Tag: nozzle

What Nozzle is This? (Field Sprayers)
Us this handy visual guide to identify a mystery nozzle you may find on a field sprayer. We’ve included the most common low-drift nozzles found on North American, European, and Australian sprayers. The list does not contain any conventional flat fan nozzles.
It’s in alphabetical order by manufacturer.
First, a reminder of the ISO colour coding of nozzles by nominal flow rate, and their approximate output at normal speeds and nozzle spacings.
ISO Flow rate colour coding and benchmark application volumes for US and metric units
Also recall that most nozzles have markings that identify their fan angle (usually 30, 40, 65, 80, 90, 110, 120, 130, or 150 degrees, with 80 and 110 being most common) or flow rate (in US gpm, as shown in figure above).
Albuz (manufactured in France)

Albuz AVI (also John Deere ULAC)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray quality: VC
Sizes Available: 01 – 10

Albuz AVI Twin
Type: Air-Induced Twin
Average Pressure: 60 psi
Average Spray quality: VC
Sizes Available: 01 – 06
Arag (manufactured in Italy)
Arag Compact Fan Air (CFA)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray quality: C
Sizes Available: 01 – 04
Arag Compact Fan Air Ultra (CFA-U)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray quality: C-VC
(intended for 2,4-D label compliance in Australia, available in 01 – 03 sizes only)
Arag Twin Fan Low Drift (TFLD)
Type: Pre-Orifice, suitable for PWM
Average Pressure: 60 psi
Average Spray Quality: VC – XC
Sizes Available: 02 – 05
Billericay Farm Systems (manufactured in UK)
Billericay Farm Systems Air Bubble Jet (ABJ)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: M-C
Sizes Available: 01 – 06
Billericay Farm Systems EasyJet (known as Pulzar in UK)
Type: Pre-Orifice, suitable for PWM
Average Pressure: 60 psi
Average Spray Quality: M-C
Sizes Available: 01 – 08
Greenleaf / Agrotop (manufactured in Germany)
Greenleaf AirMix (made by Agrotop)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C
Sizes Available: 01 – 06
Greenleaf SoftDrop (made by Agrotop)
Type: Pre-orifice, suitable for PWM
Average Pressure: 60 psi
Average Spray Quality: XC – UC
Sizes Available: 04 – 10
Greenleaf TurboDrop-XL (TDXL, made by Agrotop). TDXL-D appears same, but has larger exit size and produces coarser sprays for dicamba
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: TDXL, C-VC, TDXL-D, XC-UC
Sizes Available: 01 – 15 (08 for -D)
Greenleaf TADF (made by Agrotop). TADF-D appears same, but has larger exit size and produces coarser sprays for dicamba
Type: Air-Induced Asymmetric Twin
Average Pressure: 60 psi
Average Spray Quality: TADF, C-VC, TADF-D, XC-UC
Sizes Available: 01 – 15
Greenleaf Dual Fan (DF, made by Agrotop), asymmetric twin.
Similar to Hypro TwinCap, assembly can house two nozzles to produce a twin spray.
Greenleaf Low Drift Dual Fan for PWM (BPDF)
Uses AirMix nozzles with air portion removed.
Spray Quality M – XC
Sizes Available: 06 – 12
Hypro Pentair / John Deere (manufactured in UK and USA)
Hypro Guardian (Also John Deere LDX)
Type: Pre-orifice, suitable for PWM
Average Pressure: 40 psi
Average Spray Quality: M
Sizes Available: 015 – 08

Hypro GuardianAIR (GA, also John Deere Low-Drift Air, LDA)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C
Sizes Available: 015 – 05
Hypro Ultra Low-Drift (ULD, also John Deere ULD)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C – VC
Sizes Available: 015 – 08
Hypro Ultra Low-Drift Max (ULDM)
Type: Air-Induced, approved for PWM by Hypro
Average Pressure: 60 psi
Average Spray Quality: UC
Sizes Available: 04 – 08
Hypro GuardianAIR Twin (GAT, also John Deere GAT)
Type: Air-Induced Twin
Average Pressure: 60 psi
Average Spray Quality: M-C
Sizes Available: 02 – 08

Hypro 3D (also John Deere 3D)
Type: Pre-Orifice, suitable for PWM
Average Pressure: 40 psi
Average Spray Quality: M
Sizes Available: 015 – 08
Hypro TwinCap. Assembly can house two nozzles to produce a twin spray.

John Deere LDM
Type: Pre-Orifice, suitable for PWM
Average Pressure: 60 psi
Average Spray Quality: C – VC
Sizes Available: 03 – 10
John Deere LDM showing characteristic twin pre-orifice
Lechler (manufactured in Germany)

Lechler ID
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C – VC
Sizes Available: 01 – 10

Lechler ID3
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C – VC
Sizes Available: 01 – 10

Lechler IDTA
Type: Air-Induced Asymmetric Twin
Average Pressure: 60 psi
Average Spray Quality: C
Sizes Available: 02 – 08

Lechler IDK (Also Hardi MiniDrift)
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C
Sizes Available: 01 – 10

Lechler IDKT (Also Hardi MiniDrift Duo)
Type: Air-Induced Twin
Average Pressure: 60 psi
Average Spray Quality: C
Sizes Available: 015 – 06
MagnoJet (manufactured in Brazil)
Magnojet MUG
Approved by EPA for Dicamba in US
Type: Air-Induced
Average Pressure: 70 psi
Average Spray Quality: UC
Sizes Available: 015 – 05
TeeJet (manufactured in USA)
TeeJet AIXR
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: C
Sizes Available: 015 – 10
TeeJet AI
Type: Air-Induced
Average Pressure: 60 psi
Average Spray Quality: VC
Sizes Available: 015 – 15
TeeJet TurboTeeJet (TT)
Type: Pre-orifice, suitable for PWM
Average Pressure: 40 psi
Average Spray Quality: M-C
Sizes Available: 01 – 12

TeeJet TurboTwinJet (TTJ60)
Type: Pre-orifice Twin, suitable for PWM
Average Pressure: 40 psi
Average Spray Quality: M-C
Sizes Available: 02 – 10

TeeJet Air-Induced TurboTwinJet (AITTJ60)
Type: Air-Induced Twin (approved for PWM by TeeJet)
Average Pressure: 60 psi
Average Spray Quality: C-VC
Sizes Available: 02 – 15
TeeJet TurboTeeJet Induction (TTI)
Type: Air-Induced (approved for PWM by TeeJet)
Average Pressure: 60 psi
Average Spray Quality: XC-UC
Sizes Available: 015 – 15

TeeJet Twin TurboTeeJet Induction (TTI60)
Type: Air-Induced Twin (approved for PWM by TeeJet)
Average Pressure: 60 psi
Average Spray Quality: XC-UC
Sizes Available: 02 – 08
TeeJet AI3070
Type: Air-Induced Twin
Average Pressure: 60 psi
Average Spray Quality: C-VC
Sizes Available: 015 – 05
TeeJet AccuPulse TwinJet (APTJ)
Type: Pre-orifice Twin, suitable for PWM
Average Pressure: 60 psi
Average Spray Quality: XC- UC
Sizes Available: 015 – 08
Wilger ComboJet (manufactured in US and Canada)

Wilger ComboJet
Available as ER,SR, MR, DR, and UR models. Appear similar, requires inscription to differentiate
Type: Pre-orifice, suitable for PWM
Average Pressure: 50 psi
Average Spray Quality:
ER: M
SR: C
MR: VC
DR: XC
UR: UC
Sizes Available: 01 – 25
Adaptor for Combojet tips on TeeJet connector
June 8, 2020
Nozzle Selection for Boom Sprayers
Picking the correct nozzle for a spray job can be a daunting task. There is a lot of product selection, and a lot of different features. We try to break the process down into four steps.
1. Identify Your Needs
Before making any assumptions about the right nozzle for you, review your needs and objectives. Are you trying to reduce drift? Do you want better coverage? Are you moving towards more fungicide application? Do you need a wide pressure range?
It’s always a good idea to review your experience with your previous nozzle. What, if anything, would you like to change?
2. Identify Flow Rates
Most spray operations fall into one of three categories, (a) pre-seed burnoff (3 to 7 US gpa); (b) in-crop early post-emergence (7 to 10 US gpa); (c) late season application to mature canopies (10 – 20 US gpa).
To find the right nozzle size, you need to know the application volume, the travel speed, and the nozzle spacing. Most sprayers have 20” nozzle spacing, but some have 15” spacing. Use these metric or US units charts to find the right flow rate for common nozzle spacings. Various on-line calculators from Hypro, Greenleaf / Agrotop, Lechler, or Wilger or their apps, are also helpful.
If you use our chart, the top row lists water volumes. The columns contain travel speeds. Travel speed is somewhat flexible and can change throughout the field.
Let’s assume the water volume is 7 gpa, and the desired application speed is 13 mph. Move down the “7 gpa” column, searching for 13 mph. You will encounter 13 mph about 5 times: 02 nozzle @ >90 psi, 025 nozzle @ 60 psi, 03 nozzle @ 40 psi, and 035 nozzle @ 30 psi (the 035 size is only offered by some manufacturers) and the 04 nozzle at about 25 psi.
Nozzle chart, in US units, solving for 7 gpa at 13 mph. Five nozzles can produce the required flow, each at different pressures.
Note that for the smaller nozzle sizes, the spray pressure is perhaps too high, and for the larger sizes, it is too low. Select a size that allows optimum nozzle performance and travel speed flexibility. In this example, the 025 size is optimal, producing an expected pressure of about 60 psi. The column for the 025 nozzle can now be used to predict the travel speed range from 30 psi to 90 psi, about 9 to 16 mph. For the 03 nozzle, the minimum speed would be 11 mph, too fast for some.
For Pulse Width Modulation (PWM), slightly different rules apply. See here for instructions.
3. Select the Nozzle Model
For general spraying, we recommend intermediate spray qualities ranging from Medium to Very Coarse.
These intermediate spray qualities offer good coverage at reasonable water volumes and good drift control. Their spray quality can be tailored with pressure adjustments to suit specific needs. For images, see here. In alphabetical order:
Air Induced:
There is plenty of selection in this popular category, all manufacturers offering similar specs and performance.
Pulse Width Modulation:
PWM nozzle selection is improving, but some gaps in availability remain.
All nozzles should be operated near the middle of their pressure range, for air-induction this is 50 to 60 psi or higher, a bit less for non air-induced types. This allows maximum flexibility when travel speeds change or when spray quality is adjusted with pressure.
For fusarium headblight, consider a twin fan nozzle.
Keep your booms no more than 15” to 25” above the heads for best results.
Air Induced:
There is an excellent selection of twin fans from most manufacturers.
Pulse Width Modulation:
Relatively poor selection, limited flow rate ranges or spray qualities available for some models.
- Arag TFLD
- Easy Jet Twincap
- Greenleaf / Agrotop BPDF
- TeeJet Accu-Pulse
- Wilger ComboJet Y-adapter (assemble custom twin)
For finer sprays (lower water volumes), simply increase spray pressure or consider a non-air-induced design.
There has always been a large selection of finer sprays on the market, remnants from a time when drift was less important. Very few offer flow rates above 06 or 08, decreasing utility for PWM systems.
Notice that conventional flat fan tips and most pre-orifice tips are absent from these lists. These nozzles are not recommended for herbicides because they produce sprays that are too fine for acceptable environmental protection (ASABE Fine and Medium). The added coverage afforded by such sprays only has value with low water volumes, and in those instances is more than offset by their higher drift and evaporation. An exception is the use of insecticides with contact mode of action targetting small insects such as flea beetles or aphids. In thes cases, finer sprays (ASABE Fine or Medium) may be required to provide effective tragetting.
Very high flows are sometimes needed (11010 and above, usually for PWM). When this occurs, conventional flat fans have merit because the higher flow rates of any nozzle usually create coarser sprays, and even conventional tips will create sufficient coarseness to prevent drift.
For the best drift protection, consider these tips.
The advent of the dicamba-resistant trait in soybeans has spawned interest in very low drift tips that comply with the label requirements for these products. Although superior for drift control, they are not well suited for low volume or low-pressure spraying, nor for contact herbicides or grassy weeds, as spray retention and coverage may be poor. But they are very valuable when drift control is paramount and when higher volumes can be used to maintain adequate coverage.
The following advice is based on the rules at the time it was written. These may be suitable for 2,4-D application in Australia under the newest APVMA guidelines (check spray quality to be sure it is VC or coarser). Many are also suited for Dicamba in Canada (must be XC or coarser), or dicamba in the US (must be on approved lists such as this one for Xtendimax or this one for Engenia, but caution is advised, some low pressure limits make them impractical. Always check that spray quality can be achieved at pressures that offer travel speed flexibility.
Air Induced:
Excellent selection. This market has received much attention in recent years.
Pulse Width Modulation
Before making a selection, check the nozzle’s recommended pressure range and the spray qualities within that range from the manufacturer info. The target pressure for these tips may differ from your expectations.
4. Tweak and Confirm
Under field conditions, the spray pressures which produce the desired water volumes can vary from the charts. Make sure you trust your pressure gauge reading and know the pressure drop from the gauge signal to the nozzles, particularly with PWM, where the solenoid adds additional drop. Add the pressure drop to your target pressure reading. If using a rate controller, use the pressure gauge as your speedometer to ensure optimal nozzle performance. Adjust travel speed until the nozzle pressure meets with your spray quality and pattern goals. If that speed is too slow or fast…you have the wrong size nozzle and/or water volume.
Spray pressure is more important than travel speed – make your pressure gauge your speedometer.
May 30, 2020
Reading Airblast Nozzle Tables
Airblast operators should know how to read a nozzle table. They are found on dealer and manufacturer websites as well as in their catalogs. Table layout varies with brand, but they all relate a nozzle’s flow rate to operating pressure. The better tables also provide the spray angle and the median droplet size (i.e. spray quality).
Operators need this information to complete calibration calculations (aka sprayer math) and when deciding how to distribute nozzle rates, angles and spray quality along a boom relative to the target canopy.
This article focusses on hollow and full cone nozzles, which are commonly found on airblast sprayers. For more information on flat fan nozzle tables (e.g. for banded under-canopy or, vertical booms or broadcast applications from horizontal booms), refer to this article.
Reading the table
Let’s use the table below to determine a nozzle’s flow rate for a given pressure. First, find the nozzle colour in the top row. Second, find the operating pressure in the left-most column. Finally, the flow rate is indicated in the cell at the intersection between the row and column. For example, a red ATR hollow cone nozzle operated at 9 bar will emit a flow rate of 1.83 L/min.
Perhaps you want to determine which nozzle will give a specific flow rate. Find the rate in the body of the table and trace the column and row to determine which nozzle/pressure combination will achieve it. For example, if we want a flow rate of ~1.00 L/min, we can use a Yellow at 10 bar or an Orange at 5 bar. Yellow is the better choice since the Orange would have to be operated at the bottom of its pressure range (more on that later).
This Albuz nozzle table for 60 and 80 degree molded hollow cones gives flow rates in litres per minute.
Note: Do not to confuse TeeJet’s ISO-standardized TXA or TXB nozzles with TXVK or ConeJet nozzles. They may be the same colour, but their outputs are very different.
Higher flow rates or full cone patterns can be achieved using combination disc and core (or disc and whirl) nozzles. Depending on the manufacturer, the disc plate is defined by it’s diameter in 64th’s of an inch. The core or whirl plate might be described by the number of holes (e.g. 2-hole, 3-hole, etc.), or some other manufacturer-specific nomenclature (e.g. 45’s, 25’s etc.).
Using the table below, we see that a D2 disc and a DC35 core will emit 0.34 gpm at 80 psi. By continuing along the row, we see that the spray angle for this combination will be 47 degrees at that pressure.
This TeeJet nozzle table gives the flow rate for a disc (D#) and core (DC#) full cone combination nozzles in US gallons per minute.
Pressure problems
Do not choose a nozzle at the extreme of their flow or pressure range. A trailed PTO sprayer will experience pressure changes from driving on hills, or rate controllers will create pressure changes in response to changes in travel speed. In either situation, coverage will be compromised if the nozzle is pushed outside its optimal range.
Note: Use pressure to achieve small changes in flow, but for more extreme changes, switch nozzles. Remember, it takes 4x the pressure to get 2x the flow. Stated differently, it takes 1/4 the pressure to get 1/2 the flow.
You may not find a nozzle/pressure combination that emits the rate you are looking for. When your desired rate or pressure falls between the figures listed in the table, you can take the average. When nozzling an entire boom with different nozzle rates, get each position as close as you can to achieve the overall boom rate for a given pressure. It’s always a compromise – don’t stress over it.
Looking up nozzle rates during a spring calibration. The operator was running at 190 psi, but the catalogue only listed 180 psi and 200 psi. When the increment is only 20 psi, it’s reasonable to approximate the output. When the span is 50 psi increments, it is more difficult to determine the rate without testing the output (it’s not a linear relationship). This issue usually occurs at pressures above 200 psi, and that’s far too high for cane, bush, vine and high-density orchards. In these situations, consider using a lower operating pressure.
Different nozzles, same rate
Different disc core combinations, or molded nozzles at different pressures, can produce similar flow rates. However, their spray quality and spray cone angles can be very different (see last three columns in the TeeJet table above).
The angle of the spray cone can have a big impact on spray coverage. When the target is far away from the corresponding nozzle (e.g. the tops of nut trees), or the canopy is very, very dense (e.g. citrus canopies), consider tight-angled full cones under high pressure. This is inefficient and can give variable coverage, but it is sometimes the only option in extreme situations.
Oops! Two hollow cone nozzles on top and five full cone nozzles below is the exact opposite of how things should be. Note the lack of spray overlap with the full cones for the first few meters. Spray from the top two positions will likely not reach the intended target.
When the target is very close to the sprayer, full cones do not overlap and create undesirable striping or banded coverage. Creating a full, overlapping spray swath that spans the entire canopy is a function of nozzle spacing, distance-to-target, and sprayer air-settings. It can also be affected by humidity, wind speed and wind direction at the time of spraying.
Confirm your settings by parking the sprayer in the alley between crops. With the air on, spray clean water while a partner stands a safe distance behind the sprayer to look for gaps in the swath. The partner will see things the operator’s shoulder check will not reveal.
Here’s what the operator sees. But, shoulder checks may not show you what’s really happening. Have someone stand a safe distance behind the sprayer while spraying clean water to see the nozzle spray overlaps sufficiently to span the entire canopy.
Here’s what the partner standing behind the sprayer sees. Take a picture with a smartphone to show the operator.
Nozzle tables can be wrong
Sometimes nozzles do not perform per the nozzle table. We have discovered errors in published tables, worldwide. Here are the big three:
- Conversion errors. Manufacturers publish catalogs in Metric and in US Imperial, but we have found many errors in the conversions.
- Spray angle errors. When nozzles are operated at the extremes of their pressure ranges, spray angles deviate from those listed in the tables.
- Flow rate errors. When tables are not updated to reflect changes in nozzle design, or the manufacturing process, actual flow rates deviate from those listed in the tables.
Perhaps it’s not the table, but the nozzle itself. Most nozzle manufacturers accept a flow variability up to +/- 2.5% for new nozzles, but we have seen higher. It depends how they are made (machined, stamped, printed) and the material they are made of.
Validate flow rate and pattern
When errors are discovered and reported, the manufacturers can be slow to issue corrections and the errors will persist in old tables. Yes, even apps (which are often based on tables) can be wrong. So, predicted flow rates can prove unreliable. This is why it is important to double check by observing nozzle overlap and validating flow rate when you replace nozzles – even when they are brand new.
Thanks to Dr. David Manktelow (Applied Research and Technologies, Ltd., NZ) for input into this article.
March 2, 2020
The Pressure-Spray-Coverage Relationship
Pressure is integral to nozzle performance. Reducing hydraulic pressure reduces nozzle flow rate, increases median droplet size, and typically reduces spray fan angle. Increasing pressure increases nozzle flow rate, reduces median droplet size and typically increases spray fan angle.
You can watch this Exploding Sprayer Myths video to learn how pressure, boom height and nozzle spacing interact. In extreme cases, too low a pressure can collapse the fan angle enough to reduce overlap and compromise coverage, as explained in the video at the end of this article.
Using a flat fan nozzle as an example, a lower pressure increases the median droplet diameter, reduces the droplet count, reduces the nozzle flow rate and typically reduces the spray angle. Alternately, a higher pressure decreases the median droplet diameter, increases the droplet count, increases the nozzle flow rate and typically increases the spray angle.
Always plan to operate a nozzle in the middle of its recommended range so it can handle small changes in pressure during spraying (such as from a rate controller, or when changing PTO speeds on hilly terrain). Don’t operate an air induction nozzle below 2 bar (30 psi), even if it’s rated lower in the manufacturer’s nozzle table. Most AI nozzles perform best at >4 bar (60 psi).
Pressure can be used on-the-fly to make minor changes to flow rate while spraying. This is how rate-controllers work to compensate for changes in ground speed and maintain a constant overall rate per planted area.
However, pressure should not be used to make significant changes to flow rate. It takes a 4x change in pressure for a 2x change in flow rate, so it’s inefficient. Operating pressures at the upper or lower limit of a nozzle’s range can have undesirable impacts on nozzle wear, median droplet size and swath uniformity.
For a more in-depth discussion of the relationship between spray pressure and nozzle performance, and how rate controllers work, check out this article.
Note: It is far better to simply switch nozzles when a significant change in flow rate is required.
In 2015, we ran demonstrations at Ontario’s Southwest Agriculture Crop Diagnostic Days. The 20 minute sessions were designed to explain:
- The phenomenon of pressure drop,
- how to measure pressure drop,
- how to correct for pressure drop, and
- how low pressure affects coverage.
Although manufacturers of air induction nozzles often rate their performance as low as 15 psi, such a low pressure collapses the spray pattern and the resulting gaps reduce coverage. Additionally, the spray quality at such low pressures is coarser than at higher pressures, reducing the number of droplets available. This further reduces coverage potential.
This video covers the key speaking points from that demonstration.
February 22, 2020
Validate Airblast Output – Nozzle Calibration
Sprayer math is important. It ensures the operator applies the correct product rate and has enough to complete the job. But, it assumes the airblast sprayer is behaving as expected… and it often doesn’t. After confirming the airblast travel speed, use one of the following methods to assess sprayer output. There are pros and cons to each.
The area method
Operators that claim the sprayer empties in the same place every time assume everything’s alright. They are performing a variation on the area method.
Essentially, you fill the sprayer with enough water to spray one hectare (or acre) and then spray that area. If the tank empties where expected, you know your output rate (i.e. volume / area). But, there are a few problems with this method:
- Most operators don’t have an accurate test area marked off, and even when they think they know the area, measurements prove otherwise. They’re always amazed when this happens.
- The area method has poor resolution. It reveals the total output but does not assess individual nozzles. For example, partially-blocked nozzles and worn nozzles average out (we’ve seen it). Rate controllers provide whatever pressure is required to match the desired output, masking individual nozzle problems.
The dip stick method
Another method is to fill the sprayer to a known volume using a flow meter, while observing a sight level or a graduated dip stick. Then, while parked, the operator sprays for a given amount of time and determines the difference in the volume remaining in the tank.
This method can be defeated if volume is misread. It’s an easy error to make if the sprayer is parked on a grade, or the dipstick shifts in a tank with a rounded bottom. And, of course, it also masks individual nozzle problems.
Sight levels can be misleading when the sprayer is parked on a grade. They are often opaque and hard to read.
The timed output method
The preferred method is to measure the output of each nozzle individually. We performed a review on several timed output methods here. It can be messy and time consuming, but it’s accurate. Appropriate personal protective equipment is required to perform the timed output method – expect to get wet.
1. Fill the rinsed sprayer half-full with clean water and park it on a level surface.
2. With the fan(s) off, bring the sprayer up to operating pressure. Start spraying with all nozzles open (closing any will change the pressure).
3. You will need 1 meter (3 feet) of 2.5 cm (1″) diameter braided hose (have a second, longer hose to reach the top of a tower sprayer). It should be stiff enough that you can slip it over a nozzle body while holding the other end. Use it to guide flow into a collection vessel, held with your other hand. The hose not only reaches the top nozzle on towers, but it lets foam dissipate before it gets to the vessel.
4. When the flow from the hose is steady, direct it into the collection vessel for 30 seconds (a partner with a stopwatch is very helpful). It is preferable to collect for a minute because it improves the accuracy.
5. Determine and record the nozzle output per minute. Graduations on plastic collection vessels are unreliable. It’s preferable to weigh the output on a cheap, digital kitchen scale. One milliliter of clean water weighs one gram. Don’t forget to subtract the weight of the vessel (this is called taring) and double the output if you only collected for 30 seconds.
Interpreting the results
Once you have recorded all the outputs, you will have to convert the output to U.S. gallons or liters per minute, depending on units in the nozzle manufacturer’s catalogue (see common conversions below).
Replace any nozzles that are 10% (or preferably 5%) more or less than the rated output. This not only indicates a rate problem, but likely a problem with droplet size as well. If enough nozzles are worn, consider replacing all of them. Nozzles should go on as a set, and come off as a set (unless replacing a broken tip, of course). This can be an expensive proposition for large airblast sprayers, but it is part of operational costs.
Don’t assume new nozzles are accurate. We’ve found +/- 5% flow variation right off the shelf. Keep your receipts.
Testing and replacing nozzles is an important part of sprayer operation, no matter how many there are. This Air-O-Fan is nozzled for Australian almonds.
Helpful conversions
Anyone that has tried the timed output method in Canada knows the pain of our Metric-esque (Mocktric?) units. We’re an odd hybrid because our label rates are in metric, but our nozzles and many of our sprayers are US Imperial. You can find a complete collection of conversion tables here, but the most common calculations are reproduced below:
If collecting in ounces, converting to U.S. Gallons per minute:
If collecting in millilitres or grams converting to U.S. Gallons per minute:
If collecting in ounces, converting to litres per minute:
If collecting in millilitres or grams converting to litres per minute:
If collecting in ounces, converting to Imperial gallons per minute:
If collecting in millilitres or grams converting to Imperial gallons per minute:
A more sophisticated option
The timed output method is slow and requires math. You can avoid both problems by using electronic calibration vessels like the Innoquest SpotOn SC-4. We’ve tested both, and they are as accurate as weighing the output – but much faster.
They can, however, be fooled by foam. We’ve had good results using a length of braided hose to direct the flow and dissipate most of the foam. Typically, foaming means the sprayer wasn’t rinsed enough.
The SpotOn calibration vessel is easier, faster and more accurate than the classic pitcher-and-stopwatch approach to timed output tests. The SC-4 (pictured) is for airblast and SC-1 is for field sprayers.
Another approach is to hose-clamp multiple hoses over nozzle bodies and spray all at once. This is tricky and takes time. Plus, if you suffocate the nozzle’s exit orifice (creating back pressure) or block the air inlets on AI nozzles, you will get a false reading.
Be careful not to plug air inlets on air induction nozzles – you may get a false reading.
We prefer nozzle clamps over hose clamps (see the AAMS-Salvarani nozzle clamp pictured below). There are pincers designed to latch behind the nut of the nozzle body, but compatibility can sometimes be an issue (e.g. with Turbomist sprayers).
Passive flow meters (also pictured below) remove the need for a collection vessel, but they’re a better fit for field sprayers since they have to be held in place manually. They are difficult to source in North America because their accuracy is questionable, but they are fine for comparing relative flow from tip to tip.
Nozzle clamp or flow meter, avoid suffocating the nozzle exit orifice or AI nozzle air inlets.
Left: Nozzle body hose clamp. Right: Passive flow meter.
Some grower groups, or professional consultants, spring for very sophisticated and accurate units, such as AAMS-Salvarani flow measurement system pictured below.
AAMS-Salvarani flow measurement system. We used these on a pumpkin sprayer in New Hampshire, but they work with airblast too.
No matter your preferred method, take the time to confirm your sprayer output at the beginning of the season and whenever you make repairs or significant changes to your sprayer.
February 1, 2020