By the electromagnetic flowmeter working principle explains the measurement medium must be conductiv

Project Overview

　　Electromagnetic flowmeter is a kind of flow measurement instrument based on Faraday's law of electromagnetic induction, and its working principle determines the reason that the measurement medium must be conductive liquid, which can be detailed from the following aspects:

　　First, the working principle of electromagnetic flowmeter

　　Faraday's law of electromagnetic induction states that when a conductor moves in a magnetic field, an electric potential is induced in the conductor. Electromagnetic flowmeter using this principle, by generating a magnetic field in the fluid, so that the conductive material in the fluid (such as water, acids, alkalis, etc.) in the flow of cutting the magnetic lines of force, thereby generating a voltage between the electrodes. This voltage is proportional to the flow rate of the fluid, which in turn can be deduced from the fluid flow.

　　Second, the need to measure the conductivity of the medium

　　Generation of induced electromotive force: in the electromagnetic flowmeter, the generation of induced electromotive force depends on the fluid cutting magnetic lines of force. And this process requires the fluid must have a certain conductivity, in order to effectively sense the electric potential in the magnetic field. If the fluid is not conductive, then even if it cuts the magnetic lines of force, will not produce induced electromotive force, and therefore can not be measured by electromagnetic flowmeter.

　　Measurement accuracy: the conductivity of the fluid also affects the measurement accuracy of the electromagnetic flowmeter. If the conductivity of the fluid is too low, then the signal of the induced electromotive force will be very weak and easily affected by noise and interference, which leads to increased measurement error. Therefore, in order to ensure the accuracy of measurement, the measurement medium must have a certain conductivity.

　　Third, the structure and components of electromagnetic flowmeter

　　Electromagnetic flowmeter is mainly composed of magnetic circuit system, measuring conduit, electrode, shell, lining and converter and other parts. Among them, the magnetic circuit system is used to generate a uniform DC or AC magnetic field; measuring conduit is measured by the conductive liquid through the part; electrodes are installed in the wall of the measuring conduit, used to lead with the measured fluid flow rate is proportional to the induced potential signal. These components work together to achieve the electromagnetic flowmeter for fluid flow measurement.

　　Fourth, the electromagnetic flowmeter application scope and limitations

　　Due to the electromagnetic flowmeter working principle and the limitations of the measurement principle, it is mainly suitable for measuring the flow of conductive liquids. For gas, steam and many gases rich in liquid, or conductivity is very low liquid media (such as petroleum products or organic solvents, etc.), electromagnetic flowmeter can not be effective measurement.

　　In summary, the electromagnetic flowmeter principle of operation determines the measurement medium must be conductive liquid reasons. This feature makes the electromagnetic flowmeter in the field of industrial automation has a wide range of application prospects, but at the same time also limits its application in some specific areas.