Electromagnetic flowmeters
Abstract
Abstract A METHOD AND AN ELECTRICAL CIRCUIT TO COMPENSATE FOR VARIATIONS IN THE ENERGIZING CURRENT IN THE FIELD COILS OF AN ELECTROMAGNETIC FLOWMETER. THE CIRCUIT COMPRISES A COMPENSATING FEEDBACK LOOP WITH AN ERROR DEVICE AND A PULSE GENERATOR WHICH ACTS TO SUPPLY A REPETITIVE OUTPUT SIGNAL WITH THE RATIO OF THE PULSE DURATION TO THE TOTAL PERIODIC TIME PROPORTIONAL TO THE RATIO OF TWO SIGNALS WHICH ARE INJECTED INTO THE FEEDBACK LOOP AND WHICH ARE RESPECTIVELY PROPORTIONAL TO A STABILIZED REFERENCE SIGNAL AND THE ENERGIZING CURRENT IN THE FIELD COILS. THE CIRCUIT INCLUDES A MEASURING CIRCUIT WITH A MODULATOR WHICH ACTS TO MODULATE A SIGNAL PROPORTIONAL TO THE SIGNAL DETECTED BY THE ELECTRODES IN ACCORDANCE WITH THE RATIO OF THE PULSE DURATION TO THE TOTAL PERIODIC TIME TO PROVIDE A FINAL OUTPUT SIGNAL WHICH IS PROPORTIONAL TO THE RATIO OF THE ELECTRODE SIGNAL TO THE ENERGIZING CURRENT AND HENCE PROPORTIONAL TO THE TRUE FLOW RATE.
Inventors
- 👤 David Wildon Birnstingl
Bibliographic Details
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