Patent ID: 6371331
Filing Date: 2002-04-16
Classification: B01L,G01N

Abstract:
An apparatus for dispensing a measured quantity of a liquid comprisinga container holding a quantity of liquid to be measured and dispensed; a conduit having an inlet end and an outlet end and including a measuring section having a predetermined volume and a dispensing tip at said outlet end; sensor means for determining when said measuring section is substantially full of liquid; a passage for delivering liquid from said container to said conduit inlet end; a first source of air under pressure for forcing liquid from said container to said conduit; a first valve in said passage; a second source of air under pressure connected to said conduit; a second valve controlling delivery of air to said conduit from said second source; and control means connected to said sensor means and to said first and second valves for sequentially closing said second valve and opening said first valve to cause flow of liquid from said container to said conduit until said sensor means determines that said measuring section is full of said liquid, and then closing said first valve and opening said second valve to admit air to said conduit, thereby expelling said measured quantity of liquid from said dispensing tip.