Abstract: A conductivity sensor is disclosed that comprises a forked electrode support that includes a first opposing arm and a second opposing arm spaced apart by a slot. Both the first arm and the second arm include a plurality of electrodes embedded in each arm. The first and second arms and the slot are capable of retaining a volume of fluid within the volume defined by the arms and the slot such that the conductivity of the fluid in the slot can be determined. The conductivity sensor is wipeable by a reciprocating wiper assembly positioned adjacent the forked electrode support such that the wiper element can travel through the slot and remove contaminants from the slot and the plurality of electrodes in each of the first and second arms. Also disclosed are methods of making the conductivity sensor.

Abstract: An improved apparatus for measuring conductivity or resistivity compensates for series capacitance and parallel capacitance. A sine wave excitation potential is applied to the series combination of a reference resistance and a conductivity cell. The voltages across the reference resistance and the cell are sampled. To compensate for series capacitance, both sampled voltages are synchronously rectified with respect to the phase of the sampled reference resistance voltage. To compensate for parallel capacitance, both sampled voltages are synchronously rectified with respect to the phase of the sampled cell voltage. The rectified voltages are integrated and the cell conductivity or resistivity is calculated from the product of the reference resistance and the ratio of the integrated voltages.