Mechanical generation of charged droplets by electro spraying

Prof. Dr  Murtadha Jaleel Almamury

Department of Applied Geography

Electrospray is defined as the process of simultaneous droplet generation and charging, which happens when the electric force is stronger than the surface tension force. It consists of charged droplet generation, conveyance of particles to the target object and target deposition. Liquid coming out from the nozzle at high pressure is subjected to an electric field, with this pressure causing elongation of the meniscus so as to form a jet spindle. This process allows for the generation of fine droplets of charge of magnitude close to one-half of the Rayleigh limit, which is the magnitude of charge on droplets that overcomes the surface tension force, thereby resulting in their fission. The interactions that happen between charges on the surface of the liquid and the applied electric field give out two results: the first being the acceleration of the liquid and subsequent disruption into droplets, whilst the second is the build-up of the charges on the droplets.

Agricultural applications began after the success in the industrial field, with the first pertaining to the development of pesticide materials in powder form. Subsequently, electrostatic techniques were applied to liquid agricultural pesticides and herbicides, because there are a number of benefits in using the electrostatic principle in spraying technology,

which include: good distribution of droplets/particles, more uniform deposits on the surfaces of the intended targets as well as low or even no drift. Furthermore, pollination and biomaterial in agriculture have delivered satisfactory results through electrostatic application. However, the direct application of electrostatic paint spraying equipment in orchards is not feasible for three reasons, as explained.

Charged drops cover plant leaves

Charged drops cover plant leaves