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(855) 685-3060Wilger Spray Tips | Why Size Actually Does Matter.
Posted by Robbie Bennett on
“Which spray tip series is the best?”
Since speeds, rates, and required coverage for best spray efficacy differ dramatically for each field/crop/chemical, there is no ‘best spray tip series’.
The ‘BEST’ spray tip is sized to the speed and rate requirements, while maximizing efficacy to the chemical and crop, with the least off-target drift.
Sound like a pretty open ended statement that doesn’t help you find the best spray tip?
To help the confusion, Wilger provides as much information as possible to make an informed decision, as well as tools like Tip Wizard, to make that decision as easy as possible. Truly, geared with the chemical label and agronomist’s advice, finding the best spray tip can be made a whole lot simpler.
The real reason that Wilger manufactures 5 different series of spray tips across different flow rates is to effectively give the spray applicator a sliding scale of droplet size (and flow) to best match their ideal application.
As a sample tip selection (with examples for both standard spray systems, as well as Pulse Width Modulated Sprayers), follow along with the examples to see how easy it can be. Before you know it, you’ll have a spray tip that maximizes coverage and minimizes drift, while being able to successfully spray at speeds that you need to apply at.
For a standard spray application (meaning speed + pressure spraying), the capability of a spray tip is justified by the ability to maintain peak coverage through the normal operating pressures (and speeds):
If you’d like to use Tip Wizard to follow the example, enter the below application rate/input:
Example Application: Systemic Herbicide for a Burn-Off Application.
We would be targeting (based on chemical label) a coarse spray, or around a VMD of 400µ.
Tip Wizard shows the following results: DR110-015, DR110-02, MR110-02, DR110-025, MR110-025 […]
Application Rate & Speed: To maintain the application rate (5 US GPA), traveling an average 12 MPH, the sprayer would have to be maintaining ~73PSI (fairly high), producing a medium droplet size VMD.
Droplet Size & Efficacy: With a VMD (or Dv0.5) of 261µ, about 16% of the flow is composed of drift-able fines (%<141µ), and 97% of the flow is made up of droplets that can be considered effective (%<600µ). Overall, the drift-able fines is fairly high for a systemic herbicide application, especially if there the environmental factors (e.g. crops, lakes, etc.) that should be considered.
All in all: Since we are starting out at a very high pressure with quite fine spray, we will opt to go to a larger flow rate (to improve speed/pressure range), as well as check both the DR and MR series to better match the targeted droplet size to match the application better.
Application Rate & Speed: To maintain the application rate (5 US GPA), traveling an average 12 MPH, the sprayer would have to be maintaining ~41PSI (no issues), producing a medium droplet size VMD of ~277µ.
Droplet Size & Efficacy: With a VMD (or Dv0.5) of 27µ, about 16% of the flow is composed of drift-able fines (%<141µ), and 97% of the flow is made up of droplets that can be considered effective (%<600µ). Overall, the drift-able fines is fairly high for a systemic herbicide application, especially if the environmental factors (e.g. crops, lakes, etc.) are considered.
All in all: We’ve alleviated our issue of speed/pressure with the shift to the MR110-02, but we still have equivalent drift-able fines and finer droplet size than we’d like.
Application Rate & Speed: To maintain the application rate (5 US GPA), traveling an average 12 MPH, the sprayer would have to be maintaining ~41PSI (no issues), producing a coarse droplet size VMD of ~389µ.
Droplet Size & Efficacy: With a VMD (or Dv0.5) of 389µ, about 7% of the flow is composed of drift-able fines (%<141µ), and 87% of the flow is made up of droplets that can be considered effective (%<600µ). Overall, the drift-able fines is very reasonable for a typical systemic herbicide application, and if slower speeds are used around drift sensitive areas, it will produce even less drift.
All in all: SUCCESS! We’ve maintained the ideal speed/pressure with the -02 size, and have alleviated the excessive drift with the ‘DR’ series (shifting from the MR series). Notice, the % of effective droplets went down from 97% to 87%, as we have shifted the spectrum of droplets sprayed to be coarser; however, given the application specification, it is recommended by chemical label that coarse spray is used to maximize efficacy & maintain reasonable drift. (remember: there is always a balance between drift and coverage for each application, some fields and areas will require further drift reduction to maintain reasonable drift given the environmental factors.)
EXTRA STEP: To make sure we are not better off with a larger flow rate tip, we can check the next option (or two) within Tip Wizard’s results. This would bring us to the DR110-025.
Application Rate & Speed: To maintain the application rate (5 US GPA), traveling an average 12 MPH, the sprayer would have to be maintaining ~26PSI (Too Low). Overall, the minimum recommended pressure for a DR110-025 is ~30 PSI, so this tip would not have any room to slow down. If speed is increased to maintain a higher pressure at the same flow rate, this could be reconsidered.
Droplet Size & Efficacy: With a VMD (or Dv0.5) of 451µ, about 4% of the flow is composed of drift-able fines (%<141µ), and 76% of the flow is made up of droplets that can be considered effective (%<600µ). At a VMD of 451µ, the spray is a little coarser than our ideal at 400µ.
All in all: The DR110-025 is too large a spray tip for our operating speed/pressures, and would match our targeted droplet size/coverage at higher pressures, which would mean the sprayer would have to travel faster. (~13-18MPH, or 30-60PSI) If typical speed ranges were increased to 13-18 MPH, the DR110-025 would likely become the ideal tip choice for this example.
Switching from one sized tip to another
As a last note, it should be clear that if your flow rate cannot maintain your travel speed/pressure, going to the next (or last) size of spray tip may be necessary; HOWEVER, it is not always best to keep the same series of spray tip.
Let's say, you have to travel faster, so you want to shift from an DR110-03 to a -04 size tip to give a better speed range. If you want the same spray quality (coarse spray vs. coarse spray), you are more likely to go from from a DR110-03 to an MR110-04, than to a DR110-04 (as the DR110-04 produces more of a very coarse spray quality).
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- Tags: DR110 Series, ER110 Series, MR110 Series, Spray Nozzles, Spray Tips, Sprayer Nozzles, wilger