Experimental Assessment of a Pneumatic Level-sensing Method for Closed Tanks Applied to Water and Wooden Pellets

A measurement method is presented that determines the free volume inside a storage vessel by measuring pressure variations resulting from artificially introduced perturbations. Combined with the knowledge of the volume of the empty tank system, the method yields the volume of the substance stored inside the tank. The proposed method determines the actual fill level regardless of tank geometry, material distribution and material composition (provided that the state of aggregation is not gaseous). The only material parameter that directly influences the measurement of the fill volume is the porosity of the stored material since the pneumatic principle yields a measure of the free volume including the volume of cavities and pores in the material that are directly accessible from the tank. Experimental results that show the good linearity of the principle for both water and wooden pellet fill-level measurements are presented. [PUBLICATION ABSTRACT]