Flow measurement is widely used in industrial and agricultural production, national defense construction, scientific research, foreign trade and various fields of people's lives. In the production of the petroleum industry, from oil extraction, transportation, refining and processing to trade sales, flow measurement runs through the whole process, and any link cannot be separated from flow measurement, otherwise the normal production and trade exchanges of the petroleum industry will not be guaranteed. In the chemical industry, inaccurate flow measurement will cause imbalance in the distribution ratio of chemical components, and the quality of products cannot be guaranteed. In serious cases, production safety accidents will occur. In the production of the power industry, the measurement and regulation of the flow of liquids, gases, steam and other media occupy an important position. The accuracy of flow measurement is not only of great economic significance to ensure that the power plant operates under the optimal parameters, but also with the development of high-temperature and high-pressure large-capacity units, flow measurement has become an important link to ensure the safe operation of power plants. For example, the interruption or reduction of the instantaneous feed water flow of large-capacity boilers may cause serious dry pot or pipe burst accidents. This requires that the flow measurement device should not only achieve accurate measurement, but also send out alarm signals in a timely manner. In the production of the steel industry, the flow measurement of circulating water and oxygen (or air) in the steelmaking process is one of the important parameters to ensure product quality. In light industry, food, textile and other industries, flow measurement is also indispensable.
The transducers that are more widely used are external clamp type and insertion type. The mono-channel ultrasonic flowmeter has a simple structure and is easy to use, but this flowmeter has poor adaptability to changes in flow distribution. The leapfrog development of microelectronics technology and computer technology has greatly promoted the renewal of instruments, and new flowmeters have sprung up like mushrooms after rain. So far, it is said that hundreds of flowmeters have been put on the market, and many difficult problems in field use are expected to be solved. my country started the work of modern flow measurement technology relatively late. It is set at the upstream end of the measuring flow channel 6 and relative to the holes 11 and 12 to reduce the measured fluid flowing into the holes 11 and 12; the measuring control component 19 is used to measure the propagation time of the ultrasonic wave between the ultrasonic transducers 8 and 9; and the calculation component 20 is used to calculate the flow rate according to the signal of the measuring control component 19.
The flowmeter should avoid ferromagnetic objects and equipment with strong electromagnetic fields (such as large motors, large transformers, etc.) as much as possible to prevent the magnetic field from affecting the working magnetic field and flow signal of the sensor. The flow signal line and excitation line between the sensor and the converter. However, from the analysis of damaged parts in lightning faults, most of the induced high voltage and surge current that caused the fault were introduced from the power supply line in the control room, and the other two paths were less common. Since the electromagnetic flowmeter has a much higher chance of measuring suspended solids or dirty bodies than other flow meters, the probability of failure caused by the inner wall adhesion layer is relatively high. If the conductivity of the adhesion layer is similar to that of the liquid. Common debugging period failures are usually caused by improper installation.