Device and method employing shape memory alloy
First Claim
1. A medical device for pumping insulin, comprising:
- a plunger configured for reciprocal movement;
a displacement cavity defined by a moveable diaphragm with a wetted surface and a non-wetted surface;
a shape memory alloy wire for imparting movement to the plunger;
a digital timing circuit for activating the shape memory alloy wire including a battery for providing electrical energy to the shape memory alloy wire to cause the wire to shorten; and
a reservoir containing insulin and being in fluid communication with the displacement cavity so that as the shape memory alloy wire shortens the wire imparts movement to the plunger to move the plunger away from the diaphragm whereby the diaphragm expands and draws a predetermined volume of insulin 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.
116 Citations
33 Claims
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1. A medical device for pumping insulin, comprising:
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a plunger configured for reciprocal movement; a displacement cavity defined by a moveable diaphragm with a wetted surface and a non-wetted surface; a shape memory alloy wire for imparting movement to the plunger; a digital timing circuit for activating the shape memory alloy wire including a battery for providing electrical energy to the shape memory alloy wire to cause the wire to shorten; and a reservoir containing insulin and being in fluid communication with the displacement cavity so that as the shape memory alloy wire shortens the wire imparts movement to the plunger to move the plunger away from the diaphragm whereby the diaphragm expands and draws a predetermined volume of insulin 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, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification