Device and Method Employing Shape Memory Alloy
First Claim
1. A device for pumping a predetermined volume of insulin, comprising:
- a cavity operably associated with an inlet and an outlet, the inlet of a construction sufficient for operable communication with a source of insulin;
an inlet check valve operably associated with the inlet and an outlet check valve operably associated with the outlet;
a plunger operably associated with the cavity, the plunger urged to a first position by a biasing force and moveable therefrom to a second position, wherein the plunger travels to compress the cavity when in the first position to decompress the cavity when in the second position;
a biasing element operably associated with the plunger to provide the biasing forcean actuator including a NiTi alloy wire having a high transition temperature and a low transition temperature, wherein the actuator operably associated with the plunger moves the plunger from the first position to the second position when the NiTi alloy wire thermally transforms at the high transition temperature, and moves the plunger with the biasing element force from the second position to the first position when the NiTi alloy wire thermally transforms at the low transition temperature to the original condition; and
wherein the plunger draws insulin into the cavity when the plunger moves from the first position to the second position.
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Accused Products
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.
106 Citations
20 Claims
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1. A device for pumping a predetermined volume of insulin, comprising:
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a cavity operably associated with an inlet and an outlet, the inlet of a construction sufficient for operable communication with a source of insulin; an inlet check valve operably associated with the inlet and an outlet check valve operably associated with the outlet; a plunger operably associated with the cavity, the plunger urged to a first position by a biasing force and moveable therefrom to a second position, wherein the plunger travels to compress the cavity when in the first position to decompress the cavity when in the second position; a biasing element operably associated with the plunger to provide the biasing force an actuator including a NiTi alloy wire having a high transition temperature and a low transition temperature, wherein the actuator operably associated with the plunger moves the plunger from the first position to the second position when the NiTi alloy wire thermally transforms at the high transition temperature, and moves the plunger with the biasing element force from the second position to the first position when the NiTi alloy wire thermally transforms at the low transition temperature to the original condition; and wherein the plunger draws insulin into the cavity when the plunger moves from the first position to the second position. - View Dependent Claims (2, 3, 4, 5)
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6. A device for pumping a predetermined volume of fluid, comprising:
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a displacement cavity operably associated with an inlet and an outlet, the inlet in communication with a source of fluid; an inlet check valve operably associated with the inlet and an outlet check valve operably associated with the outlet; a plunger operably associated with the displacement cavity, the plunger urged to a first position by a biasing force and moveable therefrom to a second position, wherein the plunger travels to compress the cavity when in the first position to decompress the cavity when in the second position; a biasing element operably associated with the plunger to provide a biasing force; an actuator including a NiTi alloy having a first transition temperature and a second transition temperature, wherein the actuator is directly connected to the plunger to move the plunger from the first position to the second position when the NiTi alloy thermally transforms at the first transition temperature, and moves the plunger from the second position to the first position when the NiTi alloy thermally transforms at the second transition temperature and returns toward the original condition; and wherein the plunger draws fluid into the cavity when the plunger moves from the first position to the second position, and the plunger expels fluid from the cavity when the plunger moves from the second position to the first position. - View Dependent Claims (7, 8)
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9. A device for pumping a predetermined volume of fluid, comprising:
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a displacement cavity operably associated with an inlet and an outlet, the inlet in communication with a source of fluid; an inlet check valve operably associated with the inlet and an outlet check valve operably associated with the outlet; a plunger operably associated with the cavity, the plunger urged to a first position by a biasing force and moveable therefrom to a second position, wherein the plunger travels to compress the cavity when in the first position, and to decompress the cavity when in the second position; a biasing element operably associated with the plunger to provide a biasing force; an actuator including a NiTi alloy having a first transition temperature and a second transition temperature, wherein the actuator is directly connected to the plunger to move the plunger from the first position to the second position when the NiTi alloy thermally transforms at the first transition temperature, and moves the plunger from the second position to the first position when the NiTi alloy thermally transforms at the second transition temperature and returns toward the original condition; a timing circuit to periodically conduct current to the actuator to thermally transform the actuator via the first transition temperature; and wherein the plunger draws fluid into the cavity when the plunger moves from the first position to the second position, and the plunger expels fluid from the cavity when the plunger moves from the second position to the first position. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification