Applicability of a 3D Laser Scanner for Characterizing the Spray Distribution Pattern of an Air-Assisted Sprayer

Three-dimensional (3D) laser technology has been tested for assessing the performance of air-assisted spraying. A static test using an air-assisted sprayer equipped with two axial fans (front and back) with opposing directions of rotation was developed. The sprayer was adjusted to spread water in a static mode, at a pressure of 10 bars, with four air volumetric flow rates. Measurements were performed using a Leica HDS6000 3D laser scanner. In addition, the flow and velocity of air generated by the air-assisted sprayer were measured using a hot-wire anemometer and a 3D sonic anemometer with the objective of estimating the influence of air flow on the spatial distribution of spray droplets. To carry out the analysis, all of the droplets detected by the laser were considered to be of the same size. The distribution of products was asymmetric when the machine only worked with the back fan, with 41% of the product distributed on the left side versus 59% on the right side, as referenced to the direction of the machine’s advance. This asymmetry was corrected when the machine functioned with the two fans activated. These spray data were concordant with the measured air flow generated by the machine in the different working conditions. For the different regulation settings of the machine, taking the vertical of the machine as 0°, the angular region comprised between 40° and 60° was the one that received the highest quantity of product. The increase of the air flow produced a greater distance of the product. For the highest air flow configuration, 99% of the product detected by the laser was detected within a distance of 16 m from the axis of the machine.