Open channel flow monitoring mainly uses ultrasonic open channel flowmeter, radar velocity flowmeter and ultrasonic Doppler open channel flowmeter, as follows: Ultrasonic open channel flowmeter is a non-contact instrument suitable for flow measurement in water channels with weir structures. The ultrasonic open channel flowmeter consists of a flowmeter host and an ultrasonic probe, which are connected by a cable. The ultrasonic probe uses the principle of sound wave reflection to detect the liquid level in the water weir. The water flow through the weir is a function of the liquid level. The flowmeter host calculates the water flow through the corresponding formula. It can be widely used in surface and groundwater system flow monitoring, industrial wastewater discharge monitoring, etc., to accurately detect open channel flow. The radar velocity flowmeter is a non-contact flow measurement device, which consists of a technologically advanced radar velocity meter and an ultrasonic/radar water level meter. It can perform non-contact measurement of the flow of fluids in open channels, natural rivers, sewage outlets, etc. It is easy to install and maintain, and simple to operate. It is suitable for hydrology, flood control and drainage, environmental protection and sewage monitoring and other fields. Ultrasonic Doppler open channel flowmeter is designed for velocity and flow measurement in open channels and partially full pipes. It uses the ultrasonic Doppler principle to measure fluid velocity, measures the liquid level through pressure or ultrasonic sensors, and calculates the water flow rate through the corresponding formula based on the above measurement data.

1. In the water channel with water measuring weirs, ultrasonic open channel flowmeter is usually used for flow measurement, which has high accuracy, stable and reliable measurement, and better economy. LWULA ultrasonic open channel flowmeter is suitable for measuring weirs of various specifications, and the relationship curve between weir flow and water level can also be customized.

2. LWRD radar velocity flowmeter is suitable for measuring water flow in large canals, natural rivers, sewage outlets and other places without water weirs. It has high accuracy and long-term stability.

3.  LWULB ultrasonic Doppler velocity method is used to measure the open channel flow of the water weir and flume, and the velocity and flow of the partially full pipe. It is particularly suitable for measuring the velocity and flow of water or other liquids in partially full pipes.

Figure 1: Channel installation scenario

Figure 2: Pipeline installation scenario