HANDLING AND SPREADING OF FERTILIZERS .5. THE SPINNING DISC TYPE FERTILIZER SPREADER

The motion of particles is discussed as affected by physical properties, such as coefficient of friction, and the design of the disc including the vane type, pitch angle of the vane and surface of the vane. The influence of factors that may have an effect are studied theoretically by means of simulations as well as experimentally. When the simulation and measurement results were compared, large differences were found between them. The simulation results showed a clear effect of the coefficient of friction. This effect was, however, hardly visible in the measurements despite differences in vane surfaces that gave large differences in coefficient of friction (0.25 to 0.35 for a nylon surface versus 0.40 to 0.45 for a stainless steel surface). The measurements showed that an increase of the mass flow by a factor of two in the range tested (between 0.3 and 1.0 kg/s) resulted in an increase in the distance projected by the particles of about 1 m. The influence of vane type and pitch angle have been analysed in simulation studies and the effect proved to be dependent on the coefficient of friction. (C) 1995 Silsoe Research Institute