Pulses of low power microwaves are sent along a conductor, at the point where the waves meet the product surface, they are reflected back. The intensity of the reflection depends on the dielectric constant of the product. The higher the dielectric constant, the stronger the reflection will be, e.g. up to 80% for water.
The instrument measures the time between emission and reception of the microwave signal which is proportional to the distance. TDR guided wave radar can be used in two different modes: for level measurement or interface measurement of two different liquids.
The VF7 can measure product with a dielectric rating as low as 1.1 Dk and can provide an accuracy of ±3 mm on liquids as standard. It is suitable for high-pressure applications up to 300 bar and can measure the interface between liquids such as oil and water. In short, VF7 is a powerful and accurate TDR unit for demanding applications.