EP1991840A1 — Accurate metering system

USPTO Abstract

The present invention is directed to metering devices, systems, and methods that mitigate differential thermal expansion/contraction for the efficient, accurate, and reproducible metered delivery of fluids. The present invention allows the net fluid volume and a plunger location within a fluid dispensing container to automatically adjust under the influence of differential thermal expansion/contraction between the fluid and the fluid dispensing container that the fluid is contained within. Further, the present invention allows the metering system drive to sense the adjusted plunger (11) location and allows the metering system drive to re-zero itself to produce an accurate volumetric delivery of fluid from the fluid dispensing container (5) . The metering system includes means for controlling the travel of the metering system drive (14) , and hence the travel of the plunger into the fluid dispensing container, for delivering accurate/precise amounts of the fluid from the fluid dispensing container. The metering system may also mitigate dead volume in the metering system.