Automatização de um pulverizador hidropneumático visando o controle do espectro de gotas em função do déficit de pressão de vapor d água do ar

• Autor(a) principal: Alvarenga, Cleyton Batista de
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/717
• topic: Mecanização agrícola; Pulverizador; Automatização; Agricultural mechanization; Sprayer; Automation; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

Pesticide spraying is one of the most repeated operations in farms, this has occurred mainly due to adoption of no tillage. Facility for purchasing pesticides is notorious throughout Brazil. However, technology for its application has been difficult to reach the producers, even in regions with high agricultural potential. This work aimed to develop a system for controlling the droplet spectrum in order to change parameters for spraying pesticides according to the deficit of water vapor pressure in the air. For automating the spray we used a servomotor and a microcontroller fed by tractor battery. After selection of the tip, hollow cone JA-2, we made a droplet spectrum study throughout the pressure range recommended for use in hydro-pneumatic sprayers. For this study, a laser particle analyzer was used. Sprayings were carried out in three deficits of water vapor pressure in the air, for thirteen working pressures. The coefficient of tip variation on the pattern bench presented values between 13 and 22% for pressures of 633 and 1.477 kPa, respectively. The diameter of volume median reduced from 151 to 109 μm with the increase of pressure. The lowest percentage of droplets with size lower than 100 micron, greater than 300 μm and between 100 and 200 microns was obtained from the working pressure of 774 kPa. Increasing the deficit of water vapor pressure in the air effected spray parameters and reduced droplet size. Automation allowed the maintenance of spray volume by changing the droplet spectrum according to deficit of water vapor pressure in the air. The turbulent air flow and configuration design of fan were responsible for the liquid irregular distribution. The height of canopy, in horizontal position of the plant and canopy depth affects spraying of pesticides in orange crop. Increasing the deficit of water vapor pressure in the air, also increased risk of evaporation and reduced droplet size also reducing the deposition of the syrup.