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