Progress towards closed transfer of liquid crop protection products continues with the launch of compatible caps and couplers planned for the end of the year in Denmark and the Netherlands, followed by the UK, Germany and France in 2023.

Online information is freely available as to how the caps and couplers will work and how they will be sourced, and sprayer engineers are getting geared up towards fitting and servicing the systems.

More partners have joined a working group of agrochemical companies* initially launched by BASF to help develop the common Easyconnect cap required to work with a coupler which opens the can, dispenses the product, rinses and reseals the container this year.

Machinery manufacturers are considering ways to adapt current ranges to work with the emerging third-party couplers and recommendations from on-farm trials are being incorporated into the coupler designs.

John Deere, for example, offers optional ISO-standard connections on all its range of trailed and self-propelled sprayers to plug in a closed transfer system (CTS).

John Deere sprayer specialist Mark James says: While specific designs on couplers are emerging and we are planning to supply the Pentair Hypro Cleanload Nexus CTS via our dealers once it becomes fully available, we want to be compatible with all possible systems and not limit customers in what they might wish to use.

So, any coupler with ISO standard connections could plug onto the sprayer and be used to fill chemicals into the machine.

The ISO-standard coupling requires two connections on the side of the sprayer a dry-break chemical suction connection and a quick fit clean water rinsing connection.

A valve allows the operator to select chemical filling via the induction hopper or CTS, so that versatility is retained.

Mark says these connections are also useful for operations such as drawing product from an IBC or connecting a large external inductor, such as the Vegcraft ProFill.

Sprayer designs Whether future sprayer designs incorporate a CTS is another interesting question, he says.

On current machines, there isnt normally any suitable space to fit a CTS, as they are quite bulky and need quite a bit of space around them to use comfortably.

Customers generally like more compact machines and that means little space for additional ancillaries We expect most customers will end up using standalone CTS on the current generation of machines.

In many cases, even if the sprayer doesnt have a suitable space to permanently fit a CTS, they often have a storage space where a CTS and suitable stand could be transported.

For future generations of spray er, space will be allocated during design for a CTS.

Chemical inductors are unlikely to disappear completely during the lifespan of even the next generation of sprayers, so with both an inductor and a CTS, it probably means the overall envelope of the sprayer needs to increase a little to fit everything onboard in a way thats accessible and easy to use.

Pentair Hypro carried out successful field trials with its Cleanload Nexus coupler in 2020 and 2021, says product manager Roger James.

Important criteria which came out of the trials were that the system should be robust and last the life of the sprayer, be reliable and fail-safe and easy to maintain and repair.

They also highlighted the importance of the integrated chemical can cap being proposed by the working group, compared with previous designs that required use of an additional adaptor, he adds.

There was definite resistance to the idea of having to remove the cap and screw on a separate adaptor when the system is being used all day, every day.

Farmers in the trials group had several prototypes, swapping as the development progressed until we reached a closed system standard, which meets ISO 21191.

The ability to measure part containers accurately was another important development and cooperation with container suppliers has resulted in the calibration being printed upside down on CTS compatible packs so the measurements can be read when the can is fitted to the coupler.

Two other adaptations have been made, he says.

Horticultural applications often use smaller amounts of concentrated product to treat smaller areas so we are developing two additional ways of metering reduced quantities to work with the coupler.

The first is to calibrate the exit hose from the coupler to the suction port into 25ml divisions and the second is a convenient separate metering cylinder attached to the coupler.

Both use the coupler handle to control the flow and can measure out as little as 125-150ml with a high degree of accuracy.

Hybrid induction bowl Developments are also afoot for a hybrid induction bowl and Cleanload Nexus system that can replace a standard bowl, working with a leading UK manufacturer.

Fitting and service will be a key requirement and Pentair Hypro is developing online training for sprayer technicians, who can then join a register of qualified service providers on the companys website, cleanloadnexus.com.

Roger suggests sprayer manufacturers are likely to want to fully integrate control of the coupler in the future, using the LED panels and screens many manufacturers are now offering.

It could be as simple as scanning a barcode into the controller which could manage the quantity dispensed and dictate the mixing and rinsing regimes for a particular agrochemical.

But we have to be mindful of the cost implications of fitting such equipment for both the sprayer manufacturer and the farmer, especially while it is still not a legal requirement, and to make sure the system is simple and convenient to use.