Fluid driving system for flow cytometry

• US 6,382,228 B1
• Filed: 08/02/2000
• Issued: 05/07/2002
• Est. Priority Date: 08/02/2000
• Status: Expired due to Term

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Bonne, Ulrich, Zook, J. David, Cabuz, Cleopatra, Cabuz, Eugen Loan, Ohnstein, Thomas Raymond, Satren, Ernest Allen
• Primary Examiner(s): Buiz, Michael Powell
• Assistant Examiner(s): Krishnamurthy, Ramesh
• Application Number:
  US09/630,923
• Time in Patent Office: 643 Days
• Field of Search: 137/10, 137/14, 137/115.04, 137/115.05, 137/487.5, 137/599.01, 137/599.03, 137/599.04, 137/599.06, 137/599.07, 251/129.01, 251/129.06, 417/300, 417/302, 417/304, 417/307
• US Class Current: 137/10
• CPC Class Codes: G01N 15/1404 Handling flow, e.g. hydrodynamic focusing
• CPC Class Codes: G05D 7/0694 by action on throttling means or flow sources of very small size, e.g. microfluidics microvalves F16K99/0001; microstructural devices per se B81B
• CPC Class Codes: Y10T 137/0368 By speed of fluid
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/87265 Dividing into parallel flow paths with recombining

Abstract

A fluid driving system for portable flow cytometers or other portable devices that accepts a less precise and less stable pressure source, and then adjusts the pressure in a closed-loop manner to maintain a constant, desired flow velocity. The fluid driving system may be used in portable or wearable cytometers for use in remote locations, such as at home or in the field.

Claims

1. A fluid driving system, comprising:

a non-precision pressure source for providing a pressure to a fluid in a fluid flow path, the pressure causing the fluid to have a velocity along the fluid flow path;

valve means in fluid communication with the fluid flow path for regulating the pressure that is applied by the pressure source to the fluid in the fluid flow path;

a flow sensor for measuring the velocity of the fluid at one or more locations along the fluid flow path; and

control means coupled to the valve means and the flow sensor for controlling the valve means so that the velocity of the fluid in the fluid flow path is at a desired level.

2. A fluid driving system according to claim 1, wherein the control means at least partially opens the valve means when the velocity of the fluid in the fluid flow path increases above a predetermined value.

3. A fluid driving system according to claim 1, wherein the non-precision pressure source includes at least one electrostatic meso-pump.

4. A fluid driving system according to claim 1, wherein the non-precision pressure source is manually powered.

5. A fluid driving system according to claim 4, wherein the non-precision pressure source includes a plunger that is received within a first pressure chamber, wherein the plunger is adapted to be manually depressed into the first pressure chamber.

6. A fluid driving system according to claim 5, wherein the fluid flow path has a first valve and second valve, the first valve selectively provides a fluid flow path between the first pressure chamber and a second pressure chamber, and the second valve selectively providing a vent from the second pressure chamber.

7. A fluid driving system according to claim 6, wherein the control means at least partially opens the first valve when the velocity of the fluid in the fluid flow path drops below a first predetermined value and at least partially opens the second valve when the velocity of the fluid in the fluid flow path increases above a second predetermined value.

8. A fluid driving system according to claim 6, wherein the first valve comprises a plurality of microvalves.

9. A fluid driving system according to claim 8, wherein the plurality of microvalves are electrostatically actuated.

10. A fluid driving system according to claim 9, wherein selected microvalves or groups of microvalves are individually addressable.

11. A fluid driving system according to claim 6, wherein the second valve comprises a plurality of microvalves.

12. A fluid driving system, comprising:

two or more fluid flow paths;

two or more non-precision pressure sources, each pressure source providing a pressure to a fluid in a corresponding one of the fluid flow paths, the pressure causing the fluid in each fluid flow path to have a velocity;

two or more valves, each valve in fluid communication with a corresponding one of the fluid flow paths for regulating the pressure that is applied to the fluid in the corresponding fluid flow path;

two or more flow sensors, each measuring the velocity of the fluid in a corresponding fluid flow path; and

control means coupled to the two or more valves and the two or more flow sensors for controlling the two or more valves so that the velocity of the fluid in each of the fluid flow paths is at a desired level.

13. A fluid driving system according to claim 12, wherein each pressure source includes:

a first pressure chamber for receiving an input pressure; and

a second pressure chamber.

14. A fluid driving system according to claim 13, wherein each pressure source includes a movable plunger that moves into the first pressure chamber to provide the input pressure.

15. A fluid driving system according to claim 14, wherein the movable plunger is adapted to be manually depressed.

16. A fluid driving system according to claim 13, wherein each fluid flow path has a corresponding first valve and second valve, the first valve selectively provides a fluid flow path between the first pressure chamber and the second pressure chamber, and the second valve provides a vent from the second pressure chamber.

17. A fluid driving system according to claim 16, wherein the control means at least partially opens the first valve of a corresponding fluid flow path when the velocity of the fluid in the corresponding fluid flow path drops below a first predetermined value and at least partially opens the second valve when the velocity of the fluid in the corresponding fluid flow path increases above a second predetermined value.

18. A fluid driving system according to claim 17, wherein the first valve comprises a plurality of microvalves.

19. A fluid driving system according to claim 18, wherein the plurality of microvalves are electrostatically actuated.

20. A fluid driving system according to claim 19, wherein selected microvalves or groups of microvalves are individually addressable.

21. A fluid driving system according to claim 17, wherein the second valve comprises a plurality of microvalves.

22. A fluid driving system according to claim 12, wherein the flow sensor is a thermal anemometer type flow sensor.

23. A fluid driving system according to claim 22, wherein the thermal anemometer type flow sensor is a microbridge flow sensor.

24. A method for providing a controlled flow stream from a non-precision pressure source, comprising:

providing a non-precision pressure to a pressure chamber, which then provides a velocity to a flow stream;

sensing the velocity of the flow stream; and

alleviating the pressure in the pressure chamber if the velocity of the flow stream rises above a predetermined level.

25. A method according to claim 24, wherein the alleviating step includes opening one or more valves to vent the pressure in the pressure chamber when the velocity of the flow stream rises above the predetermined level.

26. A method according to claim 24, wherein the non-precision pressure is provided by a manual powered pressure source.

27. A method according to claim 26, wherein the non-precision pressure is provided by manually depressing a plunger into the pressure chamber.

28. A method according to claim 25, wherein the pressure chamber includes a first pressure chamber and a second pressure chamber, wherein the non-precision pressure is applied to the first pressure chamber.

29. A method according to claim 28, wherein the alleviating step includes venting the second pressure chamber when the velocity of the flow stream rises above a predetermined level.

30. A method according to claim 29, wherein the second pressure chamber is vented by opening one or more vent valves that are in fluid communication with the second pressure chamber.

31. A method according to claim 30, further comprising the step of closing one or more of the vent valves when the velocity of the flow stream falls below a predetermined level.

32. A method according to claim 28, further comprising the step of opening one or more valves between the first pressure chamber and the second pressure chamber when the velocity of the flow stream falls below a predetermined level.

33. A method according to claim 32, further comprising the step of closing one or more of the valves between the first pressure chamber and the second pressure chamber when the velocity of the flow stream rises above a predetermined level.

34. A method according to claim 28, comprising venting the second pressure chamber by opening one or more vent valves that are in fluid communication with the second pressure chamber when the velocity of the flow stream rises above a predetermined level, and opening one or more valves between the first pressure chamber and the second pressure chamber when the velocity of the flow stream falls below a predetermined level.

35. A method according to claim 34, further comprising the step of actively controlling the number of vent valves and the number of valves between the first pressure chamber and the second pressure chamber that are open so that the velocity of the flow stream falls with a predetermined range of acceptable velocities.