Abstract:
A multi-purpose spinning disc controlled droplet applicator (CDA) has been developed. The sprayer takes care of spraying applications for different needs such as: Insecticide/fungicide spraying, Herbicide spraying and even tree crop spraying eliminating the need for having different spraying machines. The machine was developed by modifying the conventional (CDA) sprayer to produce different sizes of droplets achieved by change of sprayer motor voltage and the change of sprayer configuration to provide for adjustment for tree crop spraying. An alternate power source was also identified as being more superior to conventional U2 batteries. Laboratory evaluation of the prototype revealed that the sprayer was capable of producing insecticide/fungicide droplets of 82 micron volume median diameter (vmd) at 600 rpm disc speed when the input voltage was set at: 12V and Herbicide droplets of 285 micron vmd at 2500 rpm when set at 6v. Spray volume distribution pattern tests revealed a decrease in the Coefficient of variation of spray with decrease in input voltage. The dispersion ratio range between 1.22-1-30 which are within acceptable limits for cda spraying. Field tests revealed an application rate of 7.2 L/ha for insecticide/fungicide and 24 L/ha for herbicide sprayings with spray droplet densities Of 236 and 19 droplets per square centimeter respectively. The maximum vertical height reached by droplets during tree Crop Spraying was 8 metres. Power consumption tests revealed an average consumption of 16.1 watt at 12 volt during Insecticide spraying and A.6 watt at 6 volt during Herbicide application. Annual spraying operating power cost with the modified power source was below 20% of that when conventional U2 batteries were used. The above in addition to higher field capacity, versatility, and better spray droplet spectra due to relatively constant operating voltages were some of the merits of the new prototype sprayer design.
MULTI-PURPOSE CDA SPRAYER DEVELOPMENT
