The electromagnetic flow meter is a commonly used flow measuring instrument. With the rapid development of modern fine chemical technology, it is more and more widely used in petrochemical, papermaking, metallurgy, environmental protection, food and other industries.
The electromagnetic flow meter is used for the fluid monitoring of complex industrial piping systems, real-time monitoring of the raw materials and finished products of the system, and providing a basis for automatic control of the system.
Due to the complicated operating environment of electromagnetic flow meter, and its installation process is likely to affect its operating conditions and the probability of failure, thereby affecting the operation of the entire instrument control system. Therefore, it is necessary to analyze the principle of the electromagnetic flow meter, study the installation process, and continuously summarize and update the debugging technology.
The electromagnetic flow meter is mainly composed of a signal converter and a sensor. Its principle is based on Ferrari's law of electromagnetic induction. A pair of detection electrodes are installed in the sensor perpendicular to the axis of the tube to be measured. When the flow meter is connected to the liquid medium pipeline, the conductive liquid material moves along the axis of the tube, and the conductive liquid conducts the motion of cutting magnetic lines of force to generate an induced electromotive force, which is measured by the detection electrode.
The theoretical value of the electromagnetic flow metre is: E=kVBd ( E is the induced electromotive force; k is the adjustment coefficient, which varies with the structure of the instrument; V is the average flow velocity of the liquid to be measured; B is the magnetic induction intensity; d is the inner diameter of the tube being measured) .
When measuring the flow, the fluid flows through a magnetic field perpendicular to the flow direction, and the flow of the conductive fluid induces an electric potential proportional to the average flow velocity. The induced voltage signal is detected by two electrodes and transmitted to the converter through a cable. After signal processing and related calculations, the cumulative flow and instantaneous flow of the electromagnetic flow meter are displayed on the display of the converter.