Improving the Control and Accuracy of Slurry Spreaders

prototype slurry spreading system, based on a commercially available pump discharge tanker, was designed, built and tested. The system featured a positive displacement slurry pump, an electrically operated flow control valve and a novel spreading boom fitted with fluidic diodes. The prototype slurry spreading system was tested generally in accordance to a draft international (European Committee for Standardisation) standard, and achieved a controlled, even application rate. By monitoring pump speed and valve position, the discharge rate from the tanker could be predicted to an accuracy of ±2% of the maximum flow rate. Using this system in conjunction with a control system enabled the application rate to be controlled to an accuracy of ±1·5 m3ha-1. In addition, the novel fluidic diode boom achieved lateral average deviation values which were consistently better than 9%.