The QSD653 series ultrasonic Doppler open channel flowmeter is designed specifically for measuring flow velocity and flow rate in open channels and non full pipes. It uses the principle of ultrasonic Doppler to measure fluid flow velocity, and obtains the cross-sectional area of the water body through pressure or ultrasonic sensors to measure liquid level, thereby measuring and monitoring flow rate.

QSD6537 also adds functions such as conductivity testing, temperature compensation, and coordinate correction. Due to its compact, sturdy, and low-cost characteristics, it has been widely used in recent years in the measurement of sewage and industrial wastewater, streams, rivers, drinking water, and even seawater, as well as in the flow monitoring of sponge cities and black and odorous water bodies.