Optimization of Droplet Distribution and Spray Pattern Uniformity on a Multi-Nozzle Mobile Compression Pump (MMCP) Sprayer

Abstract

This study evaluated MMCP sprayer under pump pressures between 150 – 450 kPa, nozzle height of 0.30 – 0.90 and speed of 0.10 – 0.45 m/s. Water was used with fluorescent tracer dye for patternator-based distribution. Response variables were coefficient of variation (CV) of spray, volume median diameter (VMD), drift loss, swath width, application rate, and field capacity. Results showed that pump pressure of 300 kPa produced the most uniformed spray distribution of CV of 7.3%. It had VMD of 261 μm classified as a medium-to-coarse spray. Spray drift increased above 350 kPa to 15.4% at 450 kPa; this exceeded the acceptable 5% threshold. Nozzle height of 0.50 – 0.55 m minimized distribution CV of 6.9 – 7.3%. This provides an effective swath width of 0.74 – 0.89 m. Application rate declined with increased speed, from 1,121 L/ha at 0.10 m/s to 249 L/ha at 0.45 m/s. Field capacity increased to 0.486 ha/h at the highest speed. Comparative tests confirmed that the MMCP achieved a field capacity of 0.302 ha/h; 5.3 times of manual knapsack which was 0.057 ha/h and can be compared in efficiency to motorized alternatives in capital and running costs. These findings confirmed its suitability as a technology for smallholder crop protection operations.