Measurement of flowing charges with an electrostatic voltmeter

This work presents results of measurements of voltages induced by electric charges flowing through a pipe. The materials used to conduct the study were an electrophotographic toner, glass microspheres, and aluminum oxide powder (Al₂O₃). These materials were transported pneumatically through the tube under investigation. Voltages induced on the pipe by the flow of charges were recorded with an electrostatic voltmeter (ESVM). A total charge of each powder was measured before and after it passed through the pipe. The ESVM was measuring the voltage induced by charges carried by the flux of solid particles and by the charges generated on the tube. Author was looking for a correlation between the initial and final charge of the toner and the ESVM voltage. As a result, method of flowing charges measurement with the ESVM is proposed.