Airblast sprayer

Technical presentation

An air-blast sprayer uses the lift of an air stream to spray the spray liquid in fine drops onto the vegetation.

The droplet is transported by a large air current created by a fan, traditionally a helical fan (on most machines). The volumes of air moved vary from 20,000 to 80,000 m3/hour and air speeds from 50 to 200 km/h.
These machines are designed to treat large volumes of foliage. The large volume of air generated ensures thorough mixing of the foliage and good penetration of the product inside, as well as good coverage of the vegetation.

S21 airblast sprayer

The liquid circuit of an air-blast sprayer is comparable in every way to that of a jet sprayer. However, the booms are located where the air blown by the fan exits to charge it with droplets.

Why "jet porté"?

This is because the drops produced by pressurising the liquid or centrifuging are picked up by a large volume of air as they leave the nozzle, which carries them towards the target and penetrates the vegetation. The assistance of a fan also helps to agitate the vegetation and improve penetration.

Descente MCV BELLY

PréciJet TECNOMA

The different types of airblast equipment

Air-blast sprayer with axial-flow fan

WANNER axial flow air blast sprayer

They are called axial flow fans because the air flows through the impeller parallel to the axis of rotation of the impeller.

These fans are often mistakenly referred to as aeroconvection fans. This term refers to a particular type of air-cooled device consisting of a high turbine combined with deflectors that direct the air towards the ground, which acts as a reflector. The drop-laden air is then processed from bottom to top, hence the term convection associated with aeroconvection.

Air-blast sprayer with tangential flow fan

WEBER tangential flow sprayer

These devices use fans consisting of a cylinder with a large number of small fins (with an aircraft wing profile) on its periphery.

The special feature of this system is that it generates a very homogenous volume of air over the entire height of the vegetation to be treated, into which the droplets produced by the nozzles are integrated.

This equipment, which does not use a power take-off but rather the tractor's hydraulic circuit, is much more economical in terms of fuel consumption than traditional sprayers.

Air-blast sprayer with centrifugal nozzles

This ancient and infrequent spraying method uses centrifugal force to break up the stream of liquid into droplets. The droplet is formed by the rotation of a small-diameter disc or bowl with a crenellated periphery. On some machines, the element that forms the droplet can have other shapes, such as a screened cylinder (often used for aerial spraying).
Nozzles are usually driven by a hydraulic motor, which also drives the fan to transport the drops. Sometimes, electrical energy (or more rarely pneumatic energy) can replace hydraulic energy.

In centrifugal spraying, the finer the drop, the better: