Signalling system indicating given fuel separator water level - using electrode pair impedance to damp oscillator signal

摘要

The arrangement for producing a signal when a given liq. level occurs in a container is esp. suitable for a water separator in the fuel supply of an internal combustion engine. It gives a reliable indication for a small change in conductivity between two electrodes immersed in the liq. The electrodes are connected to a signal source which is in turn connected to a circuit determining the frequency of an oscillator. The resistance between the electrodes controls the damping of the frequency regulating circuit. The oscillator is combined with a threshold switch into a circuit with two outputs. One or other output exhibits a voltage according to whether the electrode arrangement is damping the oscillators or not, i.e. according to the water level.