Knapsack air assisted electrostatic sprayer for agricultural formulations

Abstract

An experimental prototype of a backpack-type rechargeable battery-powered air-assisted electrostatic sprayer was designed and tested for performance while preserving techno-commercial competence and affordability for India's marginal and small farmer communities. The designed prototype electrostatic sprayer achieved good levels of charge induction on the spray particles at various electrode potentials (1 to 12 kV). At a charging electrode potential of 9 kV and a nozzle discharge rate of 2 mL s−1, electrostatically charged spray had a maximum charge to mass ratio (CMR) of 1.79 mC kg−1. The Electric Ducted Fan (EDF) used for high velocity air assistance was capable of transporting charged spray droplets onto distant targets such as orchard trees and field crops with a spray throw of up to 5 m. The high-pressure atomization method produced fine droplets within a Volume Median Diameter (VMD) range of 90 to 100 µm, resulting in better charge induction and wrap-around effect. As the prototype features fewer moving mechanical components, reduced total noise and vibrations, it promises operator comfort in the long run while requiring less system maintenance. Environmental contamination can be minimized as the large quantity of harmful chemicals be prevented from drifting into the soil and nearby waterbodies. The competitive performance and lower investment could encourage majority of the Indian famers to upgrade with the developed air assisted electrostatic spraying system contributing to agro-socio-economic welfare.