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Spray Droplet Size Standard S-572

Spray Droplet Size Standard S-572. Robert E. Wolf Extension Specialist Application Technology. Biological and Agricultural Engineering. Efficacy and Drift Potential is Influenced by. Size of the Spray Droplets - Volume Median Diameter (VMD) Droplet Spectrum (Range - big to small).

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Spray Droplet Size Standard S-572

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  1. Spray Droplet Size StandardS-572 Robert E. Wolf Extension Specialist Application Technology Biological and Agricultural Engineering

  2. Efficacy and Drift Potential is Influenced by • Size of the Spray Droplets - Volume Median Diameter (VMD) • Droplet Spectrum (Range - big to small) % Volume in droplets less than 200 microns in size

  3. Relationship of Drift to Drop Size One micron (m) =1/25,000 inch

  4. pencil lead 2000 (m) paper clip 850 (m) staple 420 (m) toothbrush bristle 300 (m) sewing thread 150 (m) human hair 100 (m) Comparison of Micron Sizes for Various Items: (approximate values) 150

  5. 1/2 of spray volume = smaller droplets VMD 1/2 of spray volume = larger droplets

  6. Cutting Droplet Size in HalfResults in Eight Times the Number of Droplets 250 Microns 250 Microns 500 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns

  7. Important Droplet Statistics VMD (50%) Operational Area VD0.1 (10%) VD0.9 (90%)

  8. Evaporation of Droplets High Relative Humidity Low Temperature Low Relative Humidity High Temperature Fall Distance Wind

  9. Guidance to Chemical Manufacturers Match the crop protection product to the target Adhere to label guidelines based on an industry standard ASAE S-572 Buffer Zones or No Spray Zones Maximize Efficacy Minimize Drift Example Reference Graph 900 800 very fine/ fine fine/medium medium/ coarse coarse/ very coarse 700 very coarse/ extremely coarse 600 XC 500 C VC 400 M 300 F 200 Drop Size (microns) VF 100 0 0.1 0.5 0.9 Cumulative Volume Fraction EPA Requested Changes Coming!?!? VMD

  10. ASAE S-572 Droplet Size Standard

  11. Origin Of Standardized Spray Droplet Size Categories • 1985 -- British Crop Protection Council (BCPC) • Droplet size classifications, primarily designed to enhance efficacy. • Uses the term SPRAY QUALITY for droplet size categories. 2000 -- ASAE Standard S572 • Droplet size classifications, primarily designed to control spray drift. • Uses the term DROPLET SPECTRA CLASSIFICATION for droplet size categories.

  12. Specifics of the Standard • Based on spraying water through reference nozzles. • Nozzle manufacturers can conduct the tests. • Must use a set of reference tips and a laser-based instrument. • Droplet Spectra measurements must be with the same: • Instrument, measuring method, sampling technique, scanning technique, operator, and in a similar environmental condition.

  13. Coverage • Need knowledge of the product being used. • Systemic • Contact • What is the target? • Soil • Grass • Broadleaf (smooth, hairy, waxy) • Leaf orientation – time of day

  14. ASAE DSC and Volume Median Diameter (DV0.5) From PMS* Laser Spectrometer Droplet Spectra Classification (DSC) Droplet Size Range • Very Fine (VF) < 182µm • Fine (F) 183-280µm • Medium (M) 281-429µm • Coarse (C) 430-531µm • Very Coarse (VC) 532-655µm • Extremely Coarse (XC) >656µm *USDA ARS College Station, TX

  15. Nozzle Technology? How to use?? • Nozzles designed to reduce drift • Improved drop size control • Emphasis on ‘Spray Quality’

  16. Spray Characteristics are Important to Understand: Demonstrates Turbo Flat vs TurboDrop-5 MPH Wind

  17. Nozzles Types?

  18. Extended Range Flat-fan: • Tapered edge pattern • 80 and 110 degree fan • Requires overlap - 50 to 60% • 15-60 psi range

  19. Extended Range Flat-fan: • Tapered edge pattern • 80 and 110 degree fan • Requires overlap - 50 to 60% • 15-60 psi range 80° 110°

  20. Demo

  21. Nozzles Types?

  22. Turbo Flat-fan: • Turbulence chamber as in the Turbo Flood • Tapered edge, wide angle flat pattern • Designed to work in flat-fan nozzle holder • Uniform spray distribution, 50-60% overlap • Wide pressure range, 15 – 90 psi • Large, drift resistant droplets • Plastic with superior wear characteristics

  23. Turbo Flat-fan: • Turbulence chamber as in the Turbo Flood • Tapered edge, wide angle flat pattern • Designed to work in flat-fan nozzle holder • Uniform spray distribution, 50-60% overlap • Wide pressure range, 15 – 90 psi • Large, drift resistant droplets • Plastic with superior wear characteristics XR TT

  24. Demo

  25. Nozzles Types?

  26. Air-Induction/Venturi Nozzles Where air is drawn into the nozzle cavity and exits with the fluid.

  27. Air/Induction – Venturi Nozzle: • Spraying Systems AI TeeJet • Air intake venturi section • Mixing Chamber - air and spray solution blended • Exit orifice - Pattern tip - forms large air-bubble drops • Better Penetration? • Reduced run-off? • Improved coverage? • Adequate efficacy? • Reduced drift? YES!!!

  28. XR Flat-fan and Turbo Flat-fan compared to Venturi Style 5.0 MPH wind at 40 psi XR vs TurboDrop Turbo Flat vs Turbo Drop

  29. Demo

  30. Driftable Droplets: Spraying Systems-2000

  31. Page 4

  32. Computer Models:

  33. AgDRIFT® Program Map

  34. Example of Model Use – Aerial Applicators Standard Operation

  35. For more information contact: rewolf@ksu.edu www.bae.ksu.edu/rewolf/

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