Tag: cleanout

  • Recirculating Boom Options

    Recirculating Boom Options

    If you read this site, you know we’re fans of recirculating booms. We love them for three reasons:

    1. They save money and waste by recovering spray back to the tank during priming and rinsing
    2. They make boom cleaning easier by eliminating boom-ends
    3. Most require individual nozzle shutoff, which makes for better sectional control

    If you’re new to the concept of recirculating booms, read more here.

    Until recently, these booms were only available on sprayers imported from outside North America (Horsch, Amazone, Agrifac to mention three), or via France’s Pommier booms that have been available as retrofits for many years. In 2018, Agco introduced their Liquid Logic system on the Rogator line, becoming the first North American manufacturer to offer a recirculating boom at the factory. Pattison Liquid also offers Recirculating booms as standard equipment on their Connect Sniper pull-type sprayer.

    In the meantime, three boom retrofit kits and one sectional conversion kit have become available.

    Arag Australia‘s BRS (Boom Recirculation System)

    The first was developed by Arag Australia, and is available there via Nozzles Online, and in Canada through Nozzle Ninja. Designed for John Deere R-Series and Case Patriot sprayers, the kit uses the existing line that feeds liquid to the outermost section and simply extend that line to the end where it enters the boom via two installed elbows. The liquid returns to the centre via the installed boom sections which are connected together by removing the boom end cap (or “aspirator” for John Deere) and replacing the gap with a section of hose. Back at the centre rack, the liquid from both booms meet in the middle. At this point, a three-way valve gives the choice to return the spray to the tank, or to receive pressure from the pump. There is also a manual valve that allows the return to be dumped for safe disposal.

    Arag Boom Recirculation System (Spray Mode)
    Arag Boom Recirculation System (Recirculation Mode)

    The system does not tie into the sprayer’s electronics. instead, it adds a switch in the cab that the operator uses to switch from spray mode to recirculation mode. The switch is not activated at the end of each swath, but instead to prime or flush the boom.

    A switch is added so the user chooses recirculation or spray mode. The boom would recirculate to prime or flush, and remain in spray mode during the spray operation.

    Raven

    Raven offers a recirculation kit for 3000, 4000, and 5000 series Case Patriot sprayers with Aim Command HD and an ISOBUS terminal. The approach is slightly different, as they retain the pressure feed through individual sections but also tie the sections together so the spray is returned to the tank. By including a shutoff valve between each section, the system retains the option to use conventional sectional control for high flow situations, or to isolate a section should a leak occur. The system can be configured and controlled from the sprayer monitor, either a Viper 4+, CR7, or CR12.

    Raven Boom Recircualtion System schematic (from Raven manual). Note the retention of section valves and the addition of manual valves between sections.

    John Deere

    On March 2, 2021, John Deere announced a 2022 factory option called Pressure Recirculation and Product Reclaim. The system keeps several existing sections and adds two steel lines the flull length of each boom wing. One is for supply, the other return. As these lines approach a section, the supply is fed to one end of the section and the return is connected to the other end. On a 120′ boom, there are five recirculating sections, two on each wing and the centre.

    This approach adds one more line than the other designs, and this line will hold materials that ultimately need to be cleaned, flushed, and possibly dumped or sprayed out for cleanout. A possible reason for the extra line is the ability to deliver 220 gpm to the boom, an advertised feature of John Deere high flow booms that may come in handy for topdressing liquid fertilizer. These levels of volume are not needed for pesticides.

    John Deere Boom Recirculation and Reclaim. Top two lines are supply and return and extend the length of each boom wing. These connect to the existing sections on each wing, creating several smaller recirculating sections.

    Latitude Ag

    This Wisconsin company has developed an innovative product that converts any existing plumbed section that contains boom ends into a recirculating section. It does this by incorporating a boom recirculation valve” (the “Merlin IC System“) into the original section feed line. Boom end caps are removed and replaced with sweeps and hoses that return flow to these boom valves. The flow from the boom ends is incorporated back into the sectional feed thanks to a venturi design in the recirculation valve.

    A prototype of the Merlin IC System valve made by Latitude Ag

    Advantages of this design include simplicity. No moving parts are required, the valve simply recirculates the flow from the boom ends automatically whenever that section operates. Existing sectional control, whether it’s by plumbed section or individual nozzle bodies, is unaffected. Flushing the boom with water is done with normal spraying. It takes some extra time to incorporate and dilute the contents of the boom end return lines but results in a clean boom and no section end residue. We’ve seen the results of testing and agree that it works.

    This product does not allow boom priming without spraying. However, a key advantage is that it can be used with direct injection since no product is returned to the tank. Latitude Ag says it will provide the necessary flow sensor and software to make this possible. As of 2025, this system may no longer be commercially available.

    Precision Planting ReClaim

    ReClaim is capable of operating on a sprayer with or without individual nozzle shutoff. For conventional nozzle bodies containing the original spring-loaded diaphragm check valves, the concept is to drop the liquid pressure below the cracking point of the check valves so flow continues through the sections and back to the tank without engaging the nozzles.

    Recirculation fittings are added to the end of each boom section. These feed into 3/4″ lines are installed on section ends, which in turn feed increasing diameter collector lines that eventually return all flow to the tank. Flow reaches the sections as before. When recirculation is turned on, flow exits the boom section through the new fittings and returns through 3/4″ lines to the centre of each section, where it enters 1” lines that take the flow to the center of each boom wing. There the flow in the 1” lines is combined moves to the center of the sprayer on 1.5” lines where it meets the flow from the other wing.  From there, the flow returns to the tank through an electronic ball valve and 2” line. This system ensures no back-pressure and balanced flow from each section.

    For some sprayer rate control systems such as John Deere, the pump won’t operate below about 20 psi despite operator settings. This means the priming or flushing procedure would trigger nozzles to spray if the bodies were fitted with spring-loaded diaphragm check valves. A pressure reduction kit (a second restrictor valve) is required to reduce the pressure sufficiently for ReClaim to work in these instances. More here.

    ReClaim operates independently of any electronic control systems, relying on a toggle switch to initiate recirculation. When flow back to the tank is detected, a light indicates that recirculation is working, and the operator waits approximately 60 sections for a 120’ boom to circulate all volume back to the tank. Download the operator’s guide, here.

    This system requires a lot of additional lines. A 120’ boom would require 120’ of additional 1” line and 60’ of 1.5” line. The manufacturer states that ReClaim adds about 14 gallons of volume that would need to be displaced back to the tank, adding to the standing volume. This volume can be circulated using solution from the main solution tank, or displaced back to the tank using flow from an existing clean water tank, or displaced using compressed air via an optional pneumatic port. It is not clear how spray mix in the ReClaim system can be removed from lines without returning it to the tank and draining it from there. Users should consider the additional surface area and volume that will have to be addressed during cleanout.

    Do It Yourself

    If none of the available options work for your sprayer, consider building your own system. Sprayer plumbing parts are available from the major manufacturers Banjo, Hypro, TeeJet, and Wilger. Wilger, in particular, has developed a nice suite of parts well suited to recirculating booms, including flanged sweeps and thin gauge steel booms, punched for nozzle bodies or unpunched to move product. See their support for DIY projects on this dedicated page: Wilger Retrofit.

    Take Home

    All these recirculation options improve the status quo of plumbed boom sections with boom ends. They should be considered essential equipment on sprayers.

  • Horsch Leeb sprayer gives people what they want with 6.300 VL model

    Horsch Leeb sprayer gives people what they want with 6.300 VL model

    Theodor Leeb started building self-propelled sprayers in Bavaria, Germany in 2001 and formed a partnership with Horsch LLC in 2011 (Horsch has been selling tillage and seeding equipment in North America since 2001 and has 17 dealers in the prairie provinces). The resulting company, Horsch Leeb Application Systems GmbH, is headquartered in Landau a.d. Isar, about 120 km NE of Munich. There they build pull-type and self-propelled sprayers, employ 350 staff, and had sales of approximately $80 M USD in 2019.

    This is no Johnny come lately to the sprayer scene.

    Their current flagship sprayer in North America is the Horsch Leeb 6.300 VL. I spent a day with Mike Wasylyniuk, Product Marketing Manager for Horsch, in Crossfield, Alberta to look it over.

    The Numbers

    The sprayer chassis holds a 1700 US gallon stainless steel tank and two 100 gallon clean water tanks for a total liquid capacity of 1900 gallons. A stainless steel Pentair Hypro centrifugal pump provides the flow to the boom, and a second pump is dedicated to the clean water tanks. The sprayer is powered by a familiar FPT 6.7 L producing 310 hp. The boom is 120’ wide in 5 articulated sections with 10’ nozzle spacing fitted with Raven Hawkeye Pulse Width Modulation (PWM). Top spraying speed is 20 mph, top transport is 30 mph. Horsch claims a dry weight of 32,000 lbs when fitted with Goodyear LSW 900 50R46.

    The Horsch Leeb 6.300 VL near Crossfield, AB October 2021.

    A central tubular frame creates room for four-wheel steer that has an interior turning radius of 3 m. Wheels are suspended via hydropneumatics linked to the frame with double wishbones. Track width adjusts from 120″ to 160″, independently, allowing different track widths front and rear without pinning an axle in place. Standing beside the front wheel, one has with easy access to fuel and oil filters, the radiator is on top of the machine facing up with an air-chuck outlet for cleaning.

    Four wheel steer improves maneuverability but more importantly, reduces front wheel plowing and allows use of common wheel track in headland turns.

    Plumbing

    Any loyal reader of Sprayers101 knows that we believe the biggest room for improvement in spraying is in the plumbing. Horsch Leeb seems aware of this. First, it does away with sight tubes on the tank and relies on a more accurate digital float that reads down to an empty tank. Tank slope position is considered using a gyro mounted at the rear of the sprayer. The tank can be filled with the solution pump or from the tender truck using 3” side or front fill locations. It has auto shutoff when a target amount is reached. As is common, the majority of valves are motor operated to allow automation.

    Fill station on right side of sprayer contains a 3″ fill connection as well as a 2″ drain

    The recirculating boom plumbing is standard North American 1” OD stainless steel to suit any off the shelf nozzle body clamp. It pressurizes from both ends when spraying and returns to tank from the outside of the boom when nozzles shut off or when priming or flushing. The recirculation can run during transport, allowing boom priming en-route to the field, or continuous flushing with a cleaning solution in the main tank on the way home.

    Recirculating boom feed and return lines are standard 1″ OD stainless steel.

    The second pump, an Italian Annovi Reverberi 185 BP diaphragm, powers the continuous cleaning function. It draws from the clean water tank and can push this water to the boom for overnight storage when the tank has solution left, or to the tank’s wash-down nozzles for a continuous clean at the end of a job. In continuous clean mode, the solution pump continues to supply the boom while the cleaning water washes the walls and dilutes the remainder. The tank and boom can be washed with a minimum of liquid, and the process is automated using cab or side monitor controls.

    Dedicated to the clean water tanks, this diaphragm pump can push water to the boom, to the wash-down
    Stainless tank with baffle

    The system even has a winterizing button that controls all the necessary valves to distribute antifreeze from the clean water tanks throughout the plumbing system in minutes. Remaining antifreeze in the tank can be returned to the drum at the fill station with a convenient camlock drain.

    Readout of tank levels and pump pressure via the external monitor. Priming, cleaning and winterizing routines are available.

    Some may gloss over plumbing paragraphs in haste, but let’s not underestimate the magnitude of these features. We are talking about a plumbing system that can prime the boom without spraying, spray the field, then spray out any remainder while rinsing the tank, air purge the boom, then rinse the boom without leaving the cab or wasting material unnecessarily. Even the system strainers have flush capability that returns any residue to a removable fine mesh filter before the liquid dumps back to the tank. Such a design saves time and money and pays in acres per hour.

    Boom

    The 120’ boom is well built and has channels for wiring harnesses that are neatly zip-tied in place. An aluminum shield covers the nozzle bodies at the front to protect them from any ground contact.  Access is relatively convenient through ports on the other side. The fitted triple nozzle bodies should be enough to suit most needs. The swing-away has a sturdy steel tube on the leading edge to absorb and deflect any sudden impact. There is no exposed plastic. The recirculating boom plumbing is stainless steel throughout except at hinges, where the rubber hose loop is protected from chafing by an additional sleeve.

    The sturdy boom is shielded where the nozzles are mounted to protect them from impact. Note the vertical hinge that permits improved contour-following.
    The break-away section has additional protection via a stainless steel pipe that absorbs and deflects impact.
    Access to the 10″ spaced nozzles and PWM solenoids is via the rear of the boom.

    The Leeb philosophy is to design sprayers that control drift at the source without reliance on extremely coarse sprays that can hamper efficiency. They’ve chosen boom height as the key variable and built the boom to make this possible. First, they needed to design a system that can reliably hold the boom low and level.

    Low, uniform boom height for drift reduction is the stated goal of the Horsch Leeb sprayer

    To that end, three pivot points are used to provide independence of the tractor unit and the boom. The first is at the centre rack from which the boom hangs but can pivot thanks to the same gyro that helps read the tank level. A sudden tractor movement due to ruts, for example, can then be compensated. The wings are the second pivot point (as it is for all sprayers), and a third point is halfway out the wings, where a hinge allows for up or down adjustments to better suit the land contour.

    A giro, visible just above the backup camera, monitors the tractor aspect relative to the boom.
    The vertical boom pivot can help prevent unnecessarily high boom ends or ground strikes.

    The height sensors have a modest look ahead slant, and the company claims that 8” boom height at 10 mph is possible. We certainly tried that in the field, and after multiple runs up and down a local field with modest knolls we did not strike ground, although the boom ends did rise significantly on occasion. The claim of such low booms will be a point of considerable testing and debate.

    Eight sensors provide boom height feedback.

    To take advantage of the low heights, narrower 10″ nozzle spacings are needed. The boom therefore has 144 nozzles instead of the usual 72, each half the flow rate. This is new territory for PWM, where the smaller tips are not as widely available. For example, a traditional 5 gpa tip at 20” and 12 mph is 03 in size, with 10” spacing this is now 015.  Smaller sizes require more attention to filtering, and they have inherently greater drift potential. This would only be a problem at the lower application rates.

    Because PWM allows for individual nozzle control, the operator can select 20” spacing, based on either of the 10” positions. This means one can spray with 20” spacing and then switch to a different nozzle simply by selecting the alternate.

    The lower boom height can offer unique advantages. The first of these is drift control. Droplets emerge from the tip at about 70 km/h, and this initial speed prevents even the small ones from drifting. The higher the boom, the more they slow down before targetting, creating drift potential. Wind speeds also tend to be lower nearer to the ground.

    Second, the beneficial effects of twin fans or angled single tips are greater with low booms. Readers will know that one of the fundamental prerequisites for successful angled sprays in Fusarium head blight (FHB), for example, are low booms. We may be in for some positive outcomes.

    The User Experience

    The Class cab has the usual creature comforts with a buddy seat, four cup holders, bluetooth radio and a phone mount. It can be fitted with any ISOBUS monitor, the one we had was equipped with the Raven Viper 4. The climb up the ladder is not as stair-like as the North American sprayers, but the treads are large and there are plenty of handholds so you can climb one-handed and bring your lunch or toddler along for the day.

    There is one native Horsch monitor that controls the chassis, wheel spacing, engine specs, speed, etc. It’s controlled using a rotary button selector like the one in many cars, a wheel that highlights items by turning, then selects them with a push. The second, an ISOBUS monitor, handles the rate control and thus creates easy compatibility with a variety of aftermarket monitors.

    The joystick is backlit and buttons can be customized. Like the Fendt stick, a push forward sets the speed and it can return to the neutral position without changing that speed. A pull back is required to slow down.  It takes a bit of getting used to. Motion can also be foot operated with a speed pedal and foot brake.  Cruise control has two preset speeds, and boom height can be raised to preset values when the master switch is shut off to facilitate a headland turn. The top two thumb buttons are Master on/off and autosteer resume.

    There is no throttle control. The sprayer decides how much throttle is needed to maintain speed, saving noise and fuel when it can. Throttling up was noticeable as we climbed hills during our test drive, returning to lower rpm as we descended while maintaining our cruise control speed.

    Some touches

    • a hand wash station at the ladder to prevent contaminating the hand-holds or cab
    • a camera focused on the centre rack nozzles that are invisible from the cab
    • cameras showing front wheel position
    • mud guards behind rear wheels to protect boom
    • Rain cover over electronics mounted on centre rack
    • A clean underbelly with good clearance and tow hooks front and back
    • Inductive (wireless) phone charging mount

    Overall Impression

    It’s clear that Horsch Leeb wants to succeed in North America. I’ve hardly ever seen a company so bent on delivering what the market wants (for familiarity and compatibility) while delivering what it knows they need (like plumbing and drift control). Spending the day with Mike I learned how quickly the engineers and fabricators implemented his suggestions at the factory. That is perhaps the most promising aspect of all, a company that listens to its customers and continually evolves its product as a result.

  • End of Spraying Season Checklist

    End of Spraying Season Checklist

    It’s finally that time of year to put away the most-used piece of farm equipment, the sprayer. Winterizing is a necessary step, but also an opportunity to do a few extra things.

    Winterizing

    1. Before you do anything, walk around the sprayer and note any telltale signs of liquid leaks. Once washed, the helpful dusty surfaces are gone and slow, chronic leaks may go unnoticed.
    2. Now it’s OK to clean and rinse the sprayer tank and wash the sprayer exterior.
    3. Drain any remaining water from the product and the rinse tanks. These remainders will cause unwanted dilution of the antifreeze. After you drain filter housings, inspect and clean filters.
    4. Choose your anti-freeze. Automotive anti-freeze works, but’s it’s toxic and you can’t spray or drain it on the ground. Liquid fertilizer is sometimes used, but it’s corrosive, crystallizes when cold, and is not recommended. The best product is RV Antifreeze. It’s friendly to rubber and plastic, considered non-toxic, and can protect down to the coldest temperatures. Some dealers carry specific sprayer antifreeze. Don’t use fertilizer (e.g. 28) to winterize – especially with PWM systems.
    5. Add between 25 and 50 gallons of antifreeze to the product tank, or if you have one, to the clean water tank. Most larger sprayers need at least 25 gallons just to prime the plumbing.
    6. If you have a rinse tank, start a normal rinse procedure. Run the product pump, drawing from the rinse tank and pushing the material through the wash down nozzles into the product tank. Once the rinse introduction is complete, an automatic rinse procedure may subsequently open various lines leading to the tank as it swirls the rinse solution through the tank. Familiarize yourself with the specifics of that process.
    7. If rinsing valves are manually controlled, once the antifreeze is in the product tank, run the pump, drawing from the tank and circulating back to the tank via agitation. If you have any other bypass lines, such as sparge, make sure the valve is opened. Run for two to three minutes.
    8. If you have an on-sprayer eductor system, run the antifreeze past it and activate the eductor wash process.
    9. Now, it’s time to push the antifreeze to the boom. Treat this like a boom cleaning, making sure the antifreeze gets to each nozzle body. If you have high- and low-flow options, open them to ensure the bypass gets the antifreeze.
    10. Activate one boom section at a time and ensure all nozzles have received the antifreeze. Open nozzle end caps and allow the antifreeze the push out the water that is trapped there. It helps if you first purge the system with compressed air, then you don’t need to wait for the clear water to gradually change colour as the antifreeze arrives.
    11. For extra points, rotate the nozzles through each position. As with cleaning or servicing, a remote-control boom section controller is invaluable here.
    12. Remember to activate the fence row nozzles if you have any. These usually have their own dedicated feed line coming off the outer boom section.
    13. If you filled your anti-freeze directly into the rinse tank, briefly open the rinse and product tank fill valves to allow anti-freeze to push out any water. Don’t forget the front fill line.
    14. It’s OK to leave any leftover antifreeze in the tank. Next spring, collect it for re-use in the fall. You’ll still need more but this saves you some.
    15. Don’t forget to also winterize your spray tender and any other transfer pumps.
    16. It’s always a good idea to grease fittings after equipment is washed, to displace any water that got in, and to lubricate other moving parts that should be protected from corrosion.

    Inspecting and Reflecting

    You’re going to be looking closely at a clean sprayer, and this is a good time to spend a few extra moments to ponder the big picture. But first:

    1. Inspect the full length of all hoses. Look for kinks, rubbing, small leaks, loose or defective clamps, valves, nozzle bodies. Tighten what’s loose, replace what’s worn.
    2. Check cabin air filter service interval. Most new sprayers have activated carbon filtration that requires regular replacement. Activated carbon starts deteriorating with any air contact, so if you get a new one, leave it wrapped in its plastic until you need it.
    3. Download or record sprayer performance data. How many engine and spraying hours? How many acres? How much water? A typical sprayer may calculate your acres per hour, but uses spraying hours only which paints a rosy picture. Do the calculation using gross engine hours to get a better idea of time lost to idling, transporting. Compare to previous year, perhaps set some goals.
    4. Check with the dealer to make sure you’ve got the latest controller software version. Many systems get an upgrade during the off-season, so check back in the spring.
    5. Remove the flow meter from the system and ensure it runs free. Do not use compressed air to run the impeller, this can ruin it. Simply blow on it and ensure it runs freely. This is an important part of the sprayer, so some people store it separately over winter. Did it provide accurate information?
    6. Top up the fuel tank to prevent condensation.
    7. Don’t forget to mouse-and bird-proof.

    Now:

    1. Think back on the season. What went well? What went poorly? What repairs were needed? Which ones did you put off? Are you happy with your procedures for filling and cleaning? Did you hear or read about improvements that seem interesting? Reminisce by reading the notes you wrote on your cab windows.
    2. Make a list of the improvements that would address the main issues you came up with during your reflection. Is it time for a better filling setup? Do you need a whole tender system, or just an upgraded fill pump or a better inductor? Is it time to add a continuous rinse system?

    Replacements and Improvements

    1. Some sprayer components simply wear out and need regular replacement. A rule of thumb for sprayer nozzles is about 30,000 acres for an average sprayer speed and boom width. But before you buy, make sure you know what you need. Were you happy with the spray performance? Did you have more drift than you wanted, or poor coverage? As our cropping systems change, we may need different nozzles to suit the purpose. Now is the time to think about that very coarse low-drift nozzle that would have allowed you to get the spray on before the rain that delayed you for 3 days. Or the higher volume spray that would have done a better job with desiccating the tall canola crop, speeding up harvest. Or the finer spray that works better with the contact products you need to manage resistance.
    2. Pumps can also wear. An impeller replacement can revitalize a centrifugal pump and give back more pressure and flow. Or a new pump with run-dry seals can avoid downtime from a pump failure in the middle of a good stretch of weather.
    3. We still see plastic boom lines on some sprayers. Replacing them with stainless steel eliminates warped lines and makes spray patterns more accurate, improves cleanout, and adds sparkle.
    4. A wider boom can dramatically increase productivity. After-market booms are available in 135′ and larger widths. Aluminum construction keeps them light, and corrosion-free.
    5. Pulse Width Modulation (PWM) can be retrofitted on any sprayer. This will offer improved sectional control resolution, turn compensation, and better droplet size control.
    6. Spot spraying can be added to any sprayer, and this will save 50 to 75% of pre-seed product use. In the case of WEEDit Quadro, these systems now come with stand-alone PWM that will work for general broadcast spraying in crop, with all the features mentioned above. Trimble offers the WeedSeeker II, it’s also feature rich but doesn’t offer PWM.
    7. Become part of a mesonet. Most crop imaging services and some agronomic service providers offer weather stations, and obtaining one can make you part of a large, high resolution network. Local monitoring of temperature, rainfall, and wind conditions improves spray decisions as well, and may even give you the ability to identify temperature inversions.

    The sprayer will often be the first piece of equipment used in the spring. Preparing it for its next job starts now.

  • The Most Important Developments in Spraying

    The Most Important Developments in Spraying

    Some things have improved a lot. Others have lost ground.

    Some years ago, a few of us weed scientists sat around a table and debated the most important developments in agriculture in our lifetimes. It was a great discussion, and we arrived at a few that included direct seeding (for its soil and moisture conservation as well as improved fertilizer placement), GMO crops (for slowing Group 1 and 2 herbicide resistance), and the abandonment of summer fallow in much of western Canada. Let’s apply this exercise to spray application to see what we come up with.

    What follows are my version of the most important spray technology developments in the last 50 years.

    1. Low-drift Nozzles. Spray drift is the biggest time management challenge and also perhaps the biggest public relations battle. These nozzles reduce drift, making more time available for spraying and doing it safely and effectively.
    2. Rate Controllers. I both love and hate these things. On the one hand, a rate controller matches sprayer output to travel speed. On the other, it has allowed spray pressures to go wherever they need, even beyond the optimum, to match travel speed, and that can lead to nozzle performance issues.
    3. Pulse Width Modulation. The pulsing nozzle fixes the rate controller problem mentioned above. Now, travel speed and pressure are independent. Plus, of course, a whole host of other flow management options, such as turn compensation and rate boosting, become available.
    4. Optical Spot Spraying. Once you see these in action, you can’t go back. Why would you spray a whole field when weeds only cover 10% of it? Products like WEEDit and WeedSeeker are proven green-on-brown performers after years of field success around the world.
    5. GPS Guidance. Some of us grew up with foam or disk markers, others learned to aim for brave family members perched on headlands. Achieving accuracy was stressful, overlap was insurance, and misses were common. The importance of this development is probably under-estimated.
    6. Sectional Control. The ability to adjust the spray width in individual nozzle steps makes sense, and this can come with or without PWM. In fact, that alone can save 5% of an annual chemical bill compared to conventional sections measuring about 10 to 15 feet. And it’s definitely better than the left boom or right boom options from the 70 and 80s.
    7. Operator Comfort and Safety. The refuge of the cab makes longer days bearable for all equipment, but for spraying it dramatically improves safety as well.

    But we’re far from done. We still need work in these areas.

    1. Cleaning and Waste Management. I can’t imagine another industry where managing potentially hazardous leftover materials are left to the discretion and circumstances of the applicator. Let’s make it easy and fast to thoroughly clean the sprayer and safely dispose of leftovers. Step 1 is smarter and simpler plumbing.
    2. Boom Stability. Booms are too high, resulting in more drift and poorer nozzle performance, and adding to operator stress. The sole reason is unsatisfactory levelling. It’s possible to solve this, but it seems to not be a priority.
    3. Weight. The road to productivity seems to be paved with larger, heavier machines. The side effects are fuel consumption, compaction, getting stuck. Let’s get smarter with frame design and logistics and talk acres/h rather than tank capacity and power.
    4. Cost. All farm equipment has seen cost increases that far outstrip inflation or any reasonable accounting of productivity and features. Sprayers lead the way. Yes, it’s possible to spins this as a value proposition. But it shouldn’t be necessary.
    5. Drift Management. Sprayer design continues to ignore drift management. We need sprayers that produce less drift by design, and this requires consideration of tractor unit, wheel, and boom aerodynamics. It’s more than a droplet size issue.
    6. Direct Injection. Although very handy for single product application, the plethora of product formulations and mixes has limited the success of direct injection systems. The complexity of injecting at the nozzle, and the resulting lack of available systems, has stymied some very attractive options, such as site-specific rate or product use.
    7. Ergonomics. If you need training, or to call someone before using your new sprayer for the first time, something’s wrong. Interfaces need to be intuitive and simple. The golden age of spray monitors was the 1980s. Those featured a main power toggle switch, a pump power switch, boom section switches, an agitation switch, and a simple way to enter the important information which was basically desired application volume. The screen can still be pretty, and you can still paint and monitor or tweak all the functions if you like that. But let’s at least have different tiers so beginners can also use the machine. Make interfaces using the philosophy Steve Jobs instilled in his trusted designer Jony Ive with the first iPod: no more than three clicks to achieve any desired outcome.

    A few areas show promise and may suit certain niches.

    1. In-Crop Weed Sensing. The green-on-green sensing that has been made possible by machine learning has shown some encouraging early success. Continuing improvements will eventually bring its reliability to within commercially acceptable standards. There is significant activity below the radar in this area, as all players recognize the enormous upside of a breakthrough.
    2. Autonomy. While dispensing a pesticide adjacent to sensitive areas isn’t exactly the low-hanging fruit of autonomy, such field sprayers will have a fit in the temperate plains of North and South America, Australia, and Asia and may help solve the cost and weight problem.
    3. Drone Application. The rapid pace of advancement in remotely piloted aerial systems, along with a seemingly low barrier to entry of new companies, will put pressure on the industry to make a decision on this alternate application method. If it can be done safely, it will have a dramatic impact.

    If you want to improve your sprayer, don’t ignore the small things you can do in your operation. Although we’re conditioned to look for game-changing technology, the most sustained improvements don’t come from a single innovation, but from a period of persistent evolution. A lot of small improvements add up. Spray application is no different.

  • Recirculating Booms – Introduction to the Concept

    Recirculating Booms – Introduction to the Concept

    Listen to the audio version of this article here

    A lot of people are intimidated by sprayer plumbing. One look at the spaghetti bowl of spray mix and hydraulic hoses and valves, and they walk away. It hasn’t helped that much of it is concealed under the frame and all of it is in the same black colour, so figuring it out on your own is almost impossible.

    Belly of a typical sprayer, showing black hydraulic and spray hoses.

    Let’s quickly review the basics. In all sprayers, the liquid in the tank is drawn out from the bottom and pressurized by a pump. The pressurized liquid is split into two main paths. One goes to the spray boom to hydraulic atomizers (nozzles). The other goes back to the tank to agitate the liquid and act as a pressure bypass when the booms are off. Bypass throttling changes pressure. That’s it.

    Sprayer plumbing diagram (Source: TeeJet).

    By the way, has anyone ever thought of some colour-coding or labelling the hoses and valves on a sprayer? We’d definitely appreciate that.

    Conventional boom sections

    Most North-American sprayers feed the pressurized liquid to the boom, where the flow is subdivided into physical sections that define the various portions of the boom that can spray at any one time. Older sprayers might only have two sections, the left and the right boom. Wide booms now have anywhere from 5 to 13 sections, each about two to four metres wide. Each section has a pressure feed to its middle, and each section terminates at two dead ends, at which we place caps or valves for flushing.

    A conventional plumbed boom with two sections. Each section has two terminal ends that require cleaning. Boom can only be flushed or primed by spraying or by opening boom end caps.

    Sprayer with nine sections, each controlled by its own valve and each running a dedicated feed hose.

    Two partial boom sections, each showing a central feed line and a capped boom end.

    Sectional boom end showing 10 cm of capped pipe beyond last nozzle body.

    Boom end with valve to facilitate draining and flushing.

    Any liquid that enters this type of boom must exit at the nozzle or the boom end. It must be sprayed out or drained. This poses three distinct problems.

    • If the boom contains water or a previous spray mix, the boom needs to be primed with the new product before spraying. We need to spray or drain the existing product out.
    • If we want to clean the boom or flush it with water, again we need to push the existing liquid out.
    • If we have dead spots in the boom section, such as a boom end, we need to take special care to flush those out as well.

    These characteristics complicate cleaning, create waste or contamination, and take time.

    Recirculating booms

    In a recirculating boom, the spray mixture enters the boom at one end and exits at the other, returning to the spray tank. In most cases, the left and right wing each has its own feed and return. Sectional control is achieved via individual valves (air or electric) placed on the nozzle bodies.

    There are two main types of recirculating booms on the market.

    The first system routes the pressurized mixture into the boom and shuts off the return line during spraying. When the nozzles are shut off for a turn, the return line opens automatically and the boom flow is pushed past the nozzles back to the tank. When the nozzles spray again, the return line closes to pressurize the boom. 

    Recirculating boom system offered by Pommier. One end of boom is pressurized, the other end is return. Return flows when boom spraying is shut off. Boom can be primed or flushed without spraying.

    This is the system used by Pommier, the French aluminum boom manufacturer who first introduced recirculating booms to North America.

    Pommier recirculating boom.

    Pommier boom showing stainless steel supply and return lines, as well as air-activated shutoff valve on nozzle body.

    The second type of system contains a 3-way valve, connected to the return line and the pressure side of the pump. This valve provides the option of either allowing the return line to go back to the tank, as above, or to also allow pumped flow to the return side so that the boom is pressurized at both ends.

    Recirculating boom that allows return line to be either pressurized by pump, or return to tank.

    Top view of D.O.T. Connect sprayer recirculating boom setup. Lower line is pressurized by pump. Upper line is return. Three-way valve allows return line to either go back to tank, or be pressurized by pump.

    Tidy setup of pressure and return lines on D.O.T. Connect system.

    This feature may be useful with long booms along which pressure drop is more likely to occur, or when very high flows are required, and was introduced to North America by the Dutch manufacturer Agrifac, about which we wrote here and reprinted Mick Robert’s article from Pro Operator here. A similar system is available from Rogator (starting in 2018) via their C-Series featuring LiquidLogic. It has also been used on the Connect sprayer, developed by Pattison Liquid Systems, for the D.O.T. autonomous platform.

    The main advantages of this design are that it provides the option of additional pressure to the spray boom to avoid pressure drop, and to allow any spray mix in the return line to be pushed and sprayed out to the boom for rinsing in the field. This lowers the remaining volume that needs to be diluted.

    Agrifac recirculating boom showing return loop at boom end.

    Boom end on Rogator Liquid Logic system. Note Hypro Pro-Stop E shutoff valve.

    Features

    Recirculating booms offer advantages in terms of preventing soil and water contamination and also in terms of simplifying the boom cleaning process. The design provides an opportunity to graduate to a better resolved sectional control as well due to the requirement for individual nozzle shutoff valves. 

    Due to shorter and less complex lengths of plumbing needed, stainless steel can be used for the return lines which decreases the potential for pesticide residue being adsorbed.

    To rinse a boom with product mix still in the tank, simply draw water from the on-board clean water tank and push it to the boom without activating any nozzle bodies. The mix in the boom is returned to the tank and replaced with water, nothing is sprayed or drained. The tank contents may become slightly diluted depending on the duration of the rinse.

    To rinse the tank as part of the sprayer cleanout, first spray the tank empty. Then introduce clean water into the product tank via the wash-down nozzles and spray that out. As always, either use several batches of  small clean water volumes, or a continuous rinse system, to dilute the remainder most effectively. There may be additional volume to dilute from the return lines compared to a conventional system, depending on the type of recirculating system is used. However, boom ends no longer exist and this saves effort and ensures a more thorough rinsing.

    To prime a boom that contains water, simply open the return lines back to the tank and allow the new mix to flow through the boom. Again, some dilution of the tank will occur due to the water in the boom.

    The value of spray-free rinsing and priming adds up. Each prime, for example, consumes about 30 US gallons before the spray reaches the last nozzle of the longest section. Much of that product ends up on the ground, probably while the sprayer is stationary, and probably in a similar place on the field year after year.

    Since a recirculating boom requires a powered individual nozzle shutoff, this adds some cost. However, the opportunity of improved sectional control via virtual sections is significant (most monitors offer 16 virtual sections that can be configured). Well-configured virtual sections can save several percent from overlaps.

    Recirculating booms remove many of the contamination problems associated with conventional plumbed sections. They save time, money, and reduce environmental impact. We think they should be offered on sprayers.

    Here’s a link to a nice article on recirculating booms written by Spencer Myers for the Manitoba Co-operator. A video that goes with the article can be found here.