Design and performance of a capacitance sensor for filling rate in screw feeding pipes

作者:Zhang, Xiliang; Cui, Shoujuan; Xu, Kun*; Sun, Xiang
来源:IET Science Measurement & Technology, 2018, 12(7): 925-931.
DOI:10.1049/iet-smt.2018.5296

摘要

Powder flow abounds in industrial and agricultural production such as in chemical industry, food processing, and agricultural methods, where filling rate is an important operating parameter, especially for screw quantitative feeding of powder. In order to test the filling rate in screw feeding pipe with a special feed divider, a new capacitance sensor consisted of 12 spiral electrodes, 12 radial electrodes, and a shield cover is presented. Then to optimise the geometry of the capacitance sensor, the influence of parameters such as the radius of the sensor shield, radial electrode inserted depth, and electrode field angle on the sensor is analysed through finite-element analysis. The optimal geometry dimensions are as follows: radius of the shield is 27 mm, electrode field angle is 27 degrees and radial electrode insert depth is 3 mm. On the basis of these parameters, the sensor is developed and its performance is evaluated. The results show that the relative errors of the measured values are no more than 7%. The developed capacitance sensor can be applied in filling rate measurement of screw feeding production.

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