1998 Volume 35 Issue 12 Pages 846-855
On-line measurement of electrostatic field strength caused by charged powder was carried out using a newly developed electrostatic field sensor. The sensor was connected to the end of an insulated transportation pipe and electrostatic field strength was continuously measured with glass beads flowing inside it. Specific charge of glass beads and induced current of the pipe were simultaneously measured using a faraday cage and an electrometer, respectively. The relationship between electric charge of glass beads and electrostatic field strength at various pneumatic transportation distance, air flow velocity, glass bead feed rate and diameter of glass beads were investigated. It was found that the influences of transportation distance, powder feeding speed, and air flow velocity on the electrostatic field strength depended on the space charge density. Measurement of electrostatic field strength was proven to be very effective in monitoring the electric charge of powder during powder pneumatic transportation. Performance of on-line measurement of electrostatic field using the developed sensor was also confirmed.
