Patent ID: 8727745

Claim:
A device for pumping an exact volume of insulin, comprising: a cavity operably associated with an inlet and an outlet, the inlet of a construction sufficient for operable communication with a source of insulin; an inlet check valve operably associated with the inlet and an outlet check valve operably associated with the outlet; a plunger operably associated with the cavity, the plunger urged to a first position by a biasing force and moveable therefrom to a second position, wherein the plunger travels to compress the cavity when in the first position and to decompress the cavity when in the second position; a biasing element operably associated with the plunger to provide the biasing force; an actuator including a NiTi alloy wire having a high transition temperature and a low transition temperature, wherein the actuator operably associated with the plunger moves the plunger from the first position to the second position when the NiTi alloy wire thermally transforms at the high transition temperature, and moves the plunger with the biasing element force from the second position to the first position when the NiTi alloy wire thermally transforms at the low transition temperature to the original condition; a pulse generating circuit having a 200 milliamp-hour lithium-manganese dioxide battery, a direct current (DC) to direct current (DC) converter, a capacitor, a low-resistance field effect transistor switch, a programmable digital timing circuit, an inductor, and a diode; and wherein the pulse generating circuit supplies power to the NiTi alloy wire to change the length of the NiTi wire and thereby move the plunger an exact distance so that the plunger consistently draws only 1 μl of insulin into the cavity when the plunger moves from the first position to the second position and consistently expels all of the fluid from the cavity when the plunger moves from the second position to the first position so that the 1 μl of insulin delivered over multiple plunger cycles has a linear correlation coefficient of 0.999.