A method for measuring single-nozzle distributions influenced by other nozzles
The purpose of this work was to develop a method with which to measure the spray distribution from a single-nozzle while it is under the influence of other nozzles on a sprayer boom. The nozzle distribution pattern for one nozzle on a seven-nozzle boom was evaluated, using 0.05 M KCl (potassium chloride) solution as marker. Conductivity measurements were made to detect the amount of marked liquid in the distribution along the boom. The spray distribution from the boom was measured on a patternator, with 50 mm channel spacing, and the liquid was collected in 60 graduated cylinders (250 ml). A computer program and an electronic apparatus made it possible to measure the flow rate in each cylinder automatically. To measure the distribution under the boom, the conductivity of the liquid in each cylinder was measured, by taking 100 ml of the liquid to a conductivity cell. Since conductivity is dependent on the temperature of the solution, the temperature of the liquid was measured. Once the actual temperature of the solution was known, it was possible to calculate the corresponding conductivity value at 10°C. As the conductivity of the marker solution was known, it was possible to determine the proportion of marker solution in each cylinder with the ratio conductivity(solution) / conductivity(marker). Multiplying this value by the flow rate for each cylinder makes it possible to calculate the flow rate in every cylinder, which ought to give the distribution pattern for the measured nozzle. The method was checked by adding the individual nozzle distributions, measured with the conductivity method theoretically in a spreadsheet program, to a theoretical distribution below a boom. The theoretical boom distribution was compared with the distribution measured under the boom. Measurements were made with flat fan nozzles of various sizes, for different twist angles and pressures. If the method worked, a modelled distribution ought to agree with a measured one, irrespective of these settings. The results from the conductivity method were compared with the corresponding single- nozzle distribution patterns measured free from the influence of other nozzles. The results showed that the conductivity method worked well irrespective of the parameter settings. Thus the boom distributions modelled on patterns measured with the conductivity method were very similar to the actual distributions measured under the boom. The investigation also showed that this model which simulates a boom distribution based on single-nozzle distribution patterns, measured without the influence of other nozzles were also very similar to the one measured except in the case of small nozzles (Teejet 11001 SS XR). The conductivity method makes it possible to study the interaction phenomenon on a single distribution pattern. The conductivity method worked well and could be used instead of the conventional method (without influence of other nozzles), when single-nozzle distribution patterns were measured. The distributions measured with the conductivity method are more realistic than the one measured with the conventional method, as the conductivity method includes the interaction information. It could also be used as a tool when investigating the interaction phenomenon, and ascertaining what effect different parameters have on the phenomenon. Use of single-nozzle distribution patterns measured with the conductivity method makes it possible to model a boom distribution as realistically as possible, which could be useful when setting up a boom model with which to calculate the spray distribution on the ground while the vehicle is driving.
distribution model; interaction between nozzles; nozzle performance; single nozzle distribution; spray application; nozzle
Rapport - Sveriges lantbruksuniversitet, Institutionen för lantbruksteknik
Publisher: Institutionen för lantbruksteknik, Sveriges lantbruksuniversitet
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