Electrode for an impedance measuring apparatus

Abstract

An electrode, forming a part of an apparatus for measuring the electrical impedance of a variety of sampled materials for the purpose of determining moisture content, is composed of a pair of spaced-apart conductors across which an electrical field is radiated. In a first embodiment, useful for a sample of grain or the like, the electrode comprises a box including a flat central electrode plate vertically mounted within and electrically isolated from the enclosing grounded walls of the box. In a second embodiment, adapted for stacked tissue paper or the like, the electrode comprises a pair of opposed plates, both of which are electrically driven by a sensing circuit. In a third embodiment, particularly suited for wood chips, the electrode comprises a front opening box including a flat central electrode plate mounted on and electrically isolated from a grounded backing plate. The forward walls of the box are pivotally mounted at the top of the backing plate so that the lower end of the box opens outwardly to ensure complete dumping of the sampled material. In a fourth embodiment, used for stacked lumber as it dries in a kiln, the electrode is provided by an elongated cylindrical rod which is inserted into the center of the stacked lumber, with the walls of the kiln or the rails supporting a car having the lumber stacked thereon, normally being formed from a metallic material, serving as grounded conductors.