Dust suppression

Air atomising misting nozzles for dust suppression

These nozzles use a secondary fluid or gas to break up the primary spraying fluid into an exceptionally fine spray (atomisation).  The secondary fluid is usually air, but can be any gas, but the term "air atomiing" is used for all.

Fine sprays at very low flow rates

An advantage of these over direct pressure nozzles is that they can form a finely atomised spray pattern at very low flow rates.  With impingement, spiral and whirl chamber designs the energy required to break up the fluid flow into a hollow cone pattern comes directly from the fluid being sprayed. This means that there is a natural restriction to minimum flow rates.  With air atomisation a secondary source of energy is introduced in the form of pressurised gas.  This is used to break up the fluid into the spray pattern.  As such, atomisation and spray patterns can be maintained with much lower fluid flows from this type of nozzle.

Greater control

With air atomising nozzles a greater degree of control can be exerted over the size of the droplets by varying the air pressure.  This variation is achieved independently of flow rate so the droplet size mix can be adjusted to match the dust particle size.

Improved reach for fine sprays

Air atomisers also can help overcome problems of spray drifting.  The fine sprays required for effective dust capture are very prone to being swept away from the target area by crosswinds.  If the spray is produced by a standard hydraulic nozzle then the vast majority of the fluid's internal energy will have been used to break it up into droplets.  This means the spray has very little momentum and hence is at the mercy of any air currents.  Air atomising nozzles use compressed air to break up the fluid but also use the air pressure to project the spray forwards, meaning they can deliver very fine sprays many metres, even in windy conditions.

Nozzle selection

SNP offer a number of different air atomising nozzles that might be considered for a dust suppression application.  The XApr air atomising nozzle produces a full cone pattern which can be projected up  to 8.5 metres from the spray orifice.  For wider angle spraying the XAad 70 degree hollow cone air atomiser might be considered.  For full details please click on the product box below.