Abstract: A method and apparatus are provided for maintaining a predetermined energy balance in a device, such as an aluminum reduction cell. The apparatus includes a relatively short and thin heat flow sensor having a first and second thermocouple located within opposite closed ends of a hollow thermally conductive body. Each thermocouple is composed of two wires of the same dissimilar metals. The sensor is secured by one closed end of the sensor body to an outside surface of the wall member to extend substantially perpendicular to the location on the wall without significantly affecting the heat flow from the wall surface being measured. A first wire of each thermocouple is of the same metal for electrically connecting the junctions of each thermocouple. The second wire of each thermocouple extends to a location intermediate the closed ends of the sensor body and is electrically connected to an instrument responsive to the electrical potential between the first and second thermocouples.

Abstract: A method of operating an electrolytic cell having a corrosive environment. For electrolytic operation, the cell is supplied with DC current from current carrying buses or leads located externally of the cell. AC voltage is applied between the shell and at least one of the buses, and an AC meter is electrically connected between the bus and the shell for continuously monitoring the level of electrical resistance existing between the bus and the shell. The resistance monitoring determines the existence of any leakage current flowing between the bus and the shell, which is, in turn, an indication of the quality of the insulating wall of the cell.

Abstract: A conductivity dip cell construction is provided which permits liquids to enter the dip cell electrode while inhibiting the passage of gases such as bubbles, foam, or the like, into the cell. The cell is provided with means to purge the liquid from the cell to permit subsequent entrance of a fresh aliquot of liquid for subsequent conductivity measurement.