The Foxboro Company

William E Earle

Kenneth S Fletcher, Iii

Jay M Weiner

An automatic titration system and method in which the titrant is generated electrolytically and a two-position slider type ceramic sample valve, reliably, accurately and repetitively obtains a volumetric sample from a process loop and introduces it to a titration cell containing a generator or working compartment and an auxiliary compartment separated by a porous frit. The system also includes a two-position slider type ceramic reagent valve for introducing reagent into the titration cell. Titrant created at a generator electrode surface is dispersed into the bulk of the solution by a magnetically coupled impeller in the working compartment which mixes and also pumps the contents of the cell through the reagent and sample valves in a closed loop. Generator and auxiliary electrodes are connected to a current source which provides the electrolysis current. The progress of the titration is monitored by indicating and reference electrodes in the titration cell connected to an appropriate endpoint indicator, output of which is compared to a known setpoint corresponding to the titration endpoint. The total charge delivered to the generator and auxiliary electrodes during titration is measured by a timer or integrator and read out as a trend output signal. The automatic titration system and method of this invention advantageously lends itself to microprocessor control over the titration reaction and titrator sequencing.

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North Easton, MA, United States of America

William E Earle