Model FCLI Free Chlorine Measuring System

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COMPLETE SYSTEM INCLUDES sensor, connecting cable, analyzer, and flow controller SENSOR RESPONSE IS PRACTICALLY INDEPENDENT pH between pH 6.5 and 10 NO REAGENTS NO AUXILIARY pH ELECTRODE VARIOPOL QUICK-DISCONNECT FITTINGS makes sensor replacement easy

FEATURES AND APPLICATIONS The Model FCLi free chlorine system is intended for the determination of free chlorine (hypochlorous acid plus hypochlorite ion) in fresh water. Unlike free chlorine analyzers from other manufacturers, the Model FCLi does not use expensive sample conditioning systems or messy reagents to control pH. Nor, does it require an auxiliary pH sensor for pH correction. Instead, the pH adjustment takes place inside the sensor, producing a signal that changes less than 4% per unit change in pH between pH 6.5 and 10. Below pH 6.5 the change is less than 1%. The linear range of the sensor is 0 to 20 ppm (mg/L). The Model FCLi is not intended for the determination of total or combined chlorine (like monochloramine). Nor, can the FCLi be used for the determination of chlorine in seawater. The Model FCLi uses a three electrode, membrane-covered amperometric sensor. The sensor consists of a hydrophilic membrane stretched over a gold mesh cathode. A silver/silver chloride reference electrode and an external copper auxiliary electrode complete the circuit. The fill solution is saturated succinic acid slurry. During operation, an electrochemical reaction, driven by the polarizing voltage, consumes free chlorine at the cathode surface. The auxiliary electrode provides the electrons for the cathode reaction, and a current proportional to the reaction rate flows between the electrodes. Because the concentration of chlorine at the cathode is zero, free chlorine in the sample continuously diffuses through the membrane and is destroyed at the cathode. Thus, the cathode current is proportional to the diffusion rate, which is proportional to the concentration of free chlorine in the sample.