As Canadian farmers begin to adopt closed transfer systems (CTS), growing pains are to be expected. Instructions for installation and use are primarily European and field-sprayer centric. We’ve seen precious little in the way of practical advice for incorporating CTS into airblast operations.
This is a “live” article which we’ll update periodically. We encourage readers to contact us and share their observations and experiences (and photos) so we can all learn from them. We’re happy to keep contributions anonymous if that’s preferred.
This article does not intentionally imply any brand preference. Our experience is limited at this point and we are using any information we have access to. As the article grows, so will the combinations of sprayer and CTS. Also, we are not recommending or endorsing any of the following approaches. It’s still unclear if modifying the sprayer is the purview of the manufacturer / dealer of the sprayer or the CTS. At this point, we suspect it’s likely the owner that accepts any responsibility.
Does it matter where the CTS is relative to the sprayer?
If the system is gravity-fed, the coupler, the fill line and the connection to the tank must be higher than the fill level in the tank. Liquid won’t flow uphill unless it’s pushed from behind (pressure) or pulled (suction or siphon). Be aware this means the entire fill line should be above the tank’s fill level; sags will prevent fluid transfer. If we’re observing best practices, the tank should be half-full of water before you start adding products.
If the coupler uses suction from the sprayer itself, or employs a pump, relative height won’t affect filling. In this case it is likely part of a separate transfer system (i.e. not permanently mounted on the sprayer). It might be simple, or part of a larger and more sophisticated affair, but in either case it should be level, stable, and easily accessed without the operator having to reach or squat. Two examples are pictured below.
How do I plumb the CTS to the sprayer?
If the CTS is mounted directly on the airblast sprayer, it’s typically a smaller, gravity-fed coupler. The rinse / carrier water is often from an external source (e.g. water tank, tower, pond or municipal water), but there are cases where an onboard water source can be used.
Some have suggested cutting a hole in the tank itself, above the highest possible fill line, and sealing the coupler in place. This is not simple. If you find a flat horizontal surface and you are equipped to cut poly, Fiberglas or steel (listed in ascending order of difficulty), doing so could undermine tank integrity and create potential for leaks. We won’t even entertain what would happen to your sprayer warranty… assuming someone still has one.
If the intent is to couple a fill line to the sprayer, the best approach is to tee a fitting into the suction-side of the sprayer plumbing to draw product in through the pump. Consider accessibility and safety first: Can you safely and easily reach the suction side of the sprayer plumbing? Is the PTO shaft too close for comfort? Will anything stick out past the sprayer that might create a risk of snagging a crop canopy or trellis? If a tee can be plumbed in, will it need to be secured to the chassis in some way to create stability?
There is no easy or universal answer to these questions.
As for the fitting, what style is best? A cam lever style fitting will work, but it will leak a volume of liquid when it’s detached. A quarter-turn valve will also be required on the sprayer, and preferably another on at the end of the feed line, so that’s two more valves in play when loading. And, for the sake of safety, best practice would to be to use a cam cap on the sprayer just in case the quarter-turn valve gets snagged and opens. Far safer and more efficient, a dry poppet style fitting will ensure minimal spillage when the hose is disconnected, with no additional valves or caps required.
Finally, what of the fill line itself? We’re seeking confirmation, but we have been told of a situation where the pump suction was sufficient to collapse the feed line. This is why some CTS manufacturers provide the hose and fitting with the units. At minimum, check the CTS manufacturer’s instructions and ensure the hose is rated for the degree of suction created by the pump.
Send us your experiences
And that’s all we have for now. We encourage you to reach out to us with your successes and failure and we’ll update this article for others to learn from.
Happy Spraying.