PERFORMANCES OF CONVEYING SYSTEMS FOR MANURE SPREADERS AND EFFECTS OF HOPPER GEOMETRY ON OUTPUT FLOW

Abstract

The objectives of this work were to evaluate the performances of different conveying systems for manure spreadersand to study the effect of the hopper geometry on material flow. Experiments were carried out at the University ofSaskatchewan (Canada) and at Cemagref (France). A prototype land applicator was evaluated with both a scraper conveyorand a system of four augers. The specific energy required to unload the machine with the four-auger system was found to behigher than with the scraper conveyor, with average values for all experimental runs of 184 and 73 J/kg, respectively. Athree-factor factorial design was used to study the effect of the vertical position of a flow-control gate, velocity of theconveying system, and inclination angle of the sidewalls for both types of conveying systems. The specific energy for bothconveying systems was significantly affected by the position of the gate. The characteristic flow rate, as defined in EuropeanStandard EN 13080, was influenced by all three factors in the case of the scraper conveyor. The position of the gate, thevelocity of the conveyor, and the interaction between these two factors were found to be significantly affecting thecharacteristic flow rate of the four-auger system. The output flow of three commercial manure spreaders having similarfunctional units but different hopper geometries was studied. The stretch within the tolerance zone was observed to increasewhen the length and width of the hopper were increased. The longitudinal coefficient of variation was observed to decreasewhen the length of the hopper was increased. The same effect was observed when increasing the width of the hopper and whenreducing its depth. The physical properties of the products spread were deemed to have an influence on the response of theevaluation criteria to changes in hopper geometry. Cohesive products were observed to improve the discharge flow in termsof the stretch within the tolerance zone, the longitudinal coefficient of variation, and the actual to theoretical unloading timeratio.