A study of the abrasive effects of trifluralin, diuron and fluometuron on spray nozzles

The abrasive action of some chemical herbicides can cause wear in parts of the field sprayer. Such abrasion occurs in greater degree with liquid suspensions and wettable powders, due to low solubility and certain inert materials. The nozzle orifice tips increase in discharge capacity is important because it may result in unnecessary waste of spray material, possible crop damage and added cost of nozzle tip replacement. The objective of this study was to determine the abrasive effect of trifluralin, diuron and fluometuron in varying concentrations, on different nozzle materials, size and total hours of use. The nozzle tips wear test was conducted in a laboratory spray unit. The nozzle discharge was recalibrated volumetrically after 3.5 hour intervals. In this study, spraying systems 8001, 8002, 8OO3 and 8OO4 and Century 12 NF size nozzle tips were used. Tips made of brass, hardened stainless steel and nylon were tested. The amount of increase in nozzle discharge capacity ranged from -0.26 for nylon nozzle tips to 19.41 for brass nozzle tips. The abrasive effect of the spray mixture was more severe on the smaller size brass nozzle tips as compared to the larger brass nozzle tips. The increase in the discharge capacity of the brass nozzle tips was directly related to the higher concentration of the diuron mixture. Brass nozzle tips increased discharge capacity much more than hardened stainless steel with diuron and fluometuron spray mixtures. The nylon nozzle tips showed a slight decrease in discharge capacity. The abrasivity of trifluralin, diuron and fluometuron was reduced with the continuous recirculation of the spray mixture. The increase in discharge capacity of brass nozzle tips was reduced when continuous fresh mixtures were used.