Working principle of radar water level gauge and precautions for installation and maintenance

In recent years , With the radar water level gauge 、 Ultrasonic water level gauge is widely used in Hydraulic Engineering , More and more water conservancy workers use water level gauge observation data instead of manual observation data , In order to realize the intelligent management of water conservancy projects . Radar water level gauge , At present, it is an indispensable detection instrument in the liquid level measurement industry . Because the radar water level gauge has more advantages in performance than similar contact and non-contact liquid level gauges , So it is widely used in various industries , Product advantages and measurement effect , Gradually gain the recognition of more and more users .
Radar water level gauge is a high-precision non-contact water level measuring instrument , Its outstanding advantage is to realize non-contact measurement , Easy to install , Use electromagnetic wave to detect distance , Not affected by temperature 、 humidity 、 pressure 、 The influence of environmental factors such as rain, snow and sand , It can directly measure the water level of natural river , Realize the remote transmission and automatic processing of water level data . Besides , The radar water level gauge has fast water level tracking speed 、 Non contact measurement and wind 、 sand 、 Characteristics with little influence of temperature and floating objects , It is very suitable for use in the perennial non frozen reach with large temperature difference in the middle and upper reaches of the Yellow River . This paper takes radar water level gauge as an example , The measured water level data is transmitted to PLC Upper computer , The error source of radar water level gauge measurement is analyzed by using the target real-time calibration method 、 check , So as to realize the remote transmission and automatic processing of water level data .
Working principle of radar water level gauge
Radar water level gauge is also called water level radar , It is an electronic device that uses electromagnetic waves to detect targets . It is mainly used for hydrological monitoring 、 Sewage treatment and flood warning . Its main measurement principle is to transmit radar pulses from the radar water level sensing antenna , The antenna receives pulses reflected from the water , And record the time T, Because of the propagation speed of electromagnetic waves C It's a constant , So as to get the distance to the water D. As shown in the figure below , The radar water level gauge measures the time difference between the transmission and reception of electromagnetic waves Δt, Calculate the distance between the radar water level gauge and the liquid level H2=c*Δt/2, Output water level value h=H1-H2.H1 Is the height from the canal bottom to the water level gauge , Referred to as the installation height of radar water level gauge .
The radar water level gauge records the time of pulse wave , The transmission speed of electromagnetic wave is constant , Then the distance between the liquid level and the radar antenna can be calculated , So as to know the water level on the water surface .
Precautions for installation of radar water level gauge ：

Whether the radar water level gauge can measure correctly , A signal that depends on reflected waves . If in the selected installation location , The electromagnetic wave cannot be reflected back to the radar antenna on the water surface or there are interfering objects within the range of the signal wave to reflect the interfering wave to the radar water level gauge , The radar water level gauge cannot correctly reflect the actual water level . therefore , It is very important for radar level gauge to choose the installation position reasonably , Pay attention to the following points during installation ：
（1） The axis of the antenna of the radar level gauge should be perpendicular to the reflecting surface of the liquid level .
（2） Mixing valve in the tank 、 Adhesion of groove wall, steps and other objects , If it is within the signal range of the radar level gauge , The reflected wave that will produce interference , Affect liquid level measurement . Choose the appropriate installation position during installation , To avoid the interference of these factors .
（3） The bell mouth of the horn type radar level gauge should exceed the inner surface of the mounting hole by a certain distance （》10mm）. The antenna of the rod type liquid level gauge should extend out of the mounting hole , The length of the mounting hole cannot exceed 100mm. For round or elliptical containers , It should be installed at 1/2R（R Is the radius of the container ） Location of distance , It cannot be installed at the center of the top of a circular or elliptical container , Otherwise, after multiple reflections of radar waves on the container wall , Gather at the center of the container top , Form a strong interference wave , It will affect the accurate measurement .
（4） Measure the liquid level of vessels with large liquid level fluctuation , Liquid level gauge with bypass pipe can be used , To reduce the influence of liquid level fluctuation .

After installation , It can be used PC Observe the reflected wave curve by machine , To judge whether the liquid level gauge is properly installed , If inappropriate , Then further adjust the installation position , Until you are satisfied . For some unavoidable interference waves at the installation position , The liquid level gauge can mark the interference reflection wave according to the actual liquid level , Coexist in the internal database of radar level gauge , So that the radar level gauge can recognize these interference waves during data processing , Remove the influence of these interference reflected waves , Ensure the accuracy of measurement .
Maintenance of radar water level gauge ：
Radar water level gauge is mainly composed of electronic components and antenna , No movable parts , There are few faults in use . The occasional problem encountered in use is , Some volatile organic substances in the storage tank will crystallize on the horn or antenna of the radar water level gauge , Just check and clean them regularly , Less maintenance .