Harold C. Simmons

Use of an air-assisted electrostatic sprayer to increase pesticide efficiency in greenhouses

The spraying system described in this paper uses air and electrostatics to deliver small drops (20 um Dv 0 . 5 ) to the target. The use of this system in greenhouses is especially attractive since air movement can be controlled and drift is contained. It has been found that charged drops are collected more efficiently by, and distributed more evenly upon plant targets than uncharged drops. Evaluation of spray distribution on cucumbers and poinsettias confirmed that the theoretical advantages of small, charged drops may be exploited in greenhouses. Although the lower spray volume necessitated a correspondingly high concentration of active ingredient, no phytotoxic damage was observed.

Spray triode electrostatic agricultural atomizer: Development update

A new method for the electrostatic atomization of oil-based agricultural products was introduced in ASTMs Fifth Symposium on Pesticide Formulations and Application Systems. This atomization method involves the direct injection of charge (electrons) into the flowing spray fluid within the spray head and immediately prior to the exit port. The highly charged fluid, on exiting, forms a self-dispersive charged droplet plume. Preliminary test data obtained using a prototype charge injection device, the Spray Triode atomizer, have shown that this method offers promise for the effective, precise, and predictable dispersal of oil-based agricultural fluids. As a result of additional test characteristics, coupled with an available analytic, predictive model of Spray Triode atomizer operation, a number of design improvements have been instituted. Operational characteristics, including droplet size distribution data, are presented for various hydrocarbon oils. The data indicate that Spray Triode devices have a range of inherent capabilities that meet some agricultural product application needs. The assistance of formulators and applicators in defining these needs is solicited.