Device and Method Employing Shape Memory Alloy

• US 20100068072A1
• Filed: 10/01/2009
• Published: 03/18/2010
• Est. Priority Date: 10/09/2002
• Status: Abandoned Application

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Reggiardo, Christopher V., Rush, Benjamin M.
• Application Number:
  US12/572,145
• Publication Number:
  US 20100068072A1
• Time in Patent Office: Days
• US Class Current: 417/53
• CPC Class Codes: A61M 2005/1726 the body parameters being measured at, or proximate to, the infusion site
• CPC Class Codes: A61M 2205/0288 Electro-rheological or magneto-rheological materials
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2205/702 automatically during use
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: F04B 2205/09 Flow through the pump
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F05C 2251/08 Shape memory
• CPC Class Codes: G01F 1/64 by measuring electrical currents passing through the fluid flow; measuring electrical potential generated by the fluid flow, e.g. by electrochemical, contact or friction effects G01F1/58 takes precedence
• CPC Class Codes: G01F 1/708 Measuring the time taken to traverse a fixed distance
• CPC Class Codes: G01F 1/7088 using electrically charged particles as tracers
• CPC Class Codes: G01F 25/10 of flowmeters

Abstract

A system for the metering and delivery of small discrete volumes of liquid is comprised of a small or minimal number of inexpensive components. One such component is a movable member, such as a miniature precision reciprocating displacement pump head, which is driven by an actuator that comprises a shape memory alloy material. The operating mechanism of the system is of little or minimal complexity. The system facilitates the precise metering and delivery of the small discrete volumes of liquid. Potential applications for the system include subcutaneous, long-term, automated drug delivery, for example, the delivery of insulin to a person with diabetes. In such an application, the small, simple and inexpensive nature of the invention would allow for its use as both a portable and a disposable system.

Claims

1. A device for pumping a predetermined volume of fluid, comprising:

a fluid reservoir;

a displacement cavity in communication with the fluid reservoir;

a plunger acting on the cavity;

a housing containing at least the cavity and plunger;

a biasing element mounted to the housing;

a pivoting linkage assembly joining the plunger to the biasing element, wherein the biasing element biases the plunger to a first position compressing the cavity;

a shape memory actuator, having a first transition temperature to a high temperature phase with a remembered configuration and a second transition temperature to a low temperature phase with a malleable configuration, linked to the plunger;

an electrical source providing a current to the shape memory actuator, wherein a current on state thermally transforms the shape memory actuator to the high temperature phase and moves the plunger against the biasing element to a second position decompressing the cavity, and a current off state that thermally transforms the shape memory actuator to the low temperature phase so that the biasing element biases the plunger to the first position.

2. A device for pumping a predetermined volume of fluid according to claim 1, wherein a pivot point for the pivoting linkage assembly is located at an end thereof and the pivot point is mounted to the housing.

3. A device for pumping a predetermined volume of fluid according to claim 1, wherein the shape memory actuator includes a NiTi wire.

4. A device for pumping a predetermined volume of fluid according to claim 1, wherein the fluid includes insulin.

5. A device for pumping a predetermined volume of fluid according to claim 1, wherein the first transition temperature is at about 70°

C. above an ambient temperature and the second transition temperature is at about the ambient temperature.

6. A device for pumping a predetermined volume of fluid according to claim 1, wherein the shape memory actuator includes a NiTi wire that is stretched in the low temperature phase by the biasing element.

7. A device for pumping a predetermined volume of fluid according to claim 1, wherein the pivoting linkage assembly includes a pivoting linkage pivotally connected to the housing at a first end thereof and pivotally connected to the plunger at about an intermediate point thereof.

8. A device for pumping a predetermined volume of fluid according to claim 7, wherein the pivoting linkage at a second end thereof is pivotally connected to the biasing element.

9. A device for pumping a predetermined volume of fluid according to claim 1, wherein the electrical source includes a battery and a capacitor connected in parallel.

10. A device for pumping a predetermined volume of fluid according to claim 9, wherein the capacitor includes an electrochemical capacitor.

11. A device for pumping a predetermined volume of fluid according to claim 1, wherein the electrical source includes a programmable timing circuit controlling a field effect transistor that are powered by a battery and a capacitor to pulse the current.

12. A device for pumping a predetermined volume of fluid, comprising:

a fluid reservoir contained within an enclosure, wherein the enclosure is collapsible;

a displacement cavity in communication with the fluid reservoir;

a plunger acting on the cavity;

a housing containing at least the cavity and plunger;

a biasing element mounted to the housing;

a pivoting linkage assembly joining the plunger to the biasing element, wherein the biasing element biases the plunger to a first position compressing the cavity;

a nickel-titanium alloy actuator, having a first transition temperature to a high temperature phase with a remembered configuration and a second transition temperature to a low temperature phase with a malleable configuration, linked to the plunger;

an electrical source providing a current to the nickel-titanium alloy actuator, wherein a current on state thermally transforms the shape memory actuator to the high temperature phase and moves the plunger against the biasing element to a second position decompressing the cavity, and a current off state allows the nickel-titanium alloy actuator to cool to the low temperature phase so that the biasing element biases the plunger to the first position; and

wherein the enclosure is disposable and detachable from the housing.

13. A device for pumping a predetermined volume of fluid according to claim 12, wherein the pivoting linkage assembly includes a bar pivotably mounted to the housing at one end, pivotably joined to the biasing element at an opposite end, and pivotably joined to the plunger at an intermediate position between the ends.

14. A device for pumping a predetermined volume of fluid according to claim 12, wherein the enclosure includes a resilient balloon.

15. A device for pumping a predetermined volume of fluid according to claim 12, wherein the device includes inlet and outlet valves in communication with the displacement cavity and are physically discrete and separate from the cavity.

16. A process for pumping a predetermined volume of fluid, comprising:

providing a fluid reservoir;

providing a displacement cavity in communication with the fluid reservoir;

providing a plunger acting on the displacement cavity;

providing a housing containing at least the cavity and plunger;

providing a nickel-titanium alloy actuator having a first transition temperature at a high temperature phase with a remembered configuration short in length, and a second transition temperature at a low temperature phase with a malleable configuration long in length;

pivotably linking the plunger to the nickel-titanium alloy actuator;

biasing the plunger to a first position compressing the cavity;

providing an electrical source generating a current pulse conducted to the nickel-titanium alloy actuator, wherein the current on state thermally transforms the shape memory actuator to the remembered configuration short in length to move the plunger against the bias to a second position decompressing the cavity and drawing fluid from the reservoir therein;

deactivating the current allowing the nickel-titanium alloy actuator to cool to the malleable configuration long in length; and

biasing the plunger back to the first position compressing the cavity and pumping the fluid therefrom.

17. A process for pumping a predetermined volume of fluid according to claim 16, wherein the process further includes stretching the nickel-titanium actuator while in the malleable configuration.

18. A process for pumping a predetermined volume of fluid according to claim 16, wherein the first transition temperature is about 70°

C. above an ambient temperature, and the second transition temperature is about at the ambient temperature.

19. A process for pumping a predetermined volume of fluid according to claim 16, wherein the fluid includes insulin.

20. A process for pumping a predetermined volume of fluid according to claim 16, wherein the process further includes delivering power to the electrical source with a battery connected in parallel with a capacitor.

21. A process for pumping a predetermined volume of fluid according to claim 16, wherein the process further includes conveying the fluid from the reservoir to the displacement cavity using tubing.