POLYMER AND INVERT EMULSIFYING OIL EFFECTS UPON DROPLET SIZE SPECTRA OF SPRAYS

A series of wind tunnel atomization studies were carried out to invest igate the effects of polymer and invert suspension oil ''drift control adjuvants'' upon the droplet size distribution spectra produced by no zzles typically used in aerial and ground based spraying of pesticides . A D8-46 disc and core was used as a typical aerial application nozzl e, and an 8003 fan nozzle was used for the ground based sprayers simul ation. The droplet size spectra were evaluated in a wind tunnel using a Malvern 2600 laser particle size analyzer immediately upon mixing an d at 15 minutes after re-circulation through a pumping system. The add ition of the polymer-based adjuvants significantly increased the dropl et size spectra parameters of the spray cloud, but all the polymer pro ducts showed signs of breakdown of their molecular arrangements in the liquid medium, as a result of agitation. The invert suspension oil ad juvant did not change the droplet size spectra markedly, nor did it sh ow signs of breakdown of the internal liquid structure after re-circul ation.