TeeJet Orifice & Spray Nozzle Calculator
Calculate the required flow rate (GPM) for each nozzle to achieve your target application rate (GPA).
Understanding Your Sprayer Nozzle Calculation
Achieving an effective and efficient application of pesticides, herbicides, or fertilizers is critical in modern agriculture. Applying too little can result in poor pest control or crop nutrition, while applying too much wastes money and can harm the environment. This calculator helps you determine the precise flow rate required from each spray nozzle to hit your target application rate, a crucial first step in sprayer calibration.
The Formula Explained
The calculation is based on a standard industry formula that relates your speed, nozzle spacing, and desired application rate to the necessary output of each nozzle. The formula is:
GPM = (GPA × MPH × W) / 5940
- GPM (Gallons Per Minute): This is the result we are solving for. It's the flow rate of liquid that must pass through a single nozzle every minute to achieve the target application rate.
- GPA (Gallons Per Acre): This is your target application rate. It's the total volume of liquid you want to apply over an entire acre. This value is often found on the product label.
- MPH (Miles Per Hour): This is the speed at which you will be driving the sprayer through the field. Consistency in speed is key for an even application.
- W (Nozzle Spacing in Inches): This is the distance between two adjacent nozzles on your spray boom. Common spacings are 15, 20, or 30 inches.
- 5940: This is a conversion constant. It's used to reconcile the different units in the equation (gallons, acres, miles, hours, minutes, and inches) into a single, correct output.
How to Use the Calculator: A Practical Example
Let's walk through a common scenario. You need to apply a herbicide at a rate recommended on the label, which is 20 Gallons Per Acre (GPA). You plan to operate your sprayer at a consistent speed of 6 Miles Per Hour (MPH), and the nozzles on your boom are spaced 20 inches apart.
- Enter 20 into the "Application Rate (GPA)" field.
- Enter 6 into the "Sprayer Speed (MPH)" field.
- Enter 20 into the "Nozzle Spacing (inches)" field.
- Click the "Calculate Flow Rate" button.
The calculation would be: (20 GPA × 6 MPH × 20 inches) / 5940 = 2400 / 5940 = 0.404 GPM.
The calculator will show you a result of 0.404 GPM per nozzle. With this information, you can now consult a TeeJet (or other manufacturer) nozzle catalog. You would look for a nozzle that produces a flow rate of 0.40 GPM at a practical operating pressure (e.g., 30-60 PSI). For example, a TeeJet XR11004VS nozzle delivers 0.40 GPM at 40 PSI, making it a perfect choice for this application.
Frequently Asked Questions (FAQ)
Why is accurate GPM so important?
An accurate GPM ensures you are applying the product at the rate specified by the manufacturer. This leads to optimal efficacy, prevents crop damage from over-application, minimizes environmental impact, and ensures you are not wasting expensive chemicals.
What happens if I drive faster or slower than the speed I used in the calculation?
If you drive faster, your application rate (GPA) will decrease because the nozzles have less time to spray any given area. If you drive slower, your application rate will increase. This is why maintaining a consistent speed is crucial. If you need to change speeds, you should recalculate your required GPM or use a rate controller that automatically adjusts pressure/flow.
How do I choose the right nozzle after getting the GPM?
Once you have the required GPM, you must consult a nozzle manufacturer's catalog (like TeeJet, Hypro, etc.). These charts list nozzles by type and size (often color-coded) and show their flow rate (GPM) at various pressures (PSI). Find a nozzle that provides your target GPM within its recommended pressure range. You should also consider the required droplet size (VMD) for the product you are applying to minimize drift.