Electromagnetic flowmeter is a new type of flow measurement instrument that rapidly developed in the 1960s with the advancement of electronic technology. It is made according to Faraday's law of electromagnetic induction and is used to measure the volumetric flow rate of conductive fluids. Due to its advantages, it has been widely used in the measurement of various conductive liquids in industry. For example, measuring various corrosive liquids such as acids, alkalis, salts, etc; Various flammable and explosive media; Various industrial wastewater, pulp, mud, etc.

Electromagnetic FlowmeterThe main characteristics are:

① The transmitter structure of an electromagnetic flowmeter is simple, without movable parts or any throttling components that hinder fluid flow, so it will not cause any additional pressure loss when the fluid passes through. At the same time, it will not cause problems such as wear and blockage, and is particularly suitable for measuring liquid-solid two-phase fluids with solid particles such as slurry, sewage, and various viscous slurries. Similarly, due to its structure without moving parts, it can be made of corrosion-resistant insulation lining and electrodes made of corrosion-resistant materials, which have good corrosion resistance performance and can be used for measuring various corrosive media.

② Electromagnetic flowmeter is a volumetric flow measurement instrument that is not affected by the temperature, viscosity, density, and conductivity (within a certain range) of the measured medium during the measurement process. Therefore, after being calibrated with water, electromagnetic flow meters can be used to measure the flow rate of other conductive liquids without the need for additional corrections

③ The range of electromagnetic flowmeter is extremely wide, and the range ratio of the same electromagnetic flowmeter can reach 1:100. In addition, electromagnetic flow meters are only proportional to the average flow velocity of the measured medium, and are independent of the flow state (laminar or turbulent) under axisymmetric distribution.

④ Electromagnetic flowmeter has no mechanical inertia, sensitive response, can measure instantaneous pulsating flow, and has good linearity. Therefore, the measurement signal can be directly converted linearly into a standard signal output using a converter, which can be indicated locally or transmitted over long distances.

Although electromagnetic flow meters have the above-mentioned excellent characteristics, they still have some shortcomings, which limits their use to a certain extent. There are mainly the following points:

① Electromagnetic flow meters cannot be used to measure gases, vapors, and liquids containing large amounts of gas.

② At present, electromagnetic flow meters cannot be used to measure liquid media with very low conductivity. The conductivity of the measured liquid medium cannot be lower than 10-5 (S/cm), which is equivalent to the conductivity of distilled water. I am still powerless against petroleum products or organic solvents.

③ Due to temperature limitations on the insulation lining material of measuring tubes, industrial electromagnetic flow meters are currently unable to measure high-temperature and high-pressure fluids.

④ The electromagnetic flowmeter is affected by the flow velocity distribution, and under the condition of axisymmetric distribution, the flow signal is proportional to the average flow velocity. So, there must also be a certain length of straight pipe sections before and after the electromagnetic flowmeter.

⑤ Electromagnetic flow meters are susceptible to external electromagnetic interference.