Device and Method Employing Shape Memory Alloy

• US 20100057007A1
• Filed: 10/01/2009
• Published: 03/04/2010
• Est. Priority Date: 10/09/2002
• Status: Abandoned Application

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories)
• Inventors: Reggiardo, Christopher V., Rush, Benjamin M.
• Application Number:
  US12/572,136
• Publication Number:
  US 20100057007A1
• Time in Patent Office: Days
• US Class Current: 604/153
• 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 reservoir enclosure for holding the fluid;

a displacement cavity;

a fluid inlet and a fluid outlet via fluid paths that are discrete from but in communication with the reservoir enclosure and displacement cavity;

a plunger acting on the displacement cavity;

a biasing element linked to the plunger moving the plunger to a first position compressing the fluid in the displacement 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 transforms the shape memory actuator to the high temperature phase and moves the plunger against the biasing element to a second position decompressing the displacement cavity, and a current off state allows the shape memory actuator to cool to the low temperature phase so that the biasing element biases the plunger to the first position; and

wherein the reservoir enclosure is disposable and detachable from a housing containing at least one of the displacement cavity, plunger, actuator, and biasing element.

2. A device for pumping a predetermined volume of fluid according to claim 1, wherein the reservoir enclosure includes a resilient collapsible material.

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

4. A device for pumping a predetermined volume of fluid according to claim 1, wherein the fluid paths are defined by tubing.

5. A device for pumping a predetermined volume of fluid according to claim 1, wherein the reservoir enclosure includes a resilient balloon.

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

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

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

8. A device for pumping a predetermined volume of fluid according to claim 1, wherein the shape memory actuator while in the malleable configuration is stretched elastically by 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, and at least the battery is contained within the reservoir enclosure.

10. A device for pumping a predetermined volume of insulin, comprising:

a reservoir enclosure for holding the insulin;

a displacement cavity in communication with the reservoir enclosure;

inlet and outlet valves and respective conduits that are physically discrete from the cavity but in communication with the cavity;

a plunger acting on the cavity to compress or decompress the cavity;

a biasing element acting on the plunger to bias 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 thermally transforms the shape memory actuator to the low temperature phase so that the biasing element urges the plunger to the first position; and

wherein the enclosure is physically discrete and detachable from a housing containing the cavity, plunger, actuator, and biasing element.

11. A device for pumping a predetermined volume of fluid according to claim 10, wherein the electrical source includes a battery and a capacitor, and at least the battery is contained within the reservoir enclosure.

12. A device for pumping a predetermined volume of fluid according to claim 10, wherein the electrical source includes a timing circuit controlling a field effect transistor (FET) that are powered by an electrochemical capacitor and a battery.

13. A device for pumping a predetermined volume of fluid according to claim 12, wherein the timing circuit controlling the field effect transistor (FET) generate one of a single pulse and a sequence of discrete smaller pulses.

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

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

a displacement cavity in communication with the enclosure;

a fluid inlet and a fluid outlet in communication with the displacement cavity;

a plunger acting on the displacement cavity;

a biasing element linked to the plunger moving the plunger to a first position compressing the displacement 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 displacement cavity, and a current off state allows the shape memory actuator to cool to the low temperature phase so that the biasing element moves the plunger to the first position; and

wherein the enclosure is disposable and detachable from a housing holding the plunger, displacement cavity, actuator, and biasing element.

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

16. A device for pumping a predetermined volume of fluid according to claim 14, wherein the electrical source provides current pulses to the shape memory actuator.

17. A device for pumping a predetermined volume of fluid according to claim 14, wherein the current on and current off states define one cycle, which cycle dispenses a predetermined volume of fluid.

18. A device for pumping a predetermined volume of fluid according to claim 14, wherein the electrical source includes a programmable pulse generating circuit.

19. A device for pumping a predetermined volume of fluid according to claim 18, wherein the device includes an energy storage cell powering the programmable pulse generating circuit.

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

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

a displacement cavity in fluid communication with the fluid reservoir;

a plunger acting on the displacement cavity;

a biasing element linked to the plunger biasing the plunger to a first position compressing the displacement 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 transforms the shape memory actuator to the high temperature phase and moves the plunger against the biasing element to a second position decompressing the displacement cavity, and a current off state allows the shape memory actuator to cool to the low temperature phase so that the biasing element moves the plunger to the first position; and

wherein the enclosure is disposable and detachable from a housing holding the plunger, displacement cavity, actuator, and biasing element.

21. A device for pumping a predetermined volume of fluid according to claim 20, wherein the enclosure includes a resilient balloon holding the fluid therein.