Selecting the Right Nozzles for Your Sprayer

Published online: Jun 05, 2018 Articles
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Source: Farmer's Business Network

Sprayer nozzles are responsible for converting the substance in your tank into droplets, regulating flow and dispersing the spray in a desirable pattern based on the crop you’re spraying and what you’re spraying the crop with at that time.

Nozzle spray pattern and shape

Nozzle spray patterns typically have two basic characteristics: the spray angle and the shape of the pattern.

Most agricultural nozzles have a spray angle from 65 to 120 degrees. While narrow spray angles produce a more direct and penetrating spray, flat or wide-angle nozzles can be mounted closer to the target (crop or weed), spaced farther apart on the boom and provide overlapping coverage if needed.

Though there are many spray nozzles types and sizes, there are only three basic spray patterns: the flat fan, the hollow cone and the full cone. Each one has specific characteristics and applications.¹

Nozzles_Nozzle-Sizes_Equipment_Em_Featured

Source: Hofman, V., & Solseng, E. (2004). Spray Equipment and Calibration, Agricultural and Biosystems Engineering North Dakota State University.

Nozzle size

Finding and selecting the right nozzle is one of the most important activities of a successful spray. It’s the combination of nozzle size along with nozzle pattern and shape that make for the most accurate sprays.

If you need to find the right nozzle size for your application, sometimes a simple chart is the easiest way to figure this out.

Nozzle size charts

Click on the links below to download a high-quality PDF of each chart².

U.S. 15” spacings

U.S. 20” spacing

U.S. 30” spacing

Metric, 50 cm spacing

Selecting Your Nozzle Size

If you’re not using a chart, you’ll need to determine a few factors to determine the right size. You’ll want to determine the nozzle flow rate at gallons per minute (gpm). To find that, start with your application rate in gallons per acre (gpa).

Next, find an efficient and safe ground speed in miles per hour (mph). Then, determine the spray width per nozzle (W).

Different types of spray methods will require different spray width (W):  

  • Band spraying: W = band width in inches
  • Broadcast applications: W = nozzle spacing (distance between two nozzles on the boom) in inches
  • Directed spraying: W = row spacing in inches (or band width) divided by the number of nozzles per row (or band)

Now, you’ll be able to determine the flow rate (gpm), with the following equation³:

gallons per minute nozzle rateFinally, you’ll be able to select a nozzle size that will give the flow rate (gpm) determined above. If a specific nozzle size is not available, try changing the travel speed and determine the new flow rate needed.

Common nozzle patterns

Here are some examples of nozzle patterns that work well for common herbicide, fungicide and insecticide applications¹.

broadcast spray nozzles

band and directed spraying nozzles

Source: Hofman, V., & Solseng, E. (2004). Spray Equipment and Calibration, Agricultural and Biosystems Engineering North Dakota State University