Calibration How Tos: Easy Way to Sprayer Calibration
This method uses a linear calibration course equal to 1/128th of an acre. The output from the sprayer is collected for the time required to travel 1/128th of an acre. Because a gallon is 128 ounces and the course is 1/128th of an acre, the output collected in ounces is equal to the gallons applied per acre. The Travel Distance Table shows how many linear feet the sprayer must travel to give the equivalent of 1/128th of an acre at various nozzle spacings and band or row widths. When the sprayer travels this distance, each nozzle will have sprayed 1/128th of an acre.
Hi, my name is Bill Riden from the Pennsylvania State University Pesticide Education Program.
Today I'll like to show you an easy way to calibrate your boom sprayer.
The tools that we are going to use are a tape measure, a stopwatch, a calibration cup (measuring cup in fluid ounces), some marker flags and a large tape measure to measure our course.
First thing we are going to do is: determine our spacing on our boom sprayer.
The nozzle spacing so we will take our tape measure and simply measure the distance between the nozzles.
In this case they are 20 inches apart.
We then refer to our chart to see how much distance we need to travel to cover 1/128th of an acre and you will see later why that is important.
Based on our chart.
20 inches in spacing we need to go 204 feet.
So our next step is to measure out the course we are going to run the sprayer to see how long it would take to run that distance.
Based on our nozzle spacing of 20 inches, we know we now need to measure out a course 204 feet long so we will take our long tape measure.
This would be the beginning of the course and I will measure out the 204 feet.
For todays demonstration let me remind you that we are using plain water and we are not using any pesticides.
Plus we don't have any Personal Protective Equipment on, when you do your calibration you should also be using plain water, there is no need to put the chemical in at this point.
A couple of reminders, make sure that when you do the test run that you are running the tractor at the same speed and the same RPMs that you would actually use when you are out there spraying.
Ok, I think we are ready to start.
We'll have the sprayer come and it is also good to start the sprayer before the course.
Once we get to the flag, I will start the timer and we will see how long it takes.
We can now see that it took 35 seconds to cover the course so our next step is: we are going to bring the sprayer back and see how much volume comes out of each nozzle in a period of 35 seconds.
We have now captured the volume that it took in 35 seconds.
We look at our calibration cup and we see that we have captured 20 ounces.
Therefore, the rate per gallon of gallons per acre is 20 gallons per acre.
And let me explain that a little bit because it seems complicated but if you think about it.
We are trying to cover 1/128th of an acre so if we capture one ounce and multiply that by 1/128th of an acre you will come up with 128th fluid ounces, that is the same as one gallon so that is the simplicity of this method is it automatically converts the ounces that you catch to gallons per acre.
In this case, 20 ounces means that the nozzles are putting out 20 gallons per acre.
Our next step is to see if each nozzle is putting out the same amount of water.
So we will take calibration cups and we use cinder blocks to block them up so we can catch the water effectively and we'll run this for a specified period of time and then see if each nozzle is the same.
It is very important that the nozzle output is within five percent of each other.
Now in this case you can see that one of the nozzles was clogged.
It is very important not to have clogged nozzles and that they are all uniform.
Now, we fixed the clogged nozzle and we had all four nozzles working properly, we've captured the water coming out for the same amount of time and now our next step is to check to make sure that the same volume is coming out of each nozzle.
In this case it was 20 ounces.
This one is also 20 ounces, the third one is about 19 ounces so we are a little bit light on this third nozzle and the last nozzle is 20 ounces.
Again our target is within 5 percent so for 20 ounces on the average we want 19 and 21 ounces to have even distribution.
Also keep in mind that you want to use the same pressure, the same setup that you were going to use when we spray.
Also, if you change your nozzles make sure you change them all at the same time, that way you have uniformity across your boom.
Now even though we've only done four nozzles in reality you would want to check all your nozzles across the entire boom to make sure the output is the same.
Why should you calibrate?
It is very important to have the proper calibration because you want: first of all, the right amount of chemical to go out into the plants.
Too little and you may have less effective control.
Too much and you may not only be wasting money but also damaging the plants.
So calibration is very important for: not only results but also to minimize damage to plants and also to the environment.
Also, how often should you calibrate? is once a year plenty or should you be going more often?
really you should be calibrating several times a year and this quick and easy method should not take very long for you to calibrate on a regular basis.
Also, the type of material that you are using will impact the amount of wear on your nozzles.
A wettable powder will wear and tear on the nozzles more than a liquid application.
Keep in mind on your calibration that several factors will influence the amount of chemical and the amount of water that is being put out per acre.
Your speed of travel has a major influence, also the shape and size of the nozzles that you are using, also the operating pressure.
Keep in mind that you want optimum pressure without creating drift.
If you go high a pressure, you are creating more chances for drift because of the smaller water particles.
Also, application height.
Also, make sure that you know what your effective swath width is and also the active ingredient needs to be put down on an even application.
These are all factors that influence your calibration and your actual use of your boom sprayer.
When you are calibrating your sprayer is also a good time to check the height of your boom to make sure you are getting even coverage accross the entire boom.
If you are too low, you may be having gaps or misses in your spray coverage.
Too high, you will have overlaps where the streaks are too heavy so you want to make sure that you know the height of your boom, check it and then check your pattern by running across black asphalt spaying water and you can watch the drying pattern to make sure the coverage is even.
Thank you for joining us today as we learn how to calibrate the boom sprayer.
As you can see, it is a very effective but simple method to calibrate.
Keep in mind that you want to make sure your calibration are done frequently enough that you have effective control without wasting money by either using too little or too much pesticide.
Remember, if you have any questions feel free to contact us at the Pesticide Education Program at Penn State University or contact your local Extension Agent for more information.
Thank you again and hope to see you soon!
Frequently Asked Questions