AIR CURTAIN FOR AGROCHEMICAL APPLICATIONS IN FRUIT ORCHARDS. EVALUATION OF GENERATION AND TRANSPORT SYSTEMS

Abstract

Agrochemical applications using divergent flow sprayers are non-uniform and result in high product losses in orchards operating on a trellis system. Air curtain sprayers generated by tangential fans represent a step forward towards improving the efficiency of these applications. In order to provide a technological and economical alternative for air curtains in a vertical or transverse to the row direction, a prototype with a sleeve and vertical air outlets was built and the behavior of the airflow was evaluated under different configurations: a) axial flow sleeve and axial fan; b) radial flow sleeve, with and without vortex dissipator, and axial fan; c) radial flow sleeve with vortex dissipator and centrifugal fan. The airflow rate was measured, while profile variability, rate of decrease in speed and flow rate obtained with different air outlet widths and fan regimes were analyzed. The results indicate that the fan affects the uniformity of the air profile. This effect was attenuated with the vortex dissipator, resulting in coefficients of variation lower than 10%, regardless of the type of fan or regimen used. The sleeve with central and radial incoming airflow and vortex dissipator would be the most appropriate arrangement to equip an airblast sprayer to be used in orchards operating on a trellis system.