Even fan vs tapered fan (the main point)
The Agrotop SpotFan is an even-fan nozzle. Volume is fairly uniform from one edge of the pattern to the other. That is the right design for continuous band spraying.
On an optical or camera spot system the nozzle designed to activate in isolation over a target, typically from about 70 cm. At that height a 40° fan is already around half a metre wide. An even fan therefore puts a large share of its volume out toward the edges — onto soil or crop that is not the target, especially given that your nozzle spacings are 25cm.
The ARAG CFLD-XC40 is a tapered (elliptical) fan. Volume is highest in the centre and falls away at the edges. When a single nozzle activates over a weed, a greater percentage of the volume stays in the 25cm target zone and less is wasted on the surrounds. Even fans are not wrong; they are the wrong pattern for isolated single-nozzle spot spraying applications.
Air induction vs pre-orifice (PWM and start-up)
The Agrotop SpotFan is a venturi / air-induction nozzle. PWM meters flow by opening and closing a solenoid many times a second. During each off pulse the volume inside the nozzle drops in pressure. An air-induction tip then has to refill the mixing chamber, re-establish Venturi suction and re-entrain air before the intended spray appears. That adds start-up delay on a new target.
The CFLD-XC40 is a compact pre-orifice nozzle, not air-induction. Extra Coarse droplets come from the orifice geometry. There are no air inlets, so the pattern recovers as soon as liquid is at the orifice — which is what PWM and optical spot sprayers need.
Droplet speed and bounce
Air-induction nozzles drop pressure in the venturi chamber, so droplets leave slower than from a pre-orifice tip of the same size and pressure. They are also air-filled and less dense. Lower speed and lower density reduce impact energy, which can cut bounce on hard-to-wet leaves — that part of the Agrotop story is supported by extension work (NDSU, GRDC) and impact studies.
The trade-off is unchanged: those softer droplets still follow an even fan that wets the dirt either side of an isolated target. The CFLD-XC40 is extra-coarse without the extra venturi pressure drop, so droplets stay denser and typically faster than a true air-induction spray. Whether that extra energy is a problem depends on the weed and the mix; on most broad-acre spot jobs a tapered XC pattern on the plant still beats an even, slower fan that is mainly off-target.
Drift in brief
Agrotop’s even 40° venturi family (RowFan E) has a published 90% JKI figure in continuous band use. SpotFan itself is described as “very high” drift reduction. The CFLD-XC40 is sold as extra-coarse / extreme drift reduction for optical spot and PWM. Both are low-drift 40° nozzles. For isolated activations, where the chemical lands matters as much as how coarse or soft it is.
The CFLD-XC4003 (elliptical fan) configuration was fitted to the very first Calibre/BOSS autonomous WEED-IT until today with reliable and predictable performance.
