The measurement interface of guided wave radar is based on the difference in dielectric constant of the medium and the principle of electromagnetic wave reflection.
1. Electromagnetic wave reflection mechanism:
The electromagnetic waves emitted by guided wave radar will partially reflect when encountering different media. The intensity of this reflection depends on the difference in dielectric constant between adjacent media.
A medium with a high dielectric constant will reflect stronger signals. For example, the dielectric constant of water (≈ 80) is much higher than that of oil (≈ 2-4), so the reflected signal is very obvious at the oil-water interface.
2. Signal distribution:
Electromagnetic waves first encounter the liquid surface (such as the top of an oil reservoir), where they undergo their first reflection.
The remaining electromagnetic waves continue to propagate until they reach the oil-water interface, resulting in a second reflection.
After receiving two reflected signals, the instrument calculates the liquid level height and interface height separately based on the time difference and signal strength.
3. Dual interface measurement:
For oil-water mixtures, guided wave radar can simultaneously measure the top oil level position and the bottom oil-water interface height
