Device and Method Employing Shape Memory Alloy
First Claim
1. A medical device for pumping a fluid, comprising:
- a plunger having reciprocal movement in a displacement cavity between a first limit and a second limit;
a shape memory alloy wire attached to the plunger for pulling the plunger in a first direction in the displacement cavity;
a digital timing circuit for activating the shape memory alloy wire including an electrical energy storage device for providing electrical energy to the shape memory alloy wire to thermally phase transform the wire; and
a reservoir containing a fluid and being in fluid communication with the displacement cavity so that as the shape memory alloy wire is activated, the shape memory alloy wire phase transforms and shortens, and pulls the plunger in the first direction thereby pulling a predetermined volume of fluid from the reservoir into the displacement cavity.
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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.
108 Citations
40 Claims
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1. A medical device for pumping a fluid, comprising:
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a plunger having reciprocal movement in a displacement cavity between a first limit and a second limit; a shape memory alloy wire attached to the plunger for pulling the plunger in a first direction in the displacement cavity; a digital timing circuit for activating the shape memory alloy wire including an electrical energy storage device for providing electrical energy to the shape memory alloy wire to thermally phase transform the wire; and a reservoir containing a fluid and being in fluid communication with the displacement cavity so that as the shape memory alloy wire is activated, the shape memory alloy wire phase transforms and shortens, and pulls the plunger in the first direction thereby pulling a predetermined volume of fluid from the reservoir into the displacement cavity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A medical device for pumping a fluid, comprising:
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an actuator being disposed adjacent a chamber, the chamber having a diaphragm, the actuator being in contact with the diaphragm; a shape memory alloy wire attached to the actuator to impart movement to the actuator; a digital timing circuit for activating the shape memory alloy wire including a capacitor for providing electrical energy to the shape memory alloy wire; and a reservoir containing a fluid and being in fluid communication with the chamber so that as the shape memory wire imparts movement to the actuator, the diaphragm reacts to the movement of the actuator to expand and thereby pull a predetermined volume of fluid from the reservoir into the chamber. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A medical device for pumping a fluid, comprising:
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an actuator being disposed adjacent a chamber, the chamber having a diaphragm, the actuator being in contact with the diaphragm and having reciprocal movement; a shape memory alloy wire attached to the actuator to impart movement to the actuator via phase changes; a digital timing circuit for activating the shape memory alloy wire phase changes including an electrical energy storage device for providing electrical energy to the shape memory alloy wire; and a reservoir containing a fluid and being in fluid communication with the chamber so that as the shape memory wire imparts movement to the actuator, the diaphragm reacts to the movement of the actuator to expand and thereby pull a predetermined volume of fluid from the reservoir into the chamber. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A medical device for pumping a fluid, comprising:
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an actuator being disposed adjacent a chamber, the chamber having a flexible diaphragm, the actuator being in contact with the diaphragm and having reciprocal movement to flex the diaphragm; a shape memory alloy wire, having a high temperature phase with a first transition temperature and a low temperature phase with a second transition temperature, attached to the actuator to impart movement to the actuator via phase changes; a digital timing circuit for activating the shape memory alloy wire phase changes including an electrical energy storage device for providing electrical energy to the shape memory alloy wire; and a reservoir containing a fluid and being in fluid communication with the chamber so that as the shape memory wire imparts movement to the actuator, the diaphragm reacts to the movement of the actuator to expand and thereby pull a predetermined volume of fluid from the reservoir into the chamber. - View Dependent Claims (36, 37, 38, 39, 40)
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Specification