Ferroelectric pump

• US 6,071,087 A
• Filed: 04/03/1997
• Issued: 06/06/2000
• Est. Priority Date: 04/03/1996
• Status: Expired due to Fees

• Current Assignee: National Aeronautics and Space Administration (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Hellbaum, Richard F., Jalink, Antony Jr., Rohrbach, Wayne W.
• Primary Examiner(s): FREAY, CHARLES GRANT
• Application Number:
  US08/832,246
• Time in Patent Office: 1,160 Days
• Field of Search: 417/322, 417/412, 417/413.1, 417/413.2, 251/129.06
• US Class Current: 417/322
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 35/04 the means being electric
• CPC Class Codes: F04B 43/02 having plate-like flexible members, e.g. diaphragms F04B43/14 takes precedence
• CPC Class Codes: F16K 31/005 Piezoelectric benders

Abstract

A ferroelectric pump has one or more variable volume pumping chambers internal to a housing. Each chamber has at least one wall comprising a dome shaped internally prestressed ferroelectric actuator having a curvature and a dome height that varies with an electric voltage applied between an inside and outside surface of the actuator. A pumped medium flows into and out of each pumping chamber in response to displacement of the ferroelectric actuator. The ferroelectric actuator is mounted within each wall and isolates each ferroelectric actuator from the pumped medium, supplies a path for voltage to be applied to each ferroelectric actuator, and provides for positive containment of each ferroelectric actuator while allowing displacement of the entirety of each ferroelectric actuator in response to the applied voltage.

Claims

1. A ferroelectric pump, comprising:

a pump housing;

one or more variable volume pumping chambers internal to said housing, wherein each said chamber has at least one wall comprising a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex, and a dome height measured from a plane through said rim to said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator;

an inlet means through which a pumped medium flows into each said pumping chamber in response to said actuator displacement;

an outlet means through which the pumped medium exits each said pumping chamber in response to said actuator displacement;

mounting means for mounting each said actuator, wherein said mounting means mounts each said actuator within each said corresponding wall, isolates each said actuator from the pumped medium, supplies a path for said voltage to be applied to each said actuator, and provides for positive containment of each said actuator within each said corresponding wall while allowing displacement of the entirety of each said actuator in response to said voltage; and

electrical voltage means for supplying voltage to said actuators.

2. The device of claim 1 wherein said inlet means comprises:

at least one pumped medium supply inlet connected to a pumped medium source;

a chamber supply inlet at each said chamber; and

one-way valving means interposed between said pumped medium supply inlet and each said chamber supply inlet, whereby said pumped medium enters each said pumping chamber in response to said displacement of each said actuator and whereby back-flow of the pumped medium is prevented.

3. The device of claim 1 wherein said outlet means comprises:

a chamber discharge outlet at each said chamber;

at least one pumped medium discharge outlet; and

one-way valving means interposed between each said chamber discharge outlet and said pumped medium discharge outlet, whereby said pumped medium exits each said pumping chamber in response to said displacement of each said actuator and whereby back-flow of the pumped medium is prevented.

4. The device of claim 1, wherein said voltage means comprises:

a waveform generator which generates a wave shape for said pump operation;

a voltage amplifier which raises said waveform generator voltage and current to levels required by said actuators; and

a dc power supply which provides dc voltages to said waveform generator and said voltage amplifier.

5. The device of claim 1, wherein said voltage means comprises:

a variable transformer;

an isolation transformer connected to said variable transformer,

a full wave bridge rectifier connected to said isolation transformer; and

a step-up transformer connected to said isolation transformer;

wherein said full wave bridge rectifier and said step-up transformer are connected in series.

6. The device of claim 1, wherein said pumping medium is a liquid.

7. The device of claim 1, wherein said pumping medium is a gas.

8. The device of claim 2, wherein said valving means is a ferroelectric control valve comprising a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex, and a dome height measured from a plane through said rim to said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator.

9. The device of claim 3, wherein said valving means is a ferroelectric control valve comprising a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex, and a dome height measured from a plane through said rim to said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator.

10. A ferroelectric pump, comprising:

a pump housing;

one or more variable volume pumping chambers internal to said housing, wherein each said chamber has at least one wall comprising a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex, and a dome height measured from a plane through said rim to said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator;

an inlet means through which a pumped medium flows into each said pumping chamber in response to said actuator displacement;

an outlet means through which the pumped medium exits each said pumping chamber in response to said actuator displacement;

mounting means for mounting each said actuator, wherein said mounting means mounts each said actuator within each said corresponding wall, isolates each said actuator from the pumped medium, supplies a path for said voltage to be applied to each said actuator, and provides for positive containment of each said actuator within each said corresponding wall while allowing displacement of the entirety of each said actuator in response to said voltage;

electrical voltage means for supplying voltage to said actuators; and

further wherein said mounting means comprises;

a spacer having a first planar surface and a second planar surface and having a center opening within which is positioned said actuator such that the outer boundary of said actuator is contiguous with said opening boundary;

first and second electrical contact layers, each contact layer having a center opening, first said contact layer positioned contiguous to a portion of said first spacer planar surface, second said contact layer positioned contiguous to a portion of said second spacer planar surface, which provide voltage contact to said actuator;

first and second electrical insulators, each said insulator having a first planar surface and a second planar surface, said first insulator planar surface of said first insulator centered over and positioned contiguous to a portion of the outside surface of first said contact layer and centered over said actuator, said first insulator planar surface of said second insulator centered over and positioned contiguous to a portion of the outside surface of second said contact layer and centered over said actuator;

a nonconductive fluid between said actuator and each said insulators of suitable viscosity to hold said insulators and said actuator together;

two nonconductive sealing gaskets, each gasket having a center opening centered over said corresponding contact layer opening and positioned contiguous to each said corresponding second planar surface of said insulators; and

fastening means to fix said spacer, said contact layers, said insulators, and said gaskets to said housing.

11. A ferroelectric pump, comprising:

a pump housing;

one or more variable volume pumping chambers internal to said housing, wherein each said chamber has at least one wall comprising a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex, and a dome height measured from a plane through said rim to said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator;

a fluidic valve means by which the pumped medium flows into and out of each said pumping chamber in response to said actuator displacement;

a mounting means for mounting each said actuator, wherein said mounting means mounts each said actuator within each said corresponding wall, isolates each said actuator from the pumped medium, supplies a path for said voltage to be applied to each said actuator, and provides for positive containment of each said actuator within each said corresponding wall while allowing displacement of the entirety of each said actuator in response to said voltage; and

electrical voltage means for supplying voltage to said actuators.

12. A method of mounting a ferroelectric actuator, comprising the steps:

positioning said actuator within a spacer having a first planar surface and a second planar surface and having a center opening such that the outer boundary of said actuator is contiguous with said opening boundary;

positioning first and second electrical contact layers, each contact layer having a center opening, such that first said contact layer is positioned contiguous to a portion of said first spacer planar surface, second said contact layer is positioned contiguous to a portion of said second spacer planar surface, to provide voltage contact to said actuator;

positioning first and second electrical insulators, each said insulator having a first planar surface and a second planar surface, such that said first planar surface of said first insulator is centered over and positioned contiguous to a portion of the outside surface of first said contact layer and is centered over said actuator, and said first planar surface of said second insulator is centered over and positioned contiguous to a portion of the outside surface of second said contact layer and centered over said actuator;

placing a nonconductive fluid between said actuator and each said insulators of suitable viscosity to hold said insulators and said actuator together;

positioning two nonconductive sealing gaskets, each said gasket having a center opening centered over said corresponding contact layer opening and positioned contiguous to each said corresponding second planar surface of said insulators; and

providing fastening means to fix said spacer, said contact layers, said insulators, and said gaskets to said housing.

13. A mount for a ferroelectric actuator, comprising:

a spacer having a first planar surface and a second planar surface and having a center opening within which is positioned said actuator such that the outer boundary of said actuator is contiguous with said opening boundary;

first and second electrical contact layers, each contact layer having a center opening, first said contact layer positioned contiguous to a portion of said first spacer planar surface, second said contact layer positioned contiguous to a portion of said second spacer planar surface, which provide voltage contact to said actuator;

first and second electrical insulators, each said insulator having a first planar surface and a second planar surface, said first planar surface of said first insulator centered over and positioned contiguous to a portion of the outside surface of first said contact layer and centered over said actuator, said first planar surface of said second insulator centered over and positioned contiguous to a portion of the outside surface of second said contact layer and centered over said actuator;

a nonconductive fluid between said actuator and each said insulators of suitable viscosity to hold said insulators and said actuator together;

two nonconductive sealing gaskets, each gasket having a center opening centered over said corresponding contact layer opening and positioned contiguous to each said corresponding second planar surface of said insulators; and

fastening means to fix said spacer, said contact layers, said insulators, and said gaskets to said housing.

14. A ferroelectric pump, comprising:

a pump housing;

one or more variable volume pumping chambers internal to said housing, wherein each said chamber has at least one wall comprising a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex, and a dome height measured from a plane through said rim to said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator;

an inlet means through which a pumped medium flows into each said pumping chamber in response to said actuator displacement;

an outlet means through which the pumped medium exits each said pumping chamber in response to said actuator displacement;

mounting means for mounting each said actuator, wherein said mounting means mounts each said actuator within each said corresponding wall, isolates each said actuator from the pumped medium, supplies a path for said voltage to be applied to each said actuator, and provides for positive containment of each said actuator within each said corresponding wall while allowing displacement of the entirety of each said actuator in response to said voltage;

electrical voltage means for supplying voltage to said actuators; and

further wherein said voltage means comprises;

a voltage lead positioned in said housing; and

a set screw spring contacted by said voltage lead, said spring contacting said mounting means.