Ultrasonic Doppler flowmeter, non full pipe measurement, sewage and rainwater pipe network, river flow, canal flow
Manufacturer of ultrasonic doppler flowmeter
Applicable occasions: This product is an instrument for measuring the flow rate and quantity of water in natural water bodies, channels, and pipelines. Using ultrasonic technology to detect flow velocity, the measurement point is located in front of the body without damaging the flow field; High measurement accuracy, linear flow measurement, capable of measuring instantaneous flow velocity and average flow velocity; No rotating parts, not afraid of mud blockage and water grass entanglement. The probe is sturdy and durable, without problems such as mud blockage or water grass or debris entanglement. It is most suitable for measuring in rivers with high suspended sediment content, floating objects such as water grass, and extremely harsh ice age conditions
Working principle of Doppler ultrasonic flowmeter
The principle of Doppler effect (Doppler shift): The sound waves emitted by one object are received and reflected by another object. If the object emitting the sound waves is moving relative to the receiving object, the frequency of the sound waves received by the receiving object will differ from the frequency of the emitted sound waves. If the relative distance between two objects decreases, the received frequency will increase compared to before. If the relative distance between two objects increases, the received frequency will decrease compared to before. This Doppler effect often occurs in daily life, for example: when you hear the alarm sound of a police car coming towards you (emitting a sound), the sound will appear to have a higher frequency; And when the police car is far away from you, the sound you hear will become lower.
In the ultrasonic Doppler flow measurement method, the ultrasonic transmitter is a fixed sound source, and the solid particles moving together with the fluid act as the “observer” with relative motion to the sound source. Of course, it only reflects the ultrasonic waves incident on the solid particles back to the receiver. The frequency difference between the emitted sound waves and the received sound waves is the Doppler frequency shift caused by the movement of solid particles in the fluid. Since this frequency difference is proportional to the fluid flow velocity, measuring the frequency difference can obtain the flow velocity and thus obtain the fluid flow rate. Therefore, it is suitable for measuring dirty water and slurry with high impurity content, such as urban sewage, sludge, etc.
Application of Doppler Ultrasonic Flow Meter
·Flood disaster monitoring, sewage discharge, and natural rivers and streams
·Municipal water supply and drainage, water loss/infiltration monitoring, irrigation process monitoring
·Research on estuaries and tides, fisheries/water conservancy, and coastal erosion
·Monitoring of Underdrain Processes, Monitoring of Road Drainage, and Research on Canal Processes
·River flow monitoring
Precautions for Doppler Ultrasonic Flow Meter
Try to choose straight channels with standard cross-sections, meeting the requirements of the top 10 and bottom 5 (i.e. the upstream straight section of the instrument has 10 times the channel width, and the downstream straight section has 5 times the channel width). If this requirement is not met, the flow state of the water will not be very stable, and there may be situations where the measurement results are too large or too small. In this case, correction is needed, usually by multiplying by a correction factor (which is generated through on-site calibration) or adjusting the installation position.
The communication cable of the flowmeter probe cannot be bent excessively to prevent it from breaking due to the presence of a ventilation pipe inside.
The ventilation pipe inside the communication cable is connected to the circuit board inside the probe and should not allow water to enter. During installation, the end of the ventilation pipe should face downwards to prevent moisture from accumulating and flowing into the probe circuit along the pipe wall.
The ultrasonic transducer probe at the front end of the flowmeter probe should not be subjected to impact or scratches.
During installation, it is necessary to be parallel to the direction of water flow and maintain a certain distance from the bottom silt.
During installation, it is necessary to avoid covering the flowmeter probe with debris, which may prevent measurement.
It is best to use steel pipes and PVC pipes to fix the edges of all communication wires on the side, so as to avoid tension caused by hydraulic impact, especially in channels with a lot of water and grass. When grass is hung on the cable line, it will generate a lot of tension and may break the cable.
When using for the first time, it is necessary to set the parameters of the water level gauge and the calibration coefficient of the flow meter.