Multi-sensor mass flow meter along with method for accomplishing same

Abstract

A device for measuring fluid flow rates over a wide range of flow rates. The invention is particularly adapted for use in micro-fluidic systems including fluids administration to a body of a patient. The device operates by producing characteristics variations in the fluid, or pulses, that are subsequently sensed by more than one detector spaced apart from the point of creation of the mark to derive a flow rate. Each pulse comprises a small fluid volume, whose characteristics are different from the mean characteristics of the fluid, such as by composition variations created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species, or a thermal variation created by focused electromagnetic radiation. The device comprises at least two detectors (also sometimes referred to as sensors) to improve the accuracy of the measurement in varying flow rates, to compensate for errors resulting from the drift of the pulses in the fluid, to compensate for varying or unstable flow rates, and to establish a positive signal for sub-range flow. A method of measuring fluid flow rate is proposed where measurements comprising data of one mark from at least two sensor readings plus one other time event are combined to determine the reported flow rate.