Analysis of the working principle of electromagnetic flowmeter and its limitations in practical appl

Project Overview

　　Electromagnetic flowmeter is a kind of instrument that utilizes Faraday's law of electromagnetic induction to measure the flow of conductive liquid. It is widely used in chemical, petroleum, pharmaceutical, water treatment and other fields. In this paper, we will introduce the working principle of electromagnetic flowmeter and its limitations in practical application analysis.

　　I. Working principle

　　The main components of electromagnetic flowmeter include measuring tube, electrode, electromagnetic field generator and signal processor. When the conductive liquid flows through the measuring tube, the liquid will carry current. The electrode receives the current carried by the liquid and sends it to the signal processor. At the same time, the electromagnetic field generator produces an alternating magnetic field in the measuring tube, and the conductive liquid will generate an induced electromotive force under the action of the alternating magnetic field, which is proportional to the average flow rate of the liquid according to Faraday's law of electromagnetic induction. The signal processor calculates the flow rate of the liquid by measuring the current received by the electrode and the induced electromotive force of the liquid.

　　Supmea electromagnetic flow meter picture

　　Second, the limitations of the analysis

　　1. Limited scope of application: electromagnetic flowmeter is only suitable for conductivity greater than 5μS/cm of liquid, for low conductivity liquid or non-conductive liquid, electromagnetic flowmeter can not be measured.

　　2. Higher requirements for the fluid: as the electromagnetic flowmeter measures the current in the liquid, so the conductivity of the fluid has an important impact on the measurement results. If the liquid contains suspended solids or air bubbles and other substances, it will affect the measurement accuracy.

　　3. High installation requirements: the installation of electromagnetic flowmeter needs to ensure that the level and verticality of the measuring tube, as well as the accuracy of the electrode and the distance between the liquid and other parameters, which puts forward high requirements for the technical level of the site installers and installation conditions.

　　4. Higher cost: compared to other types of flow meters, electromagnetic flowmeter cost is higher, this is due to the electromagnetic flowmeter manufacturing and maintenance costs are higher, and need to be equipped with the corresponding signal processor and electromagnetic field generator and other equipment, increasing the cost of use.

　　5. Temperature effects: electromagnetic flowmeter in a high temperature environment will be affected, this is due to the high temperature will affect the performance of the electromagnetic field generator and electrode, thus affecting the measurement accuracy.

　　In summary, the electromagnetic flowmeter is a high precision, wide range of flow measurement instruments, but its practical application also has certain limitations. In the selection of electromagnetic flowmeter need to take into account the characteristics of the measured liquid, the site installation conditions and the use of cost and other factors, and combined with the actual situation for selection.