Variable volume, shape memory actuated insulin dispensing pump
First Claim
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1. A method of dispensing liquid from a pump, comprising:
- drawing a first volume of the liquid into a pumping chamber by causing a shape memory material to contract and move a piston to a first position of a plurality of positions;
expelling a second volume of the liquid from the pumping chamber by causing the shape memory material to relax and move the piston to a second position of the plurality of positions;
monitoring each of the plurality of positions of the piston using an encoding grid disposed on the piston, wherein a first location on the encoding grid indicates the first position of the plurality of positions of the piston and wherein a second location on the encoding grid indicates the second position of the plurality positions of the piston; and
measuring a first time period, wherein the first time period is the time it takes to draw the first volume of liquid into the pumping chamber;
comparing the first time period to a predetermined time period; and
determining that the pump is not primed when the first time period is below the predetermined time period by a threshold amount of time.
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Abstract
A portable pumping system provides insulin or other drugs to a user. A shape memory element is used to actuate the pump and an intelligent system controls the actuator in order to minimize stresses within the system and provide accurate and reliable dosage delivery. The control system utilizes various types of feedback to monitor and optimize the position of the pumping mechanisms. Physical design aspects also minimize stress and the combination of the physical design aspects and the intelligent operation of the system results in a lightweight and cost effective pump that may be used in a disposable fashion if desired.
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Citations
22 Claims
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1. A method of dispensing liquid from a pump, comprising:
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drawing a first volume of the liquid into a pumping chamber by causing a shape memory material to contract and move a piston to a first position of a plurality of positions; expelling a second volume of the liquid from the pumping chamber by causing the shape memory material to relax and move the piston to a second position of the plurality of positions; monitoring each of the plurality of positions of the piston using an encoding grid disposed on the piston, wherein a first location on the encoding grid indicates the first position of the plurality of positions of the piston and wherein a second location on the encoding grid indicates the second position of the plurality positions of the piston; and measuring a first time period, wherein the first time period is the time it takes to draw the first volume of liquid into the pumping chamber; comparing the first time period to a predetermined time period; and determining that the pump is not primed when the first time period is below the predetermined time period by a threshold amount of time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for dispensing a liquid from a pump, the system comprising:
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a chamber; a piston disposed within the chamber; a shape memory element coupled to the piston and configured to move the piston from a first position of a plurality of positions to a second position of the plurality of positions, wherein when the piston is in the first position, the liquid is drawn into the chamber and wherein when the piston is in the second position, the liquid is expelled from the chamber; an encoding grid operatively coupled to the piston, wherein a first area of the encoding grid corresponds to the first position of the piston and wherein a second area of the encoding grid corresponds the second position of the piston; a plurality of conducting strips disposed in the chamber, wherein each of the plurality of conducting strips are configured to monitor the position of the piston based on the encoding grid; and a processor programmed to measure a first time period, wherein the first time period is the time it takes to draw a first volume of liquid into the chamber, to compare the first time period to a predetermined time period, and to determine that the pump is not primed when the first time period is below the predetermined time period by a threshold amount of time. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for dispensing liquid from a pump, the method comprising:
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moving a piston within a chamber of the pump from a first position of a plurality of positions to a second position of the plurality of positions using a shape memory element, wherein when the piston is in the first position of the plurality of positions a first volume of liquid is drawn into the chamber and wherein when the piston is in the second position of the plurality of positions a second volume of liquid is dispensed from the chamber; monitoring the movement of the piston using a grid disposed thereon, wherein a first area of the grid corresponds to the first position of the plurality of positions and wherein a second area of the grid corresponds to the second position of the plurality of positions; measuring a first time period, wherein the first time period is the time it takes to draw the first volume of liquid into the chamber; comparing the first time period to a predetermined time period; and determining that the pump is not primed when the first time period is below the predetermined time period by a threshold amount of time. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification