The classification of the drift risk of sprays produced by spinning discs based on wind tunnel measurements

The present study assesses the drift potential of spinning discs using wind tunnel tests, by comparing the drift profiles of sprays from discs with those from standard fan nozzles. Drift from fan nozzles was used as a reference, and comparison tests were performed of drift produced by discs and fan nozzles with droplets of similar volume median diameter (VMD). Droplets from spinning discs drifted much more than those produced by fan nozzles under most conditions, except when wind speed was<2.0 m s−1 and the disc rotational speed was<2000 rpm. The higher the wind speed and the smaller the droplets, the larger the gap in drift between the two spraying systems. Using the comparison tests, a classification of the drift potential of sprays produced by spinning discs was proposed.