Factors that should be considered when designing signal processing for radar level gauges/level transmitter

The radar level transmitter is a very practical level measurement. In the actual industrial application site, there will be a variety of non-ideal conditions and the following five factors:

1. The application occasions of radar level gauges/level transmitter are often limited and small spaces, rather than open huge spaces. The signal emitted by the radar level gauge/level transmitter is an electromagnetic wave, which diverges in space and has all the characteristics of an electromagnetic wave, such as reflection, diffraction, and refraction. Any object in the propagation room will reflect the signal. A small space will produce many reflected signals, including direct reflection signals on the surface of the object, and back and forth reflections and oscillations of the signal (multiple reflections on the surface).

2. When the height of the liquid level is different, it is equivalent to the continuous change of the measurement space, and the reflection and oscillation of the signal are different. Especially when the space to be measured has a curved surface, such as a vaulted tank, a spherical container or a horizontal elliptical lift, because the curved surface has a focusing effect on electromagnetic waves, the height change of the liquid level has a greater impact on the reflection.

3. After the radar level gauge/level transmitter is installed and put into use, the space surface conditions of the application occasions are constantly changing. Taking the reaction tank as an example, the medium that needs to be measured in the chemical process is various, and the liquid level will change when feeding. Material adhesion, changes in the physical or chemical properties of the inner surface of the tank, etc., these changes will inevitably affect the intensity of the reflected signal.

4. The medium of some application sites will directly affect the transmission and reception of radar waves. On the one hand, it affects the antenna, such as steam condensing on the surface of the antenna, and physical crystals on the surface of the antenna. On the other hand, the volatilization or atomization of the medium in the tank will also affect the propagation of radar waves, which will affect the measurement.

5. The measured liquid level also has a variety of changes, such as a mirror when it is still; the surface will fluctuate when the liquid level changes; sometimes there may be bubbles. Under different circumstances, the multiple reflections of the signal will change.