Patent ID: 7959606

Claim:
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.