a person using a cleaning device featuring an air atomizing nozzle

Air Atomizing Nozzles Spray Pattern

When applying liquids to surfaces, sometimes a fine coating is desired to ensure full coverage while also minimizing product waste. Spray nozzles are used to apply the liquid in a process called air atomization. Many industries rely on air atomizing techniques for their products or equipment when manual application done by hand is not efficient or may be dangerous. Learn more about air atomizing processes and spray patterns.

What is Air Atomizing?

Air atomization is when air or gas is added to liquid to create a fine mist. This mixing of the air and liquid may be done within the nozzle itself or directly outside the nozzle opening. Called two-fluid nozzles, these nozzles have a liquid feed line and an air/gas feed line inside the nozzle. How they are mixed will depend on whether the nozzle is designed for internal mixing or external mixing.

Internal mixing nozzles have an air/gas feed, liquid feed, liquid cap, fluid cap, and an annular area where the spray will emit from the nozzle. Both the liquid feed and the air/gas feed meet inside the annular area, where everything mixes together. Then the mixture leaves the annular area in the desired spray pattern depending on the nozzle design. In this design, both feeds are dependent on each other. Any changes made to the air pressure will directly impact the liquid flow. Internal mixing nozzles are commonly used for liquids that have a lower absolute viscosity (centipoise or cP) rate of under 200.

External mixing nozzles do not have an annular area. Instead, while the liquid and air travels through their feeds, both exit out of separate openings at the end of the nozzle. There may be more than one aperture for the air/gas to exit from the nozzle, such as one opening directly beside the liquid aperture and a second opening further out. Since both feeds are kept separate, the flow rates for the air and liquid can be independently adjusted without impacting each other. This design allows for more precise fluid metering. An external mixing nozzle can handle most fluids in addition to viscous fluids that have more than a 200 cP rate.

What is an Air Atomizing Nozzle?

Air atomizing nozzles create very small droplets of water for applications. They function by mixing compressed air or gas and liquids together, as the gas further breaks down the liquid into fine, even-sized droplets with a diameter ranging from 10 μm or less.

These nozzles have adjustable spray flows without having a large variation in spray distribution or droplet sizes (large turndown ratio). They have small spray angles ranging from 15° to 30° and can handle a large range of flow rates from 1.10 gallons per hour (gal/h) to 81gal/h or from up to 0.04 gallons per minute (gal/min) to 75gal/min.

Why Use Air Atomizing Nozzles?

Air atomizing nozzles are ideal when needing to break down water or fluids at low pressures into fine to very fine droplets for applications while still maintaining an adequate flow rate and pressure. They provide various options for mixing the liquid and gas, either internal or external, to obtain a consistent dispersion of droplets that is most suited for operations. In addition, air atomizing nozzles can be used for a wide variety of applications, such as cooling, humidification, and the atomization of viscous liquids.

Industry Applications for Air Atomizing Nozzles

Air atomizing nozzles can be used in various industries based on the application. The nozzles can be used to apply liquids as coatings, or for humidifying, gas cooling, lubrication, fogging, and other applications.

Coating Applications

Coatings applications are common for product manufacturing industries such as food, automotive, pharmaceutical, and other companies. They may apply edible color coatings to medication, paints on cars and consumer products, as well as coatings on surfaces that may come in direct or indirect contact with food.

Humidifying Applications

Humidifying applications involve the use of air atomization to push out moisture into the air. This extra moisture may prevent things from drying out or becoming damaged. A common humidifying application would involve a greenhouse area where spray mist is applied to plants to water them as well as to clean dust off leaves. Humidifying air atomizing nozzles may also be seen along produce aisles in grocery stores where the mist keeps vegetables fresh and prevents leaves from wilting.

Lubrication Applications

Companies operating equipment may rely on air atomizing methods to lubricate working parts to decrease wear and tear, eliminate friction, and prevent damage to components. These air atomizing nozzles can be used for hard-to-reach areas of places where it would be dangerous for workers to apply the lubricant by hand.

Fogging Applications

Some industries that produce large amounts of airborne dust or dirt during operations. To improve the air quality and prevent the dust or dirt from entering processes or damaging products and equipment, air atomizing nozzles may emit vapor in the form of fog into the space. When the airborne dust or dirt comes into contact with the fog, it adheres to the droplets and becomes heavy enough to fall to the ground.

Cooling Applications

Companies may create objects that are required to be cooled down before they are further processed, or equipment that needs to be cooled after experiencing high temperatures. Air atomizing nozzles can cool down objects, equipment, and even gasses for operations.

Cleaning Applications

Industries from product manufacturing to food may use atomizing nozzles for cleaning and sanitizing purposes. For example, beverage companies may use air atomizing nozzles to clean bottles before liquid products are poured inside.

Spray Pattern of Air Atomizing Nozzles

Air atomizing nozzles come in spray patterns of full cone, flat fan, and solid stream. By having options with the spray pattern, you can further customize the nozzle to fit the application.

Full cone spray patterns come in wide and narrow circular diameters. The entire width of the diameter provides an even distribution of small liquid droplets for full coverage. These nozzles can be used for air cooling and humidification,

A flat fan atomizing nozzle has a sheet-type or flat pattern to the water droplets. Flat fan spray nozzles can be used for humidification of goods, belt humidification, cooling, and atomization of viscous liquids.

Solid stream atomizing nozzles are often used when dealing with liquids that have viscous properties. The stream of water droplets is appropriate for lubrication, glazing, and coating applications.

What Type of Liquid/Gas Can Be Applied?

When applying liquid droplets, atomizing nozzles may operate using a pressure principle or a siphon and or supply principle. The pressure principle uses the pressure from the liquid and transforms it into kinetic energy along the cross-section of the nozzle's hole. The siphon/supply principle uses gravity or the liquid siphon to create the liquid droplets.

Types of liquid that can be used with these nozzles include water, chemicals, lubricants, liquid agents, and viscous liquids. The types of gas used in air atomizing nozzles include compressed air, steam, or nitrogen.

Lechler's Air Atomizing Nozzle Designs

Lechler offers pneumatic air atomizing nozzles with full cone, flat cone, and solid stream spray patterns. Our nozzles have internal and external mixing designs along with pressure principle and siphon/supply liquid supply types. When you are looking for the most options for your spray nozzles, we have the products that can offer the best solutions. Contact us today.

Best Spray Nozzles for Air Atomizing

When selecting air nozzles, keep in mind the required flow rates desired for both the liquid and the air/gas. Also, determine the droplet size and where the liquid tank setup that will feed into the nozzle. If the liquid supply tank is located at a higher level as gravity will be used to push the liquid through the nozzle, then Lechler pneumatic air atomizing nozzles can be designed to accommodate this setup. In other instances, the liquid supply may be under pressure, which would require high flow pressure nozzles.

Spray pattern also plays an important role when it comes to spray nozzle selection. If you are going to apply paint coatings or food toppings, then a flat fan nozzle is appropriate. If circular coverage is required or liquids will be injected into a pipe, a full cone nozzle type is preferred.

Lastly, consider the viscosity of the liquid. For low viscosity liquids such as water, Lechler's AirMists nozzles fine atomized sprays. For very viscous liquids such as syrups or thick oils, lecher ViscoMists nozzles can provide even coatings without clogging. For more information regarding our air atomizing systems, contact us today.