Novel Multi Parameter Sensor Approach for Interface Measurement

摘要

A new method to measure the interface of two separated liquids in a vessel is presented, where twornindependent measurement principles, namely the Time-Domain Reflectometry (TDR) and therncapacitance measurement are combined in one device. This method needs only minimal effort forrnhardware, since the same probe can be used for both measurement principles. On the other hand itrnyields a wealth of complementary information for the signal evaluation.This information is used to makernthe measurement more robust: The determination of both, level and interface position under difficultrnconditions like presence of emulsion or foam and varying dielectric constants of the media is nowrnpossible, where one measurement principle alone would not deliver satisfying results. Additionally, inrncase of clearly separated media, the information is used for self calibration, so that knowledge of therndielectric constant is not necessary for device setup. Plausibility checks are possible to increasernmeasurement reliability as well as self diagnostics to detect buildup of process media on the probe.