The Research of Electrical Capacitance Tomography System for Large Industrial Equipments

The applications of electrical capacitance tomography (ECT) was studied for visualizing the inner distribution of materials in a closed vessel. In the most of applications, none of the system was of inner diameter exceeding 1 meter. When large equipment with some meters diameter needed to be monitored its inner materials distribution, the existed ECT system had encountered some difficulties of low capacitance measurement. To improve the sensitivity of monitoring for large equipment, the paper proposed a high voltage AC ECT system whose low capacitance measurement circuit employed a high AC excitation voltage that was 10~50 times than the previous AC-based one and a C/V circuits based on transformer ratio arms bridge circuit. An 8-electrodes ECT sensor model was constructed in laboratory and experiment results show that the method was suitable for large industrial equipment applications. The switch array and reconstruction algorithm for new ECT system introduced too.