Patent ID: 6640649
Filing Date: 2003-11-04
Classification: A61B,A61M

Abstract:
A low-flow metering device for measuring the volume of an amount of liquid exceeding 0.05 ml., comprising:a) a first chamber having an inlet for introduction of liquid into said first chamber, and an outlet in fluid communication with a second chamber, said first chamber being divided into an upper reservoir chamber and a lower drop generator chamber and orifice, said reservoir chamber and lower drop generator chamber being interconnected by an intermediate flow restriction element creating a laminar flow, said outlet of said first chamber being provided with a drop generator leading to said second chamber and sized to release a series of droplets, each of said droplets forming and breaking away under its own weight from liquid in the drop generator chamber via said drop generator orifice, b) an overflow conduit extending between an upper area of said first chamber and a lower area of said second chamber for equalizing gas pressure between said two chambers; c) electronic means positioned in said second chamber below said drop generator for counting the passage of each droplet exiting therefrom; and d) an information processing unit connected to said electronic means for receiving and recording information and for measuring the time interval between successive droplets and for calculating flow rates and total volume therefrom while dealing with variations in droplet size as a function of the time interval between successive droplets.