Flow measurement is widely used in various fields, including industrial and agricultural production, national defense, scientific research, foreign trade, and people's daily lives. In the petroleum industry, flow measurement is essential throughout the entire process, from extraction and transportation to refining and processing, and finally to trade and sales. No stage can function without flow measurement; otherwise, normal production and trade cannot be guaranteed. In the chemical industry, inaccurate flow measurement can lead to imbalances in chemical composition, compromise product quality, and even serious production safety accidents. In the power industry, the measurement and regulation of the flow rates of liquids, gases, and steam are crucial. Accurate flow measurement is not only economically significant for ensuring power plants operate at optimal parameters, but also, with the development of high-temperature, high-pressure, and large-capacity units, has become a vital link in ensuring the safe operation of power plants. For example, an interruption or reduction in the instantaneous feedwater flow of a large-capacity boiler can cause serious boiler dry-out or tube rupture accidents. This requires flow measurement devices to not only measure accurately but also issue alarm signals promptly. In the steel industry, the flow measurement of circulating water and oxygen (or air) during steelmaking is one of the important parameters for ensuring product quality. Flow measurement is indispensable in light industry, food, textiles, and other sectors.
The most commonly used transducers are clamp-on and insertion types. Single-channel ultrasonic flow meters are simple in structure and easy to use, but they have poor adaptability to changes in flow distribution. The rapid development of microelectronics and computer technology has greatly driven the upgrading of instruments, and new types of flow meters have emerged rapidly. To date, it is said that hundreds of flow meters have been launched on the market, and many difficult problems in field applications are expected to be solved. my country started its work on modern flow measurement technology relatively late. The flow meter is located upstream of the measuring flow channel 6, relative to orifices 11 and 12, to reduce the flow of the measured fluid into orifices 11 and 12; the measurement control component 19 is used to measure the propagation time of the ultrasonic waves between ultrasonic transducers 8 and 9; and the calculation component 20 is used to calculate the flow rate based on the signal from the measurement control component 19.
Flow meters should be kept away from ferromagnetic objects and equipment with strong electromagnetic fields (such as large motors and transformers) to avoid the magnetic field affecting the sensor's working magnetic field and the flow signal. The flow signal line and excitation line between the sensor and the converter. However, analysis of components damaged by lightning strikes shows that the induced high voltage and surge current causing the faults are mostly introduced from the control room power supply lines, with the other two pathways being less common. Since electromagnetic flowmeters measure fluids containing suspended solids or contaminants far more often than other flowmeters, the probability of faults caused by internal wall deposits is relatively high. If the conductivity of the deposited layer is similar to that of the liquid, common commissioning failures are usually due to improper installation.