The working principle of electromagnetic flowmeter
When the conductor cuts the magnetic field line in a magnetic field, the conductor will produce EMF, size and conductor EMF in a magnetic field and the effective length of conductor in a magnetic field perpendicular to the magnetic field direction is proportional to the speed. Similarly, the conducting fluid flows vertically in the magnetic field, and when the magnetic induction line is cut, the induction potential is generated at the electrodes on both sides of the pipe.
Electromagnetic flowmeter is a flowmeter based on Faraday's law of electromagnetic induction. The advantage of electromagnetic flowmeter is that the pressure loss is very small, and the range of flow measurement can be large. The ratio of the maximum flow and minimum flow rate is generally more than 20:1, the applicable industrial diameter range, up to 3m, the output signal and the measured flow rate is linear, high precision, fluid flow can be used to measure the conductivity of more than 5 s/cm of the acid, alkali, salt solution, water, sewage and corrosive liquid and slurry, slurry the pulp, etc.. But it does not measure the flow of gas, steam, and pure water.
According to the above formula, when the pipe diameter D is fixed and the magnetic induction intensity B remains unchanged, the measured volume flow is linearly related to the induction potential. If an electrode is inserted on both sides of the pipe, the induced potential Ex can be introduced. The magnitude of the potential can be measured to obtain the volume flow.
