是以物理学中的多普勒效应为基础，根据声学多普勒效应，当声源和观察者之间有相对运动时，观察者所感受到的声频率将不同于声源所 The Doppler ultrasonic flowmeter is based on the Doppler effect in physics. According to the acoustic Doppler effect, when there is relative motion between the sound source and the observer, the sound frequency experienced by the observer will be different from the sound. Origin
Issued frequency. This frequency change due to relative motion is proportional to the relative speed of the two objects. Jinhu Dongxiang Doppler ultrasonic flowmeter can simultaneously record the instantaneous flow, total flow, flow rate, pH value and downhole in the pipeline
Various parameters such as temperature.
There are three main reasons for the Doppler ultrasonic flowmeter's error in use:
(1) The error of the flow meter itself.
(2) Flowmeter area / rate sensor installation error.
(3) Reasons for current hydraulic conditions.
The measurement error of Doppler ultrasonic flowmeter is mainly caused by objective reasons such as sensor installation and hydraulic conditions. In order to reduce the error, the position must be accurate when installing the rate / area sensor.
The liquid level of the section is preferably above 6cm, and the relative accuracy of the flow meter itself can basically meet the requirements for use.
Dongxiang Instrument proposes to use the measurement principle of Doppler ultrasonic flowmeter and corresponding rate / area sensor, which can be applied to the current flow monitoring in the drainage pipeline. It can be more realistic and coordinated with the graphs of various data.
Fully reflect the current flow change law in the drainage pipeline, and be able to measure relatively real flow data. 配备相应数据发送和采集设备，可以对现况排水设施流量的动 The Doppler ultrasonic flowmeter is equipped with corresponding data transmission and acquisition equipment, which can monitor the flow of current drainage facilities.
Monitoring, and real-time grasp of the changes in water volume in the drainage network, combined with drainage operation monitoring information management system, the use of GIS technology can achieve more flexible, accurate and real-time comprehensive analysis, optimized operation and adjustment
Degree mode, creating conditions for the realization of "digital drainage" in cities.
The measurement principle of the Doppler ultrasonic flowmeter is based on the Doppler effect in physics. According to the acoustic Doppler effect, when there is relative motion between the sound source and the observer, the frequency of the sound perceived by the observer will be different from the sound
The frequency emitted by the source. This frequency change due to relative motion is proportional to the relative speed of the two objects.
In the flow measurement method of the Doppler ultrasonic flowmeter, the ultrasonic transmitter is a fixed sound source, and the solid particles moving with the fluid play the role of an "observer" that moves relative to the sound source.
The ultrasonic waves incident on the solid particles are reflected back to the receiving data. The frequency difference between the transmitted sound wave and the received sound wave is the Doppler frequency shift of the sound wave due to the movement of solid particles in the fluid. Since this frequency difference is proportional to the fluid
Velocity, so measuring the frequency difference can get the flow velocity. Further, the flow rate of the fluid can be obtained.
性能特点 Doppler ultrasonic flowmeter performance characteristics
Host display: Chinese / English display, which can display instantaneous flow, accumulated flow, flow rate and other information. Fixed Doppler ultrasonic flowmeter
Signal output: current signal: 4-20mA, with load capacity 0 ~ 600Ω
Data interface: standard RS-232C or RS-485
Data record: 65,072 data records can be stored (leading domestic technology)
Tube diameter range: Ф25 ～ Ф3048mm
Velocity range: 0.1m / s ～ 10.0m / s
Measurement accuracy: ± 0.5% ~ ± 2% FS
Suspended matter content: ≥100mg / L
Length of straight pipe section: 10D on the upstream side and 5D on the downstream side, 30D from the pump outlet (D: refers to the pipe diameter)
Installation: external binding or plug-in optional
Working temperature: host -20 ℃ ~ 50 ℃; sensor -40 ℃ ~ 82 ℃
Power voltage: AC85 ~ 265V can work, suitable for harsh power voltage occasions
Relay output: upper and lower limit alarms can be set
Dimensions: 240 × 185 × 120mm