Rotational molding: EXAIR Super Air Amplifiers compared to fans

Super Air Amplifier Family

A customer contacted EXAIR to find a better way to cool a die in a rotational molding facility.  Rotational molding, or Rotomolding, involves a heated hollow mold which is filled with plastic material. It is then slowly rotated (usually around two perpendicular axes), causing the softened material to disperse and cling to the walls of the mold. In order to maintain an even thickness throughout the part, the mold has to continue to rotate during the heating phase. After the desired timing sequence, the heating is turned off to allow the material to harden. 

This particular company was making plastic containers.  To try and improve the cycle rate between each container, they were using two fans (reference photo below) for cooling.  Time is money in this industry, and they wanted to target the fans to improve cooling.  They mentioned that water jackets for cooling would affect the life of the molds due to thermal shock.  So, they needed to cool with air; and EXAIR had a solution for them; the Super Air Amplifiers.

The Super Air Amplifiers as compared to fans are compact, easy to use, and very effective in cooling.  The capacity to cool is determined by the mass of air and the temperature difference. Since the mold is heated to 650oF (343oC) and the ambient air is 80oF (27oC), we have a good temperature difference for cooling.  For this application, I recommended to replace their fans with our model 120024 4” Super Air Amplifiers.  Each one can move 2,190 SCFM (6,1977 SLPM) of air while only needing 29.2 SCFM (826 SLPM) of compressed air at 80 PSIG (5.5 Bar). 

I also recommended to add one piece of a model 120022 2” Super Air Amplifier for cooling the inside of the mold.  Because the opening in the center of the mold is relatively small, a fan would take up most of the area.  Thus, not allowing the hot air to escape.  Since the 2” Super Air Amplifier is much smaller, they were able to place the air stream in the center allowing the hot air to escape around the edge of the hole.  With this combination, we were able to cool the mold 25% faster than the fans.  EXAIR did a comparison video between a Super Air Amplifier and a fan for cooling.  Watch it here.  

To expand on the comparison, EXAIR Super Air Amplifiers and electrical fans are designed to move air.  Fans use motors and blades to push the air toward the target.  There are mainly two types, centrifugal fans and axial fans.  The customer above was using axial fans.  The air enters from directly behind the fan, and the blades “slap” the air forward to the target. This creates a turbulent and loud air noise.  The EXAIR Super Air Amplifiers does not use any blades or motors to push the air.  They use a Coanda profile with a patented shim to create a low pressure to draw the air.   (You can read more about it here: Intelligent Compressed Air: Utilization of the Coanda Effect.)  So, they create laminar air flow which is much quieter. 

Super Air Amplifier – flow region

In physics, it is easier to pull than it is to push.  The same goes for moving air.  Fans are designed to “push” the air and the Super Air Amplifiers are designed to “pull” the air.  This method of pulling makes it simple to create a laminar flow in a small package which is more efficient, effective, and quiet.  With the patented shims inside the Super Air Amplifiers, they maximize the amplification by “pulling” in large amounts of ambient air while using less compressed air.  More air means better cooling.  If you want to move away from blower systems or axial fan systems to get better cooling, drying, cleaning, and conveying; you can contact an Application Engineer for more details about our Super Air Amplifiers. 

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

Super Air Amplifiers Provide Safe Air During Mine Rescue Missions

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I have recently had the pleasure of working with a customer developing a method of delivering air to trapped miners during a multi-man mine rescue mission. The federal government mandates that in the event of an explosion, miners must have a safe place to retreat for a minimum of 96 hours. This system will provide them with a supply of air during that period of time. In the initial stages, they had tried using some old venturis left over from a previous project. While this did work, they weren’t as effective or efficient as they needed. Through a little bit of research, they found EXAIR.

Generally, the Super Air Amplifier utilizes a source of compressed air. In this case, instead of using compressed air as the source, they’re using cryogenic liquid air. That air passes through a series of cold plates and heat exchangers and gets to the Super Air Amplifier at about 70°F. This air is then carried into the chamber, giving the miners a source of clean air.

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Model 120021 in prototype

EXAIR Super Air Amplifiers utilize a patented shim design that allows the unit to entrain ambient air at a rate of up to 25:1 from the compressed air supply. This balanced outlet airflow minimizes wind shear, producing sound levels that are typically three times quieter than other air movers. The Super Air Amplifiers are supplied with a .003” slotted air gap and can be adjusted by replacing the shim with a thicker .006” or .009” shim or by regulating the air pressure supplied to it. In addition to making gross adjustments to the airflow by changing the shim thickness, flow can also be dialed in by regulating the air pressure supplied. All Super Air Amplifier Kits come complete with the a properly sized Auto-Drain Filter to keep the air clean and dry, a Pressure Regulator to “dial” in the airflow, and a shim set. When the filter is installed just upstream of the Super Air Amplifier, there is no need to perform any regular maintenance. With no moving parts to wear out, you can expect many years of reliable operation.

Do you have a cooling or drying application that could benefit from a Super Air Amplifier? Contact an Application Engineer today to find out how EXAIR can help you save compressed air in your application!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Compressed Air Amplifiers Outperform Fans for Cooling Parts

When seeking a suitable solution for cooling or drying your parts, you may be tempted to try out a low-cost fan to get the job done. While fans do a great job of keeping you cool during the warmer months, they’re not the best choice for cooling or drying parts. Have you ever noticed that when standing in front of a fan the flow pattern is not consistent? This is due to the nature in which the fan blades create that air flow by “slapping” the air as they spin rapidly. The air flow that exits from the fan is turbulent and is not as effective as the laminar air flow pattern that is produced by EXAIR’s Super Air Amplifier. The Super Air Amplifier utilizes a patented shim design that maintains a critical position of the air gap and creates a laminar air flow pattern that will exit the outlet of the unit.

fan data2

In addition to providing laminar air flow more conducive for cooling and drying, the Super Air Amplifier provides much more air that can be directed at the target. A standard 2.36” x 2.36” DC operated fan provides anywhere from 12-27 CFM at the outlet, depending on the model. For comparison, a Model 120022 2” Super Air Amplifier will provide 341 SCFM at the outlet when operated at 80 psig. At just 6” away from the outlet, this value increases to 1,023 SCFM!! When compared to the fan outlet air flow, the Super Air Amplifier produces more than an 1,100% increase in air volume!

When replacing a fan with a Super Air Amplifier, the process time can be dramatically reduced. The increase in air volume significantly reduces the contact time that your part will need to be exposed to the air flow, allowing you to increase your line speed and decrease the overall production cost of the part. This is achieved due to the nature in which a Super Air Amplifier draws in air from the ambient environment. At amplification ratios as great as 25:1, the Super Air Amplifier is the best way to move a lot of air volume across the part with very little compressed air supplied to it. Check out the video

In addition to providing laminar airflow and increasing the volume of air, the Super Air Amplifier is also infinitely adjustable through one of two ways. Each size Super Air Amplifier has a shim set that can be purchased. Swapping out the stock shim for a thinner shim will reduce the compressed air consumption, force, and flow. Installing a thicker shim will increase it. Additionally, the force and flow can also be adjusted by regulating the input supply pressure through the use of a pressure regulator. With sizes ranges from ¾” up to 8”, there’s a Super Air Amplifier for all applications. Give us a call today to see how you can optimize your process by replacing your fans with one or more Super Air Amplifiers.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@Exair.com
Twitter: @EXAIR_TD

Super Air Amplifiers vs. Electric Fans

EXAIR’s product offerings contain many products that can be used for cooling. The focus of this blog will be Super Air Amplifiers. These often times get placed in a head to head competition with an electric fan. The best part, they easily come out on top.

Our own Tyler Daniel produced a great video showcasing how efficient it is to cool a part using the Super Air Amplifier rather than a fan.

When looking at the benefits other than performance and rate of cooling due to air entrainment, many customers prefer the Super Air Amplifier due to the fact there are no moving parts. This comes into play when cooling within in a hard to reach area or within a harsh process is needed.  Placing an electric motor with a blade held on by fasteners may not be desirable from a maintenance standpoint. The Super Air Amplifiers do not require electricity, meaning there is not a motor or bearings that would need to be replaced or inspected.

Another benefit is the small footprint of the Super Air Amplifier. This can also be seen within the video above where the Air Amplifier is shown is able to produce 341 SCFM (9,650 SLPM) in amplified airflow.  This gives the ability to place a small unit inside of a chamber that needs large volumes of air flowed through it.  For instance, a rotomolded part that has a large chamber and it needs surfaces to be cooled in order for the part to hold its shape from the mold rather than warp.  This can also be coupled with the fact that a Super Air Amplifier can be ducted on either the suction or discharge side in order to retrieve cool air or move the warm air out of the area.

Speaking of warm, the Super Air Amplifiers are also manufactured to withstand up to 275°F (135°C) from stock.  Stainless Steel and High-temperature models go well beyond that temp, as seen above. Custom-designed (flanges and different materials are common) versions are also available in short lead-times.

If you would like to discuss the benefits to a Super Air Amplifier further, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF