As a flow measurement device based on Faraday's law of electromagnetic induction, electromagnetic flowmeter has a series of significant advantages, but it also has some shortcomings.
Advantages of electromagnetic flowmeter 1. The diameter range of electromagnetic flowmeter can range from several millimeters to several meters. At present, there are real flow calibration equipment with a diameter of 3m in China, which has laid the foundation for the application and development of electromagnetic flowmeters. 2. The sensor structure of the electromagnetic flowmeter is simple. There are no moving parts in the measuring tube and no throttling parts that hinder the flow of fluid. It is one of the flow meters with the lowest operating energy consumption among flow meters. 3. The electromagnetic flowmeter can measure the flow rate of dirty media, corrosive media and suspended liquid-solid two-phase flow. Only the measuring tube lining and electrodes of the electromagnetic flowmeter are in contact with the measured medium, and their materials can be selected according to the properties of the measured fluid.
For example: (1) The electromagnetic flowmeter is lined with polytrifluoroethylene or polytetrafluoroethylene and can measure various corrosive media such as acids, alkalis, and salts. (2) The electromagnetic flowmeter uses a wear-resistant rubber lining, which is particularly suitable for measuring liquid-solid two-phase flows such as slurry and cement slurry with solid particles and large wear, as well as various suspended liquids such as fiber-laden liquids and paper pulps. . 4. The measuring range of the electromagnetic flowmeter is extremely wide, and its measuring range can reach 100:1, or even the operable flow range of 1000:1. 5. The electromagnetic flowmeter has no mechanical inertia and is sensitive in response. It can measure instantaneous pulsating flow. The intelligent electromagnetic flowmeter can measure flow in both forward and reverse directions. 6. The electromagnetic flowmeter is not affected by the temperature, viscosity, density and conductivity (within a certain range) of the medium being measured during the measurement process. The electromagnetic flowmeter is a volume flow measuring instrument that can be used to measure the flow of other conductive liquids only after being calibrated with water.
At present, electromagnetic flowmeters have the following shortcomings: 1. Electromagnetic flowmeters cannot currently be used to measure the flow of liquid media with very low conductivity, such as petroleum products or organic solvents. 2. Electromagnetic flowmeters cannot currently be used to measure the flow of gas, steam and liquids containing large amounts of gas. 3. The installation and debugging of electromagnetic flowmeters have strict requirements. (1) The electromagnetic flowmeter sensor and converter must correspond one to one, and different models of products cannot be used interchangeably. (2) The installation of the electromagnetic flowmeter must comply with the installation specifications. 4. When the electromagnetic flowmeter measures dirty or viscous media, the medium will adhere to the inner wall or the electrode (the scraper electrode can remove the dirt covering the electrode). The electromagnetic flowmeter will cause errors as the thickness of the dirt increases, and even Not working properly. 5. The internal aperture of the electromagnetic flowmeter will change the original flow value of the flowmeter due to scaling or wear, causing measurement errors. 6. To improve the measurement accuracy and anti-interference ability of the electromagnetic flowmeter, a high-performance converter is required, which increases the cost significantly. 7. The electromagnetic flowmeter is easily affected by strong external electromagnetic signals
Hangzhou Economic Development Area，Hangzhou 310018，China
