EMD-based electrostatic detection of screw conveyor blade motion
Screw conveyor is widely used in chemical industry,metallurgy,grain and transport and other fields,and the movement of its screw blade has a direct impact on the conveying state.Most of the closed transport,and harsh operating environment,after a long time of work,easy to deformation of the spiral blade,or even broken shafts and other accidents,through real-time detection of the movement speed of the spiral blade,can be timely access to the operating status of the screw conveyor.For the lack of effective means of detecting the movement speed of the spiral blade,an electrostatic sensor was designed,and the problem of serious noise interference of the electrostatic signal was proposed based on the empirical mode decomposition(empirical mode decomposition,EMD)of the electrostatic signal filtering method,and the filtered signals could be obtained through the mutual correlation calculation of the rising speed of the spiral blade.The rising speed of the spiral blade could be obtained by the cross-correlation calculation of the filtered signal.The experimental results showed that the electrostatic signal detected at the pipe wall during the spiral conveying process was periodic and consistent with the frequency of the spiral blade passing through the electrodes,and the relative error of the spiral speed measurement was 0.67%after the filtering process based on EMD and the correction of the spiral speed.