Phase Detection Electromagnetic Flowmeter-Design and Use

Two types of gated sine-wave electromagnetic flowmeter are examined critically, and found to be sensitive to phase shift in the transducer signal. This phase shift is always found in a sine-wave flow transducer because of imperfection in construction, particularly in those used for physiology and medicine. A flowmeter design that discards amplitude modulation and is sensitive to phase change only is described. Advantages over other types of electromagnetic flowmeter are discussed. Results obtained with the phase detection flowmeter are illustrated.