Measuring and testing – Liquid level or depth gauge – Immersible electrode type
Patent
1981-05-13
1984-12-04
Yasich, Daniel M.
Measuring and testing
Liquid level or depth gauge
Immersible electrode type
34087016, 364509, 377 19, G01F 2326, G01R 2700
Patent
active
044856733
ABSTRACT:
An improved system for generating a signal representative of the level of a material having a dielectric constant within a vessel is disclosed. The system features use of a first probe for generating a signal indicative of the dielectric constant of the material which is divided into a signal varying with the level of the material whereby a compensated level signal irrespective of the actual dielectric constant is measured. In a preferred embodiment, a single integrator is used to perform the division operation whereby inaccuracies due to component variation including long-term drift are eliminated. The instrument is disclosed as functioning in a two-wire instrument system having low power requirements, permitting use of conventional signal limits. Means for calibrating the instrument in a fail-safe manner such that the operator is assured of proper calibration are disclosed, as is means whereby bridge circuits used to measure in the capacitance measurements supplied to the division circuit are both supplied by a single oscillator means, again increasing reliability and accuracy of the system.
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Drexelbrook Engineering Company
Yasich Daniel M.
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