Measuring and testing – Liquid level or depth gauge – Immersible electrode type
Patent
1984-09-21
1985-12-03
Yasich, Daniel M.
Measuring and testing
Liquid level or depth gauge
Immersible electrode type
73 1H, 324 57Q, 34087016, 364509, G01F 2326, G01R 2726
Patent
active
045559414
ABSTRACT:
A system and probe for indicating the level of material in a vessel as a function of material capacitance comprising a resonant circuit including a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An rf oscillator has an output coupled to the resonant circuit and to a phase detector for detecting variations in phase angle as a function of probe capacitance. Level detection circuitry is responsive to an output of the phase detector and to a reference signal indicative of a predetermined level of material for indicating material level as a function of a difference between capacitance at the probe and the reference signal. In the preferred embodiments of the invention disclosed, an automatic calibration circuit adjusts the resonance characteristics of the parallel resonant circuit of the reference signal indicative of a predetermined reference material level.
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Fathauer George H.
Hood Charles F.
Berwind Corporation
Yasich Daniel M.
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