Internal Mix Atomizing Spray Nozzle Used In Feed Additive Process

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.

Model AF1030SS Internal Mix Flat Fan Pattern Atomizing Nozzle

When considering an Atomizing Nozzle for an application, there are some general parameters that can be helpful in making the best selection.

  1. Do you have a pressurized liquid source?
  2. What is the fluid viscosity?
  3. What spray pattern best fits the process?
  4. 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.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Viscosity – Why it Matters

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.Capture

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.

atomizing nozzle

Atomizing Spray Nozzle

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.

HLRDVpr_openpit_3mbcmyk (2)

High Lift Reversible Drum Vac

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.

Brian Bergmann
Application Engineer

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EXAIR E-Vac For Degassing

Recently a new application using the EXAIR E-Vacs has arisen. This is not a pick and place or system bleeding application. This is an application that some may not realize there is a need for. This is a degassing operation, the purpose is to remove any and all gas from a liquid or any viscous fluid.  A picture of some silicon mold resin during the degassing process is shown below.

I recently encountered this through the molding of acrylic.  In order to get a good finish part that is not going to have air bubbles in it you need to degas the liquid resin before it is poured into the mold.  Depending on what you’re mold is made out of you may even need to degas it.   In the instance I worked with a mold, it was made from silicon.  This meant the resin for the mold needed to be degassed as did the acrylic resin after the mold was formed and being used.

To degas you need a container that will withstand vacuum being pulled on it.   Then you simply set your container of liquid resin inside the “degassing chamber” and seal it up.  All you need is a vacuum port to hook the E-Vac to and you’re up and running.   You will actually be able to see the bubbles coming to the top of the resin.  In some cases it may even appear to fill the bucket.

If you would like to discuss  a similar application or have any questions about how you can use an E-Vac, feel free to contact an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

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