Patent ID: 7959609

Claim:
An accurate metering device comprising: (a.) a fluid dispensing container for containing a fluid to be dispensed, wherein said fluid dispensing container comprises a reducible volume; (b.) a movable portion slidably disposed within said fluid dispensing container, said movable portion being capable of automatically adjusting in response to changes in fluid volume due to differential thermal expansion and/or contraction of said fluid contained within said fluid dispensing container, wherein said movable portion and said fluid dispensing container define a net fluid volume that changes as said movable portion moves with respect to said fluid dispensing container, and wherein an interference fit of said movable portion and said fluid dispensing container creates a friction force wherein the differential thermal expansion and/or contraction force is greater than the friction force of said fluid dispensing container; (c.) a metering drive that selectively contacts said movable portion, wherein said metering drive comprises an engaged position wherein said metering drive is in contact with said movable portion of said fluid dispensing container and a disengaged position wherein said metering drive is not in contact with said movable portion of said fluid dispensing container, wherein said engaged position is used as a starting point for incremental movement of the metering drive for delivering a specific quantity of fluid, said starting point comprising a point wherein said metering drive is re-zeroed; (d.) a sensor that senses when said metering drive contacts said movable portion; wherein said metering drive is actuated a known amount from said starting point thus moving said movable portion and reducing said reducible volume of said fluid dispensing container and causing the specific quantity of said fluid to be dispensed from said fluid dispensing container; wherein said specific quantity of said fluid from said fluid dispensing container further comprises a dose, wherein said fluid dispensing container comprises more than one dose, and; wherein said metering device is capable of delivering more than one substantially accurate and substantially reproducible dose.