A means of winnowing hydraulic nozzles to control droplet drift

Authors: Mckinley, K.S., Ford, R.J. And W.K. Martin
Description: The behavior of pesticide sprays is largely determined by droplet size. How ever, all commercially available spraying equipment produces droplets in a wide range of sizes and the presence of large numbers of small droplets in the spray can cause serious problems due to pesticides drifting out of the target area (1,2). One obvious solution to this problem would be to develop equipment that would produce homogeneous sprays of chosen drop sizes. Sprays of very uniform droplets can be produced by winnowed spinning discs (5, 9). Such devices are extremely useful for research purposes in the laboratory or field but their low flow rates, complexity, and cost make it seem unlikely that they will come into commercial use. A number of other devices such as the Vibrajet (4), the Microfoil (3), and the vibrating boom (7), reduce drift by producing coarse sprays with reduced numbers of small droplets. Unfortunately, when large drops are used one must either increase the spray volume or accept reduced coverage. A simpler solution to the drift problem would be to remove the small-drop component from the sprays produced by the ordinary hydraulic nozzles. Roth and Porterfield (8) reported results of preliminary tests in which a counter flow of air was used to remove small drops from the spray produced by a fan-jet nozzle. Similar experiments were carried out by Wiens and Bigsby (10). In both of these instances the movement of the air was directly opposed to the direction of movement of the spray droplets. Using a TeeJet 650067 nozzle at 35 psi (2.5 kg/cm2), Wiens and Bigsby reported that the number of droplets below 100 um were reduced from 20.5 to 7.5% by winnowing.
Keywords: a means of winnowing hydraulic nozzles to control droplet drift
Citation: McKinley, K.S., Ford, R.J. and W.K. Martin 1973. A MEANS OF WINNOWING HYDRAULIC NOZZLES TO CONTROL DROPLET DRIFT. Canadian Agricultural Engineering 15(1):24-25.
Volume: 15
Issue: 1
Start page number: 24
End page number: 25
Date: 1973
Coverage: Canada
Located in: Volume 15 (1973)