Device and method employing shape memory alloy
First Claim
1. A method of pumping a predetermined dose of insulin to a patient, comprising:
- providing an insulin pump having a plunger configured for reciprocating movement in a displacement cavity;
providing an inlet conduit extending from an insulin reservoir to the displacement cavity for carrying insulin to the displacement cavity and an outlet conduit extending from the displacement cavity to the patient;
the inlet conduit being spaced apart from the plunger;
activating a shape memory alloy wire attached to the plunger;
shortening the shape memory alloy wire thereby pulling the plunger in the displacement cavity to a first limit associated with a maximum volume in the displacement cavity;
drawing insulin from the reservoir, through the inlet conduit, and into the displacement cavity as the plunger moves to the first limit;
deactivating the shape memory alloy wire; and
providing a biasing spring configured to move the plunger to a second limit associated with a minimum volume in the displacement cavity, thereby forcing insulin out of the cavity and into the patient.
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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.
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Citations
47 Claims
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1. A method of pumping a predetermined dose of insulin to a patient, comprising:
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providing an insulin pump having a plunger configured for reciprocating movement in a displacement cavity; providing an inlet conduit extending from an insulin reservoir to the displacement cavity for carrying insulin to the displacement cavity and an outlet conduit extending from the displacement cavity to the patient; the inlet conduit being spaced apart from the plunger; activating a shape memory alloy wire attached to the plunger; shortening the shape memory alloy wire thereby pulling the plunger in the displacement cavity to a first limit associated with a maximum volume in the displacement cavity; drawing insulin from the reservoir, through the inlet conduit, and into the displacement cavity as the plunger moves to the first limit; deactivating the shape memory alloy wire; and providing a biasing spring configured to move the plunger to a second limit associated with a minimum volume in the displacement cavity, thereby forcing insulin out of the cavity and into the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of pumping a predetermined dose of insulin to a patient, comprising:
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providing an insulin pump having a plunger configured for reciprocating movement in a displacement cavity; providing an inlet conduit between an insulin reservoir and the displacement cavity, the inlet conduit being spaced apart from the plunger; applying electrical energy to a shape memory alloy wire attached to the plunger; heating the shape memory alloy wire thereby shortening the wire and pulling the plunger in the displacement cavity to a first limit associated with a maximum volume in the displacement cavity; drawing insulin from the reservoir through the inlet conduit and into the displacement cavity as the plunger moves to the first limit; deactivating the shape memory alloy wire; and providing a biasing spring configured to move the plunger to a second limit associated with a minimum volume in the displacement cavity, thereby forcing insulin out of the cavity and into the patient. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification