Patent ID: 8172800

Claim:
A medical device for pumping a fluid, comprising: a plunger having a shaft sized for slidable movement through a rigid restraint; a piston attached to the plunger shaft and configured for reciprocal movement in a displacement cavity between a first projection and a second projection extending outwardly from a cavity wall; an inlet conduit spaced apart from the piston and in fluid communication with the displacement cavity; a shape memory alloy wire attached to the plunger for pulling the plunger in a first direction relative to the displacement cavity; 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 an insulin reservoir containing insulin and being in fluid communication with the displacement cavity via the inlet conduit so that as the shape memory alloy wire is activated the wire shortens and pulls the plunger in the first direction thereby drawing a predetermined volume of insulin from the reservoir into the displacement cavity.