Electrostatic spray coating of objects with powder

摘要

A procedure for electrostatic coating of objects with powder in a fluidised layer has honeycomb electrodes in the fluidised layer which are closed at the top and bottom, at a high voltage. In the electrodes, points form where a very high field strength exists similar to corona peaks. This way the discharge voltage can be maintained at a low value, between +/- 3kV and +/-20 kV. The negative high voltage is passed through a protective resistance of 1000 kilohms to the honeycomb electrode which has a specific volume resistance of between 10 and 100 ohm-cm and a specific surface resistance of between 100 and 1000 ohms. Between the electrodes is a further movable honeycomb electrode to increase the field strength and for workpiece matching.