Flow meters are one of the major categories of process automation instruments and devices. They are widely used in various fields of the national economy, such as metallurgy, electric power, coal, chemical industry, petroleum, transportation, construction, light textile, food, medicine, agriculture, environmental protection, and people's daily life. They are used to develop industrial and agricultural production, save energy, and improve product quality, An important tool for improving economic efficiency and management level occupies an important position in the national economy. In process automation instruments and devices, flow meters have two main functions: as a detection instrument for process automation control systems and as a total quantity meter for measuring material quantities.

The most widely used transducers are external clamp type and plug-in type. The mono channel ultrasonic flowmeter has a simple structure and is convenient to use, but it has poor adaptability to changes in flow pattern distribution. The rapid development of microelectronics and computer technology has greatly promoted the upgrading of instruments, and new types of flowmeter have sprung up like mushrooms. So far, it is said that hundreds of flowmeter types have been put on the market, and many thorny problems in on-site use are expected to be solved. The work of developing modern flow measurement technology in China is relatively late, and it is installed at the upstream end of the measurement flow channel 6 and relative to the orifices 11 and 12 to reduce the measured fluid flowing into the orifices 11 and 12; A measurement control component 19 for measuring the propagation time of the ultrasonic wave between the ultrasonic transducers 8 and 9; And a calculation section 20 for calculating a flow rate based on the signal of the measurement control section 19.