Atomizing Spray Nozzles: Breaking Down The Spray Patterns

Once upon a time, there was a process engineer that needed to solve a production issue on a rinsing line. They had used a spray nozzle that had too large of a spray pattern, with too much volume. And used a hollow cone pattern with not enough heat removal…Okay, so maybe I took this a little too far into the fairytales. I have legitimately had a very similar discussion with customers that are trying to find a spray pattern that is “Just Right” for their needs – the Goldilocks discussion of spray patterns. The best part of Atomizing Spray Nozzles from EXAIR is that we do help you find the nozzle that fits your needs. The shape of the spray pattern is one of the key variables that is decided first.

When determining what spray pattern is needed we need to take into account the purpose of the spray, whether it be to coat, rinse, cool, or add humidity. To go along with the purpose we need to understand the geometry of the part/target and whether the part is stationary, is the part moving, or is the nozzle moving. Once those variable are determined then we can select one of the three main spray patterns to drill down the final selection.

The main three patterns are:
Round Pattern
Flat Fan
Hollow Cone

FullStream – Round Pattern Liquid Atomizing Nozzle rinsing parts after coating.

Round Pattern – These are found in air atomizing and liquid atomizing. The air atomizing are available in both siphon fed liquid or pressure fed liquid. These are also broken into narrow angle or wide angle round. The diameter of the full cone spray of liquid will expand on both styles however the narrow angle tends stay more concentrated and can often be seen in rinsing, washing or heavy coating applications. Distance from the target that the nozzle can be will also help with whether a wide angle or narrow angle will be needed.

Flat Fan Spray Pattern rinsing parts after a chemical wash.

Flat Fan Pattern – These are currently offered in the air atomizing spray nozzles and both siphon fed or pressure fed options. They are also offered in narrow angle flat fan, wide angle flat fan, and deflected flat fan. These options will all be dictated by the target area needing covered and the distance to the target area. Flat fan pattern nozzles are often used with fine surface finish coatings that are being applied to either moving parts, or with nozzles that move around stationary parts.

Model AT5010SS 1/2 NPT 360° Hollow Circular Pattern Atomizing Spray Nozzles are ideal for smooth, even coatings in large pipe or duct ID’s, or for a mist or fog over a large area.

Hollow Cone – This pattern is available in both liquid atomizing and air atomizing. The liquid atomized hollow stream nozzle is great for rinsing, or washing parts. The center of the cone being hollow can help to conserve liquid where it is not needed. The air atomizing hollow cone 360° nozzle can spray so wide it has been used for inside pipe wall cleaning / coating as well as for dust suppression in large areas.

No matter the application, there is a combination of spray nozzles that should fit “just right”. The Application Engineer team here at EXAIR are all equipped with knowledge and experience to help determine what is needed or at the very least some methods to get to a final solution. If you would like to discuss the needs within your facility, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Choosing the Right Air Atomizing Nozzle

Atomizing your liquid has many benefits. You will use far less product, while covering more surface. Whether you are covering, coating or cooling, atomization is your best option. EXAIR has a vast selection of Air Atomizing Spray Nozzles, and it can appear difficult to select the best one for your application, but with some of these tips and guidance, you will be able to find exactly what you need.

In choosing a nozzle, there are a few standard details and a few necessary questions we need to get out of the way.

  1. All of our nozzles are Stainless Steel
  2. There are options with 1/8″, 1/4″ and 1/2″ NPT inlets
  3. Max temp is 400°F
  4. All Nozzles are CE compliant
  5. Do you have adequate compressed air at the point of use?
  6. Is your Liquid pressurized?
  7. How far from your product will / can the nozzle be mounted?
  8. What is the Viscosity (cP) of your liquid?
  9. How many gallons per minute do you need to disperse?

EXAIR’s Air Atomizing Nozzles all have 3 components. The nozzle itself (see #2 above), the liquid cap that controls the liquid flow, and the air cap that controls the air flow / pattern. For the most part these are inter changeable based upon the original size of your nozzle. For example, you could fit a new air cap onto the same liquid cap and change from a round pattern to a flat pattern (Note -not all are caps interchangeable). By using these variables, we are bale to get many different flow rates, patterns and coverages.

There are also 3 groups of nozzles, Internal Mix, External Mix, and Siphon Fed, based on how your liquid is fed to the nozzle. Here is an excerpt from our catalogue that explains this very well:

Let’s assume that your liquid is pressurized. You now have 2 choices, internal and external mix. Internal mix will only work if your air pressure and liquid pressure are pretty close to the same (within about 20-25 psi of each other). These mix the air and liquid inside the nozzle, so if more pressure is received on either side, it could back pressure the other side. The external mix nozzles can have a wide variety of pressures on either side, as these mix externally of the nozzle. Lastly, if your liquid has a viscosity of 300 cP or higher, your only option is the External Mix Nozzle – see below for a viscosity table…

We need to have a solid understanding of the centipoise (cP) of the liquid. To save you some time in looking this up, here are some examples of common products and their centipoise. As you can see above, the cP can determine the type of nozzle you can use effectively.

By this time, we should have narrowed the nozzle down to the style (Siphon Fed, Internal Mix, or External Mix). Now we need to find the right size, and spray pattern for your specific application. The main data points you need to have are 1) Spray pattern (width etc…) 2) Liquid Pressure 3) Air Pressure 4) distance from the nozzle to the surface you are spraying (ideally this is variable). Once you know these data points, you can proceed.

PRO TIP: Use the catalogue section for reference – click here to get it online . Or you can open up a chat on our website and ask us to send you one (M-F 7AM -4PM EST), or you can send an email or request by phone that we send you a physical printed copy!!! Yes these still exist!!! With the catalogue section in hand, you will have each performance table readily available to start narrowing down your choices. Pro tip #2 – you can also download drawings…

To find the best size and pattern fit, you will want to focus on the lookup tables in the catalogue section. First, an idea of how your nozzles will need to mount (their location, distance from target) and a desirable spray pattern to cover your target will be helpful. For instance, you may need a fan pattern to cover a wide area. Let’s say that you need to cover an area that is about 12″-13″ wide, we can look for a nozzle that will meet that requirement. Keep in mind that if you need to cover 60″, you may need 1, 2, 3 or more nozzles depending on the other information required.

Back to our example of a 12-13″ spray… You will next need determine how many gallons per hour this nozzle would need to spray. How fine, or thick of a covering do you need? Sometimes this is an unknown, so we will look at liquid and air caps that are in a mid range, so that you can adjust with the air and liquid pressures. Let’s assume you need to apply close to 4 gallons per hour. We can now find both factors on the look up table below. The second row, under 30 psi liquid shows 4.1 gallons per hour, when we use 26 psi of air pressure. As we slide over the width, we see that this will give us a 13″ width of spray pattern (when the nozzle is 9″ away – that is width “B” in the spray pattern above). Pro Tip # 3- start with your non variable of width (spray pattern) needed, and work back from there. We can always find ways to adjust the air and liquid pressure, but you will still need the pattern to cover.

The application engineers at EXAIR are ready to help as well. We can walk you through the steps and ask the right questions to assist you in selecting the correct nozzles. If you can grab a few pictures and or videos to share, as well as the data mentioned above, we will be able to get you to the best solution.

Application Engineer

Brian Wages

EXAIR Corporation
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5 Important Factors When Selecting an Atomizing Spray Nozzle

The most recent EXAIR Webinar is up and ready to be viewed as an on demand video. This presentation showcases five important factors when selecting an atomizing spray nozzle. Throughout the webinar you will gain several key takeaways that are outside of the five factors as well. If you have a liquid spray application and are not sure where to start, this video has a wealth of information for you. As always, the Application Engineer department is also here and ready to assist as needed. We can walk through any application with you and help right over the phone, through email, or even live chat.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Liquid Spray Nozzles Improve Gummy Candy Production

One of the more popular treats for kids and adults are gummies.  They can be sweet, sour, and in different shapes and colors.  A candy company that makes gummy bears was looking for a better way to spray food-grade oil onto their product.  They contacted EXAIR about our Air Atomizing Spray Nozzles. 

We discussed their setup and process for making the gummy candies; or in this case gummy bears.  The sugary mixture is poured into molds that are coated with corn starch.  The corn starch helps to keep the gummy from sticking to the mold.  Once hardened, the bears will be released from the molds and travel through a stainless-steel spinning drum.  In here, they apply a light food-grade oil onto the bears.  This process will hide the starch and give the candy that glazed and colored feature.  The drum was near 60” (1.52 meters) long and spun at 19 RPM.  The gummy bears would tumble along the length of the drum at a designed production rate of 2000 Kg/hr. (4,400 Lbs./hr.).  They used drip tubes along the top to apply the food-grade oil onto the gummy bears.  They noticed that the color was not as good and the coverage was spotty.  The oil pump was metered in a range of 0.35 – 3 gal/hr. (1.32 – 11.3 l/h).  The temperature inside the drum could reach up to 150oF (65oC), and the viscosity of the food-grade oil ranged between 190 – 400 cps.  In order to get the best results for quality, they had to reduce their production rates to about 1,700 to 1,800 Kg/hr. 

To determine the correct solution, we had to dive a bit more into their application.  The details of the EXAIR Atomizing Nozzles are measured with water as the liquid.  Since they are using an oil at different temperatures, the specific gravity will change slightly.  For their oil, the specific gravity is 0.92 at 20oC and 0.89 at 65oC.  We can use Equation 1 to convert the required flow rate from the food-grade oil to water.

Equation 1:

Q1 = Q2 * SQRT (SG2 / SG1)

Q1 – Flow of water (gph)

Q2 – Flow of oil (gph)

SG1 – Specific Gravity of water

SG2 – Specific Gravity of oil

The Specific Gravity of water is 1.  With the range of specific gravity for the oil, we can calculate the range that is needed as indicated by water.  Then we can make a selection as referenced by our data in the catalog.  Since we want to make sure that we can cover the range of the metered oil pump, we will use the maximum flow rate of 3 gph.  In adding the values, we get the following:

@20oC  Q1 = 3 gph * sqrt(0.92) = 2.88 gph

@65oC  Q1 = 3 gph * sqrt(0.89) = 2.83 gph  

Since the viscosity ranges above 300 cps., I recommended the External Mix Atomizing Nozzles to be mounted along the length of the rotating drum.  The External Mix can handle viscous liquids up to 800 cps.  Unlike the drip method, the EXAIR Liquid Atomizing Spray Nozzles use compressed air to shear the oil into small droplets and to disperse the oil in a wide pattern.  With the smaller particle size, we can get more coverage area which will allow them to use less food-grade oil.  The coverage area on the gummy bears was near 15” (38cm) as they rolled down the drum.  I also recommended the No-Drip option to allow for versatility in their process.  The No-Drip option for the Atomizing Nozzles is a very nice option which will stop the liquid solution from dripping when not in use.  When they needed to apply the oil, they would just turn on the compressed air to the Atomizing Nozzle.  It made it very easy to control.  This was important to reduce excess usage and non-conforming parts. It also keeps the inside of the drum oil free during cleaning cycles.   

EB2010SS

From the data above, I recommended three pieces of the model EB2010SS, No Drip External Mix Wide Angle Flat Fan Pattern.  The spray pattern was 14” (35.6cm) wide to cover part of the 60” (1.52m) length of the drum.  With an estimated 1 gph for each nozzle, we would be able to spray the maximum requirement as calculated above (2.88 gph).  After installation, they were able to get a consistent deep color of the gummy bear at the maximum production rate of 2,000 Kg/hr.  They also noticed that with the fine particle spray, they were able to use less oil.  With the three pieces of the model EB2010SS, they were able to reach maximum production rates with less food-grade oil and reduce scrap rates.

If you have a liquid that you would like to spray evenly, efficiently, and effectively; EXAIR Atomizing Nozzles can do that for you.  You can contact an Application Engineer for help.  For the customer above, they were able to create those gummy treats for kids and adults.  Yummy.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Picture: Giant Gummy Bear by Alexas_FotosPixabay licence.