HEAT FLOW CALORIMETER

This invention generally relates to heat flow calorimeter devices for measuring heat liberated from or absorbed by an object and particularly concerns a calorimeter device capable of measuring the thermal output of sealed nickel-cadmium batteries or cells during charge-discharge cycles thereof. In the preferred embodiment, the invention contemplates the provision of a thermally isolated calorimeter vessel into which an object, such as a nickel-cadmium cell, is placed, heat exchange taking place between the object and the vessel. An elongated metal heat conducting rod is coupled between the calorimeter vessel and a heat sink, thus providing the only heat exchange path from the calorimeter vessel itself. Heater wires disposed within the calorimeter vessel supply additional heat to the vessel to maintain a constant temperature head therein or, more specifically, to maintain a constant temperature differential between the vessel and the heat sink. Any variation in the amount of heat supplied to the vessel and specifically any variation in power supplied the calorimeter vessel heater besides that necessary to maintain the constant temperature difference between the vessel and the heat sink is equal to the amount of heat liberated or absorbed by the object within the vessel itself, and means are provided for measuring this heater power. The apparatus is constructed into electrically insulated split halves so that the heat conducting rod and other components of the system are themselves utilized to conduct power to and from nickel-cadmium cell disposed within the calorimeter vessel.