Device and Method Employing Shape Memory Alloy
First Claim
1. A medical device for pumping a fluid, comprising:
- an actuator being disposed adjacent a chamber, the chamber having a resilient tubing, the actuator being in contact with the resilient tubing;
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 the fluid and being in fluid communication with the chamber so that as the shape memory wire imparts movement to the actuator, the resilient tubing reacts to the movement of the actuator to expand and thereby pull a predetermined volume of fluid from the reservoir into the chamber.
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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.
107 Citations
30 Claims
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1. A medical device for pumping a fluid, comprising:
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an actuator being disposed adjacent a chamber, the chamber having a resilient tubing, the actuator being in contact with the resilient tubing; 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 the fluid and being in fluid communication with the chamber so that as the shape memory wire imparts movement to the actuator, the resilient tubing 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 (2, 3, 4, 5, 6, 7, 8, 9)
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10. A medical device for pumping a fluid, comprising:
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an actuator being disposed adjacent a displacement chamber, the displacement chamber defined by a resilient tubing having an inlet valve and an outlet valve at opposite ends, wherein in an advancement stroke the actuator engages and deforms the resilient tubing to compress the displacement chamber, and in a withdrawal stroke decompresses the resilient tubing enabling the resilient tubing to restore to an original shape decompressing the displacement chamber; a shape memory alloy wire attached to the actuator to impart movement to the actuator via phase changes in the shape memory alloy wire; a digital timing circuit including a capacitor connected to and activating the shape memory alloy wire, providing electrical energy to the shape memory alloy wire; and a reservoir containing the fluid and being in fluid communication with the displacement chamber so that as the shape memory wire imparts movement to the actuator, the resilient tubing reacts to the withdrawal stroke and advancement stroke of the actuator to one of decompressing and compressing the displacement chamber, and thereby one of pulling a predetermined volume of fluid from the reservoir via the inlet valve into the displacement chamber, and pushing the fluid from the displacement chamber through the outlet valve, respectively. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A medical device for pumping insulin, comprising:
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a resilient tubing having an inlet valve and an outlet valve at opposite ends defining an interior chamber; a plunger engaging and deforming the resilient tubing at the chamber; a shape memory alloy wire attached to the plunger to impart reciprocal movement to the plunger to compress and decompress the resilient chamber; a digital timing circuit for cyclically activating the shape memory alloy wire by providing electrical energy to the shape memory alloy wire; and a reservoir containing the insulin and being in fluid communication with the chamber so that as the shape memory wire imparts movement to the plunger, the resilient tubing reacts to the movement of the actuator to expand and thereby pull a predetermined volume of insulin from the reservoir into the chamber. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification