RESONANCE LEVEL INDICATOR Russian patent published in 2003 - IPC

FIELD: check of level of liquid media; oil-refining industry, chemical industry and other industries. SUBSTANCE: proposed device includes piezoelectric transducer, first and second detectors, matching transformer, sweep-frequency generator, radio- frequency cable, separating capacitor, amplifier, first and second comparators, source of reference voltages of reverse polarity and indicator unit. Piezoelectric transducer is acoustically linked with outer surface of reservoir. First detector, matching transformer and piezoelectric transducer are connected in parallel. Matching transformer is connected with sweep-frequency generator and second detector by means of RF cable. Separating capacitor is connected between output of second detector and input of amplifier. Amplifier output is connected to inputs of first and second comparators. Second inputs of first and second comparators are connected with sources of reference voltages of reverse polarity. Comparator outputs are connected to indicator unit. EFFECT: extended temperature range of liquid level indication. 2 cl, 1 dwg