7.4 Sprayer Calibration
A simple vertical patternator can be constructed in the farm workshop using readily available materials; a build list and photographs can be found online at: www.nysaes.cornell. edu/ent/faculty/landers/pdf/Patternator.pdf.
Videos showing calibration and nozzle selection may be found on the internet at: www.youtube.com. Type in: "Calibration of airblast sprayers for orchards part 1 selecting and changing nozzles" or "Calibration of airblast sprayers for orchards part 2 measuring liquid flow"34187
7.4.1 Travel Speed Calibration
Sprayer travel speed will influence spray deposition and is a critical factor in maintaining accurate application rates. Although results of studies to determine the effect of travel speed on average spray deposition have been inconsistent, all studies have been in agreement that the higher the travel speed, the greater the variability in spray deposit. This variability is an important factor where uniformity of spray coverage throughout the canopy is required. Conclusions from research were drawn using travel speeds of 1-4 mph.
Factors that will affect travel speed include:
- weight of sprayer to be pulled
- slope of terrain
- ground conditions traveled over (wheel slippage)
The best way to measure travel speed is to pull a sprayer half full of water over the same type of terrain on which the actual sprayer will be operated.
Using a tape measure, set up a test course at least 100 feet long. Do not pace the distance. The longer the course, the smaller the margin of error.
Run the course in both directions. Use an accurate stopwatch to check the time required to travel the course in each direction. Average the two runs and use the following to calculate the speed in MPH.
Tractor gear___________ Engine revs.___________34188
7.4.2 Airblast Sprayer Calibration
- use clean water
1. Pressure check
Place the pressure gauge on the nozzle fitting farthest away from the pump and turn the sprayer on. If pressure is lower at the nozzle than specified, increase pressure at the regulator.
Pressure at nozzle ______________psi
Pressure at sprayer gauge _____________psi
2. Nozzle output
Use a flow meter (obtainable from Gemplers, Spraying Systems, etc.) attached to individual nozzles OR
- Connect hoses to each of the nozzles and measure the flow from each nozzle into a calibrated jug. Record and total your results using Figure 7.4.1.
- Replace all nozzle tips which are more than 5% inaccurate.
- Calculate gallons per acre using the following formula.
Total GPM X 495
mph X row spacing (ft.)
GPM X 495
____mph X ____ft.
Figure 7.4.1. Airblast Sprayer Calibration
7.4.3 Calibrating a Kinkelder Sprayer
-use clean water
Rate of sprayspeed spacing
Gals/acre X mph X ft X 60 gals/hr delivery
500 = or index setting
50 gals/acre x 3 mph x 9 ft x 60 = 162 gals/hr delivery
or index setting
gallons/acreX mph X ft X 60 = gals/hr delivery
500 or index setting
This figure should be set on both scales.
Both taps should be set on the distribution conduit in such a way that the index is set on the sign 162 on the index plate of the distribution conduit. The emission indication on the index plate has been fixed at a working pressure of 21 lbs (1.5 bar).
Check the output of the sprayer:
1. Divide the gallons/hour figure obtained above by 60 to give output/minute
e.g. 162 gpm divide by 60 = 2.7 gallons/minute total of
left and right side then divide 2.7 gallons/minute by 2 = 1.35 gallons/minute/side
2. Remove the plastic pipes from the nozzles on the left or right side, tie together and place in a measuring jug
3. Run the sprayer for one minute at correct engine speed, collecting the output in a measuring jug
Remember 128 fl. ozs in one gallon. Example: If the output of one side has been measured at 173 fl.ozs, then output is divided by 128 = 1.35 gallons per minute.
4. Then check the output of the opposite side.34191
7.4.4 Calibrating an AgTec Sprayer
-use clean water
1. Calculate the gallons/minute/side:
Speed x gallons/acre x row width = gallons/minute/side
e.g. 3 x 50 x 9 = 1.35 gallons/minute/side
mph Xgallons/acre X ft = gals/min/side
2. Check AgTec tables for correct meter setting, select the gal/min as calculated above, and then find meter setting, e.g. meter #12 @ 30psi gives 1.34 gallons/min.
3. Remove the hoses from the nozzles on the left or right side, tie together and place in a measuring jug
4. Run the sprayer for one minute at correct engine speed, collecting the output in a measuring jug
Remember 128 fl. ozs. in one gallon. Example: If the output of one side has been measured at 173fl.ozs, then output is divided by 128 = 1.35 gallons per minute.
5. Then check the output of the opposite side.34192
7.4.5 Boom Sprayer Calibration
-use clean water34193
Step 1. Check your tractor/sprayer speed
Your tractor sprayer speed:
Step 2. Record the inputs
Nozzle type on your sprayer (all nozzles must be identical)
110 04 flat fan
Recommended application volume (from manufacturer's label)
Measured sprayer speed
Step 3. Calculate the required nozzle output.
GPA X mph X nozzle spacing
20 X 4 X 20
= 0.27 GPM
Step 4. Operate the sprayer
Set the correct pressure at the gauge using the pressure regulating valve.
Collect and measure the output of each nozzle for one minute. The output of each nozzle should be the approximately the same as calculated in Step 3 above.
Replace all nozzle tips that are more than 5% inaccurate.