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Drift. Why Interest in Drift?. Spotty Pest Control Wasted chemicals Off-target damage Higher costs - $$$ Environmental impact Water and Air Quality Public more aware of pesticide concerns! (Negative) Spraying in more populated areas? (Suburbs). Misapplication Facts.

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Presentation Transcript

Why interest in drift
Why Interest in Drift?

  • Spotty Pest Control

  • Wasted chemicals

  • Off-target damage

  • Higher costs - $$$

  • Environmental impact

    • Water and Air Quality

  • Public more aware of pesticide concerns! (Negative)

  • Spraying in more populated areas? (Suburbs)


Misapplication Facts

Source: Farmland Insurance 1996



What is drift
WHAT IS DRIFT?

  • Movement of ..

    • spray particles

    • vapors off-target

  • Less effective control

  • Possible injury to susceptible vegetation and wildlife.


  • Spray characteristics affecting drift

    Equipment & Application Factors Affecting Drift

    Spray Characteristics Affecting Drift

    - Nozzle type

    • Nozzle size

    • Nozzle orientation

    • Nozzle pressure

    • Height of release

    • Chemical Properties

    • Formulation

    • Evaporation

    • Drop size

    • Volume


    Reducing Pesticide Drift

    Nozzles, Nozzles

    and More Nozzles!!


    Low drift nozzles
    Low Drift Nozzles

    • 87% reduction in drift prone droplets

    • < 150 microns

    • Low drift nozzle @ 0.2 gal/min flow rate - 40 psi

    • Compared to 8002 Standard Flat-fan nozzle


    8003 tip

    80 means 80o fan

    03 means 0.3 gallons per minute at 40 psi(38 ½ ounces per minute)


    Low drift nozzles1
    Low Drift Nozzles

    • Larger droplets

    • At the same flow rate

    • Same operating pressure than standard flat-fan (SFF) nozzles.

    PRE-ORIFICE

    REDUCES LIQUID VELOCITY

    Reduces small droplets (200 microns) by 50 to 80 percent


    Drift potential is influenced by
    Drift Potential is Influenced by:

    Droplet Spectrum (Range - big to small)


    Comparison of micron sizes approximate

    2000 m

    850 m

    420 m

    300 m

    150 m

    100 m

    #2 Pencil lead

    paper clip

    staple

    toothbrush bristle

    sewing thread

    human hair

    Comparison of Micron Sizes(approximate)


    Driftability of Spray Droplets of Varying Sizes

    Crosswind @ 3 mph

    • 20 m

    • 50 m

    • 100 m

    • 150 m

    • m

    • 8 ft 22 ft. 48 ft. 178 ft. 1065 ft.

    10 feet

    \


    Nozzle drop size classes
    Nozzle Drop Size Classes

    Very Fine to Fine < 200 um

    Medium to Coarse – 200 to 450 um

    Very Coarse > 450 um


    Tip spray selection by drop size
    Tip Spray Selection by Drop Size

    Turbo TeeJet Flat-fan


    Secondary Break-Up

    Droplet elongation and fracture produces small droplets

    \


    Sources of Spray Mist or Fines

    Secondary Break-Up

    Droplet elongation and fracture produces small droplets

    \


    Sources of Spray Mist or Fines

    Aerodynamic Effects

    Air friction due to speed of the application vehicle causes additional production of small droplets


    Sources of Spray Mist or Fines

    Aerodynamic Effects

    Air friction due to speed of the application vehicle is dependent upon the nozzle orientation angle. 90o produces the greatest number of small droplets

    Movement


    Hypro ultra low drift
    Hypro Ultra Low Drift

    • 15 – 100 psi range

    • 120o pattern

    • $4.00 - $5.00

    • Fits Standard fan tip caps


    Spraying systems dg teejet
    Spraying Systems DG TeeJet

    • Removable Pre-orifice

    • $4.50 - $5.00


    Turbo Tee Jet

    • Spraying Systems

    • Flat Fan pattern

    • wider range of pressures 15 to 90 psi

    • produce fewer drift-prone droplets compared to SFF.

    • Fits standard TeeJet Nozzle caps


    Turbo flood nozzles
    Turbo Flood Nozzles

    • Spraying Systems

    • Clog resistant

    • Wide angle


    Conventional ssf

    Turbo Tee Jet

    Conventional SSF

    25 psi at 30” spacings. 20” height


    Turbo drop nozzle
    Turbo Drop Nozzle

    • Greenleaf Technologies

    • Air Induction (AI)

    • Venturi pressure reduction chamber

    • Droplets are filled with air and expand when leaving tip

    • Better coverage

    • $10.00


    Tee jet air induction
    Tee Jet Air Induction

    • Operates at higher psi to work efficiently

    • Needs special caps

    $6.00

    TeeJet Banding Tip $7 - $8.00


    Cp nozzle
    CP Nozzle

    • Dial-an-orifice

    • Pattern similar to flood jet

    • Mainly used by aerial sprayers


    Weather and other factors affecting drift
    Weather and Other Factors Affecting Drift

    • Temperature & humidity

    • Air movement (direction and velocity)

    • Air stability/inversions

    • Topography


    Evaporation of droplets
    Evaporation of Droplets

    High Relative Humidity

    Low Temperature

    Low Relative Humidity

    High Temperature

    Fall Distance

    Wind


    Evaporation and deceleration of various size droplets
    Evaporation and Deceleration of Various Size Droplets*

    Droplet

    Terminal

    Final Drop

    Time to

    Deceleration

    Diameter

    Velocity

    diameter

    evaporate

    distance

    (microns)

    (ft/sec)

    (microns)

    (sec)

    (in)

    20

    .04

    7

    0.3

    <1

    50

    .25

    17

    1.8

    3

    100

    .91

    33

    7

    9

    150

    1.7

    50

    16

    16

    200

    2.4

    67

    29

    25

    *Conditions assumed: 90 F, 36% R.H., 25 psi., 3.75% pesticide solution


    Strategies to reduce drift
    Strategies to Reduce Drift

    • Increase drop size

    • Increase flow rates - higher application volumes

    • Avoid adverse weather conditions

    • Consider using buffer zones

    • Consider using new technologies:

      • drift reduction nozzles

      • drift reduction additives

      • shields, electrostatics, air-assist

    • Use lower pressures

    • Use lower spray (boom) heights


    Adjuvant Influence on Spray Pattern(Note Fan Angle)

    Polymer Drift Supressants produce larger droplets across the spectrum, but will decrease the fan angle. Nozzles on the Left have the polymer supressant.


    Adjuvant Influence on Spray Pattern(Note Uniformity of Pattern)

    LI 700

    R-11

    Tallow Amine

    Water

    Source: FRI New Zealand




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