Atomizers for the Aerial Application of Herbicides: Ideal and Available

摘要

Reduction of spray drift is essential when herbicide sprays are applied from aircraft, so sprays with a narrow spectrum and a volume median diameter of about 225 micrometers are required. Analysis of the performance of currently available atomizers suggests that one of the best is a flat fan hydraulic nozzle set at 45 degrees downwards and backwards relative to the flight direction. This atomizes about 33% of the volume emitted within 25% of this desired size. A new 50 mm. diameter windmill disc atomizer produced 70% of the volume emitted in this size range with less than 5% in droplets smaller than 150 micrometers. This is achieved by having far greater control over the actual atomizing condition ensuring ligament formation even at flow rates approaching one litre per minute. A strong radial airflow at the atomizing edges is found to be extremely beneficial.