Easy Way to: Sprayer Calibration


Speaker 1: Hi, my name is Bill [Ryden 00:00:04] from the Pennsylvania State University Pesticide Department. Today I’d like to show you an easy way to calibrate your boom sprayer. The tools that we’re going to use are a tape measure, a stop watch, a calibration cup, some marker flags and a large tape measure to measure our course.
The first thing we are going to do is determine our spacing on our boom sprayer, the nozzle spacing. 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 one 1/128th of an acre. You’ll see later why that is important.
Based on our chart, 20 inch spacing, we need to go 204 feet. Our next step is to measure out the course we’re going to run the sprayer to see how long it will 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. We’ll take our long tape measure. This will be the beginning of the course and I’ll measure out the 204 feet.
For today’s 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.
Couple of reminders. Make sure when you do the test run, that you are running the tractor at the same speed and the same RPMs that you would use when you are actually spraying.
I think we are ready to start. We’ll have the sprayer come and it’s also good to start the sprayer before the course. Once we get to the flag, I will start the timer and we’ll see how long it takes.
We can now see that it took 35 seconds to cover the course. Our next step is we’re 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 gallons per acre is 20 gallons per acre. Now, let me explain that a little bit because it seems complicated but if you think about it we’re trying to cover 1/128th of an acre. If we captured one ounce and multiplied that 1/128th equal one acre, you would come up with 128 fluid ounces. That is the same as one gallon. 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. We’ll take calibration cups and we have used cinder blocks to block them up so we can catch the water effectively. We’ll run this for a specified period of time and then see if each nozzle is the same. It’s very important that the nozzle output is within five percent of each other. Oh, you know what the-
Now in this case, you can see one of the nozzles was closed. It’s very important not to have clogged nozzles and that they all be uniform.
Now, we have 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 and make sure the same amount of volume has come out of each nozzle. In this case, it was 20 ounces. This one is also 20 ounces. The third one is about 19 ounces.
Speaker 2: [00:05:39] is quite low.
Speaker 1: We are a little bit light on this third nozzle. The last nozzle is 20 ounces. Again, our target is within 5 percent. For 20 ounces, on average, we want between 19 and 21 ounces to be even distribution. Also keep in mind that you want to use the same pressure, the same set up that you are going to use when we spray.
If you change your nozzles, make sure you change them all at the same time. That way you have uniformity across your boom. Even though we have 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’s very important to have the proper calibration because you want, first of all, the right amount of chemical to go out unto the plants. Too little and you may have less effective control. Too much and you may be not only wasting money, but also damaging the plants. Calibration is very important for not only results but also to minimize damage to the 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 wet-able powder will wear and tear on a nozzles more than a liquid application.
Keep in mind on your calibration, that several factors will influence the amount of chemical and 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. You go too high a pressure, you are creating more chances of drift because of the smaller water particles. Also, application height. Also, make sure you know what your effective swath width is. 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, it’s also a good time to check the height of your boom to make sure you will get even coverage across 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 at where the streaks are too heavy. You want to make sure you know where the height of your boom. Check it and then check your pattern by running across black asphalt spraying water and you can watch the drying pattern to make sure the coverage is even.
Thank you for joining us today as we learned how to calibrate a boom sprayer. As you can see, it’s a very effective but simple method to calibrate. Keep in mind that you want to make sure your calibrations are done frequent 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.