Sprayer Calibration

Sprayer calibration (1) readies your sprayer for operation and (2) diagnoses tip wear. This will give you optimum performance of your TeeJet® tips.

Equipment Needed:
TeeJet Calibration Container
Calculator
TeeJet Cleaning Brush
One new TeeJet Spray Tip matched to the nozzles on your sprayer
Stopwatch or wristwatch with second hand

STEP NUMBER 1
Check Your Tractor/Sprayer Speed! Knowing your real sprayer speed is an essential part of accurate spraying.
Speedometer readings and some electronic measurement devices can be inaccurate because of wheel slippage. Check the time required to move over a 30- or 60-meter strip on your field. Fence posts can serve as permanent markers. The starting post should be far enough away to permit your tractor/sprayer to reach desired spraying speed. Hold that speed as you travel between the “start” and “end” markers. Most accurate measurement will be obtained with the spray tank half full. When the correct throttle and gear settings are identified, mark your tachometer or speedometer to help you control this vital part of accurate chemical application.

STEP NUMBER 2
The Inputs
Before spraying, record the following: EXAMPLE
Nozzle type on your sprayer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TT11004 Flat
(All nozzles must be identical) Spray Tip
Recommended application volume . . . . . . . . . . . . . . . . . . . . . . . . . 190 l/ha
(From manufacturer’s label)
Measured sprayer speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 km/h
Nozzle spacing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 cm

STEP NUMBER 3

Calculating Required
Nozzle Output
Determine l/min nozzle output from formula.
l/ha x km/h x W
FORMULA: l/min =
60,000
EXAMPLE: l/min = 190 x 10 x 50
60,000
ANSWER: 1.58 l/min

STEP NUMBER 4

Setting the Correct Pressure. Turn on your sprayer and check for leaks or blockage. Inspect and clean, if necessary, all tips and strainers with TeeJet brush. Replace one tip and strainer with an identical new tip and strainer on sprayer boom. Check appropriate tip selection table and determine the pressure required to deliver the nozzle output calculated from the formula in Step 3 for your new tip. Since all of the tabulations are based on spraying water, conversion factors must be used when spraying solutions that are heavier or lighter than water. Turn on your sprayer and adjust pressure. Collect and measure the volume of the spray from the new tip for one minute in the collection jar. You have now adjusted your sprayer to the proper pressure. It will properly deliver the application rate specified by the chemical manufacturer at your measured sprayer speed.

STEP NUMBER 5
Checking Your System For Problem Diagnosis: Now, check the flow rate of a few tips on each boom section. If the flow rate of any tip is 10 percent greater or less than that of the newly installed spray tip, recheck the output of that tip. If only one tip is faulty, replace with new tip and strainer and your system is ready for spraying. However, if a second tip is defective, replace all tips on the entire boom. This may sound unrealistic, but two worn tips on a boom are ample indication of tip wear problems. Replacing only a couple of worn tips invites potentially serious application problems.