Piezoelectric actuator and pump using same

• US 20040000843A1
• Filed: 03/17/2003
• Published: 01/01/2004
• Est. Priority Date: 09/18/2000
• Status: Active Grant

• Current Assignee: Par Technology Corporation
• Original Assignee: Adaptivenergy, LLC
• Inventors: East, W. Joe
• Granted Patent: US 7,198,250 B2
• Time in Patent Office: Days
• US Class Current: 310/331
• CPC Class Codes: F04B 43/046 with piezoelectric drive
• CPC Class Codes: F16K 31/005 Piezoelectric benders
• CPC Class Codes: F16K 31/006 having a free end

Abstract

Thin chamber diaphragm-operated fluid handling devices, including thin chamber pumps and thin chamber valves, facilitate device compactness and, in some configurations, self-priming. Diaphragm actuators of the thin chamber devices either comprise or are driven by piezoelectric materials. The thinness of the chamber, in a direction parallel to diaphragm movement, is in some embodiments determined by the size of a perimeter seal member which sits on a floor of a device cavity, and upon which a perimeter (e.g. circumferential or peripheral portion) of the diaphragm actuator sits. The diaphragm actuator is typically retained in a device body between the floor seal member and another seal member between which the perimeter of the actuator is sandwiched. The devices have an input port and an output port.

Claims

1. A valve comprising:

a valve chamber having an elastomeric wall, the valve chamber being provided with an inlet port and an outlet port;

a piezoelectric element which is external to the valve chamber, the piezoelectric element being operable in a first state to configure the elastomeric wall of the valve chamber to a first position and to close a controlled port, and in a second state to configure the elastomeric wall of the valve chamber to a second position and to open the controlled port, the controlled port being one of the inlet port and the outlet port.

2. The apparatus of claim 1, wherein the piezoelectric element is a cantilever-shaped piezoelectric element, the piezoelectric element having an essentially stationary proximal end and a distal end which is connected to the elastomeric wall of the valve chamber.

3. The apparatus of claim 2, further comprising an actuator rod which connects the piezoelectric element to the elastomeric wall of the valve chamber.

4. The apparatus of claim 3, wherein the actuator rod has a distal end which extends through the elastomeric wall and terminates in an actuator head, and wherein when the piezoelectric element is in the first position the actuator head closes the controlled port.

5. The apparatus of claim 1, wherein the piezoelectric element is a bimorph piezoelectric element.

6. The apparatus of claim 1, further comprising a drive circuit connected to the piezoelectric element.

7. The apparatus of claim 1, wherein the controlled port is the outlet port.

8. The apparatus of claim 1, wherein substantially the entire valve chamber is elastomeric.

9. The apparatus of claim 8, wherein the valve chamber comprises a unitary elastomeric part.

10. The apparatus of claim 7, further comprising a housing which substantially encases the valve chamber and the piezoelectric element, the inlet port and the outlet port also being formed in the housing.

11. The apparatus of claim 1, wherein the valve chamber isolates the piezoelectric element from fluid in the valve chamber.

12. A valve comprising:

an elastomeric valve chamber provided with an inlet port and an outlet port;

a piezoelectric element which is external to the valve chamber, the piezoelectric element being operable in a first state to move the elastomeric valve chamber to a first configuration so as to close a controlled port, and in a second state to move the elastomeric valve chamber to a second configuration so as to open the controlled port, the controlled port being one of the inlet port and the outlet port.

13. The apparatus of claim 12, wherein the piezoelectric element is a cantilever-shaped piezoelectric element, the piezoelectric element having an essentially stationary proximal end and a distal end which is connected to the elastomeric wall of the valve chamber.

14. The apparatus of claim 13, further comprising an actuator rod which connects the piezoelectric element to the elastomeric wall of the valve chamber.

15. The apparatus of claim 14, wherein the actuator rod has a distal end which extends through the elastomeric wall and terminates in a actuator head, and wherein when the piezoelectric element is in the first position the actuator head closes the controlled port.

16. The apparatus of claim 12, wherein the piezoelectric element is a bimorph piezoelectric element.

17. The apparatus of claim 12, further comprising a drive circuit connected to the piezoelectric element.

18. The apparatus of claim 12, wherein the controlled port is the outlet port.

19. The apparatus of claim 12, wherein the valve chamber comprises a unitary elastomeric part.

20. The apparatus of claim 12, further comprising a housing which substantially encases the valve chamber and the piezoelectric element, the inlet port and the outlet port also being formed in the housing.

21. The apparatus of claim 12, wherein the valve chamber isolates the piezoelectric element from fluid in the valve chamber.

22. A valve comprising:

a body for at least partially defining a valve chamber, the valve chamber having an inlet port and an outlet port, one of the inlet port and the outlet port being a controlled port;

at least one piezoelectric actuator provided in the valve chamber;

the piezoelectric actuator comprising an essentially planar piezoelectric element having an essentially planar fluid-contacting layer adhered thereto;

a sealing gasket provided around a mouth of the controlled port;

the piezoelectric actuator being operable by selective application of an electric field to a first state and a second state, in the first state the fluid-contacting layer of the piezoelectric actuator being positioned against the sealing gasket of the controlled port to prevent transmission of fluid between the valve chamber and the controlled port, in the second state the fluid-contacting layer of the piezoelectric actuator being positioned away from the sealing gasket of the controlled port to permit transmission of between the valve chamber and the controlled port.

23. The apparatus of claim 22, wherein the fluid-contacting layer of the piezoelectric actuator is a stainless steel membrane.

24. The apparatus of claim 22, wherein in the first state the piezoelectric actuator has no electromagnetic field applied thereto, and wherein in the second state the piezoelectric actuator has an electromagnetic field applied thereto.

25. The apparatus of claim 22, wherein when the controlled port is open fluid travels between the controlled port and the valve chamber in a direction essentially perpendicular to a plane of the fluid-contacting layer.

26. The apparatus of claim 22, wherein the sealing gasket for the controlled port is provided on a wall of the valve chamber.

27. The apparatus of claim 22, wherein the valve chamber has a valve chamber perimeter gasket provided around an interior floor thereof.

28. A diaphragm pump comprising:

a body for at least partially defining a pumping chamber and an inlet port for the pumping chamber;

a diaphragm which, in conjunction with application of an electric field to a piezoelectric material, acts upon a fluid in the pumping chamber;

a wicking material situated in at least one of the pumping chamber and the inlet port, the wicking material facilitating priming of the pump with a liquid by capillary action.

29. The apparatus of claim 28, wherein the wicking material is a micro fiber fabric or a wicking foam material.

30. The apparatus of claim 28, wherein the diaphragm has a diameter of one inch or less.

31. The apparatus of claim 28, wherein the wicking material is situated in the pumping chamber but is not compressed by movement of the diaphragm.

32. The apparatus of claim 28, wherein the wicking material is situated in the pumping chamber and is shaped essentially as a disk.

33. The apparatus of claim 28, wherein the wicking material extends through the inlet port.

34. The apparatus of claim 28, wherein the wicking material is situated both in the pumping chamber and in the inlet port.

35. The apparatus of claim 28, wherein the wicking material is situated in the pumping chamber and is shaped essentially as a disk.

36. The apparatus of claim 35, wherein the disk has a first hole aligned with the inlet port and a second hole aligned with the outlet port.

37. The apparatus of claim 36, wherein a channel connects the first hole and the second hole.

38. The apparatus of claim 28, further comprising a sealing member which extends around an inner periphery of the pumping chamber and which defines a height of the pumping chamber between the piezoelectric actuator when unactuated and the body.

39. A method of self-priming a diaphragm pump, the diaphragm pump comprising a body for at least partially defining a pumping chamber and a diaphragm which is actuated by selective application of an electric field to a piezoelectric material to act upon a liquid in the pumping chamber;

the method comprising;

putting a wicking material in one of the pumping chamber and an inlet port of the pumping chamber;

putting a wicking material into a vessel;

inserting a first end of the vessel into the pumping chamber so that the wicking material in the vessel contacts the wicking material in the pump;

inserting a second end of the vessel into a liquid;

actuating the diaphragm to facilitate priming of the pump with the liquid by capillary action.

40. The method of claim 39, further comprising using a micro fiber fabric or a wicking foam material as the wicking material.

41. The method of claim 39, wherein the diaphragm has a diameter of one inch or less.

42. The method of claim 39, further comprising inserting the wicking material in the pumping chamber but not to an extent that the wicking material is compressed by movement of the diaphragm.

43. A diaphragm pump comprising:

a body for at least partially defining a pumping chamber, the pumping chamber having a pumping chamber first lateral portion, a pumping chamber second lateral portion, an inlet port, and an outlet port;

a first diaphragm which, in conjunction with application of an electric field to a first piezoelectric element, acts upon a fluid in the pumping chamber first lateral portion;

a second diaphragm which, in conjunction with application of an electric field to a second piezoelectric element, acts upon a fluid in the pumping chamber second lateral portion;

a driver circuit which actuates the first diaphragm and the second diaphragm.

44. The apparatus of claim 43, wherein the driver circuit actuates the first diaphragm and the second diaphragm whereby in a deformed state the first diaphragm and the second diaphragm simultaneously draw fluid into the pumping chamber first lateral portion and the pumping chamber second lateral portion, respectively.

45. The apparatus of claim 43, wherein the pumping chamber further has a pumping chamber central portion, and wherein the pumping chamber first lateral portion communicates with the pumping chamber central portion through a first window and the pumping chamber second lateral portion communicates with the pumping chamber central portion through a second window.

46. The apparatus of claim 45, wherein the pumping chamber first lateral portion and the pumping chamber first lateral portion both have a disk shape with the pumping chamber first lateral portion lying in a first plane and the pumping chamber second lateral portion lying in a second plane which is parallel to the first plane, wherein a projection of a circumference of the first pumping chamber on the first plane is a circle, and wherein a projection of a circumference of the first window on the first plane is a ellipse having an axis which when extended forms a chord of the circle.

47. The apparatus of claim 45, wherein at least one of the first window and the second window has an elliptical shape.

48. The apparatus of claim 43, further comprising a diverter which diverts fluid introduced by the inlet port toward the pumping chamber first lateral portion and toward the pumping chamber second lateral portion.

49. The apparatus of claim 48, wherein

the pumping chamber has a pumping chamber central portion;

the pumping chamber first lateral portion communicates with the pumping chamber central portion through a first window and the pumping chamber second lateral portion communicates with the pumping chamber central portion through a second window,

the diverter has a diverter first edge proximate the first window and a diverter second edge proximate the second window, and

the first diaphragm draws fluid around the diverter first edge from the inlet port to the outlet port and the second diaphragm draws fluid around the diverter second edge from the inlet port to the outlet port.

50. The apparatus of claim 49, wherein the first diaphragm lies in a first plane and the second diaphragm lies in a second plane, wherein in a third plane which is perpendicular to the first plane and the second plane the diverter strut has a quadrilateral cross-sectional shape, and wherein in the third plane two corners of the quadrilateral are aligned with a fluid flow axis of the inlet port and the outlet port.

51. The apparatus of claim 49, wherein the first diaphragm lies in a first plane and the second diaphragm lies in a second plane, wherein in a third plane which is perpendicular to the first plane and the second plane the diverter has a quadrilateral cross-sectional shape, and wherein in the third plane two corners of the quadrilateral are aligned with a fluid flow axis of the inlet port and the outlet port.

52. The apparatus of claim 48, wherein:

the pumping chamber first lateral portion communicates with the inlet port through a pumping chamber first lateral portion first window;

the pumping chamber first lateral portion communicates with the outlet port through a pumping chamber first lateral portion second window;

the pumping chamber second lateral portion communicates with the inlet port through a pumping chamber second lateral portion first window;

the pumping chamber second lateral portion communicates with the outlet port through a pumping chamber second lateral portion second window.

53. The apparatus of claim 52, wherein the diverter has a first wall which is essentially parallel to a plane of the first diaphragm when unactuated and a second wall which is essentially parallel to a plane of the second diaphragm when unactuated.

54. The apparatus of claim 52, wherein:

the first diaphragm draws fluid through the pumping chamber first lateral portion first window, into the pumping chamber first lateral portion, and out the pumping chamber first lateral portion second window toward the outlet port; and

the second diaphragm draws fluid through the pumping chamber second lateral portion first window, into the pumping chamber second lateral portion, and out the pumping chamber second lateral portion second window toward the outlet port.

55. The apparatus of claim 43, wherein the pumping chamber first lateral portion and the pumping chamber first lateral portion both have a disk shape with the pumping chamber first lateral portion lying in a first plane and the pumping chamber second lateral portion lying in a second plane which is parallel to the first plane, wherein a projection of a fluid flow axis of the inlet port and the outlet port on a circumference of the pumping chamber first lateral portion in the first plane forms a chord with respect to the circumference.

56. The apparatus of claim 43, further comprising:

a first sealing member which extends around a periphery of the pumping chamber first lateral portion and which defines a height of the pumping chamber first lateral portion between the first diaphragm when unactuated and the body; and

a second sealing member which extends around a periphery of the pumping chamber second lateral portion and which defines a height of the pumping chamber second lateral portion between the second diaphragm when unactuated and the body.

57. The apparatus of claim 56, wherein the first sealing member and the second sealing member are O-rings.

58. The apparatus of claim 56, wherein the first sealing member and the second sealing member are essentially flat gaskets.

59. The apparatus of claim 56, wherein the height of at least one of the pumping chamber first lateral portion and the pumping chamber second lateral portion is 20 mils or less.

60. The apparatus of claim 56, wherein the height of at least one of the pumping chamber first lateral portion and the pumping chamber second lateral portion is 10 mils.

61. A diaphragm pump comprising:

a body for at least partially defining a pumping chamber, the pumping chamber having an inlet port and an outlet port;

a diaphragm which, in conjunction with application of an electromagnetic field to a piezoelectric element, acts upon a fluid in the pumping chamber;

a flapper valve situated in one of the inlet port and the outlet port, the flapper valve comprising a thin wafer having an arcuate cut therein.

62. The apparatus of claim 61, wherein the thin wafer is a circular wafer.

63. The apparatus of claim 61, wherein the thin wafer is a silicon wafer.

64. The apparatus of claim 61, wherein the thin wafer has a thickness of about 0.002 inch.

65. The apparatus of claim 61, wherein the arcuate cut is a substantially U-shaped cut.

66. The apparatus of claim 61, further comprising a retainer member which holds the flapper valve in place relative to the one of the inlet port and the outlet port.

67. The apparatus of claim 61, wherein the flapper valve has a modulus which forces the flapper valve to close after action of the diaphragm has filled the pumping chamber, but which also causes automatic closure of the flapper valve without requiring pressure of the diaphragm.

68. A flapper valve for a diaphragm fluid handling device, the flapper valve comprising a thin wafer having an arcuate cut therein.

69. The apparatus of claim 68, wherein the thin wafer is a circular wafer.

70. The apparatus of claim 68, wherein the thin wafer has a thickness of about 0.002 inch.

71. The apparatus of claim 68, wherein the arcuate cut is a substantially U-shaped cut.