Spray nozzle selection

Scott Bretthauer

Department of Agricultural and Biological Engineering

University of Illinois at Urbana-Champaign

Droplet size: influences coverage and spray drift

Small droplets provide better coverage but are more likely to drift

Need to select droplet size based on application: balance need for coverage with drift reduction

Droplet size and number

Droplet size and number

Droplet size spectrums recommended for various pesticide uses

Droplet Spectrum (by ASAE S572)

Contact insecticide

and fungicide

Systemic insecticide

and fungicide

Contact foliar

herbicide

Systemic foliar

herbicide

Soil-applied

herbicide

Incorporated soil-applied herbicide

Very fineVF

FineF √

MediumM √ √ √ √

CoarseC √ √ √ √

Very CoarseVC √ √

Extremely CoarseXC √

Calibration exampleGPA x MPH x W

5,940GPM =

GPM: nozzle flow rate in gallons per minuteGPA: gallons per acre – 15MPH: miles per hour – 7W: effective sprayed width – 20 inches5,940: constant used for converting units

15 GPA x 7 MPH x 20 inches5,940

0.35 GPM =

Calibration example

Select turbo nozzle tips

Flow rate = 0.35 GPM

Medium droplet spectrum

TT11003 @ 54 psi

Extended range flat-fan nozzleModified orificeallows operation atlower pressures

Coarse droplets

Fine droplets

Pre-orifice or drift reduction flat-fan nozzle

Pre-orifice reducespressure

Reduces small droplets

Turbo (turbulence chamber) flat-fan nozzle

Pre-orifice

Turbulence chamber

Reduces small droplets

New pre-orifice flat-fan nozzle

Pre-orifice design

One-piece fast cap

Primarily coarse and medium droplet spectrums

Air induction flat-fan nozzleInduce air into spray – increase droplet sizeMany designs – different droplet spectrums

Air induction flat-fan nozzle

Turbo air induction flat-fan nozzleCombine turbulence chambers with air induction

15 to 100 psi pressure range

Twin spray nozzles

Single tip with dual orifice design

Dual tip design

Improved penetration and coverage over single flat-fan nozzles in lower canopy of some crops

High flow rate nozzlesWide angle pattern – improved uniformityReduced formation of small spray droplets

Rate controllers and droplet sizeMonitor application factors– Flow rate– Pressure– Speed

Information entered by applicator– Effective sprayed width– Target GPA

Controller automatically maintains GPA during speed changes– Adjusts nozzle flow rate using PRESSURE– Changes droplet spectrum

Speed ChangeNozzle spacing: 20 inchesGPA: 10Initial speed: 13 MPHFlow rate: 0.44 GPMNozzle: TT11004 @ 48 psiDroplet size: Coarse

Speed ChangeIncrease speed to 18 MPHW still 20, GPA still 10Flow rate: 0.61 GPMNozzle: TT1104 @ 93 psiAbove nozzle pressure limit; unknown droplet size

Questions?Scott Bretthauer(217) 333-9418

sbrettha@uiuc.edu