A thesis submitted in the partial fulfillment of the requirement for the degree of Master in Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 1991

Successive discoveries and the rapid advancement of the formulation of various chemicals for various purposes have likewise spurred rapid development of techniques of application as well as the equipment to be. used for these techniques. Further, these developments have led to the discovery and improvement of new and improved technologies of chemical application. At the Asian Institute of Technology, electrostatic technology application for pesticides have been given due attention and importance as a USAID funded project on this aspect was realized to further investigate and verify t h e potentials of this technology. In line with this, a Knapsack Twin Electrostatic Herbicide Sprayer for Lowland Rice has been developed to advance the investigation of the technology under AIT, Thailand condition and is envisioned to be disseminated to the farmers in the near future. Results of the ma chine testing revealed some very promising results. Lighter in weight than the common knapsack (hydraulic) sprayer, this machine has an effective working capacity of 0. 05 ha/hr with an average weeding efficiency of 8896 which is relatively comparable to the efficiency of the common knapsack sprayer. Relatively cheaper at an estimated cost of $120, the machine relatively safeguards the operator from the danger of drift as experiment shows that it was reduced by about 72% compared to the unshielded sprayers.