Thermal system for measuring liquid levels

摘要

A thermal liquid level measuring system including a heat sensor with a sheathed heating resistor and a measuring resistor. Power is supplied to the heating resistor in a series of pulses. The measuring resistor is connected to two filters which extract the a.c. and d.c. components from the measuring signal. A temperature measuring device determines the difference in temperature of the liquid and the gas above the liquid. A computer receives signals from the filters and the temperature measuring device to determine the level of the liquid and its temperature.