Design and FEM analysis of multi segment capacitive level sensor based on local and global E-fields)

This paper presents various designs of a multi segment capacitive level sensor for fluid monitoring. Among the investigated designs, the mixed model (with global and local E-field or electric fields concept) of capacitive level sensor probe encompasses an efficient sensitivity which is approximately same as basic model (without global and local electric fields concept) of sensor. The main advantage of mixed model is to simultaneously detect the coating effect on the sensor by using local electric fields and the continuous level monitoring by global electric fields. The capacitive level sensor probe is based on basic model with a length of 1 m which is divided into 11 segments. Each segment has a length and separation distance of 89.5 mm and 1.55 mm respectively. Polypropylene material is used for insulation in between the sensor and fluid. Finite element method analysis is used as a main tool to examine the sensitivity of the various designs in different permittivity of liquids. An algorithm is also developed and measurements are evaluated for a basic model.