Permanent Magnet Electromagnetic Flow Sensor

The electromagnetic flowmeter (EMF) based on Faraday's law of electromagnetic induction is a kind of flowmeter to measure the volumetric flow of conducting fluid. Because of its prominent advantages, such as high precision, wide measurement range and low pressure loss, the electromagnetic flowmeter is widely used in all fields As a key part of EMF, the electromagnetic flow sensor is used to measure the induced votage. There are two aspects for the sensor design:excitation mode and electrode.The paper introduce a electromagnetic flow sensor excited by permanent magnets, which have advantages of structure simplification, micro power and quick response. For the electrode surface polarization, the sensor use a signal processing method to control polarization voltage.Analying measurement principle, the paper design a measurement circuit based on a microcontroller unit (MCU) and prove the practicability and feasibility of the study by relevant experiment. With clean water,3.6% salt water and 25% salt water, this experiment obtains 1% relative error of the experimental results in 0.800m3/h and 0.725m3/h flow rate, which made it possible that electromagnetic flowmeter excited by permanent magnets is used in the measurement of normal conducting fluid.