How EXAIR Uses Fluidics To Make Efficient, Quiet, and Safe Compressed Air Products

EXAIR Intelligent Compressed Air Products incorporate several distinct principles of fluidics into our engineered designs. To be clear, these principles aren’t exclusive to making quiet and efficient compressed air products. I personally have used them all for business and pleasure over the years. In the Navy, for example, the air ejectors that pulled vacuum on the main condensers where our turbines dumped their ‘used’ steam were basically great big Venturis – they restricted the diameter through which a fluid (steam, in this case) flowed, gradually increased that diameter, and doing so, changed the velocity so that a low pressure area (or vacuum) developed in the throat:

Graphic representation of the Venturi effect.

EXAIR E-Vac Vacuum Generators use the Venturi effect to draw vacuum of up to 27″Hg. They’re typically used with Vacuum Cups for pick-and-place material handling applications.

Here are a few examples of Mr. Venturi’s discovery, implemented in modern industry.

I first learned about the Bernoulli principle on a grade school field trip to the National Air Force Museum at Wright Patterson Air Force Base, about an hour from where I grew up. See, this Bernoulli guy discovered that when there is an increase in the speed of a fluid, a simultaneous decrease in fluid pressure occurs at the same time. That’s why airplane wings are shaped like they are – flat on the bottom and curved on top…when the air flowing that extra distance over the top speeds up to get to the back of the wing as fast as the air that’s simply flowing underneath the wing does, the decrease in pressure on top causes the wing (and the plane it’s attached to) rise in the air.

Bernoulli’s Equation: this is the math that proves it works.

The Bernoulli principle is incorporated in to the design & operation of EXAIR engineered Air Knives, Air Wipes, Air Amplifiers, and Air Nozzles.

The Coanda effect is the third fluidics principle that’s incorporated into the design & operation of many EXAIR engineered compressed air products. Its namesake, Henri Coanda, was an early 20th Century aeronautical engineer who discovered that if a jet of fluid exiting an orifice flows across a surface, it’ll tend to not only adhere to and follow that surface (even if it curves or bends), but also entrain fluid from the surrounding area.

EXAIR Intelligent Compressed Air Products such as (left to right) the Air Wipe, Super Air Knife, Super Air Nozzle, and Air Amplifier all use the Coanda effect to entrain enormous amounts of air from the surrounding environment.

There are a couple of easy – and interesting – experiments that demonstrate the Coanda effect, both of which I used when I was a Cub Scout leader and our Pack’s Webelos den was earning their Science Activity Pin:

Turn a faucet on and let the running water flow over the convex ‘bottom’ of a spoon. Everything we know about the laws of gravity say that when the water reaches the ‘bottom-most’ point on the spoon’s convex surface, it ought to fall straight down…but it doesn’t:

Another experiment that defies everything we think we know about gravity can be performed with a ball, and a source of air flow. Here’s a short video, showing how the air flow from an Air Amplifier ‘wraps’ around a ball and holds it in that jet of air:

The Webelos den did this with a leaf blower and a playground ball. Unlike a lot of things I’ve done, I DEFINITELY encourage you to try THAT at home.

For forty years now, EXAIR has been putting these principles of fluidics into practice by engineering & manufacturing the most efficient, quietest, and safest compressed air products on the market. If you’d like to find out how we can help you get the most out of our products – and your compressed air system – give me a call.

Russ Bowman, CCASS

Application Engineer
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Super Air Amplifiers vs. Fans

Super Air Amplifier Family

Many times we get the question, “What’s the difference between a fan and an Air Amplifier?”. The best way to answer is to do a comparison. EXAIR Super Air Amplifiers and electrical fans are both 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 air enters from directly behind the fan, and the blades “slap” the air forward to the target. This creates turbulent and loud air noise that may or may not actually impact the target.  The EXAIR Super Air Amplifiers do not use any blades or motors to push the air.  They use a Coanda profile with a patented shim, allowing compressed air to escape in such a way that a low pressure area is created to draw in surrounding, ambient air.  (You can read more about it here: Intelligent Compressed Air: Utilization of the Coanda Effect.) So, they create laminar (non-turbulent) output flow, which is much quieter and has the same direction and velocity, making it more effective to move heat energy out of or into a target, depending on your application goals. Side note: EXAIR Air Amplifiers can be used in high temperature ambient conditions right out of the box. Fans by comparison, generally cannot be used unless they are specifically designed for the purpose.

In one example application, a customer contacted EXAIR to find a better way to cool a die in a rotational molding facility.  Rotational molding, or Roto molding, involves a heated hollow mold that 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 solidify.

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.  Water has a higher specific heat, but using water for cooling would affect the life of the molds due to thermal shock.  Cooling with air was their only option. EXAIR had a solution for them: the Super Air Amplifier.

Super Air Amplifier – flow region

The Super Air Amplifier, when 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 replacing their fans with our model 120024 4” Super Air Amplifiers.  Each one can move 2,190 SCFM (6,1977 SLPM) of air while only using 29.2 SCFM (826 SLPM) of compressed air at 80 PSIG (5.5 Bar).  With the 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

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, while 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 that is more efficient, effective, and quiet.  With the patented shims inside the Super Air Amplifier, they maximize the amplification by “pulling” in large amounts of ambient air while using less compressed air.  More air mass means better cooling. And no moving parts in an Air Amplifier means no maintenance. 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
Twitter: @EXAIR_jb

Optimizing Your Compressed Air Usage With Engineered Products

The first new car I ever bought was a 1995 Ford Escort Wagon. I’ve mentioned this before in posts about preventive maintenance, the importance of proper filtration, and brand loyalty. Those blogs were primarily about my experiences with that little red wagon, but today I wanted to discuss the primary reason I bought the car in the first place.

I had a 50-mile round trip commute to work, and my old Pontiac Grand Prix with the small block V8 engine was a great ride for sure. Some quick math, however, showed that if I went with something with better gas mileage, I could save quite a bit of money on gasoline. My calculation was almost $1,000 a year, just on driving back & forth to work. After figuring in the rest of my driving for the first year, it was more like $1,400 a year.

Similar to my “upgrade” to a more fuel efficient vehicle, upgrading blowoff, cooling and drying operations using engineered compressed air products is Step #3 in EXAIR’s Six Steps To Optimizing Your Compressed Air System. We’ve assigned an order to these steps in accordance with basic good engineering practice & protocol, but it’s not necessary to follow them in any particular order. In fact, all six steps really don’t apply to every single compressed air system.

Step #3 does apply to most systems, though. I spent a fair amount of time in all sorts of industrial facilities in my previous roles, servicing industrial & chemical pumps, and almost all the time, regardless of the industry or the size of the facility, the maintenance part of the facility used air guns. However, I don’t recall ever seeing an engineered nozzle on one before I came to EXAIR. Since then, I’ve worked with a BUNCH of users to dramatically reduce compressed air consumption by replacing their cheap and inefficient air guns with EXAIR Safety Air Guns, or by retrofitting EXAIR Super Air Nozzles onto their existing air guns. We actually carry adapters to fit our Super Air Nozzles to a number of readily commercially available air guns for that very purpose.

The five families of EXAIR handheld blowoff products include VariBlast Precision & Compact, Soft Grip, Heavy Duty, SuperBlast, and TurboBlast Safety Air Guns. They’re available with a range of engineered Super Air Nozzles, Extensions, and Chip Shields.

In addition to air guns & nozzles, our Air Knives have a long history of replacing drilled pipes & pipe manifolds with inefficient nozzles used to make a curtain of air flow. The following chart details the savings you can realize from the use of a 24″ Super Air Knife instead of similar devices for a 24″ wide air curtain:

Even though an electric powered blower will use less electricity than the amount of electricity an air compressor uses to supply an engineered product like the Super Air Knife, the maintenance costs make the total cost of ownership eclipse that of the engineered Air Knife.

Our Case Study Library (registration required, but it’s free & fast) documents many real-world situations where customers worked with us to gather & publish “before/after” documentation, proving out the benefits of Step #3. I encourage you to check those out, and if you think you might have an opportunity to do a Case Study with us, we offer discounts or credit for that…give me a call.

Russ Bowman, CCASS

Application Engineer
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Custom Super Air Amplifier

A customer called in looking to incorporate some more airflow to help materials flow properly through their processing line. This line included several legacy machines, so we had to get creative to fit something with in the system in place. It just so happened there were several 3/4″ FNPT ports in the sections where the increased air flow was needed!

So we came up with a 3/4″ Super Air Amplifier, 120020. But rather than the typical smooth OD outlet we extended it a bit and put a 3/4″ MNPT thread on the end! See it below next to a photo of the 120020.

Right side is a stock 120020, and to the left is the Custom 120020 with a 3/4″ MNPT threaded outlet!

EXAIR’s Super Air Amplifiers achieve air amplification ratios ranging from 12:1 on our smallest units and up to 25:1 for our 4” and 8” models. EXAIR’s Super Air Amplifiers utilize a patented shim design to maintain critical positioning of component parts. This allows a precise amount of compressed air to be released at exact intervals toward the center of the Super Air Amplifier. This creates a constant, high velocity outlet flow across the entire cross-sectional area. Free, ambient air is entrained through the unit, resulting in high amplification ratios. The balanced outlet airflow minimizes wind shear to produce sound levels far lower than other similar air movers.

Super Air Amplifiers are supplied with a .003” thick shim that is ideal for most applications. Flow and force can be increased by replacing the shim with a thicker .006” or .009” shim. The flow of air is also controlled by adjusting the input pressure supplied to the amplifier. Higher pressures increase both the force and flow, while lower pressures decrease both force and flow. All Super Air Amplifiers are available in kits that come with a shim set as well as a suitably sized pressure regulator and auto-drain filter.

EXAIR has a solution for you if you need to move A LOT of air, even if we need to customize it to fit perfectly in your application. Also, this custom product only took a few weeks to produce, so delivery times are still reasonable!  Reach out to an Application Engineer today if you have an application that you believe could be served with a low-cost, simple solution!

Jordan Shouse
Application Engineer

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