The principle of electromagnetic flowmeter and its advantages

1, the measurement principle of electromagnetic flowmeter

The electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. It consists of two parts: the sensor and the converter. The sensor is mainly composed of a measuring tube lined with insulating material, a pair of electrodes installed through the wall of the measuring tube and a working magnetic field. It consists of a coil and an iron core. When the conductive medium flows through the sensor measuring tube, there is a stable magnetic field generated by the transmitter in a section perpendicular to the flow direction of the medium, and the average flow velocity is a cutting magnetic field when the conductive fluid flows through the magnetic field region. motion. Then, on the two detecting electrodes parallel to the cross section of the pipe and perpendicular to the direction of the magnetic line, an induced potential is generated, which is obtained according to the law of electromagnetic induction: when the pipe diameter D has been determined and the magnetic induction day is constant, Is a constant. At this time, the induced potential has a linear relationship with the volume flow, that is, the induced potential E is measured, and the volume flow rate q of the medium is also measured.

2, the advantages of electromagnetic flowmeter

（1） Measurement of no throttling and moving parts in the duct, so the pressure loss is small, energy is saved, and the flow rate of fluids such as particles and suspended solids can be measured.

（2） Only the lining and the electrode are in contact with the medium. As long as the materials of both are selected, the purpose of anti-corrosion can be achieved; as long as the electrode is not contaminated, the accuracy of the instrument for a long time will not be lowered.

（3） electromagnetic flowmeter has a linear relationship between output current and flow. It is not affected by the physical properties of the liquid; therefore, it can be used to measure the flow rate of other conductive liquids or solid-liquid two-phase media as long as it is calibrated with water, without modification.

（4） SMART converter adopts novel excitation mode, low power consumption, stable zero point, high precision, flow range up to 100 : 1, convenient parameter setting, reliable programming, self-test and self-diagnosis.

（5） No mechanical inertia, sensitive response, can measure pulsating flow.