Electrical characteristics of an electrostatic valve used for bulk transport of agricultural seeds

In an electrostatic valve used for bulk transport of agricultural seeds, th e interparticulate electroclamping forces can be established by applying el ectric potential gradient between a separated pair of conducting electrode grids placed perpendicularly across the flow. The Bow control of particulat e material is thus achieved using no moving parts. When an electric field i s applied, several types of electric field forces are generated, depending on the bulk and surface resistivities of the particles, the geometry of the electrodes, the applied field, and the geometry and the conductivity of th e materials used for the transport channel, In this study the current-volta ge characteristics of the valve were experimentally investigated for differ ent Bow control parameters, The triboelectrification of turnip seeds caused by the frictional contact on the channel walls was investigated and compar ed with the valve current. A range of wall liner materials with different e lectrical properties conductive to insulating were tested. The materials us ed for the wall liner did not significantly influeuce the current character istics of the electrostatic valve. The effect of pulse duration of the appl ied potential on charge-to-mass ratio of the discharged material was studie d. The results obtained show that the level of net charge acquired by the p articles could be controlled by controlling the duty cycle of the electrocl amping field.