Abstract: An electrical resistance corrosion monitoring probe having a single lateral face of each of two rectangular prismatic elements of similar temperature-resistance characteristics but different thicknesses exposed to the corroding environment. Both the faces are corroded away, but the resistance change is different due to the inverse relationship between resistance and cross-sectional area. A measurement bridge network is used to monitor the change in cross-sectional area of both elements. A preferred probe embodiment, employing resistance elements having equivalent thermal masses and electrical resistances, as by using elements of the same material and of substantially equal lengths and cross-sectional areas, allows the use of a complementary measurement bridge network in its most sensitive region.

Abstract: A coulometric titrator for determining, at high accuracy and without time delay problems, small amounts of a specific ion in a solution by the addition of a reactive ion. A sensor provides a signal voltage representing the logarithm of the specific ion concentration to a differential amplifier which also receives as an input a signal from a reference electrode. The differential amplifier produces an error signal applied to a comparator and referenced therein to a certain reference voltage representing a desirable range of rates of change of the error output voltage. The comparator provides a sensor signal voltage representing the difference between the error signal and reference voltage. This sensor signal voltage is applied to an antilogarithm converter which produces an output signal that is proportional to the antilogarithm of the sensor signal voltage.