Skip to main content
ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #96765
Title: UNIFORMITY OF A DIRECT INJECTION SPRAYER

Author
item Sumner, Harold
item SUMNER, P.
item MULLINIX, BENJAMIN - UNIVERSITY OF GEORGIA

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Sprayers that inject chemicals into the water system near spray nozzles responds rapidly to required changes in travel speed and/or concentrations of diluted sprays. These sprayers should apply chemicals uniformly along crop rows (direction of travel) and also deliver the same amount of chemical to all rows. Components of a direct nozzle injection sprayer were evaluated to determine the effect of chemical injection pump frequency from 100 to 1725 cycles per minute, on chemical uniformity along and among crop rows. The system sprayed fluorescent dye onto collector strings with two spray nozzle types and with one and two nozzles per row. The uniformity of fluorescence on the strings was used as an indicator of spray uniformity along rows and among rows. Injector pump frequencies greater than 300 cycles per minute provided acceptable sprayer uniformity along the nozzle path or crop rows. Cone nozzles had an advantage over fan nozzles at low injection frequencies in providing better uniformity of materials along rows. Distribution of injection materials through 6.1 m(20 ft) long micro-tubes 1.3 mm (0.05 in) I.D. to each nozzle provided uniform flow to each row at flow rates of 30 to 60 mL/min (1 to 2 oz/min). A fluorometer with a String Analysis System was effective for evaluating sprayed collector strings. Data were used to compare injector pump frequencies, nozzle type and nozzle arrangement for distribution of injection materials along spray nozzle path and among rows. These results should provide important design information for the development of injection sprayers for precision farming requiring variable chemical inputs.

Technical Abstract: The effect of four spray nozzle arrangements, flow circuit design, and injector pump frequency on uniformity along the spray path was evaluated using collector strings sprayed with fluorescent dye. Injector pump frequency and nozzle type were significant factors effecting uniformity differences along rows. Uniformity of cone nozzles with large or wide spray patterns along the row were affected less than fan type nozzles by low pump frequencies. Injector pump frequencies above 300 rpm had string fluorescence coefficient of variation (CV) values < 10 and were not significantly different from CV values at pump frequencies of 1725 rpm. Uniformity of dye solution flow among rows was controlled by micro-tubes to each row with injection near the spray nozzle. There was no significant difference between mean fluorescence of four strings on different rows each injected with dye solution flows of 30, 45, or 60 mL/min (1.0, 1.5, or 2.0 oz/min) through 1.3 mm (0.05 in) I.D. tubing. Application uniformity along and among rows, measured with a WRK String Analysis System was an acceptable method for determining effects of injection sprayer parameters.