| 摘要 |
A device for electric monitoring of the level of a liquid present in a container, with a temperature-dependent resistance probe which is immersed in the liquid the level of which is to be monitored, a source of constant current connectable, controlled by a timer, to the resistance probe, a circuit, controlled by the timer, for detecting and storing an initial voltage drop on the resistance probe at an initial time and a measurement voltage at a defined time after the connection of the source of constant current, and a circuit for evaluating these voltages by subtraction of the measurement voltage from the initial voltage and if necessary under circumstances inversion of the difference in order to form a display voltage which corresponds to the level. There are provided a resistance probe structure for compensating for the influence of the change in level of the liquid on the display voltage due to thermal expansion as a function of its initial temperature and a computation circuit for compensating for different heat transfers from the resistance probe to the liquid as a function of the initial temperature. |
