Tdr measuring apparatus for determining the dielectric constant

A Time Domain Reflectometry (TDR) measuring device for the determination of at least the dielectric constant of a medium flowing through a pipeline, comprising:

• signal generation electronics configured to generate TDR measurement signals;
• transmission and reception electronics configured to transmit and to receive the TDR measurement signals;
• a coupling/decoupling device embodied to couple the TDR measurement signals to an electrically conductive measurement probe having a predetermined length and to decouple the TDR measurement signals from the measuring probe;
• and
• a control/evaluation electronics configured to determine the dielectric constant and material properties derived therefrom, including a moisture content and a conductivity of the medium, on the basis of a propagation time and a damping of the TDR measuring signals on the measuring probe,
• wherein the measuring probe is arranged outside the interior of the pipeline, through which the medium flows the measuring probe is placed in the pipeline such that an outer surface of the measuring probe facing the medium is flush with an inner surface of the pipeline facing the medium, and
• wherein the measuring probe is configured such that the propagation time of the measuring signals on the measuring probe is dependent on the dielectric constant of the medium flowing through the pipeline.