spraying information & calibration...

SPRAYING INFORMATION &CALIBRATION PROCEDURES

RS052010

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SPRAYING INFORMATION & CALIBRATION PROCEDURES

Accurate calibration is an essential element of any spraying function as it ensures that the pesticide/herbicide is applied at the rate on the product label. Application in excess of the recommended rate is prohibited, can damage crops and is uneconomical.

Calibration must always be carried out:When spraying for the first time with new spray equipment•At the beginning of each season•After changes of nozzle tips, spraying pressure or speed•After every 100 hectares of spraying•

The following pages give some information on how to calculate spray application rates, a sample worksheet and a blank copy for you to print to record your calculations on. There is also general information about types of nozzles and spray techniques.

Please note: This information is general in nature and no responsibility or liability is accepted by Rapid Spray. In no sense does this document constitute advice or recommendations.

INTRODUCTION

FReeCAll: 1800 011 000

PH: 61 2 6578 8100Fax: 61 2 6571 2951

35 enterprise CresPO Box 3119

Singleton NSW 2330Australia

email: [email protected]

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ISJ AGRICULTURAL NOZZLES

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SPRAYING

Spraying coverage

Overall spraying is when the entire field is to be treated.The width that each nozzle sprays, adjusted for spray overlap, is the distance between nozzles on the spray boom.

Band spraying is when planted rows or unplanted gaps are treated. The width that each nozzle sprays is the width of the treated band.

Sprayer SpeedForward speed of the spraying machine should be measured accurately. Sensors should be calibrated after installation or servicing. Wheel-driven speedometers should be calibrated whenever the driving surface changes, such as after cultivation. Speed can be determined if it is known how long it takes to drive a measured distance:

distance in metres x 3.6Speed in Km/h = time in seconds

Higher speeds (12-20 Km/h) improve work rates and timeliness; lower speeds (8-12 Km/h) give improved canopy penetration and reduce spray drift.

Application RateRead the pesticide label closely to determine an appropriate spray application rate. If a range of acceptable application rates is listed, choose a rate that best matches your situation. For example, application rates of less than 150 l/ha will increase work rates and improve timeliness whereas higher application rates (>150 l/ha), are required for good coverage in dense canopies.

Flow RateDetermine the exact flow required from the nozzles by calculating:

l/ha x km/h x nozzle spacing (m)l/min = 600

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Use of no-water based solutionsThe reported values have been calculated using water.In case of liquids with a different specific weight (density), if you want to know the real delivery, you have to multiply the values on the charts with a conversion factor, as follows:

Density kg/dm3 0,85 0,90 0,95 1 1,10 1,15 1,20 1,25 1,30 1,40Conversion factor 1,08 1,05 1,03 1 0,95 0,93 0,91 0,89 0,88 0,85

Obviously, the more density, the more pressure you need to reach the required delivery.

Pressure dropThis is the pressure difference between the inlet and the outlet of a hydraulic plant. Beside of the pipe length, this drop is due to branches lines, curves, filters, valves, sections variations etc.

In our catalog we report the values indicated on the technical charts of our products.

Filtering elements sizeThe filter efficacy depends on the positioning of the correct net size on the different points of hydraulic system. On the chart you can find the minimum required net size:

ISO Nozzlel/ha Filter (mesh)

8 km/h3 bar

Suction Lines Booms

ISO 11001 ÷ 11002 < 120 l/ha 50 80 100

ISO 11003 ÷ 11006> 120 l/ha< 450 l/ha

32 50 80

ISO > 11008 > 450 l/ha 16 32 50

This way you have:

- correct filtration- low pressure drop - low maintenance = low costs

MEASUREMENT CONVERSION

Volume unit English Metric1 lt. 0.2199 Imp. gal. 0.26417 US gal.1 US Gallon 0.833 Imp.gal. 3.785 lt.1 Imp. Gallon 1.2 US gal. 4.546 lt.

Delivery unit English Metric

1 l/min0.26417 US GPM0.22 Imp. GPM

1 l/ha 0.1069 US GPA1 US GPM 0.833 Imp. GPM 3.785 l/min1 Imp.GPM 1.2 US GPM 4.546 l/min1 GPA 9.346 l/ha

Pressure unit English Metric1 bar 14.503 psi 0.1 Mpa1 Mpa 145.03 psi 10 bar1 psi 0.069 bar

0.0069 Mpa

Following you will find some formulas and charts, that can be very useful for proper spraying.

How to calculate the forward speedSpeed is a basic datum to calculate the sprayed volume (litres/hectares or GPA). When it’s not possible to have a speedometer (and when you want to check its precision), you can do the following:

- Fill half the tank- Measure 100 mt on the field- Drive the distance using gear position and RPM, that you require

for spraying. Record the time it takes you.- Repeat the previous point at least 5 times and calculate the

average time it took you to drive 100 mt- Apply the following formula:

V = 3,6s

t

V= Speed (km/h) s = Distance (mt) t = Time (1” seconds)

or:

S = 88

d · 60

t

S= Speed (MPH) d = Distance (ft) t = Time (1” seconds)

How to calculate delivery and sprayed volumeBefore spraying you need to choose the correct nozzle, accord-ing to volume and speed. You can do this calculation with the help of several nozzle delivery charts, but if you want to know the exact delivery of the nozzle you are using, you can do the following:

Q =D · V · i

60.000

Q = Nozzle delivery (l/min)D = Application rate (l/ha)V = Speed (km/h)i = Nozzle spacing (cm)

or:

Q =D · S · i

5940

Q = Nozzle delivery (GPM)D = Application rate (GPA)S = Speed (MPH)i = Nozzles spacing (inch)

How to calculate the required pressure When the charts don’t report the pressure value, which allows the nozzles to supply the required delivery, you can use the following formula to calculate it:

P1 = (Q1 / Q2)2 · P2

P1 = required pressure P2 = pressure on the chartQ1 = required deliveryQ2 = delivery on the chart

TECHNICAL SUGGESTIONS

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BOOM SPRAYERS HYDRAULIC NOZZLES EXAMPLE

Read the LABELSpray VOLUMEProduct DoseSpray QUALITY

Measure TIME per 100 Metres Measure time in seconds over land similar to that to be sprayed

Calculate SPEED SPEED = 360 divided by TIME km/h seconds

Measure Nozzle SPACING Normally 0.5 metres (50cm)

Measure TIME per 100 Metres OUTPUT = VOLUME x SPEED x SPACE ÷ 600 litres/min litres/hectare km/h metres

Select NOZZLERefer to nozzle manufacturers data charts or other sources and select the size and type of nozzle that will produce the calculated OUTPUT and required spray QUALITY

NOW, CHECK THE CALIBRATION ON THE SPRAYER

Check Nozzle OUTPUT

With water, check outputs of 4 or more nozzles using a calibrated jug or flow meter.Check all nozzles are aligned correctly and spray patterns are good

Calibrate SPRAYER SPEED = 360 divided by TIME km/h seconds

As the nozzle output and therefore the spray volume are less than target figures, increase the pressure to, say 2.5 bar and repeat the calibration to achieve 200 litres/hectare

NOW, RECORD THE DETAILS AS CALCULATED

Nozzle fitted

Spray Volume

Spray Pressure

Spray Quality

Forward Speed

CALIBRATION PROCEDURESThe following table gives a step-by-step guidance on the standard method of sprayer calibration

See page 6 for a copy of this table with blank fields for data entry.

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BOOM SPRAYERS HYDRAULIC NOZZLES DATA

Read the LABELSpray VOLUMEProduct DoseSpray QUALITY

Measure TIME per 100 Metres Measure time in seconds over land similar to that to be sprayed

Calculate SPEED SPEED = 360 divided by TIME km/h seconds

Measure Nozzle SPACING Normally 0.5 metres (50cm)

Measure TIME per 100 Metres OUTPUT = VOLUME x SPEED x SPACE ÷ 600 litres/min litres/hectare km/h metres

Select NOZZLERefer to nozzle manufacturers data charts or other sources and select the size and type of nozzle that will produce the calculated OUTPUT and required spray QUALITY

NOW, CHECK THE CALIBRATION ON THE SPRAYER

Check Nozzle OUTPUT

With water, check outputs of 4 or more nozzles using a cali-brated jug or flow meter.Check all nozzles are aligned correctly and spray patterns are good

Calibrate SPRAYER SPEED = 360 divided by TIME km/h seconds

If the nozzle output and therefore the spray volume are less than target figures, increase the pressure to, say 2.5 bar and repeat the calibration to achieve 200 litres/hectare

NOW, RECORD THE DETAILS AS CALCULATED

Nozzle fitted

Spray Volume

Spray Pressure

Spray Quality

Forward Speed

To print this page, select Print from the File menu, choose Current Page from the print options.

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CALIBRATION PROCEDURES - PRINT VERSION

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Flat Fan pattern

Available as a tapered spray for boom applications or an even spray for single nozzle applications; e.g. knapsacks. They have an elliptical orifice, which produces a narrow oval pattern. Tapered nozzles produce a triangular spray pattern where most of the spray is deposited immediately under the nozzle. By overlapping tapered sprays across a boom, an even distribution across a boom can be obtained.

Deflect pattern

Also known as anvil or flood nozzles, deflect nozzles produce wide angled flat pattern when operated at low pressures (1-2 bar). The nozzles generally produce a coarse, even spray and are ideal for use with knapsack sprayers or mounted on tillage equipment.

Hollow cone pattern

Nozzles produce a hollow circular footprint. Hollow cones are used on air-assisted sprayers and traditional boom sprayers when good coverage in dense canopies is required.

“Spray Drift” comprises small, wind bourne droplets of pesticide carried away from the intended target area into the environment.Recent research has shown that up to 20% of pesticides being released is contained in droplets less than 100µm in diameter. These, of course, are drift prone droplets capable of travelling great distances taking the benefits of the pesticide away from the target, to contaminate the environment.INTeRNATIONAl SPRAY JeTS’s low Drift Nozzles are developed with a dual orifice nozzle tip which generates larger droplets even at standard spray pressures, with a significant reduction in the percentage of droplets below 103µm, therefore reducing the percentage of pesticide available for transmission to non-target areas.low Drift nozzles really helps to reduce environmental impact by reducing the percentage volume of driftable droplets, minimising off-target spray contamination.

Percentage Volume of Droplets <103µm at 3 bar pressure

Typical110° STANDARDFLAT FAN

SF110015 SF11002 SF11003 SF11004

LOW DRIFT110° NOZZLE

LD110015 LD11002 LD11003 LD11004

Percentage reduction in volume of droplets below 103µm using LOW DRIFT tips

33% 42% 48% 54%

SPRAY PATTERN TYPE

THE ADOPTION OF LOW DRIFT NOZZLES

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For effective spraying ensure you have taken the following factors into account

1. WORK RATES

Speed of operation•

Water points or nurse tanks•

Rate of travel•

Swath width•

Spray volume applied•

2. WIND AND DRIFT

Wind Speed•

Wind Direction•

Airspeed at boom height•

Avoid spraying on still warm days as convection currents may cause drift in unpredictable directions.

Optimum wind speeds are between 3km/h to 7 km/h.

Wind direction and drift is controlled by;:•

Reducing nozzle height•

Reducing pressure and using larger nozzles•

Fit low-drift nozzles producing larger droplets•

3. FIELD WORK (See diagram)

Swath marking and spraying

Mark out to ensure proper pass matching – use flags foam •markers or tramlines

Where large obstructions exist in the middle of an area to •be sprayed, mark out and spray the area like a separate headland.

The perimeter of the field should be sprayed first. The •width of two swaths will give adequate turning space at the ends of spray runs.

Never spray while turning.•

4. SPEED

Maintain a constant speed when spraying. Should you need to increase your spraying speed, larger delivery nozzles must be fitted. Re-calibrate as required.

SPRAYING

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