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International Society for Industrial Process Tomography

5th World Congress on Industrial Process Tomography

Effect of Number of Sensors on Tribo-electric Tomography System

M. Machida1, M. Kaminoyama2

1 Process Development Center, Idemitsu Kosan Co., Ltd.

1-1 Anesaki-Kaigan, Ichihara, Chiba, 299-0193 Japan, Email:

2 Dept. of Chemical Engineering, Yokohama National University, 79-5 Tokiwadai Hodogaya-ku, Yokohama, 240-8501, Japan, Email:


An electrodynamic sensor senses the electrostatic charge carried by a particle. A tomography system using an electrodynamic sensor is called a tribo-electric tomography system. The source of the signal induced on the electrodynamic sensor is brought by the object to be measured and no excitation circuit is necessary. This electrodynamic sensing is a passive sensing and a fast and light weighted tomography system is expected. On the other hand, most of the tomography systems, like capacitance or resistance tomography systems, demand excitation circuit and are of the active sensing type. The number of measurements possible with passive sensing is equal to the number of sensors and that of active sensing to the number of the combination of two sensors. The passive sensing tomography system demands more sensors to be settled.

We plan to improve the reconstructed images by increasing the number of the electrodynamic sensors in a tribo-electric tomography system. In our previous work, the image reconstruction methods were compared with both the back-projection and the least-square method using the ideal simulated data, which contains no noise. Increasing the number of sensors causes a decrease in the sensor's circumferential length and surface area. A smaller surface area in an electrodynamic sensor induces a smaller electrical current signal and the relative signal-noise ratio decreases. We investigate the influence of the surface area to signal intensity by solving the electrical field in the sensing zone using the finite element method.

Keywords Electrodynamic Sensor, Tribo-electric Tomography System, Finite Element Method, Electrical Field

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