Automated flow-rate meter for flow-analysis systems

An automated flow-rate meter easy to construct and operate is described. This is contralled by a micracomputer connected to an analog/digitai converter interface and by a contrai software. It uses two acrylic flow cells, each comprising a bicolor light-emitting diode anda phototransistor piaced on opposite sides. The performance of this flow-rate meter was evaiuated by appiying it to three flow manifoids: one monosegmented flow titration system by binary sampling; one conventionai monosegmented flow system, and one singie-iine FIA system. The FIA system flow rate was assessed by means of a Vanderslice's expression. The time range of measurement of the flow rates was of 3.5-19.5 seconds and relative errars of 0.2-2.6% as well as relative stanCorrespondence to: Mario Cesar U. Araujo. © 1999 John Wiley & Sons, Inc. CCC 0895-7533/99/020097-08 dard deviations fram 0.4 to 3.1 % were attained. The flow-rate meter allows one to optimize precision and velocity of measurements just by changing one of its parameters. Moreover, the flow-rate meter can be used with flow systems, therefore ailowing one to perform on-line measurements, which facilitates a quick and effective contrai of the channeis flow rate. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 97-104, 1999