Radar level gauge problem?

It doesn't matter, waves can propagate in any medium, but the propagation speed is different.

The measurement of the radar level gauge is related to the dielectric constant of the material. Different dielectric constants have different reflected waves. This can be used to perform layered measurements. In addition, when measuring a medium with a small dielectric constant, the surface reflected pulse energy is low, so the direct reflection method cannot be used to measure the liquid level. In this case, a short-circuit position is set at the bottom of the tank, and the length of the probe is known. The microwave pulse propagates in the air at the speed of light, decelerates when it encounters the medium (depending on the dielectric constant of the medium), and returns when the wave encounters the short-circuit position. The return time of microwaves in the air is known, so the time difference between microwave reflection and return can be calculated. This time difference is proportional to the material level.

Radar level gauges are not all-purpose liquid level gauges. For non-conductive liquids with very small dielectric constants, the signal reflected back by the radar wave is very weak, and the energy received by the antenna is even smaller. If it is less than 1% of the energy of the emitted wave, it will affect the measurement accuracy. In addition, if liquid level fluctuations and foaming occur, the accuracy will be even more affected. Therefore, it is still necessary to consider the factors of the medium. If you want to use it, you can also choose the guidance radar to minimize the impact.

But I think dielectric constant should not be an indicator that major cities should consider.

Radar waves can propagate in any medium, but the propagation speed is different.

Guided wave radar level gauges need to consider the dielectric constant, but it is not a very important parameter. The larger the dielectric constant, the stronger the signal reflected by the radar. I don’t understand what the third floor said about setting a short-circuit point at the bottom of the tank. Does it mean a distance shielded from the lower part of the liquid level gauge, or does the end of the cable of the liquid level gauge have to be a certain distance away from the bottom of the tank? Please enlighten me.

Setting a short-circuit point at the bottom of the tank refers to the reflection point of microwaves at the bottom of the tank. To prevent microwaves from being reflected in other directions, a metal plate perpendicular to the microwave should be added. In this way, the time it takes for the microwave to return to the short circuit point after reaching the short circuit point is different when the tank is empty and when there is material. This method is less accurate than the direct method and is generally used for dielectric constant œr

Don’t know what medium to measure? The radar level gauge used by our factory to measure asphalt often has problems.

For radar level meters, the dielectric constant of the medium must be considered. Generally speaking, the dielectric constants of various media will be found in the product instructions. When setting the instrument, set it according to the dielectric constant mentioned in the instruction manual, otherwise the instrument cannot measure accurately.