body has been selected once.

3. A method according to claim 1 comprising the step of using an elastic force to prevent movement of all non-selected diaphragms.

4. A method according to claim 1 further comprising the step of using an electrostatic force to prevent movement of all non-selected diaphragms.

14. A method as in claim 1 wherein the first position is adjacent a first side of said chamber and the second position is adjacent a second side of said chamber.

5. A method of pumping a fluid in a pump comprising a body forming at least one chamber having a volume and a first electrode mounted relative to a wall of the chamber, the chamber further having a diaphragm with a second electrode, the method comprising the steps of:

using an electrostatic force by applying a voltage between the first and second electrodes to move the diaphragm to a first position on a first side of said chamber;

using an elastic force to move the diaphragm from the first position to a second position on a second side of said chamber.

6. A method according to claim 5 wherein the fluid being pumped does not pass between the diaphragm and the electrode.

7. A method according to claim 5 wherein the elastic force is generated by a tension applied to the diaphragm.

8. A method according to claim 5 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.

9. 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 using an electrostatic force by applying a voltage between two or more electrodes including the first electrode to move said first diaphragm from a first position on said center wall to a second position on said chamber wall defining part of said first portion;

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

pushing fluid out of said second portion through said outlet;

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 by applying a voltage between two or more electrodes including the second electrode to pull said second diaphragm towards the second electrode while applying an elastic force to pull the first diaphragm from the second position to the first position until the first diaphragm covers the inlet, preventing fluid flow through said inlets.

10. A method according to claim 9 wherein the fluid does not pass between the first electrode and the first diaphragm.

11. A method according to claim 9 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.

12. A method according to claim 9 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.

13. 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 by applying an electrostatic force to the diaphragm in the first elementary cell by providing a voltage between two or more electrodes to move the diaphragm in the first (elementary cell from a first position on one side of the first elementary cell to a second position on another side of the first elementary cell;

drawing the amount of fluid from the first elementary cell into the second elementary cell by applying an electrostatic force to the diaphragm in the second elementary cell by providing a voltage between two or more electrodes, and further applying only an elastic force to the diaphragm in the first elementary cell to move the diaphragm in the first elementary cell from the second position to the first position;

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.

15. A method of pumping a fluid in a pump comprising a body forming a chamber, wherein the chamber includes a diaphragm mounted in said chamber and adapted to move within said chamber;

the method comprising the steps of;

using an electrostatic force by providing a voltage between two or more electrodes to move the selected diaphragm across more than half of said chamber from a first position to a second position, the diaphragm elastically deforming when moved from the first position to the second position; and

deactivating the electrostatic force, wherein the diaphragm returns to the first position under elastic restoring forces.