Comparison of Off-Target Deposits for Conventional Spray Nozzles and Venturi Nozzles

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Comparison of Off-Target Deposits for
Conventional Spray Nozzles and Venturi Nozzles

• Robert Wolf
• Biological and Agricultural Engineering Dept.
• Dallas Peterson and Cathy Minihan
• Department of Agronomy

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New Technology for the Spray Industry
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Nozzle is still an important part of the
application process!

• Determines the application rate
• Determines the uniformity
• Determines the coverage
• Determines the drift potential

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Whats new in nozzle technology?

• Nozzles designed to reduce drift
• Improved drop size control

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Air-Induction/Venturi Nozzles

• Where air is drawn into the nozzle cavity and
  exits with the fluid.

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Example Design -TurboDrop

• Dual Air inlet/venturi
• Mixing Chamber - air and spray solution blended
• Pattern contains large air-bubble drops
• Better Penetration????
• Reduced run-off?????
• Improved coverage?????

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1/2 of spray volume smaller droplets
VMD
1/2 of spray volume larger droplets
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What to Expect in the Future?

• Match the crop protection product to the target
• Adhere to label guidelines based on an industry
  standard
• ASAE X-572
• Maximize Efficacy and Minimize drift

VMD
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Objectives of this study

• Compare drift characteristics of conventional vs.
  air induction -venturi style nozzles
• Determine if the DropletScan? software will
  provide quick and useful information regarding
  drift for various nozzle types.

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What is DropletScan? ?

• A software program that will allow accurate and
  rapid measure of spray droplet impressions on
  water-sensitive paper.
• Developed at K-State by Devore Systems - modeled
  after Crumbscan, a software program to
  determine hole sizes in slices of bread.
• Marketed by WRK for specific use in aerial
  applications spray analysis concentrating on
  spray droplet characterization.

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DropletScan? is Field Ready Simple!
Water Sensitive Paper
Software lock-key
Color Scanner
Portable computer
Color Printer
System Components
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Procedures Involved

• Use the spot cards during spray run to collect
  spray that travels out of target area
• horizontal and vertical
• Scan cards and analyze by software
• Droplet stains are measured
• Spread factors are used for material sprayed
• Equivalent droplet diameter is calculated
• target area being covered
• application rate

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Basic system processes

• Acquiring an image from water sensitive paper or
  other color contrasting material.
• 2-step process
• Low resolution
• High resolution
• Select report
• options

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Sample Printout
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Sample Printout
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Sample Printout
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TD _at_ 40
XR _at_ 40
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XR _at_ 40
TD _at_ 40
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Spray Characteristics are Important to Understand
Click on spray to see video
Demonstrates Turbo Flat vs TurboDrop-5 MPH Wind
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Drop Data Descriptions

• Dv0.1 (µm) - 10 of the spray volume in drops lt
  number reported
• Dv0.5 (µm) - 50 of the spray volume in drops lt
  number reported
• (also is VMD- volume median diameter)
• Dv0.9 (µm) - 90 of the spray volume in drops lt
  number reported

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Study With 3-Parts involving Air Induction
Venturi Nozzles and Droplet Scan Analysis

• Comparing On Target(under the boom) Droplet
  Characteristics Reported at 1999 ASAE Summer
  Meeting paper 991026.
• Field Efficacy/Drift Study Reported in
  Successful Farming Magazine, Nov. 99 vol. 97, 12
  pp. 46-8.
• Drift Comparison Analysis NCWSS 99

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Materials and Methods for all 3 parts

• 3 conventional nozzles
• 4 air-induction/venturi
• 138, 276, 551 kPa
• 76 L/A, 76cm, 51cm

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Part 1 - Sample of an under boom collection

• Passed sprayer over a collector board with five
  equally spaced water-sensitve cards attached.
• 5 cards were collected for each of the 7 nozzles
  at each pressure.

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Part 2 -Air-Induction/Venturi Nozzle Efficacy
Study May 1999
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Part 2 Plot Layout

• 3 reps, 7 nozzles, 3 psis
• 20 GPA, Gromoxone, 10 boom
• 5 buffer

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Part 3 Drift Collector Study
4 ft.
3 ft.
8 ft.
9 ft.
10 ft.
Card Holder
4 ft.
2 ft.
1 ft.
8 ft.
Tower Vertical Collector
Horizontal Collector
Center Line of Spray
Wind direction
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Example of a collection

• Sprayed past a collector board and tower with six
  equally spaced water-sensitve cards attached.
• 3 cards were collected horizontal and 3 cards
  were collected vertical for each nozzle at 138,
  276, and 551 kPa pressure.
• 2 passes per collection

Horizontal
Vertical
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XR Flat-fan _at_138-276-551 kPa
Turbodrop XL _at_138-276-551 kPa
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Results and Discussion
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Findings for Part 3

• DropletScan? does appear to be a software program
  that will provide quick and useful information
  regarding drift for various nozzle types.
• Data supports that drift potential is less with
  the venturi nozzles compared to the conventional
  nozzles.
• The collection technique needs to be fine-tuned
  to make better use of the data collection
  possibilities.

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Important to note that

• May be advantages to analyzing the spray droplet
  at the target site rather than as it leaves the
  spray tip.
• Will measure stains as small as 50 microns.
• Good analysis of lower application rates and
  driftable size fines.

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Important to note that

• Humid/moist conditions currently will not allow
  system to be effective.
• Even though the wind confused the data in this
  study, wind does have a major affect on
  deposition and drift and must be factored in for
  each application scenario.

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Thanks