Microvalve assemblies and related structures and related methods

• US 20060016486A1
• Filed: 07/22/2005
• Published: 01/26/2006
• Est. Priority Date: 07/23/2004
• Status: Active Grant

• Current Assignee: AFA Controls LLC (IMI PLC)
• Original Assignee: AFA Controls LLC (IMI PLC)
• Inventors: Laski, James C., Douglas, Kevin R., Gibson, Paul W., Harris, Donald C., Teach, William O.
• Granted Patent: US 7,448,412 B2
• Time in Patent Office: Days
• US Class Current: 137/596.170
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/0074 using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/008 Multi-layer fabrications
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0007 of cantilever type
• CPC Class Codes: F16K 99/0028 Valves having multiple inlets or outlets
• CPC Class Codes: F16K 99/0051 using electrostatic means
• 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 137/0491 Valve or valve element assembling, disassembling, or replacing
• CPC Class Codes: Y10T 137/0497 Fluid actuated or retarded
• CPC Class Codes: Y10T 137/2213 Electrically-actuated element [e.g., electro-mechanical transducer]
• CPC Class Codes: Y10T 137/2224 Structure of body of device
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/86558 Plural noncommunicating flow paths
• CPC Class Codes: Y10T 137/87169 Supply and exhaust
• CPC Class Codes: Y10T 137/87217 Motor
• CPC Class Codes: Y10T 137/87225 Fluid motor

Abstract

A valve chip may include a substrate having first and second faces and openings between the first and second faces, and a plurality of flexible valve flaps on one of the faces of the substrate with each flexible valve flap being associated with at least one of the openings. The valve chip may be packaged by forming a frame having an opening therein, and securing the valve chip in the opening of the frame. More particularly, the valve chip may be secured in the opening so that central portions of the first and second faces of the substrate are exposed through the opening in the frame and so that a fluid seal is provided between the frame and edges of the substrate. Related valves, valve assemblies, and methods are also discussed.

Claims

1. A valve assembly comprising:

a main housing defining five chambers, a first chamber coupled to a low pressure exhaust port, a second chamber coupled to a first actuator port, a third chamber coupled to a high pressure supply port, a fourth chamber coupled to a second actuator port, and a fifth chamber coupled to a low pressure exhaust port;

a first valve between the first and second chambers wherein the first valve allows or substantially blocks fluid communication between the first chamber and the second chamber responsive to a first electrical signal;

a second valve between the second and third chambers wherein the second valve allows or substantially blocks fluid communication between the second chamber and the third chamber responsive to a second electrical signal;

a third valve between the third and fourth chambers wherein the third valve allows or substantially blocks fluid communication between the third chamber to the fourth chamber responsive to a third electrical signal;

a fourth valve between the fourth and fifth chambers wherein the fourth valve allows or substantially blocks fluid communication between the fourth chamber and the fifth chamber responsive to a fourth electrical signal; and

a controller configured to generate the first, second, third, and fourth electrical signals for the respective valve assemblies wherein the controller is configured to advance the valves through the following sequence of conditions,

in a first condition, opening the second and fourth valves and closing the first and third valves so that fluid communication is allowed between the second and third chambers and between the fourth and fifth chambers and so that fluid communication is substantially blocked between the first and second chambers and between the third and fourth chambers,

in a second condition after the first condition, opening the second valve and closing the first, third, and fourth valves so that fluid communication is allowed between the second and third chambers and so that fluid communication is substantially blocked between the first and second chambers, between the third and fourth chambers, and between the fourth and fifth chambers,

in a third condition after the second condition, opening the second and third valves and closing the first and fourth valves so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers and so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers,

in a fourth condition after the third condition, opening the third valve and closing the first, second, and fourth valves so that fluid communication is allowed between the third and fourth chambers and so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, and between the fourth and fifth chambers, and

in a fifth condition after the fourth condition, opening the first and third valves and closing the second and fourth valves, so that fluid communication is allowed between the first and second chambers and between the third and fourth chambers and so that fluid communication is substantially blocked between the second and third chambers and between the fourth and fifth chambers.

2. A valve assembly according to claim 1 wherein the controller is configured to provide the sequence of conditions further including,

in an initial condition before the first condition, closing the first, second, third, and fourth valves so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

3. A valve assembly according to claim 1 wherein the controller is configured to provide the sequence of conditions further including,

in a sixth condition after the fifth condition, closing the first, second, third, and fourth valves so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

4. A valve assembly according to claim 1 wherein the controller is configured to provide the sequence of conditions further including,

in a sixth condition after the fifth condition, closing the second and third valves so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers, and opening the first and fourth valves so that fluid communication is allowed between the first and second chambers and between the fourth and fifth chambers.

5. A valve assembly according to claim 1 wherein the controller is configured to provide the sequence of conditions further including,

in a sixth condition after the fifth condition, closing the first and fourth valves so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers, and opening the second and third valves so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers.

6. A valve assembly according to claim 1 wherein the controller is further configured to provide the sequence of conditions further including,

in an initial condition before the first condition, closing the second and third valves so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers, and opening the first and fourth valves so that fluid communication is allowed between the first and second chambers and between the fourth and fifth chambers.

7. A valve assembly according to claim 1 wherein the controller is configured to provide the sequence of conditions further including,

in an initial condition before the first condition, closing the first and fourth valves so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers, and opening the second and third valves so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers.

8. A method of operating a valve assembly including a housing having a first chamber coupled to a low pressure exhaust port, a second chamber coupled to a first actuator port, a third chamber coupled to a high pressure supply port, a fourth chamber coupled to a second actuator port, and a fifth chamber coupled to a low pressure exhaust port, the valve assembly further including a first valve between the first and second chambers, a second valve between the second and third chambers, a third valve between the third and fourth chambers, and a fourth valve between the fourth and fifth chambers, the method comprising:

opening the second and fourth valves and closing the first and third valves to provide a first condition so that fluid communication is allowed from the third chamber to the second chamber and from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the first and second chambers and between the third and fourth chambers,

after the first condition, opening the second valve and closing the first, third, and fourth valves to provide a second condition so that fluid communication is allowed from the third chamber to the second chamber and so that fluid communication is substantially blocked between the first and second chambers, between the third and fourth chambers, and between the fourth and fifth chambers,

after the second condition, opening the second and third valves and closing the first and fourth valves to provide a third condition so that fluid communication is allowed from the third chamber to the second chamber and from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers,

after the third condition, opening the third valve and closing the first, second, and fourth valves to provide a fourth condition so that fluid communication is allowed from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, and between the fourth and fifth chambers, and

after the fourth condition, opening the first and third valves and closing the second and fourth valves to provide a fifth condition so that fluid communication is allowed from the second chamber to the first chamber and from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the second and third chambers and between the fourth and fifth chambers.

9. A method according to claim 8 further comprising:

before the first condition, closing the first, second, third, and fourth valves to provide an initial condition so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

10. A method according to claim 8 further comprising:

after the fifth condition, closing the first, second, third, and fourth valves to provide a sixth condition so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

11. A method according to claim 8 further comprising:

after the fifth condition, closing the second and third valves and opening the first and fourth valves to provide a sixth condition so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers, and so that fluid communication is allowed between the first and second chambers and between the fourth and fifth chambers.

12. A method according to claim 8 further comprising:

after the fifth condition, closing the first and fourth valves and opening the second and third valves so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers, and so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers.

13. A method according to claim 8 further comprising:

before the first condition, closing the second and third valves and opening the first and fourth valves to provide an initial condition so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers, and so that fluid communication is allowed between the first and second chambers and between the fourth and fifth chambers.

14. A method according to claim 8 further comprising:

before the first condition, closing the first and fourth valves and opening the second and third valves to provide an initial condition so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers, and so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers.

15. A method according to claim 8 wherein the first and fifth chambers are coupled to a same low pressure exhaust port.

16. A method according to claim 8 wherein the first and fifth chambers are coupled to different low pressure exhaust ports.

17. A method according to claim 8 wherein each of the valves comprises a respective valve chip including a respective plurality of valve flaps thereon.

18. A method according to claim 17 wherein the first valve chip is spaced apart from the second valve chip.

19. A method according to claim 17 wherein the first valve chip is parallel with respect to the second valve chip.

20. A method according to claim 8 further comprising:

during each of the first and fifth conditions, monitoring an external power source;

upon detecting an interruption in the external power source during the first condition, maintaining the first condition; and

upon detecting an interruption in the external power source during the fifth condition, maintaining the fifth condition.

21. A method according to claim 8 further comprising:

during each of the first, second, third, fourth, and fifth conditions, monitoring an external power source; and

upon detecting an interruption in the external power source during any of the first, second, third, fourth, and fifth conditions, closing the first, second, third, and fourth valves to provide a default condition so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

22. A method according to claim 8 further comprising:

during each of the first, second, third, fourth, and fifth conditions, monitoring an external power source; and

upon detecting an interruption in the external power source during any of the first, second, third, fourth, and fifth conditions, closing the second and third valves and opening the first and fourth valves to provide a default condition so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers, and so that fluid communication is allowed between the first and second chambers and between the fourth and fifth chambers.

23. A method according to claim 8 further comprising:

during each of the first, second, third, fourth, and fifth conditions, monitoring an external power source; and

upon detecting an interruption in the external power source during any of the first, second, third, fourth, and fifth conditions, closing the first and fourth valves and opening the second and third valves to provide a default condition so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers, and so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers.

24. A valve comprising:

a substrate having first and second opposing faces, a hole through the substrate between the first and second faces, and a pair of input pads thereon;

a moveable valve member on the substrate with the movable valve member being associated with the hole in the substrate, wherein the movable valve member is configured to open or substantially block the hole responsive to an electrical signal applied to the pair of input pads; and

a frame surrounding and supporting the substrate at edges thereof so that central portions of the first and second faces of the substrate are exposed through an opening in the frame and so that a fluid seal is provided between the frame and edges of the substrate.

25. A valve according to claim 24 wherein the movable valve member comprises a flexible valve flap.

26. A valve according to claim 24 further comprising:

first and second conductive leads in the frame, the first and second conductive leads being electrically coupled to the respective input pads on the substrate.

27. A valve according to claim 26 wherein portions of the first and second conductive leads are exposed along an outside edge of the frame.

28. A valve according to claim 27 wherein the exposed portions of the first and second conductive leads are oriented in a direction substantially perpendicular with respect to the substrate.

29. A valve according to claim 27 wherein the exposed portions of the first and second conductive leads are exposed through slots in the frame.

30. A valve according to claim 26 wherein the first and second conductive leads are wire bonded to the respective input pads.

31. A valve according to claim 24 wherein the frame has a thickness greater than a thickness of the substrate and wherein the frame includes a recessed ledge along the opening in the frame with the edges of the substrate being supported by the recessed ledge.

32. A valve according to claim 31 further comprising:

a flexible gasket between the recessed ledge and the edges of the substrate.

33. A valve according to claim 31 wherein the edges of the substrate are secured to the gasket and the recessed ledge with portions of the frame overlapping edges of the substrate opposite the recessed ledge.

34. A valve according to claim 31 wherein the edges of the substrate are secured to the recessed ledge using an adhesive.

35. A valve according to claim 24 further comprising:

a baffle on the frame and spaced apart from the substrate, the baffle having at least one opening there through.

36. A valve according to claim 35 wherein the valve member is between the substrate and the baffle.

37. A valve according to claim 35 wherein the baffle and the substrate define a baffle camber there between.

38. A valve according to claim 35 wherein the baffle provides a restriction to fluid flow in series with the plurality of holes through the substrate.

39. A valve according to claim 35 wherein the baffle has a wedge shape.

40. A valve according to claim 39 further comprising:

first and second conductive leads on a first edge of the frame, the first and second conductive leads being electrically coupled to the respective input pads on the substrate, wherein a thin portion of the baffle is adjacent the first edge of the frame and wherein a wide portion of the baffle is adjacent a second edge of the frame opposite the first edge.

41. A valve according to claim 35 wherein the baffle, the frame and the substrate define an enclosure with the moveable valve member being included in the enclosure.

42. A valve according to claim 35 further comprising:

a flexible gasket on the frame such that the frame is between the flexible gasket and the baffle.

43. A valve according to claim 24 further comprising:

a flexible gasket on the frame with the substrate being recessed in the frame relative to the gasket, the flexible gasket defining an opening therein having dimensions greater than dimensions defined by a perimeter of the substrate.

44. A valve according to claim 24 wherein the frame comprises a rigid polymer material.

45. A method of packaging a valve chip including a substrate having first and second faces and a hole through the substrate between the first and second faces, a moveable valve member on one of the faces of the substrate with the moveable valve member being associated with the hole, the method comprising:

forming a frame having an opening therein; and

securing the valve chip in the opening of the frame so that central portions of the first and second faces of the substrate are exposed through the opening in the frame and so that a fluid seal is provided between the frame and edges of the substrate.

46. A method according to claim 45 wherein the moveable valve member comprises a flexible valve flap.

47. A method according to claim 45 wherein forming the frame comprises molding the frame separate from the valve chip, and wherein securing the valve chip comprises securing the valve chip in the opening of the frame after completion of molding.

48. A method according to claim 45 wherein the valve chip includes a pair of input pads on the substrate, and wherein providing the frame includes providing first and second conductive leads in the frame, the method further comprising:

after securing the valve chip in the opening, electrically coupling the first and second conductive leads to the respective input pads on the substrate.

49. A method according to claim 48 wherein portions of the first and second conductive leads are exposed along an outside edge of the frame.

50. A method according to claim 49 wherein the exposed portions of the first and second conductive leads are oriented in a direction substantially perpendicular with respect to the substrate.

51. A method according to claim 49 wherein the exposed portions of the first and second conductive leads are exposed through slots in the frame.

52. A method according to claim 48 wherein electrically coupling the first and second conductive leads comprises wire bonding the first and second conductive leads to the respective input pads.

53. A method according to claim 45 wherein the frame has a thickness greater than a thickness of the substrate and wherein the frame includes a recessed ledge along the opening therein with the edges of the substrate being supported by the recessed ledge.

54. A method according to claim 53 further comprising:

before securing the valve chip in the opening, forming a flexible gasket on the recessed ledge wherein securing the valve chip comprises securing edges of the substrate on the flexible gasket.

55. A method according to claim 54 wherein forming the frame and forming the flexible gasket comprise molding the frame and the gasket using a first shot of a first material for the frame and a second shot of a second material for the gasket.

56. A method according to claim 53 wherein securing the valve chip includes placing the valve chip on the recessed ledge and then deforming portions of the frame to overlap edges of the substrate opposite the recessed ledge so that edges of the substrate are secured between the recessed ledge and the deformed portions of the frame.

57. A method according to claim 53 wherein securing the valve chip includes providing an adhesive between the edges of the substrate and the recessed ledge.

58. A method according to claim 45 further comprising:

providing a baffle on the frame wherein the baffle is spaced apart from the substrate and wherein the baffle has at least one opening there through.

59. A method according to claim 58 wherein the baffle provides a restriction to fluid flow in series with the plurality of holes through the substrate.

60. A method according to claim 58 wherein the baffle has a wedge shape.

61. A method according to claim 60 wherein the frame includes first and second conductive leads on a first edge of the frame, the first and second conductive leads being electrically coupled to the respective input pads on the substrate, wherein a thin portion of the baffle is adjacent the first edge of the frame and wherein a wide portion of the baffle is adjacent a second edge of the frame opposite the first edge.

62. A method according to claim 58 wherein the baffle, the frame, and the substrate define an enclosure with the moveable valve member being included in the enclosure.

63. A method according to claim 58 further comprising:

forming a flexible gasket on the frame such that the frame is between the flexible gasket and the baffle.

64. A method according to claim 45 further comprising:

before securing the valve chip in the opening, forming a flexible gasket on the frame, the flexible gasket defining an opening therein having dimensions greater than dimensions defined by a perimeter of the substrate.

65. A method according to claim 64 wherein forming the frame and forming the flexible gasket comprise molding the frame and the gasket using a first shot of a first material for the frame and a second shot of a second material for the gasket.

66. A method according to claim 45 wherein the frame comprises a rigid polymer material.

67. A method according to claim 45 further comprising:

providing a housing defining first and second chambers and a valve chip enclosure between the first and second chambers, wherein the first and second chambers and the valve chip enclosure are open at one end;

after securing the valve chip in the opening of the frame, inserting the frame in the valve chip enclosure; and

after inserting the frame in the valve chip enclosure, securing a base on the open end of the housing so that the first and second chambers are separated by the valve chip.

68. A method according to claim 67 wherein the housing includes a first port providing fluid communication into and/or out of the first chamber and wherein the base includes a second port providing fluid communication into and/or out of the second chamber.

69. A valve assembly comprising:

a main housing defining first, second, and third chambers, the main housing further defining a first valve enclosure between the first and second chambers and a second valve enclosure between the second and third chambers;

first, second, third, and fourth electrical housing leads in the main housing with portions of each of the first and second electrical housing leads being exposed in the first valve enclosure and with portions of the third and fourth electrical housing leads being exposed in the second valve enclosure;

a first valve in the first valve enclosure electrically coupled with the first and second electrical housing leads wherein the first valve is configured to allow or substantially block fluid communication between the first and second chambers responsive to electrical signals provided on the first and second electrical housing leads;

a second valve in the second valve enclosure electrically coupled with the third and fourth electrical housing leads wherein the second valve is configured to allow or substantially block fluid communication between the second and third chambers responsive to electrical signals provided on the third and fourth electrical housing leads; and

a controller electrically coupled to the first, second, third, and fourth electrical housing leads wherein the controller is configured to generate the electrical signals to allow or substantially block fluid communication between the first and second chambers and between the second and third chambers.

70. A valve assembly according to claim 69 wherein the first valve comprises a first planar substrate having a plurality of holes through the first planar substrate, wherein the second valve comprises a second planar substrate having a plurality of holes through the second planar substrate.

71. A valve assembly according to claim 70 wherein the first and second planar substrates are substantially parallel with respect to each other.

72. A valve assembly according to claim 70 wherein the first valve comprises a plurality of flexible valve flaps on a surface thereof with the flexible valve flaps being configured to open or substantially block respective holes responsive to the electrical signals applied to the first and second electrical housing leads.

73. A valve assembly according to claim 69 further comprising a filter in at least one of the first, second, and/or third chambers.

74. A valve assembly according to claim 69 wherein the first valve comprises a planar substrate having a plurality of holes through the substrate, and a frame surrounding and supporting the planar substrate at edge portions thereof so that central portions of the planar substrate are exposed through an opening in the frame and so that a fluid seal is provided between the frame and edges of the substrate.

75. A valve assembly according to claim 74 wherein the first valve further comprises a baffle on the frame so that the baffle, the frame, and the planar substrate define an enclosure, and wherein the baffle includes at least one opening therein.

76. A valve assembly according to claim 74 wherein the first valve has a wedge shaped profile.

77. A valve assembly according to claim 69, wherein the main housing further defines a fourth chamber and a third valve enclosure between the third and fourth chambers, the valve assembly further comprising:

a fifth electrical housing lead in the main housing with portions of each of the second and fifth electrical housing leads being exposed in the third valve enclosure; and

a third valve in the third valve enclosure electrically coupled with the fifth and second electrical housing leads wherein the third valve is configured to allow or substantially block fluid communication between the third and fourth chambers responsive to electrical signals provided on the fifth and second electrical housing leads;

wherein the controller is electrically coupled to the fifth electrical housing lead and wherein the controller is configured to generate the electrical signals to allow or substantially block fluid communication between the third and fourth chambers.

78. A valve assembly according to claim 69 further comprising:

a first flexible gasket providing a fluid seal between the first valve and the first valve enclosure; and

a second flexible gasket providing a fluid seal between the second valve and the second valve enclosure.

79. A valve assembly comprising:

a valve housing defining first and second chambers;

a valve in the housing between the first and second chambers wherein the valve includes a planar substrate having a hole therethrough and a moveable valve member adjacent to the hole, and wherein the valve is configured to allow or substantially block fluid communication between the first and second chambers; and

a filter in the second chamber of the housing.

80. A valve assembly according to claim 79 wherein the moveable valve member comprises a flexible valve flap.

81. A valve assembly according to claim 79 wherein the valve housing further defines a third chamber, the valve assembly further comprising:

a second valve in the housing between the second and third chambers wherein the second valve is configured to allow or substantially block fluid communication between the second and third chambers.

82. A valve assembly according to claim 81 further comprising:

a second filter in the third chamber of the housing.

83. A valve assembly according to claim 81 wherein the valve housing further defines a fourth chamber, the valve assembly further comprising:

a third valve in the housing between the third and fourth chambers wherein the third valve is configured to allow or substantially block fluid communication between the third and fourth chambers.

84. A valve assembly according to claim 83 further comprising:

a second filter in the fourth chamber of the housing.

85. A valve assembly according to claim 83 wherein the valve housing further defines a fifth chamber, the valve assembly further comprising:

a fourth valve in the housing between the fourth and fifth chambers wherein the fourth valve is configured to allow or substantially block fluid communication between the fourth and fifth chambers.

86. A valve assembly according to claim 85 further comprising:

a second filter in the fourth chamber.

87. A valve assembly according to claim 86 further comprising:

a third filter in the third chamber.

88. A valve assembly according to claim 85 wherein the third chamber is configured to be coupled to a high pressure fluid supply, wherein the second and fourth chambers are configured to be coupled to respective ports of a cylinder, and wherein the first and fifth chambers are configured to be coupled to low pressure exhaust.

89. A valve assembly according to claim 79 wherein the valve comprises an electro-statically actuated valve.

90. A valve assembly according to claim 89 wherein the electrostatically actuated valve includes a substrate having a hole therethrough and a moveable valve member on a surface of the substrate facing the first chamber adjacent the hole.

91. A valve assembly according to claim 79 wherein the housing includes a main portion having openings to the first and second chambers and a base portion secured to the main portion to seal the openings in the main portion to the first and second chambers.

92. A method of operating a valve assembly including a housing having a first chamber coupled to a low pressure exhaust port, a second chamber coupled to a first actuator port, a third chamber coupled to a high pressure supply port, a fourth chamber coupled to a second actuator port, and a fifth chamber coupled to a low pressure exhaust port, the valve assembly further including a first valve between the first and second chambers, a second valve between the second and third chambers, a third valve between the third and fourth chambers, and a fourth valve between the fourth and fifth chambers, the method comprising:

providing a first condition by applying opening electrical signals to the second and fourth valves and by applying closing electrical signals to the first and third valves so that fluid communication is allowed from the third chamber to the second chamber and from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the first and second chambers and between the third and fourth chambers; and

providing a second condition by applying opening electrical signals to the first and third valves and by applying closing electrical signals to the second and fourth valves so that fluid communication is allowed from the second chamber to the first chamber and from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the second and third chambers and between the fourth and fifth chambers.

93. A method according to claim 92 further comprising:

providing a third condition by closing at least the first and second valves so that fluid communication is substantially blocked between the first and second chambers and between the second and third chambers, or closing at least the second and third valves so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers, or closing at least the third and fourth valves so that fluid communication is substantially blocked between the third and forth chambers and between the fourth and fifth chambers, or by opening at least the first and second valves so that fluid communication is allowed between the first and second chambers and between the second and third chambers, or by opening at least the second and third valves so that fluid communication is allowed between the second and third chambers and between the third and fourth chambers, or by opening at least the third and fourth valves so that fluid communication is allowed between the third and fourth chambers and between the fourth and fifth chambers.

94. A method according to claim 92 further comprising:

providing a third condition by closing at least the first and fourth valves so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers, or by closing at least the second and third valves so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers.

95. A method according to claim 94 wherein providing the third condition comprises opening the second valve and closing the first, third, and fourth valves so that fluid communication is allowed from the third chamber to the second chamber and so that fluid communication is substantially blocked between the first and second chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

96. A method according to claim 94 wherein providing the third condition comprises opening the second and third valves and closing the first and fourth valves so that fluid communication is allowed from the third chamber to the second chamber and from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the first and second chambers and between the fourth and fifth chambers.

97. A method according to claim 94 wherein providing the third condition comprises opening the third valve and closing the first, second, and fourth valves so that fluid communication is allowed from the third chamber to the fourth chamber and so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, and between the fourth and fifth chambers.

98. A method according to claim 94 wherein providing the third condition comprises opening the first and fourth valves and closing the second and third valves so that fluid communication is allowed from the second chamber to the first chamber and from the fourth chamber to the fifth chamber and so that fluid communication is substantially blocked between the second and third chambers and between the third and fourth chambers.

99. A method according to claim 94 wherein providing the third condition comprises closing the first, second, third, and fourth valves so that fluid communication is substantially blocked between the first and second chambers, between the second and third chambers, between the third and fourth chambers, and between the fourth and fifth chambers.

100. A method according to claim 94 wherein providing the third condition comprises providing the third condition as an intermediate condition in time between providing the first and second conditions.

101. A method according to claim 94 wherein providing the third condition comprises providing the third condition as an initial condition in time before providing the first and second conditions.

102. A method according to claim 94 wherein providing the third condition comprises providing the third condition as a final condition in time after providing the first and second conditions.

103. A method according to claim 94 wherein providing the first condition precedes in time providing the second condition.

104. A method according to claim 94 wherein providing the second condition precedes in time providing the first condition.

105. A method according to claim 92 wherein each of the valves comprises an electrostatically actuated valve.

106. A method according to claim 92 wherein the valve assembly includes a coupling to an external power source, the method further comprising:

while providing each of the first and second conditions, monitoring the external power source;

upon detecting an interruption of the external power source while providing the first condition, maintaining the first condition during the interruption of the external power source; and

upon detecting an interruption of the external power source while providing the second condition, maintaining the second condition during the interruption of the external power source.

107. A method according to claim 106 wherein the valve assembly further includes a coupling to a back-up power source, wherein maintaining the first condition during interruption of the external power source comprises maintaining the first condition using the back-up power source, and wherein maintaining the second condition during interruption of the external power source comprises maintaining the second condition using the back-up power source.

108. A method according to claim 107 wherein the back-up power source comprises a battery.

109. A valve assembly comprising:

a valve housing defining first, second, and third chambers;

a first valve between the first and second chambers, the first valve comprising a first valve substrate, wherein the first valve is configured to allow or substantially block fluid communication between the first and second chambers; and

a second valve between the second and third chambers, the second valve comprising a second valve substrate, wherein the second valve is configured to allow or substantially block fluid communication between the second and third chambers and wherein the first and second substrates are separate.

110. A valve assembly according to claim 109 wherein the first and second substrates are non-parallel.

111. A valve assembly according to claim 109 wherein the first and second valves comprises first and second electro-statically actuated valves.

112. A valve assembly according to claim 109 wherein the first substrate comprises a first hole therethrough and a first valve member adjacent the first hole with the first valve member being configured to open and close the first hole responsive to first electrical signals applied thereto, and wherein the second substrate comprises a second hole therethrough and a second valve member adjacent the second hole with the second valve member being configured to open and close the second hole responsive to second electrical signals applied thereto.

113. A valve assembly according to claim 112 wherein the first and second valve members comprise respective first and second flexible valve flaps.

114. A valve assembly according to claim 109 further comprising:

a baffle between the first valve and one of the first and second chambers wherein the baffle defines a baffle chamber between the baffle and the valve and wherein the baffle includes an orifice there through.

115. A valve assembly according to claim 109 further comprising a filter in at least one of the first and second chambers.

116. A valve assembly according to claim 109 wherein the valve housing further defines fourth and fifth chambers, the valve assembly further comprising:

a third valve between the third and fourth chambers, the third valve comprising a third valve substrate, wherein the third valve is configured to allow or substantially block fluid communication between the third and fourth chambers; and

a fourth valve between the fourth and fifth chambers, the fourth valve comprising a fourth valve substrate, wherein the fourth valve is configured to allow or substantially block fluid communication between the fourth and fifth chambers and wherein the first, second, third, and fourth substrates are separate.

117. A valve assembly according to claim 109 further comprising:

a controller coupled to each of the first and second valves, wherein the controller is configured to control opening and closing of the first and second valves.

118. A valve assembly according to claim 117 wherein a first electrical signal coupling is provided between the controller and the first valve, wherein a second electrical signal coupling is provided between the controller and the second valve, and wherein the first and second couplings are different.

119. A valve assembly according to claim 109 further comprising:

a tube wherein the valve housing is mounted to a first end of the tube so that the second valve chamber is in fluid communication with an interior of the tube;

a piston in the tube defining a cavity between the piston and the valve housing; and

an end cap on a second end of the tube.

120. A valve assembly according to claim 119 wherein the valve housing provides an end cap sealing the first end of the tube.

121. A valve assembly according to claim 119 wherein the valve housing comprises a rigid valve housing wherein the first and second valves are in the rigid valve housing and wherein the rigid valve housing is mounted directly to the tube.

133. A method according to claim 120 wherein the valve assembly further includes a fourth chamber coupled to a second actuator port, a fifth chamber coupled to a low pressure exhaust port, a third valve between the third and fourth chambers, wherein providing the first condition further includes allowing fluid communication from the third chamber to the fourth chamber and substantially blocking fluid communication between the fourth and fifth chambers, and wherein providing the second condition further comprises allowing fluid communication from the fourth chamber to the fifth chamber and substantially blocking fluid communication between the third and fourth chambers.

122. A method of forming a valve assembly, the method comprising:

forming a housing defining first, second, and third chambers, the first and second chambers being separated by a first valve enclosure for a valve chip, and the second and third chambers being separated by a second valve enclosure for a valve chip, wherein chambers and valve enclosures are open at an open end of the housing;

after forming the housing, inserting a valve chip in one of the valve enclosures wherein the valve chip includes a substrate having a hole therein and a moveable valve member configured to open and close the valve hole, with opposite sides of the valve chip being exposed to chambers on opposite sides of the valve enclosure; and

after inserting the valve chip, securing a base to the open end of the housing thereby closing the chambers and the valve enclosures.

123. A method according to claim 122 wherein the moveable valve member comprises a flexible valve flap.

124. A method according to claim 122 wherein the housing further defines fourth and fifth chambers, the third and fourth chambers being separated by a third valve enclosure for a valve chip, and the fourth and fifth chambers being separated by a fourth valve enclosure for a valve chip.

125. A method according to claim 124 wherein inserting a valve chip comprises inserting a first valve chip in the first valve enclosure, inserting a second valve chip in the second valve enclosure, inserting a third valve chip in the third valve enclosure, and inserting a fourth valve chip in the fourth valve enclosure.

126. A method according to claim 124 further comprising:

before securing the base, inserting a sealing plug in a another of the valve enclosures so that chambers on opposite sides of the plug are sealed from one another.

127. A method according to claim 124 wherein the housing includes a first output port providing fluid communication from the second chamber through the housing and a second output port providing fluid communication from the fourth chamber through the housing, wherein the base includes a first exhaust port providing fluid communication from the first chamber through the base, a supply port providing fluid communication from the third chamber through the base, and a second exhaust port providing fluid communication from the fifth chamber through the base.

128. A method according to claim 122 wherein the housing includes conductive leads therein providing electrical coupling from the valve chip to outside the housing.

129. A method according to claim 122 wherein forming the housing comprises molding the housing and providing the leads as inserts while molding the housing.

130. A method of operating a valve assembly including a housing having a first chamber coupled to a low pressure exhaust port, a second chamber coupled to an actuator port, and a third chamber coupled to a high pressure supply port, the valve assembly further including a first valve between the first and second chambers and a second valve between the second and third chambers, the method comprising:

providing a first condition so that fluid communication is allowed from the second chamber to the first chamber and so that fluid communication is substantially blocked between the second and third chambers;

providing a second condition so that fluid communication is allowed from the second chamber to the third chamber and so that fluid communication is substantially blocked between the first and second chambers;

while providing each of the first and second conditions, monitoring an external power source;

upon detecting an interruption of the external power source while providing the first condition, maintaining the first condition during the interruption of the external power source; and

upon detecting an interruption of the external power source while providing the second condition, maintaining the second condition during the interruption of the external power source.

131. A method according to claim 130 wherein maintaining the first condition during interruption of the external power source comprises maintaining the first condition using a back-up power source, and wherein maintaining the second condition during interruption of the external power source comprises maintaining the second condition using the back-up power source.

132. A method according to claim 131 wherein the back-up power source comprises a battery.