Brief description of the measurement advantages of split-type electromagnetic flowmeters

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　　The split-type is a new type of measuring instrument that was developed in the 1950s and 1960s; strictly speaking, it should be considered a subset of electromagnetic flowmeters. Electromagnetic flowmeters are classified into split-type and integrated-type according to the assembly method of the converter and sensor. A split-type electromagnetic flowmeter is defined in contrast to an integrated type; its main components are: the measurement tube, electrodes, excitation coil, core, and yoke housing. It is primarily used to measure the volumetric flow rate of conductive liquids and slurries in closed pipelines. 　　Analysis of the main measurement advantages of split-type electromagnetic flowmeters: 1. The sensor structure of electromagnetic flowmeters is simple; there are no moving parts inside the measurement tube, nor any throttling elements that could impede the flow of the fluid. Therefore, when fluid passes through the flow meter, it does not cause any additional pressure loss, making it one of the flow meters with the lowest operating energy consumption. 　　2. It can measure the flow rate of contaminated media, corrosive media, and suspension-type liquid-solid two-phase flows. This is because there are no moving parts inside the measurement tube, and it is only the lining of the measurement tube and the electrodes that come into contact with the fluid being measured; the material used for these components can be selected based on the properties of the fluid in question. For example, using polytrifluoroethylene or polytetrafluoroethylene as the lining allows for the measurement of various corrosive media such as acids, bases, and salts; whereas using wear-resistant rubber as the lining is particularly suitable for measuring slurry and cement slurry, which are liquid-solid mixtures containing solid particles and subject to significant wear, as well as various suspended liquids containing fibers and pulp. 　　3. An electromagnetic flowmeter is a device for measuring volumetric flow rate; during measurement, it is not affected by the temperature, viscosity, density, or conductivity (to a certain extent) of the medium being measured. Therefore, after being calibrated with water, an electromagnetic flowmeter can be used to measure the flow rate of other conductive liquids. 　　4. The output of an electromagnetic flowmeter is proportional only to the uniform flow velocity of the medium being measured, and it is independent of the flow regime under symmetric conditions (laminar or turbulent). Therefore, electromagnetic flowmeters have an extremely wide measurement range, with a ratio that can reach 10:1. 　　5. Electromagnetic flowmeters have no mechanical inertia, allowing for rapid response; they can measure instantaneous pulsating flow rates as well as flow in both forward and reverse directions. 　　6. Industrial electromagnetic flowmeters come in a very wide range of diameters, from a few millimeters to several meters. In China, there are already flow calibration devices with a diameter of 3 meters, which lays the foundation for the use and development of electromagnetic flowmeters. 　　Flow measurement is one of the components of metrological science and technology, and it is closely related to the national economy, national defense construction, and scientific research. Doing this work well plays an important role in ensuring product quality, improving production efficiency, and promoting the development of science and technology. Especially in today’s era of energy crises and an increasing level of automation in industrial production, the significance and role of flow meters in the national economy have become even more evident.