A novel twin outlet spray nozzle designed to optimise spring and summer spray applications to dense canopied crops is proving a hit on a Yorkshire arable farm.
Richard Hinchliffe was among the first growers to try the GuardianAIR Twin nozzle when a number of prototypes were made available for field evaluation.
Having carried out his own deposition and target coverage tests using water sensitive paper on different crops, he now uses the production version for a range of spray treatments.
"We use it for fungicides, insecticides and broad-leaf weed killers - pretty much everything apart from graminicides,†he says. “The combination of drift control and target coverage is just what we need here."
The GuardianAIR Twin, designed and manufactured by Hypro-EU at its base near Cambridge, combines two of the most significant developments in spray nozzle technology - air inclusion to produce a narrower range of droplet sizes within the output and forward/reverse angling to improve canopy penetration and target coverage.
Using advanced computer-aided design and rapid prototyping technologies, Hypro-EU chief engineer Trevor Swan produced a one-piece tip and cap assembly spraying two 110deg flat fans angled 30deg forward and back.
Air is drawn in from the underside of the nozzle through holes protected by a skirt in the moulding, then combined with spray liquid in a mixing chamber. A reduction in pressure at this point causes the liquid to atomise into a ’medium’ quality spray with a relatively narrow range of droplet sizes.
By eliminating the very fine droplets that are prone to drifting, the GuardianAIR Twin keeps the spray on target to optimise the application dosage and minimise the risk of contaminating susceptible neighbouring crops or sensitive areas of the surrounding environment.
"This is an important characteristic because we have a lot of water courses - two or three around every field" notes Richard Hinchliffe, who farms near Goole, East Yorkshire. "Drift reduction is essential to give us the most spraying days possible without compromising treatment quality; that’s why we’ve used air inclusion nozzles, including the single GuardianAIR, for many years."
Having adopted the technique of facing the single nozzle forward and back alternately across the boom, he was eager to try the Twin version with its two angled fan sprays.
Using water sensitive paper to see where droplets from the prototype nozzle landed, Mr Hinchliffe discovered excellent coverage of oilseed rape plants, particularly for sclerotinia fungicide treatments that need to penetrate deep into the canopy to be fully effective.
He also saw positive results spraying beans and wheat, and since then has used either the single GuardianAIR or the Twin version for all applications except grass weed treatments in the autumn.
"I still use the single nozzle for T3 treatments to wheat because I find having them all facing backwards gives best ear coverage" says Richard Hinchliffe. "But the GuardianAIR Twin is used for most applications from autumn onwards."
The HGCA’s Nozzle Selection Chart shows that the GuardianAIR Twin produces the finest droplets of any air inclusion nozzle at a given pressure, points out Roger James of Hypro. This is an important characteristic for target coverage because sprays with an average droplet size only 15% bigger will contain around a third fewer droplets.
"The Twin is best operated at 3 bar pressure and between 2 bar and 3 bar has 50-75% less drift than a standard flat fan in the LERAP test, qualifying for a two-star rating," he adds. "It also has exceptional spray pattern evenness because the twin outlets deliver the total volume in four overlapping sprays."
Hypro regards its GuardianAIR Twin as a premium design that is likely to have the edge over other air inclusion nozzles for treatments such as oilseed rape and bean foliar fungicides, urgent potato blight fungicide applications in less than ideal conditions, and for tackling larger weeds with pre-harvest or stubble cleaning glyphosate sprays.
"In many other situations we expect it to give similar performance to a single GuardianAIR but with the advantage of inclined sprays from every nozzle," Roger James adds. "It also has the convenience to operators of being a one-piece design with an integral Fast-Cap that attaches to the boom nozzle holders with a smooth twist action."
