FREMGANGSMAATE OG MAALEANORDNING TIL BESTEMMELSE OG OVERVAAKING AV GRENSEFLATEOMRAADER MELLOM MINST TO FORSKJELLIGE MEDIER, SAERLIG VANN, OLJE OG GASS I TANKER FOR LAGRING AV RAAOLJE.

摘要

In a method for determining the interface between different media, particularly water, oil and gas in storage tanks for crude oil a number of thermal sensor units are employed provided in a vertical tube immersed in the medium or the media. Each sensor unit comprises two sensor elements (T1, T2) which measures a first and a second absolute temperature (t1, t2) respectively, which are detected and generated as a function of the vertical position of the sensor unit and employed for indicating a thermal resistance (Δt) which is the difference between (t1 and t2). Based on the measured temperatures (t1 and t2) and the thermal resistance values of the respective media threshold values for the interfaces between the different media are determined and the position and the level of interfaces are found as intersection points of respectively the function of the second absolute temperature (t2) or the thermal resistance (Δt) and the determined threshold values. A measuring device for performing the above-mentioned method is also disclosed.