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According to statistics, the total amount of water on the Earth’s surface is approximately 14 billion cubic meters, but the amount of fresh water available is only 3.5 billion cubic meters. Of this limited supply of fresh water, only 0.34% is accessible to humans. Due to uneven distribution and waste in consumption, 60% of the world’s regions suffer from water shortages, with a severe crisis in water availability. With population growth and rapid economic and social development, water resource issues, particularly the conflict between water scarcity and economic and social development, have become fully apparent. On average, about 400 million mu of land in our country is affected by drought each year. In normal years, national irrigation areas suffer from a water shortage of 30 billion cubic meters per year, while cities face a shortage of 6 billion cubic meters. Along with water scarcity, there is also severe waste in water use; the utilization coefficient for agricultural irrigation across the country is mostly only 0.4, while in many areas it has reached 0.7–0.8 ； In our country, the water consumption per 10,000 yuan of industrial output is 103 cubic meters, which is 10 to 20 times higher than that in developed countries. The reuse rate of water in our country is around 50%, whereas it is over 85% in developed countries. China’s industrial water consumption is four times the world average. We must fully recognize that there is still a long way to go in conserving and protecting water resources and achieving their sustainable use. To reduce the loss and waste of water resources, improve water efficiency and effectiveness, and make rational and efficient use of water resources, it is essential to carry out proper water measurement. At the same time, the selection of high-flow water metering devices is extremely crucial. Water metering instruments are among the measuring instruments subject to mandatory inspection. There are many types of water metering devices. For measuring large flow rates, I recommend electromagnetic flowmeters first, and the main reasons for this are their following characteristics: (1) The electromagnetic flowmeter has a simple structure without moving parts or elements that could cause turbulence, which eliminates problems such as pipe blockages. The measurement principle of electromagnetic flowmeters is based on Faraday’s law of electromagnetic induction. The measuring tube of the flowmeter is a short tube made of a non-magnetic alloy lined with insulating material. Two electrodes pass through the wall of the tube in the direction of the tube diameter and are fixed to the measuring tube. Its electrode tip is essentially level with the inner surface of the lining. When the excitation coil is excited by bidirectional square wave pulses, a working magnetic field with a flux density of B is generated in a direction perpendicular to the axis of the measurement tube. At this time, if a fluid with a certain electrical conductivity flows through the measuring tube, it will cut the magnetic field lines, thereby inducing an electromotive force E. The electromotive force E is proportional to the product of the magnetic flux density B and the inner diameter d of the measuring tube multiplied by the average flow velocity v. The electromotive force E (flow signal) is detected by the electrodes and sent to the converter via a cable. After amplifying the flow signal, the converter can display the fluid flow rate and can output signals such as pulses and analog currents for the control and regulation of flow. (2) Without throttling elements, the measurement channel is a smooth straight tube that does not get clogged; it is suitable for measuring liquid-solid two-phase fluids containing solid particles, such as pulp, sludge, and wastewater ； It does not cause pressure loss resulting from flow detection, offering excellent energy-saving effects ； The measured volumetric flow rate is actually not significantly affected by changes in fluid density, viscosity, temperature, pressure, and conductivity. (3) The range ratio of electromagnetic flowmeters is usually 20:1 to 50:1, offering a wide range of flow rates and pipe diameters – from a few millimeters to 3 meters – to meet various process requirements. (4) It is not sensitive to distortions in the flow velocity distribution, offering advantages over ultrasonic, vortex street, turbine, and conventional differential pressure flowmeters. It requires a shorter straight pipe section; generally, a straight pipe section of more than 10D is sufficient for proper operation, and no flow rectifier is needed. (5) It can measure positive and negative flow rates as well as pulsating flow rates, provided that the pulsation frequency is lower than the excitation frequency. It is easy to select the material type for fluid contact parts, and it can be used with corrosive fluids. (6) The electromagnetic flowmeter has good stability ； Repeatability is 0.1% ； It has high measurement accuracy. The instrument features good output linearity, meets the requirements of national standards GB17167-2006 and GB/T20901-2007, has a long service life, and can be used for trade settlement. (7) Other conductive liquids can be measured simply after calibration with water, without the need for adjustments. (8) The measurement assurance measures and systems are more comprehensive. After passing the initial inspection with the wet calibration, as long as the flow meter maintains stable performance and good consistency, dry calibration can be used during the second re-inspection, eliminating the need for wet calibration. At the same time, the dry calibration technology for electromagnetic flowmeters is becoming increasingly mature. Its working principle involves measuring the geometry of the electrodes and flow channels of the electromagnetic flowmeter, as well as the boundary conditions of the operating magnetic field; thereafter, it calculates the output signal of the instrument using theoretical formulas for the velocity distribution at different flow rates. Electromagnetic flowmeters are a type of water meter that is widely used and in large quantities. In the use of high-flow water metering, it exhibits the above advantages prominently. It is the responsibility of those in the field of metrology to strongly advocate the use of energy-saving measuring instruments, raise awareness of conservation, and make rational and efficient use of water resources. For more information, please visit the company’s official website at http://www.yb1518.com/. Please retain this link when reproducing the content! http://www.yb1518.com/UploadFiles/2012717174126829.jpg