ID 334

Modeling Nozzle Wear Effects on Spray Pattern Coefficient of Variation

 

Abstract:

Coefficient of variation is a measure used to determine the relative variability of spray pattern distribution. Uneven spray pattern distribution and pattern collapse may occur in the presence of excessive nozzle wear resulting in reduced application efficiency and agronomic efficacy. Industry standard recommendations are to replace nozzles when 10% wear is reached. Trials were performed using a spray nozzle patternator to model coefficient of variation in the presence of increasing nozzle wear. When spraying with rate control equipped sprayers, the pressure will be adjusted to maintain spray rates. When nozzles wear the rate controller will lower the pressure to maintain the rate. Therefore, the effect of nozzle wear when spraying at 1.38 bar with a rate controller equipped sprayer was simulated in Hypro variable pressure flat fan 04 nozzles by altering pressure, beginning with 1.38 bar to represent 0% wear. An approximate 10% reduction in spray pressure was used to simulate 5% nozzle wear. Subsequent 10% reductions in spray pressure were used to simulate progression of nozzle wear at 5, 10, 15 and 20%. Coefficient of variation was measured for all nozzle and pressure combinations tested. Three replications were tested for each pressure and nozzle combination.