sprayer calibration

04/20/23 1

SPRAYERCALIBRATION

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OBJECTIVE

• 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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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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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

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

fan nozzles should overlap 30%.

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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 plastic are the most common.

– Stainless steel is probably the best choice

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RELATIVE NOZZLE WEAR

Nozzle material Relative wear

brass 1

stainless steel 3.5

hardened stainless steel

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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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Spraying Accuracy

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University of WyomingCooperative Extension Service

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CALIBRATION OF SPRAYERS

• Sprayer calibration consists of three major steps:– Ensure a uniform discharge from each

nozzle tip– Document the sprayer output in GPA– Determine the amount of pesticide to add to

the spray tank

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• Items needed for calibration– Measuring tape– Stop watch– Collection tube– Flags or markers

• MEASURE NOZZLE OUTPUT UNDER FIELD CONDITIONS

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• Ensuring uniform flow from all nozzles– Determine best operating speed to suit field

conditions.– Select proper nozzle.– Make sure nozzles deliver in desired rate

range.– Remove and clean all nozzle tips and screens.

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– Use clean water and flush sprayer system.– Replace all screens and tips. Make sure all

nozzles are the same.– Check flow from each nozzle. Do this daily.– Adjust pressure.

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Allowing a + or - 5% variation from a new nozzle which of the following 8002 nozzles should be replaced?

• 5% of 20 is 20 x 0.05 = 1 oz

• Need to replace any nozzle that sprays less than 20 - 1 = 19 oz.

• Need to replace any nozzle that sprays more than 20 + 1 = 21 oz.

• Replace nozzles 4, 7 and 10.

Nozzle Flow Rate (oz/min at 40 psi)1 20 (new nozzle)2 20.53 20.14 225 19.66 207 188 20.19 20.4

10 26.1

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• STEP 2. DETERMINE SPRAYER OUTPUT IN GALLONS PER ACRE

• 1. Field acres vs. treated acres (band)

– a) Field acres = Crop acres

– b) Treated acres = amount of land sprayed

– When banding only a portion of the total crop receives the spray.

– Calibration is based on the actual treated acres.

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• 2. Gallons per acre applied depends on:– 1) orifice size of nozzle tip

– 2) pressure of liquid at the tip

– 3) speed nozzle tip is moved across the field

– 4) the viscosity of the liquid being sprayed

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THE REFILL METHOD OF CALIBRATION

• Broadcast Application– 1. Fill spray tank with water– 2. Adjust pressure within recommended

range for nozzles used.– 3. Select easily maintained speed that fits

field conditions.– 4. Spray a measured area. Need to know

sprayed swath width (ssw) not boom length.

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• ssw = noz spacing (ft) x # of noz

• Example: A boom has 18 nozzles spaced 20 in. apart.

• ssw = (20 / 12) x 18 = 30 ft

• Measure off an area to equal 1/10 of an acre.

• 30 ft x X ft = 43,560 ft/a / 10

• X = 4356 / 30 = 145.2 ft

• Therefore, measure off an area 30 ft by 145.2 ft and this will = 1/10 acre.

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• 5. Return to filling point.

• 6. Measure amount of water to refill tank.

• 7. Calculate spray rate with this formula:

– gpa = gallons sprayed x 43,560 ft2/a swath width x swath length (ft)

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Example: A field sprayer with a 30 ft spray swath is sprayed for a distance of 145.2 ft. 4 gallons of water are needed to refill the tank. What is the spray rate?

gpa = 4 gal sprayed x 43,560 / 30 x 145.2 = 40 gpa

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• Band Application

– 1. Fill spray tank with water

– 2. Adjust pressure

– 3. Select speed

– 4. Measure band width (ft) and multiply by number of bands treated at one time

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– 5. Spray a measured distance in field

– 6. Return to filling point

– 7. Measure amount of water to refill tank

– 8. Calculate spray rate on the band with this formula:

• gpa = gallons used x 43,560 ft2/a treated width x distance (ft)

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• Example: A 6-row planter sprays a 12 inch band centered over 36 inch rows. It is sprayed for 300 ft and uses 0.75 gallon of water. What is the spray rate?

• treated width = 12 x 6 / 12 = 6 ft

• gpa = 0.75 gal x 43,560 ft2 / 6 ft x 300 ft = 18.2 gpa

• A 100 gallon tank can treat 100 / 18.2 = 5.5 acres of bands.

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• However, actual field coverage is equal to:

• FAT = TAT x ROW / BAND

• FAT = Field acres/tank• TAT = Treated acres/tank• ROW = Row spacing (in)• BAND= Band width (in)

• FAT = 5.5 x 36 / 12 = 16.5 acres

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• STEP 3. Adding the proper amount of pesticide to the tank

– 1. Divide the capacity of the tank by the gallons applied per treated acre to find the treated acres per tank of spray.

– 2. To determine how much chemical to add to the tank, multiply the recommended formulated rate per acre by the number of treated acres the tank will cover.

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– 3. Field acres represent the normal reference to field size. In broadcast spraying field acres/tank and treated acres/tank are the same. When banding, treated acres/tank will always be less than field acres per tank.

• BROADCAST: FAT = TAT

• BAND: FAT = TAT x ROW BAND– Where: FAT = Field acres/tank– TAT = Treated acres/tank– ROW = Row spacing, inches– BAND= Band width, inches

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• EXAMPLE: 200 gallon tank, 10 gallon/acre, 36 inch row, 12 inch band, 2.5 lbs/acre of AAtrex 80W.

– Step 1. 200 gal / 10 gpa = 20 TAT

– Step 2. 2.5 lb/a x 20 TAT = 50 lb/Tank

– Step 3. FAT = 20 x 36 / 12 = 60 FAT

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• EXAMPLE: 300 gallon tank, 40 gallon/acre, 0.5 qt/acre of Banvel.

– Step 1. 300 gal / 40 gpa = 7.5 TAT

– Step 2. 0.5 qt/a x 7.5 TAT = 3.75 qt/Tank

• WHAT IF YOU ONLY WANT TO TREAT 5.2 ACRES?

– 5.2 a x 40 gpa = 208 gallons

– 5.2 a x 0.5 qt = 2.6 qt

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• WHAT IF YOU HAVE 35 GALLONS LEFT IN THE SPRAY TANK AND YOU WANT TO TREAT 4 ACRES?

– 40 gal will cover 1 acre therefore,

35 gal / 40 gpa = 0.875 acres

– 4 a - 0.875 a = 3.125 acres

– 3.125 a x 40 gpa = 125 gallons of water

– 3.125 a x 0.5 qt = 1.56 qt or 50 oz of Banvel

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• WHAT IF PESTICIDE RATES ARE LISTED IN TERMS OF POUNDS OF ACTIVE INGREDIENT PER ACRE?

• Example: You are told to apply 2 lb ai/a of 2,4-D. 2,4-D has 4 lb ai/gal. How many quarts of 2,4-D will you need to apply per acre?

• chem needed = rate (lb ai/a) / chem conc.

• 2 lb ai / 4 lb ai = 0.5 gal or 0.5 x 4 = 2 qt/a 2,4-D

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• Example: You need to apply 0.5 lb ai/a of an 80% WP. How many pounds of product will you need to apply per acre?

• chem needed = rate (lb ai/a) / chem conc.

• 0.5 lb ai / 0.80 ai = 0.625 lb/a

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1/128 Method Of CalibrationCalibrating Hand Sprayers And High

Pressure Hand Guns• Because a gallon = 128 ounces and the

area to be sprayed is 1/128 of an acre, ounces collected = gallons per acre.

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STEP 1

• Measure out an area equal to 1/128th of an acre. Approximately 340 sq. ft. or an area 18.5 by 18.5 ft.

18.5 ft

18.5 ft

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STEP 1

• Measure out an area equal to 1/128th of an acre. Approximately 340 sq. ft. or an area 10 by 34 ft.

10 ft

34 ft

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STEP 1

• Measure out an area equal to 1/128th of an acre. Approximately 340 sq. ft. or an area 1.5 by 228 ft.

1.5 ft228 ft

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STEP 2

• Measure the time it takes to spray the measured area. Repeat several times and take the average time.

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STEP 3

• Spray into a container for the same amount of time it took to spray the measured area. Measure the water collected, in ounces. The amount collected in ounces equals gallons per acre.

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• Step 1. Measure area. 18.5 by 18.5 ft = 340 sq ft

• Step 2. Time to spray = 51 seconds

• Step 3. Amount collected = 40 ounces

• Therefore; 40 ounces = 40 GPA

EXAMPLEHAND SPRAYER

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DETERMINING HOW MUCH PESTICIDE TO ADD TO THE SPRAY MIXTURE

• Recommendation is to apply 1 quart of 2,4-D per acre

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• The sprayer is applying 40 gallons per acre. Therefore; you will need to add 1 quart of 2,4-D to each 40 gallons of water.

• Your sprayer only holds 1 gallon of spray mixture. So how much pesticide will you need to add to the gallon of water?

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• 1 quart or 32 ounces divided by 40 gallons means that each gallon of water contains 0.8 ounces of 2,4-D

• 1 fluid ounce = 2 tablespoons. Therefore; you will need ~ 2 tablespoons of 2,4-D per gallon of water.

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• 1 fluid ounce = 30 (cc) or (ml). Therefore; if measuring in cc you would need 0.8 ounces X 30 cc/ounce = 24 cc per gallon of water.

– A plastic syringe is an easy and accurate way to measure liquid pesticides.

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• How large of an area will 1 gallon spray? There are 43,560 ft2/acre. If 40 gallons will spray one acre then one gallon will spray an area 1/40 that size.

• 43,560 ft2

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• = 1089 ft2

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1/128 Method Of Calibration

• This method of sprayer calibration gives sprayer output in gallons per acre when nozzle discharge is measured in ounces over a course length that = 1/128th of an acre or 340 ft2

MULTIPLE NOZZLE BOOM-TYPE SPRAYERS

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STEP 1

• Adjust the sprayer pressure and check for uniformity. Operate the sprayer for 1 minute and measure spray from each nozzle. Clean or replace any nozzle that delivers + or - 5% than the output from a new nozzle in good condition.

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STEP 2

• Measure the spray band width or nozzle spacing in inches on the boom to determine the course length.

• The area to be sprayed must equal 1/128th of an acre or 340 ft2

• If the nozzle spacing = 20" then the distance to travel would be 204 ft.

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• 20" (1.67 ft) X 204 ft = 340 ft2

204 ft

1.67 ft 340 ft2 or 1/128 of an acre

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STEP 3

• Catch the spray from ONE nozzle while operating the sprayer under field conditions or for the time required to travel the needed distance at a desired speed.

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STEP 4

• Measure the spray collected in ounces. The number of ounces collected is the same as the number of gallons per acre.

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EXAMPLE

• You have a sprayer that has 15 nozzles on a 30 inch spacing. How would you calibrate it using the 1/128th method?

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STEP 1

• Make sure sprayer is adjusted properly and nozzles are in good working order.

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STEP 2• Measure nozzle spacing in inches on the

boom to determine the course length.• Using the formula:

• 4084 / 30 inches = 136 feet

• Or from Table 1. W = 30 inches and D = 136 feet

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Table 1. Distance (D) to travel and seconds required for selected speeds when nozzle coverage is (W) inches.

W (in) D (ft) 2 mph 3 mph

20 204 70 seconds 46 seconds

24 170 58 39

26 157 54 36

28 146 50 33

30 136 46 31

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STEP 3

• Time how long it takes to travel the 136 ft at a desired speed. Travel this distance several times and get an average time.

• Perhaps it takes an average of 31 seconds to travel the 136 feet.

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STEP 4• Collect the spray from ONE nozzle in a

container for 31 seconds.• Measure the water collected in ounces.• The amount collected in ounces equals

gallons per acre.• If in 31 seconds you collected 20 ounces

your sprayer output would be 20 gallons per acre.

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DETERMINING HOW MUCH PESTICIDE TO ADD TO THE SPRAY

MIXTURE

• The recommendation from the label is to apply 1 quart of 2,4-D per acre.

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• The sprayer is applying 20 gallons per acre.

• Therefore; you will need to add 1 quart of 2,4-D to each 20 gallons of water.

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• Your sprayer holds 200 gallons. So how much pesticide will you need to add to the 200 gallon spray tank?

– 200 gallons divided by 1 qt 2,4-D per 20 gallons water = 10 quarts of 2,4-D per tank

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• How large an area can be sprayed by your 200 gallon tank?

– 200 gallons divided by 20 gallons per acre = 10 acres

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CALIBRATING GRANULAR APPLICATORS

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CALIBRATING GRANULAR APPLICATORS

• 1. Adjust orifice and fill hopper.

• 2. Operate the unit in the field to be treated and collect the granules as the unit is operating.

• 3. Weigh the amount of chemical delivered.

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• 4. Calculate the area treated.

– band width x number of rows x length

– or row spacing x number of rows x length

– or swath width x length

• 5. lb of granules/a =

– [43,560 x lbs of granules collected] divided by [the area of the measured course in ft2]

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• 6. The above steps may have to be repeated until the desired amount is delivered.

• Example: A granular applicator treats a swath width of 20 ft and is driven over a distance of 217.8 ft. The unit delivers 0.7 lb. What amount of granules are being applied per acre?

• 43,560 x 0.7 / 4356 = 7 lb/a

• You want the unit to deliver 100 lbs of product per acre. What needs to be done?

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• Unit should deliver:

• [100 lbs x 4356 ft2] / 43,560 ft2 = 10 lbs in the measured course.

• Adjust the orifice until 10 lbs are collected per 4356 ft2.

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FACTORS AFFECTING GRANULAR APPLICATORS

• 1. Exposed area of the metering orifice• 2. Speed of the agitator• 3. Ground speed of the applicator• 4. Nature and size of the granules• 5. Roughness of the field• 6. Humidity and temperature

– When any of the above factors change the applicator should be recalibrated.

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SOLUTIONS AS PERCENT OR PPM

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• SOLUTIONS AS PERCENT OR PPM

• Percent concentration by weight:

– lbs to use = [% by wt x gal final mix x 8.34] divided by [% strength of chem to be used]

– Example: How much WP containing 40% ai should be added to a 250 gallon tank if the recommended treatment is 0.25% by weight?

– [0.0025 x 250 x 8.34]/0.4 = 13 lbs

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• Percent concentration by volume:

– gal to use = % by vol x gal final mix

– Example: When using Ally it is suggested you add a surfactant at 0.25% by volume. How much surfactant should be added to a 300 gallon spray solution?

– 0.0025 x 300 = 0.75 gallons or 3 quarts

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• Parts per million (ppm): Wettable Powder (dry material)

– lbs to use = [ppm desired x gal final mix x 8.34] divided by [1 million x % strength of chem used]

– Example: How much WP containing 40% ai should be added to a 100 gallon tank if the recommended treatment is 1200 ppm?

– 1200 x 100 x 8.34 / 1 mil x 0.4 = 2.5 lbs

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• Parts per million: Liquid

– gal to use = [ppm desired x gal final mix x 8.34] divided by [1 million x lbs ai/gal]

– Example: How much liquid EC containing 0.625 lbs of ai/gal should be added to a 100 gallon tank if the recommended treatment calls for 300 ppm ai of a liquid chemical?

– 300 x 100 x 8.34 / 1 mil x 0.625 = 0.4 gallons

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• SUMMARY

– Find a calibration method you understand and use it every time.

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Exams with calibration problems on them

• Ag pest control-weed & insects (901 A & B)• Chemigation (901 F)• Forest pest control (902)• Ornamental & turf-weeds (903 A)• Aquatic pest control (905)• Right-of-way pest control (906)• Industrial, institutional, structural & health related pest

control (907)• Regulatory pest control (909)• Demonstration & research pest control (910)• Aerial (912)

sprayer calibration

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