SPRAYER ACCURACY

July 2003 1

SPRAYERACCURACY

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Objective of Calibration

• Determine the volume or weight that application equipment will apply to a known area under a given set of conditions.

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VOLUME OF PESTICIDE SOLUTION APPLIED DEPENDS

UPON:

• NOZZLES

• PRESSURE

• SPEED

• Spacing of Nozzles

• Viscosity of liquid

• WHY CALIBRATE??

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1984 Colorado SprayCheck Program

Commercial Applicators

Private Applicators

average initial error 17.5% 25.8%

average corrected error

6.6% 5.5%

under-application 50% 40%

over-application 17% 37%

with 10% range 33% 23%

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TeeJet nozzle examples

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Hypro Nozzles

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NOZZLE TIP DESIGNATIONS

SPRAYING SYSTEMS CO.• HSS8002E

• HSS 80 02 E

• HSS = HARDENED STAINLESS STEEL

• 80 = 80 DEGREE SPRAY ANGLE

• 02 = 0.2 GALLON PER MINUTE AT 40 PSI

• E = EVEN FLAT FAN PATTERN FOR BAND APPLICATION

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HOW TO CHOOSE THE RIGHT NOZZLE SIZE

• GPM = GPA x MPH x Nozzle spacing in inches 5940

• GPM = Gallons per minute per nozzle

• GPA = Gallons per acre

• MPH = Miles per hour

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EXAMPLE

• GPA = 30

• MPH = 4

• Nozzle spacing = 20

• GPM = 30 GPA x 4 MPH x 20 in 5940

• GPM = 0.40

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• Find nozzle capacity in GPM in manufacture's catalog.

• Desired spraying pressure = 40 psi

• Using Spraying Systems catalog an 8004 nozzle would work the best.

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TeeJet Standard FlatSpray Tips

GPA - 20 inch spacingTip No. PSI GPM 4 mph

6502-SS 30 0.17 12.9

8002-SS 40 0.2 14.9

11002-SS 50 0.23 16.6

6504-SS 30 0.35 26

8004-SS 40 0.4 30

11004-SS 50 0.45 33

6505-SS 30 0.43 32

8005-SS 40 0.5 37

11005-SS 50 0.56 42

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Rule of Thumb

• An 8004 nozzle will deliver 40 gpa when used at 3 mph with 40 psi.

• Likewise an 8002 will deliver 20 gpa under the same conditions.

• An 8001 will deliver 10 gpa.

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HOW TO CHANGE SPRAYER OUTPUT

• NOZZLES– Best for large changes in output

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• Pressure– Only feasible within a limited pressure range– Pressure must be increased by a factor of 4

in order to double the flow

– 10 GPA at 20 PSI– 20 GPA at 80 PSI

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• SPEED– Only feasible within a limited range of

speeds– Double ground speed will decrease output by

50%– 1/2 ground speed will increase output by

50%

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MAXIMIZING SPRAYER PERFORMANCE

• NOZZLES– Nozzle types

• Flat fan is best for broadcast application of herbicides

Flat fan Even fan

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BOOM BUSTERSPRAY NOZZLES THAT WORK WITHOUT BOOMS

• FEATURES– All nozzles machined from solid stainless steel.

All have replaceable industrial grade nylon diffusers. (Tests have shown that this nylon will outlast stainless steel.)

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Boom Buster (con’t)

– Extra wide spray pattern. – Excellent pattern and distribution. – All models spray chemicals and fertilizers. – All nozzles have standard pipe threads.

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Boom Buster (con’t)

• USES– Row Crops, Grain and Pastures – State and County Right-of-Ways – Orchards and Vineyards – Forestry and Utility Right-of-

Ways – Lawn and Turf – Roads, Hedge Rows and Fence

Rows

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• Nozzle uniformity– Nozzle types and orifice sizes must be the

same across the boom

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• Nozzle orientation– Directed straight down toward the ground

and angled 5 to 10 degrees from parallel to the boom to prevent collision of spray droplets from adjacent patterns

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• Nozzle materials– Stainless steel,

brass and polymer are the most common.

– Stainless steel is probably the best choice

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RELATIVE NOZZLE WEAR

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• Screens and filters– Use appropriate

screens and filters• 0.2 GPM or more

use 50 mesh

• Less than 0.2 GPM use 100 mesh

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Spray Drift Management

July 2003

Misapplication Facts

2%8%

24%

33%

33%Equipment

Drift

Tank Mix

WrongFieldOff Label

Source: Farmland Insurance 1996

July 2003

Contributions to Drift

13%

26%

38%

23%

Nozzle

Applicator

Physical

Other

July 2003

One micron (m) =1/25,000 inch

• Particle drift results by creating smaller drops.

• Spray droplets are measured in microns and expressed as Volume Median Diameter (VMD).

Relationship of Drift to Drop Size

July 2003

Comparison of Micron Sizes for Various Items (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

150

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Droplet Size

• Large droplets have less potential to drift because they:– Fall more quickly

– Evaporate more slowly

– Are less affected by wind

• Small droplets often result from:– High spray pressure

– Small nozzle tips

– Wind shear across the nozzles

July 2003

Drift Potential is Influenced by

• Volume Median Diameter (VMD) 50%• Droplet Spectrum (Range - big to

small)

% Volume in droplets less than 200 microns in size

361/2 of spray volume = larger droplets

VMD

1/2 of spray volume = smaller droplets

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Cutting Droplet Size in HalfResults in Eight Times the Number of

Droplets

500Microns

500Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

250Microns

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Cutting Droplet Size

in Half

Results in Eight Times the Number of

Droplets

==2 more droplets fill in the sphere

500Microns

500Microns

250Microns

July 2003

Evaporation and Deceleration of Various Size Droplets*

DropletDiameter(microns)

TerminalVelocity(ft/sec)

Final Dropdiameter(microns)

Time toevaporate

(sec)

Decelerationdistance

(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

July 2003

Low Drift Nozzle Types• Flat-fan(Spraying Systems, Hardi,

Delavan, Lurmark, others)

• Raindrop (Delavan)

• Drift Reduction Flat-fan (Several)

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Low Drift Nozzle Types, cont:•Turbo Flood (Spraying Systems)

•Turbo Flat-fan (Spraying Systems)•TurboDrop•AI Flat-fan•SprayMaster Ultra•Compact Venturi

July 2003

Nozzle type(all nozzles areSpraying Systemsnozzles)

40 psi @0.2 gpm

40 psi @0.5 gpm

60 psi @0.5 gpm

% spray volumeunder 200microns (0.5gpm @ 40 psi)

XR 80o 270* 370 300 11

XR 110O 224 310 250 22

Turbo Flat-fan 340 450 400 6

Drift Guard110o

330 390 320 11

Flood - 450 410 3

Turbo Flood - 710 650 less than 1

Dropsize Comparisons (Data provided by Spraying Systems Co.)

*Numbers listed are in Microns (Dv.5)

July 2003

Nozzle Dropsize ClassificationSelection based on droplet size:

• Very Fine

• Fine

• Medium

• Coarse

• Very Coarse

• <119 m

• 119-216 m

• 217-353 m

• 354-464 m

• >464 m

Insecticidesand Fungicides

Herbicides Postemergence

Soil Applications of Herbicides

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Air Inclusion

Just air pressure, or both air and liquid pressure used to atomize and carry the spray solution to the target.

Sprayer operator can vary droplet size independently of nozzle flow rate.

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Air Atomizers

AirJet (Spraying Systems Co., Illinois)

Shear Guard Plus

(Spray-air USA inc., Idaho)

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AirJet Atomizer--- Flow rate vs. Droplet size

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Air Inclusion Technology"Air Inclusion technology over last five years, has

done more to reduce off target trespass than any other technology that I am aware of, past or present. This technology has come to the market and has been widely adopted without mandated regulation. It has been a voluntary effort by manufacturers, researchers, growers, and retailers to develop and promote low-drift application practices which are in the best interest for agriculture." Thomas M. Wolf, PhD

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Droplet Dynamics

50

20 psi

40 psi

75 psi

Hypro ULDAir Bubble Jet

TurboDrop Delavan UltraTeeJet XRHypro TR

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Droplet Speed• At tip:

– all droplets: (43mph)

• 20 inches below tip:– Large droplets: (17mph)– Small droplets: (4.3 mph)

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Droplet Direction• Large droplets:

– combination of nozzle and travel direction

– e.g. (18 mph) , (6 mph)

• Small droplets:– whichever way the wind is

blowing

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Droplets in a Grass Droplets in a Grass CanopyCanopy

InterceptionInterception

PenetrationPenetration

Large dropletsLarge droplets Small dropletsSmall droplets

InterceptionInterception

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If I use lower Water Volumes, what are my

nozzle choices?

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Glyphosate on Tame Oats

Volume Median Diameter (µm)

Ave

na

con

tro

l (%

)

30

40

50

60

70

80

90

100

200 300 400 500 600

12 gpa

8 gpa

4 gpa

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Glyphosate on Oriental Mustard

Volume Median Diameter (µm)

Bra

ssic

a co

ntr

ol (

%)

30

40

50

60

70

80

90

100

200 300 400 500 600

12 gpa

8 gpa

4 gpa

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13.36 GPA 9.09 GPA 4.81GPA

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Nozzle Air-

Induced Optimal Pressure

(psi) Relative

Droplet size Minimum Volume

TeeJet XR No 20 to 60 Smallest (*) 3

Hypro TR, VP, Albuz AXI No 20 to 60 * 3

ComboJet ER No 20 to 60 * 3

Turbo TeeJet No 15 to 90 ** 5

Hypro LD, Albuz ADI No 30 to 60 ** 5

Air Bubble Jet Yes 40 to 60 *** 7

Greenleaf AirMix Yes 40 to 60 *** 7

Hypro Ultra Lo-Drift Yes 40 to 60 *** 7

ComboJet MR No 40 to 60 *** 7

Greenleaf TurboDrop, XL Yes 60 to 80 **** 9

Albuz AVI Yes 60 to 80 **** 9

Spraying Systems AI Yes 60 to 80 **** 9

Lechler ID / Hardi InJet Yes 60 to 80 **** 9

ComboJet DR No 60 to 80 ***** 10

SprayMaster RainDrop Ultra

Yes 80 to 120 ***** 10

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Is Boom Height important?

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Droplet Size Within Spray Pattern

Dro

plet

Num

ber

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Spray Height Chart

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• BOOM HEIGHT– Rule-of-thumb when using 80 degree tips– Set the boom above the target by whatever

the distance is between nozzles• If nozzle spacing is 20" then set boom 20" above

target

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• Nozzle placement– Need to be placed for proper overlap. Flat

fan nozzles should overlap 30%.

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Boom Height and OverlapD

ropl

et N

umbe

r

30 % Overlap30 % Overlap

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Boom Height and OverlapD

ropl

et N

umbe

r

100 % Overlap100 % Overlap

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Strategies to Reduce Drift• Select nozzle to increase drop size.• Increase flow rates - higher application

volumes.• Use lower pressures.• Use lower spray (boom) heights.• Avoid adverse weather conditions.• Consider using buffer zones.• Consider using new technologies:

– drift reduction nozzles– drift reduction additives– shields, electrostatics, air-assist

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Spraying Accuracy

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University of WyomingCooperative Extension Service

SPRAYER ACCURACY

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