09,22,2026 37 views
Rectangular weirInstallation of flow meters for triangular weir and Bacher trough open channelapplicationUltrasonic open channel flow meters are widely used in factories, enterprises, urban sewage treatment departments, environmental monitoring systems for total sewage discharge control, measurement of open channel flow for domestic water and water supply and drainage, etc; It can also be applied to agricultural water conservancy irrigation, river flow and liquid level measurement.
The physical quantity directly measured by the ultrasonic open channel flowmeter is the liquid level. When used for measuring flow in open channels, a measuring weir groove is installed on the open channel. The measuring weir channel converts the flow rate in the open channel into the height of the liquid level. The instrument measures the water level in the measuring weir tank, and then calculates the flow rate based on the corresponding water level flow relationship of the measuring weir tank The correspondence between flow rate and water level in ordinary open channels is influenced by the slope ratio and surface roughness of the channel. Install a measuring weir groove in the channel to generate throttling effect, so that the flow rate in the open channel has a fixed correspondence with the liquid level. This correspondence mainly depends on the structural dimensions of the water measuring weir, minimizing the influence of the channel.
When the instrument is working, the ultrasonic sensor is fixedly installed above the measured liquid level. The probe emits pulsed ultrasonic waves towards the water surface. Sound waves reach the liquid surface through the air, and are reflected by the liquid surface as reflected waves. The probe receives the reflected waves, which are called echoes. The reflection generated by the calibration rod under the probe and received by the probe is called a calibration wave. The instrument calculates the distance from the probe to the liquid surface based on the time difference between the transmitted wave and the echo, and between the transmitted wave and the calibration wave. Subtract the distance L from the probe to the zero water level to obtain the liquid level height H. As shown in the figure.
The installation of rectangular weirs, triangular weirs, and Bacher trough open channel flow meters uses probes installed at the water level observation points of the measuring weir trough to measure the water level flowing through the measuring weir trough. During the installation of the instrument, the water level and flow rate relationship of the corresponding measuring weir groove should be recorded in the form of a numerical table and stored in the instrument's internal memory through buttons. The microprocessor of the instrument calculates the corresponding flow rate value using a lookup table method based on the measured water level. Calculate the number between two adjacent values in a numerical table using linear interpolation.
Installation diagram of ultrasonic open channel flowmeter
Main characteristics of ultrasonic open channel flowmeter
Utilizing ultrasonic sensing technology to achieve non-contact measurement with the measured medium.
The ultrasonic transmitter is equipped with temperature compensation function, which ensures that the measurement data is not affected by the ambient temperature.
The ultrasonic transmitter uses a 4-20mA output current to the integrator, so the transmission distance is long (up to 1000 meters) and it is not easily affected by on-site noise interference.
Adopting high-performance microelectronic control technology, the measurement accuracy (liquid level resolution can reach 1mm) and reliability are high.
It has multiple display modes including liquid level, instantaneous flow rate, and cumulative flow rate, and can display the dynamic flow chart of the day.
High reliability data storage design ensures that data is not lost in harsh environments.
The operation is particularly simple, and the instrument stores multiple types of weirs for users to choose from, without the need to input relevant parameters. Before use, simply select the type of weir in the function menu and perform zero water level calibration.
Adopting LCD display, the friendly and simple display interface makes it easy for people to see at a glance.
RS232/485 communication interface with optoelectronic isolation and 4-20mA output, especially suitable for environmental monitoring and total control, and can achieve remote data transmission.
Technical specifications of ultrasonic open channel flowmeter
Measurement range: 1~10000L/S (determined by the specifications of the measuring weir tank used)
The maximum range of the ultrasonic transmitter is 1.3m
Blind zone of transmitter: 0.30m
Flow measurement error: MPE ± 5%
Liquid level measurement error: MPE ± 3mm
Liquid level resolution: 1mm
Temperature of the tested medium: 0~40 ℃
Output signal: RS232/RS485 analog 4-20mA with optoelectronic isolation
Transmission distance of transmitter signal: ＜ 1000m
Power supply: AC 200~240V 50 ± 1HZ
