How to Pick the Right Atomizing Spray Nozzle

Atomizing spray nozzles atomize fluids with compressed air to create a fine spray in a variety of patterns for a variety of uses. They are commonly used to mark products, paint or coat, cool, reduce dust, lubricate and clean parts.

With the numerous types of Atomizing Nozzles, it can be challenging to sift through all the information. But with a few basic questions you can narrow down the right nozzle type for you and your application:

142 distinct models. 8 different patterns. Liquid flow rates from 0.1 to 303 gallons per hour. If you’ve got a spraying application, EXAIR has an Atomizing Nozzle for you!

Are you using a pressurized liquid feed? In some cases, a pressurized liquid source is not available for the nozzle, so you would have to rely on a gravity or siphon fed nozzle. While you lose the complexity of having a liquid pump pressurizing your liquid, you do have a few draw backs. Your siphon height is typically with in 36” so your liquid source has to be fairly close to your nozzle. Siphon fed nozzles are hard to turn off and on, they are best used for applications where you are continuously spraying a low viscosity liquid with a low gph.  

Internal Mix Atomizing Spray Nozzles

What is the viscosity of the fluid? Another deciding factor is the viscosity of the liquid you are spraying. Different nozzles are designed for different viscosity. For example, two of the main nozzle types are internal mix nozzles and external mix nozzles. They function just like they sound, internal mix nozzles mix the compressed air and liquid source inside the nozzle. And because of this they typically can not spray liquids over 300 cP. And because external mix nozzles mix the liquid and air outside the nozzle, they can handle liquids well above 300 cP.

What is the liquid flow rate in gallons per hour(gph)? Another factor in choosing the right nozzle is if your application has a set gph you are looking to achieve. Some nozzles are designed to flow more liquid then others. For example, the external mix nozzles inherently flow more liquid then the internal mix. As there is less restriction on the liquid flow. If you are looking for even higher gph you can source a liquid only atomizing nozzle, its going to give you a large bump in gph. But your droplet size will suffer with the liquid only nozzles.

Full Cone Liquid Only Atomizing Spray Nozzle

What droplet size are you looking for? Fine droplet sizes are one of the primary reasons atomizing nozzles are used. Benefits of small droplet sizes include even coating and liquid conservation. Internal mix nozzles will do the best at providing the smallest droplet size possible. While external mix and liquid only will give you larger droplet sizes but they will give you a larger gph some applications need.  

Should I use a No-Drip option?  The No-Drip option positively shuts off liquid flow when the    compressed air supply is shut off.  One benefit of this is appreciated in coating applications, where an errant droplet of liquid would mar an otherwise smooth, even coating.  Operationally, though, it also means you can precisely turn the liquid flow on & off, in short, quick bursts, up to 180 times a second.

No Drip External Mix

If you are in the need for a Liquid Nozzle to assist in your facility, please reach out! We have a team of application engineers waiting from 8AM – 5PM EST to help you size and fit a product to your specific application! 

Jordan Shouse
Application Engineer

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Atomization: What is it?

Atomization is a word that can be seen throughout the industry in rinsing, coating, painting, lubricating, and cooling applications. The act of atomization is simple, we often refer to it when looking at liquids and it means to break up the liquid stream and form fine droplets.  This is essentially a transfer of energy. There are two mainstream methods to atomize liquids for an application, both with their own advantages.

142 distinct models. 8 different patterns. Liquid flow rates from 0.1 to 303 gallons per hour. If you’ve got a spraying application, EXAIR has an Atomizing Nozzle for you!

The first is air atomizing. This action is done by combining a stream of compressed air with either a pressurized fluid or a siphon/gravity fed liquid.  The air stream can be combined with the liquid internally to the nozzle, hence Internal Mix Atomizing Nozzles. It can also combine outside of the nozzle, like the External Mix Atomizing Nozzles. We have blogged before on where to use each of these as the reason to select between Internal Mix or External Mix is its own topic.

Benefits to air atomization are, smaller droplet/particulate size is achievable.  The compressed air atomization gives the ability to break up more viscous fluids to get better coverage or thinner layers of spray.  Air atomization also gives the ability to use smaller amounts of liquid because the air takes up a portion of the total flow exiting any nozzle.

The second type of atomizing nozzles are hydraulic atomization. This uses the energy from the liquid being pressurized to break up the liquid stream.  Sometimes there are physical impacts within the nozzle that cause the atomization, other times it is just the liquid leaving an orifice that causes the atomization. This gives the ability to still spray a liquid into droplets of various shapes, dimensions, and flow rates. The lack of compressed air often results in larger droplet sizes as well as higher liquid flow rates. Because the liquid has to be pressurized to certain levels it also becomes difficult to spray higher viscosity fluids through hydraulically atomized nozzles.

Benefits to hydraulically atomized spray nozzles range from stronger spray force for rinsing, ease of installation from not needing to plumb compressed air, ability to flow slurries, or other liquids that may clog or dry due to the design of air atomized spray nozzles.

If you would like to discuss the correct nozzle for your spray application, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Benefits of Atomized Liquid Nozzles vs. Liquid Nozzles

There are a great many applications that require a spray (as opposed to a stream) of liquid. Certain droplet sizes, and flow rates, are beneficial for certain applications. For example, if you’re fighting a fire, you want as high of a flow rate as possible – the more water you douse the fire with, the quicker it goes out.  You also want a fairly large droplet size, since a mist would tend to evaporate instead of extinguishing the flames.

Pressure washers also benefit from higher (though not near as high as fire hose) flow rates, and droplet sizes.  You want an appreciable flow rate, because that means high velocity, and good sized droplets combine that velocity with their relative mass to “blast” away dirt and detritus from the surface.

Medicine delivery devices, like asthma inhalers, are designed to produce mid-sized droplets, but pretty low (and controlled) flows.  The droplets need to be small enough to efficiently spread the medicine through the breathing passages, but large enough to where they won’t evaporate before they ‘plant’ on the nasal & bronchial membranes to get absorbed.

These are examples of “liquid-only” nozzles…no other media or means of force are used to effect the spraying action.  Most of the time, the droplet sizes in these applications are measured in hundreds of microns, which “liquid-only” nozzles are ideally suited to generate.  Other applications, however, call for much smaller droplet sizes…such as those only attainable through atomization.

EXAIR Atomizing Spray Nozzles use compressed air to create a fine mist of liquid, with droplet sizes as low as 22 microns.

A typical “liquid-only” nozzle is capable of producing droplet sizes of 300-4,000 microns. Atomizing Nozzles’ droplet sizes are consistently under 100 microns, and can be as small as 20 microns!

Small droplet size is key to cost effectiveness in many applications:

  • Think about expensive coatings…the smaller the droplet size, the better and more even the coverage, and the less you have to spray (and pay) out.
  • Or humidification…smaller droplet size means more stays airborne, for longer, and in a larger space.
  • Petroleum based lubricants, by their nature, only require a thin layer for best results.  Smaller droplets make as even and thin of a layer as possible.
  • Dust control is much more effective with smaller droplet sizes, since the longer the mist lingers in the air, the more dust particles the individual droplets will adhere to…and then drop with them to the surface.  This also prevents getting the surface of the material any wetter than it has to be.
142 distinct models. 8 different patterns. Liquid flow rates from 0.1 to 303 gallons per hour. If you’ve got a spraying application, EXAIR has an Atomizing Nozzle for you!

If you’d like to discuss a liquid spraying application, I’d love to hear from you.  Call me.

Russ Bowman
Application Engineer
EXAIR Corporation
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No Drip Internal Mix Atomizing Nozzles

Eliminate drips to conserve valuable liquids and improve product finishes!  EXAIR’s patented No Drip Atomizing Nozzle provides the same great performance as the the standard atomizing nozzles with the added benefit of positive liquid flow stoppage when the compressed air is shut off.

The No Drip option eliminates the occurrence of post spray liquid flow that results in unwanted drips that can mar a finish on painted or coated surfaces.  Also, excess liquid loss is minimized saving on expensive materials like chemicals or coatings.  When the compressed air is shut-off, the No Drip nozzle positively seals off the flow, eliminating the chance for a drip or lost liquid. Only one compressed air line is needed, as the line to combine and atomize the liquid also provides the no drip operation and control.

The No Drip Atomizing Nozzles are available in (3) types – Internal Mix, External Mix, and Siphon Fed.

The Internal Mix type operates under the principle that the air and liquid come together and mix ‘internal’ to the nozzle.  This type provides the finest atomization and smallest droplet size. The Internal Mix type of nozzle can be used with liquids up to 300 cP in viscosity.  Both the air and liquid sides are pressure fed.  The No drip Internal Mix Atomizing Nozzles are best for pressure fed applications not requiring independent air and liquid control.

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A No Drip Internal Mix Flat Fan Nozzle applying anti-corrosion fluid to stamped parts

The No Drip Atomizing Nozzles are available in (3) sizes – 1/8, 1/4, and 1/2 NPT – to provide a wide range of flow rates and pattern sizes.  The No Drip feature does not impact the flow rates compared to the standard models.  Minimum air pressure operation is 30 PSIG for the 1/4 and 1/2 NPT, and just 20 PSIG for the 1/8 NPT models.

Like the standard Internal Mix Atomizing  Nozzles, spray patterns include narrow and wide angle round, flat fan, deflected flat fan and a 360° hollow circular pattern offering a wide selection to best meet the application needs.

Operation at up to 180 spray cycles per minute is possible.  Air and Liquid Caps can be switched out to change the pattern and flow rates.

Typical Applications

  • Painting
  • Coating
  • Rinsing
  • Cooling
  • Quenching
  • Wetting
  • Humidification
  • Dust Control

Advantages

  • No post spray drip
  • Adjustable
  • Easily used with EFC
  • Minimizes air and liquid consumption
  • All stainless steel construction
  • Fine atomization
  • Interchangeable liquid and air caps
  • Compact

If you need an Atomizing Spray Nozzle or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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