The image above shows a material transfer process for starch. At the top of the tower the starch rests inside of tumbling tanks (shown below) which blend larger pieces into small, finely blended particles. In order to achieve the proper blend, an hydration level of 5% water must be maintained within the tank. For the water introduced to the tank, the smaller the droplet size of the water particles, the better the blend. The current setup in this application is to spray water directly into the tanks, by hand, using a pump sprayer.
The investigation into droplet sizes led this customer to EXAIR Atomizing Nozzles, searching for a method to introduce small droplet water particles into the blending tanks. The ultimate question was “How small of a particle size can we achieve with an EXAIR Atomizing Nozzle?”
The answer to that question can be found here on our website and in our catalog as well. Our smallest confirmed droplet size is currently 22µm when using our 1/4″ NPT Siphon Fed Atomizing Nozzles, which was more than enough for this application.
By installing SR1010SS atomizing nozzles into this application this customer is able to achieve the required hydration level with small droplet size water particles. These particles ensure proper blending of the starch and proper quality for the final product. And, the atomizing nozzles prevent an operator from having to manually add the necessary water to achieve the required hydration in the blending tanks.
If you have a solution in need of an atomized liquid solution, contact an EXAIR Application Engineer. We’re here to help.
Last week I took a call from an agricultural customer looking to replace the spray nozzle used in their feed additive process. The soy oil/beeswax solution they are applying to the feed, is slightly viscous (close to 100 cP) which seems to be clogging the tight clearances inside the current nozzle, resulting in varying flow rates and an erratic spray pattern. They had tried to contact the current manufacturer several times for a solution but were unhappy with the lack of assistance they were receiving, not to mention the long lead times of 6-8 weeks for a replacement.
After further discussion, they confirmed they weren’t as concerned with the flow rate or spray pattern, as they were with the nozzle potentially getting clogged. They were able to obtain some internal dimensions of the existing nozzle and after further review, I recommended they use our Model # AF1030SS Internal Mix Flat Pattern Atomizing Nozzle as a replacement. This nozzle has larger inside diameters which would reduce the potential for clogging. Our Internal Mix Atomizing Nozzles mix the liquid and air inside the air cap and produce the finest atomization. The flow rate can be changed by adjusting the control valve on the nozzle and/or by adjusting the liquid pressure. Internal Mix nozzles are capable of handling fluids up to 300 Centipoise. All of our Atomizing Nozzles are In STOCK, so delivery is never an issue.
When considering an Atomizing Nozzle for an application, there are some general parameters that can be helpful in making the best selection.
Do you have a pressurized liquid source?
What is the fluid viscosity?
What spray pattern best fits the process?
How much flow (GPH/LPH) do I need?
If you have an application requiring a fine mist of atomized liquid spray, please contact an application engineer for assistance.
EXAIR has been manufacturing Intelligent Compressed Air Products since 1983. We work every day with air properties, such as compressed air pressures and flow rates, when evaluating product performance to provide a solution to a customer problem. We also need to be versed on a certain liquid property, viscosity, as it relates to the operation of (2) of the EXAIR product families, the Atomizing Spray Nozzles and the Industrial Housekeeping liquid vacuums (Reversible Drum Vac and Chip Trapper).
Viscosity is often referred to the thickness of a fluid. A common example would be water and honey. Water is a low viscosity fluid, while honey is a high viscosity material.
Dynamic, Shear, or Absolute Viscosity is a measure of the resistance to shearing flow. If you think of 2 plates (see below) with the bottom one stationary and the top one moving horizontally, and with a fluid between them – this illustrates Absolute Viscosity. When the top plate moves to the right, there will be induced multiple horizontal layers of the fluid, each moving at different speeds (the fluid will be at rest at the bottom, and the top layer will move with the top plate.) The friction generated between the layers will give rise to a force resisting this motion. The force is proportional to the speed and area of the plate and inversely proportional to the distance between the plates.
In simplest terms, viscosity is the ratio of the shear stress, τ, to the velocity gradient du/dy. Of concern to us, it takes more force to cause a very viscous (thick like honey) fluid flow.
Centipoise, cP, is the common unit of measure for viscosity, and 1 cP is equal to 0.01 g/cm/s.
Water has a viscosity of 1 cP at room temperature and honey ranges from 2,000-10,000 cP.
How does all this relate to EXAIR? It relates to EXAIR because we engineer products to specifically move and use liquids. There are limitations to the viscosity each of these products can handle and still perform well.
The EXAIR Atomizing Spray Nozzles can be used with liquids up to 800 cP. The Internal Mix type nozzles can be used on liquids up to 300 cP. The External Mix nozzles can be used with liquids over 300 cP and up to 800 cP. Lastly, the Siphon Fed models are good to 200 cP, and do not require a pressure source for the liquid. Each nozzle type will atomize the fluid and provide a very small droplet size, which is ideal for washing, rinsing, coating, cooling and other applications. Exceeding the cP each of these nozzles are designed to use will result in larger droplet sizes and a more inconsistent fluid flow, which may impact your process.
The other EXAIR product family where viscosity is important, is the Industrial Housekeeping Products, especially the High Lift Reversible Drum Vac and High Lift Chip Trapper. They are capable of moving liquids with viscosities of up to 1400 cP through 20′ of hose. Simply provide compressed air and turn any closed head drum into a high powered liquid vacuum. Great for coolant, hydraulic oils, waster water, and many other fluids. For these products, as the cP increases, so does the time it will take to move the liquids into or out of the drum.
To discuss your fluid viscosity and how an EXAIR Intelligent Compressed Air Product can make your process better, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.
I have been working with a customer from the grain milling industry. They take a grain like corn, and mill it to sizes that range from coarse product like grits to fine product like flour. The customer had a special application where steam was injected into a mixing screw process to add moisture to the grain. Steam can be expensive and dangerous to work with, due to the energy required to make, store, transport and use, along with the high temperatures and pressures involved.
The customer was aware of our products from previous work we had done involving Super Air Knives. He approached me about the Atomizing Nozzles and whether they could be used to replace the steam injection system. We reviewed the process details such as target flow rate, the spray pattern desired, and the available distance from the target we had to work with. We determined that (3) of the EF1030SS – External Mix Flat Fan, each capable of delivering 14 Gallons Per Hour, were the solution. The nozzles would be placed equidistant along the mixing screw, to provide an even delivery of water.
To operate the nozzles, all that is needed is a supply of water, and 3.5-15.1 SCFM of compressed air at 10-95 PSIG. Varying the liquid and air pressure will change the flow rate and pattern size of the spray. Charts are published to help with the set-up and tuning of the nozzles to match the process needs.
The use of the Atomizing Nozzle allows for precise application of very fine droplets. For the External Mix type, droplets sizes of 39 to 57 micron are possible. Smallest droplet size is achieved by operating at higher air pressures and lower liquid pressures.
EXAIR also manufactures Internal Mix type nozzles and even a Siphon type, that can operate under siphon or gravity fed conditions (no liquid pump/pressure is required.) Nozzles are available with flow rates from 0.1 to 303 Gallons per Hour, in flow patterns such as Narrow Angle Round, Wide Angle Round, Flat Fan, and 360° Hollow Circular.
To discuss your application and how the EXAIR Atomizing Spray Nozzle can be a benefit at your facility, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.
One of the common questions we receive with regards to our Atomizing Spray Nozzles, is whether they will spray a specific liquid. Most of the time this is a simple answer, found by referencing the viscosity of the liquid and the viscosity range of the specific atomizing nozzle in question. But, sometimes the viscosity of a fluid isn’t readily available and the best path forward is testing of the specific fluid or application.
Such was the case with a recent application to spray a specific mixture comprised of catnip biomass onto materials as they pass along a conveyor. There was no specific flow rate required, we simply needed to spray a specific width at a specific distance away from the product.
Per the customer, the spray nozzles in this application needed a wide angle and flat fan spray pattern. The video below shows the most suitable solution we found in testing at EXAIR.
The suitable nozzle in this application was our model AD2010SS, an internal mix nozzle with deflected flat fan spraying pattern and a patented technology to prevent liquid flow after compressed air to the nozzle is turned off. This nozzle provided the right solution for this application, and shipped from stock on the same day we received the order.
Fast forward a few weeks and this same application found benefit from an Electronic Flow Controller (EFC) model 9057. The EFC allows for sensor-based control of compressed air flow, and thereby control of liquid flow to the AD2010SS nozzles. This prevents operation of the nozzles when there is no need to spray the liquid.
The discussion, testing, and implementation of this solution are an excellent example of the engineering support available behind EXAIR products. We really do help our customers find solutions, and if there is an unknown in an application we’re willing to find the answers together.
Fog. Nobody likes driving in it. It’s downright perilous to sailing vessels on the open water, but especially those near the shore, or other watercraft. Flights get delayed or cancelled, stranding travelers in airport terminals far from home, and keeping many from pressing matters that necessitated the speed of an airline flight in the first place. Oh, and it’s ALWAYS where the bad guy is hiding in the movies. You can tell by the ominous low-string music that starts playing right before things get real nefarious.
You know who LIKES fog, though? Greenhouse operators. Their plants get plenty of water to sustain their growth from the well-irrigated soil, but the leaves & petals can wither and get discolored if the humidity isn’t kept at a high level.
The same is true for the parts of a greenhouse that folks don’t see when they’re selecting the annuals to plant on the next nice spring weekend (which we should be coming up on quite soon here!) – like the seed germination chambers. I had the pleasure of helping a greenhouse operator recently, who needed to replace some old, and malfunctioning, nozzles in one of their germination chambers. They were interested in the extremely fine mist that our Atomizing Spray Nozzles produce. After some experimentation with a couple of different flow rates & patterns, they determined that the Model AW1020SS (Wide Angle Round Pattern, Internal Mix) Atomizing Spray Nozzles provided optimal results.
As the fogging systems in their other chambers start to fail, they’ve been replacing them with the AW1020SS’. We shipped them two earlier this week.
One of the most difficult aspects of handling and working with dusty materials is suppression of airborne contaminants. Small particles can easily become a dust cloud, minimizing visibility and decreasing the quality of working conditions. This then leads to lower productivity, low morale, and a missed opportunity to maximize the potential of personnel and equipment.
Our distributor in New Zealand recently assisted one of their customers facing this set of problems when working with cement and microsilica as it was poured into a mixer. An exhaust fan was in place, but failed to extract the dust sufficiently, so a new approach was needed to minimize the dust.
The solution was to use an EXAIR AN2010SSNo Drip Internal Mix Atomizing Nozzle, shown above in the red box, to produce an atomized water mist. The dust produced during pouring is captured by the small droplets of atomized water produced with this nozzle, reducing the dust and allowing proper use of the mixer.
In order to position the nozzle exactly where it needs to be, an 18” Stay Set Hose, shown above with the red arrow, was used to position the nozzle. This hose is built specifically to have “memory” of the desired position, allowing for quick, easy, and repeatable position of the nozzle attached to the hose.
This simple setup is controlled through a timer to ensure water and compressed air use realize maximum efficiency. It’s an easy solution to a painful problem for this customer.
If you’d like to explore how an EXAIR solution can solve problems in your facility or application, please contact an EXAIR Application Engineer.