Robson Shigueaki Sasaki

Parameters of electrostatic spraying and its influence on the application efficiency

A pulverizacao eletrostatica, quando utilizada de maneira correta, proporciona vantagens em relacao aos sistemas convencionais. No entanto, diversos fatores podem interferir na eficiencia do sistema. Por isso, objetivou-se, com este trabalho, avaliar a relacao carga/massa (Q/M) em diferentes distâncias de pulverizacao (0, 1, 2, 3, 4 e 5 m) e a eficiencia de deposicao de liquido no alvo. Na avaliacao da relacao Q/M, utilizou-se o metodo da gaiola de Faraday e, na avaliacao da eficiencia da deposicao de liquido, posicionaram-se alvos artificiais, nos sentidos longitudinal e transversal ao jorro de pulverizacao. Verificou-se que a distância de pulverizacao afeta a relacao Q/M e, consequentemente, a eficiencia na deposicao de liquido. Na distância proxima ao alvo, a relacao Q/M foi de 4,11 mC kg-1, e, nas distâncias de 1, 2, 3, 4 e 5 m, reduziu-se para 1,38; 0,64; 0,31; 0,17 e 0,005 mC kg-1, respectivamente. Quanto a deposicao de liquido, o sistema eletrostatico foi afetado pela orientacao em relacao ao alvo e pela distância de pulverizacao. Com o alvo na transversal, o sistema nao proporcionou aumento da deposicao de liquido, ja com o alvo na longitudinal, houve aumento na deposicao ate a distância de 3 m.

Deposição e uniformidade de distribuição da calda de aplicação em plantas de café utilizando a pulverização eletrostática

In the scope of the application technology of pesticides, electrostatic spraying is a system commercially available, however, little used because there is some disagreement as to the efficiency of this system, so understanding this technology and its interactions with the plant become necessary. In this context, the aim of this study was to evaluate the electrostatic spraying on coffee as to the deposition efficiency and distribution uniformity of spray. We used an electrostatic sprayer, manufactured by Electrostatic Spraying Systems Co., model ESS MBP 4.0. The experiment was set on split plot design, (2x3x6), with two spraying systems (electrostatic system on and off), three parts of the plant (top, medium and bottom) and six positions of leaves collection, with four replications. As for the distribution uniformity of spray, it was observed there was more variability in the deposition when the electrostatic system remained on, with higher deposition in the outer canopy. The coefficients of variation for the electrostatic system on and off were 40.3 and 33.08%, respectively. The electrostatic spraying system was effective in coffee plants and increased spray deposition of 37% compared to when the electrostatic system was off.

Spectrum of droplets produced by use of adjuvants

Los adyuvantes son productos anadidos a la solucion de pulverizacion con el objetivo de auxiliar en la aplicacion de pesticidas. Sin embargo, sus efectos en los parametros tecnicos de la pulverizacion aun no estan totalmente aclarados. Siendo asi, el objetivo fue evaluar los efectos de la adicion de cinco adyuvantes (A, B, C, D y Y) y cinco diluciones (D1 = 30; D2 = 40; D3 = 50; D4 = 60 y D5 = 70 ml por 100 litros de agua), y mas el testigo (agua destilada) en los parametros tecnicos de la pulverizacion (Dv0,1; Dv0,5; Dv0,9 y Amplitud relativa). El analisis del espectro de gotas fue realizado utilizandose un analizador laser de particulas en tiempo real (Spraytec, Malvern Instruments Co.), lente focal de 750 mm. Las pulverizaciones fueron realizadas con un pulverizador a presion constante (CO2) dotado de una punta XR i1002VK. Todas las pulverizaciones fueron realizadas a presion de 300 kPa. Se observo que no existe una relacion lineal entre dilucion y producto en relacion con los parametros tecnicos de la pulverizacion. Con respecto al parametro Dv05 el mayor valor observado fue para el producto C en la dosis D5 con 232,4 μm, siendo que el testigo presento un valor medio de 148,99 μm. En la evaluacion de la amplitud relativa, los diferentes productos y dosis probados no mejoraron significativamente, comparados al testigo.

Avaliação ergonômica de pulverizadores costais utilizados no setor florestal

Knapsack sprayers have been widely used in forestry. However, some equipment may cause different levels of stress for the operators, causing harm to their health. Therefore, this study aimed to evaluate ergonomically four knapsack sprayers (thermal sprayer, pneumatic motorized, hand sprayer and electric sprayer), regarding to noise parameters, body vibration level, energy expenditure and physical effort. For noise evaluation, a dosimeter 01dB was used, and the results were compared with the regulatory norm NR-15. For vibration levels, we used a triaxial accelerometer connected to a signal processor Maestro type, and data were compared to the European directives. For caloric expenditure and physical effort, we used a gas metabolic analyzer manufactured by Medgraphics® model VO2000 and a heart monitor from Polar brand. We observed that the hand and electric knapsack sprayers did not present problems related to the noise level. However, the pneumatic motorized knapsack and the thermal sprayer, showed levels above than recommended by regulatory norm NR-15 with levels of 99.97 and 94.33 dB(A), respectively. Similarly, the motorized equipment presented high levels of vibration compared to the other equipments, with global vibration (A8) of 2.09 m s-2 for the thermal sprayer and 2.15 m s-2 for the pneumatic. Regarding to energy expenditure, there were small variations between the kind of equipment used, with expenditure ranging from 3.0 to 3.96 kcal min-1.

Controle automático do espectro de gotas de pulverizador hidropneumático em função do déficit de pressão de vapor d'água no ar

The principle of fractionation and droplets size are crucial for the success of pest control. This study aimed at developing and evaluating an automated system to control the spraying droplet spectrum according to the vapor pressure deficit in the air. The automatic control system consisted of a temperature and relative humidity sensor, a microcontroller, a servomotor and a hydropneumatic sprayer. Spraying was performed on water sensitive paper labels arranged on wooden supports for different vapor pressure deficits in the air. After scanning and analysing the paper labels, three working pressures were selected (633 kPa, 844 kPa and 1,055 kPa) for use in the automated system. The results indicated that the controller efficiently maintained the droplets spectrum when spraying pesticides. Automation enabled the maintenance of the spray volume by altering the working pressure, according to the vapor pressure deficit in the air. Spraying with the automated system presented a droplet spectrum quality superior to the one obtained by using the manual system at the pressure of 633 kPa.

Desempenho operacional de um pulverizador costal elétrico

The knapsack sprayer is a very popular equipment, due to its low acquisition cost and wide applicability. In recent years, electric backpack sprayers, which increase the operator’s comfort and improve the spraying operation quality, have come up. This study aimed at evaluating an electric backpack sprayer, by using four flat spraying nozzles (XR 110.02, AXI 110.03, AXI 110.04 and AXI 110.05). The variables studied were: liquid flow and pressure, battery charge duration, axis rotation and pump noise. The electric sprayer provided constant flow and pressure for the XR 110.02, AXI 110.03 and AXI 110.04 nozzles. By using the AXI 110.05 nozzle, a variation was observed for the liquid flow and pressure, mainly at the end of each repetition, since the flow increase also increased the pump power demand. Similarly, the battery charge duration was proportional to the power demand. For the flows studied, the pump noise fitted the regulation standards, for a daily working journey of 8 hours.