Ultrasonic open channel flowmeter is a widely used device for measuring open channel flow, and its working principle is based on the propagation characteristics of ultrasonic waves.

When ultrasound propagates in a medium, it will encounter reflections at different interfaces of the medium. The ultrasonic open channel flowmeter utilizes this characteristic by emitting ultrasonic pulses to the surface of the open channel through a transmitter. When ultrasonic pulses come into contact with the water surface, they are reflected back and received by the receiver. By measuring the time difference between the emission and reception of ultrasonic waves, combined with the propagation speed of ultrasonic waves in the air, the distance from the water surface to the probe, that is, the water level height, can be accurately calculated.

In open channel flow measurement, there is a certain correspondence between water level height and flow rate, but this relationship is not a simple linear relationship. It is also closely related to the type and size of the weir groove in the open channel. Common types of weirs include triangular weirs, rectangular weirs, equal width weirs, and Bacher weirs. Different weirs have different water level flow relationship curves. After measuring the water level height, the ultrasonic open channel flowmeter will convert the water level height into flow data based on the pre-set weir type and size, using the corresponding water level flow relationship formula.

In addition, in order to improve the accuracy and stability of measurement, ultrasonic open channel flow meters also adopt a series of advanced technologies. For example, using high-precision signal acquisition modules combined with filtering algorithms can effectively eliminate interference and errors during the measurement process; Using real-time sound velocity, temperature compensation and other technologies to compensate for flow rate, in order to meet measurement requirements under different environmental conditions.