The development of twin-fluid nozzle for precision agriculture

Spray information and lateral distribution data are presented for two confi gurations of a twin-fluid nozzle arrangement designed to give a wide range of delivery rates with a given droplet size distribution. The droplet size measurements showed that a similar size range was produced over a wide rang e of liquid flows; 425 to 1790 ml/min/nozzle for one nozzle design and 320 to 1780 for the other. Air volume requirements were mostly less than 10 lit res/min per nozzle or at least 50% less than for competitive commercial twi n fluid nozzle designs. Surprisingly, liquid flow was found to increase vir tually linearly with increasing pressure. The latter effect and the low air requirement are suggested to result from the effects of the Venturi insert . Lateral spray distribution was found to have a coefficient of variation o f less than 10% for most of the flow rates tested. A high level of air entr ainment in the droplets was also noted when a non-ionic surfactant was used . It is concluded that the nozzle design has an important role when operati ng boom sprayers over wide speed ranges or for patch spraying applications.