Pneumatic atomising nozzles have two inlet media: fluid and compressed air. The air collides with the fluid, creating the smallest droplet sizes of any spray nozzle we make. Pneumatic atomising nozzles are available in various designs to generate specific spray and flow requirements:
Air and fluid mix inside the nozzle chamber so that it leaves the orifice as an atomised fluid. Best for spraying water or other low-viscosity fluids. Normally very low flow rates.
Air and fluid mix outside the nozzle chamber. Best for higher viscous fluids that might otherwise tend to clog the nozzle. Involves somewhat higher flow rates than internal mix nozzles.
Spray pattern type
Full cone (round) pattern
Most appropriate when a compact, circular impact or a major coverage is required (such as for fluid injection into a duct or pipe).
Flat fan pattern
Most appropriate for humidifying and cooling of product, for web dampening, or for whenever a broad linear impact is required (such as applying paint or food toppings).
Pressure principle (supply from a pressurised source)
Most common form of feed principle. Metered air is input into the nozzle along with the inlet fluid. Pressure can be adjusted as needed for flow or atomisation requirements.
Gravity principle (supply located above the nozzle)
Can be used when compressed air is not available or very low pressure is required. Only pressure involved is that of gravity feeding the fluid from the source to the nozzle. For very low flow rates.
Siphon principle (self-aspirating; supply located below the nozzle)
Can also be used when compressed air is not available or when inlet air pressure is not a requirement. Only pressure is from a siphon force which draws the liquid up from its source to the nozzle. For very low flow rates.
Lechler manufactures three different types of pneumatic atomising nozzles:
AirMist (Series 136) – These nozzles have two inlets – one for liquid and one for air. They come in either flat fan or full cone (round) patterns and are either internal or external mix. They are designed for spraying water-like or moderate viscosity fluids. A number of different attachments are available for the AirMist which can help control nozzle performance.
ViscoMist (Series 176) – These nozzles come in three different varieties, each with a different number of inlets. The more inlets, the greater the control over the spray performance. All ViscoMist nozzles are external mix and have their own pneumatic valve which control the on-off operation of the nozzle. As its name suggestions, ViscoMist nozzles are designed to spray more viscous fluids, such as oils and syrups. The different models of ViscoMists are:
Body 2 – Contains three inlet connections: one for liquid and two for air. One of the air inlets controls both atomizing (droplet size) and fan (shape of spray) air; the other controls on-off operation.
Body 4 – Contains four inlet connections: one for liquid and three for air. One air inlet controls atomizing air, one controls fan air, and the third controls on-off operation.
Body 5 – Contains five inlet connections: two for liquid (to inject two separate liquids or recirculate one liquid) and three for air. One air inlet controls atomizing air, one controls fan air, and the third controls on-off operation.
Full cone siphon nozzle (Series 140) – This nozzle creates very fine droplets with very low flow rates. It operates under the siphon principle, meaning that it aspirates fluid which is located beneath the level of the nozzle. It is an internal mix nozzle with its own integrated regulating device for operation.
Please note that one option of the AirMist line is Series 166. This series is an assembly of any basic AirMist nozzle along with an attached solenoid which can electronically activate the nozzle from a remote location.
General applications for pneumatic atomising nozzles include: