Method and apparatus for measuring moisture content as a function of thermal response

摘要

Moisture content measurements are accomplished as a function of temperature by measuring the temperature-difference versus natural-logarithm-of-heating-time response of a sample of a predetermined material during a predetermined interval of application of a predetermined quantity of heat, determining the slope of that response at a portion thereof of substantially maximum slope, determining the mean sample temperature through the duration of that response portion, and calculating the moisture content of the sample as a function of that slope and that mean temperature. A thermal probe is used for both applying controlled heat to a material sample and sensing resulting temperature changes within the sample. The probe includes a line heat source and either a thermocouple sensing element or a thermistor sensing element. Sample holders are employed which limit diversion of heat from the heater via paths other than through the sample material. In one embodiment the sample holder has an externally controllable internal volume to facilitate measurements by establishing a predetermined sample density.