Abstract: A control system for a water rinse tank or the like which continuously monitors the rinse water quality by means of electrical conductivity and adds clean water when the water-contamination conductivity of the rinse water builds up through use to a predetermined value. A conductivity cell which is transparent and may be disassembled, and adjustable for operation over a wide range of conductivity settings. A power circuit with triac for switching power to a valve solenoid. A silicon controlled rectifier (SCR) and its associated circuitry located at the conductivity cell for controlling the triac, with the SCR operation directly controlled by the conductivity cell. A zener diode-transistor voltage regulating circuit for consistently maintaining substantially the same spiked waveform across the conductivity cell both for water off and water on conditions.

Abstract: Method and apparatus for measuring the conductivity ratio of a sample for determining deviation from a standard and particularly suited for use in measuring the syrup to water ratio in soft drinks and the like. A pair of conductivity cells for receiving the standard and sample, with the cells connected in a bridge circuit operated at relatively high frequency and having a full wave recitifier at the bridge output providing an input to an operational amplifier for driving an indicating meter which can be read in percent deviation from the standard. A side by side cell mounting with electrodes in the lower cell sections and a metal heat exchanger forming the upper cell sections. A pair of plungers for insertion into the cells for equalizing the amounts of material in the cells and the temperature of the materials. A calibration procedure for adapting the instrument for use with various products.