Extendable liq. level detector - has electrode pairs with contact surfaces at desired level giving infinite resistance when dry

摘要

A switching device (1) containing a transformer, rectifier, threshold switch and an output conductor for the circuit of a magnetic valve (3) is connected to a network of electrodes (2). From the switching device a conductor leads to the electrodes (5a, b) of a first electrode pair having surfaces bent at right angles at the corresponding level of the surface to be detected. The conductors pass from the first electrode pair to a second and successive electrode pairs of a similar nature. From the last electrode pair, the conductors pass to a resistor, whose resistance corresponds to the immersion resistance of a pair of electrodes, and a test switch.