Air Amplifiers – Done Your Way

Photo by Ryan McGuire Licensed by Pixabay

Air Amplifiers are amazing tools that pack a punch (if the punch is a ton of air flow). Imagine an amplification rate up to 25 times. You supply 29 SCFM and yield 730 SCFM coming out? It’s incredible. These little beauties work by flowing compressed air (80psig) through the inlet to the annular chamber. It is then throttled through a small ring nozzle at a high velocity. This Airstream employs the Coanda profile directing all this air to the outlet. Although you should never blow air at a person, a little bit of air input, would easily produce the results to the right!

Why would you use these? See below for starters:

Although we have many options to choose from, sometimes you may need something outside the box. Maybe it’s a different size? A different Material? A different fitting? Ask us we do have many ways to customize this product. Here are 3 examples of things we have done in the past.

The High Temp Air Amplifier (right) was developed for moving hot air to surface needing uniform heating while in a furnace or oven. This is designed for temps up to 700°F, and is now a standard offering in 1 1/4″.

Another example of a “Special” Air Amplifier is a stainless steel version with a flange mount (left). This was designed for exhausting flue gases from a furnace. If there were a power failure, this Special Air Amplifier will quickly evacuate harmful fumes, prior to affecting the workers.

A third “Special” was made when we were brought an application that required a sticky material to be pulled through the Air Amplifier, and it was unable to stick to the inside of the Amplifier. So we developed an Adjustable Air Amplifier with e PTFE Plug (Right), so the material would not stick.

If you have an application that requires a tool that is not quite in line with what we offer, don’t hesitate to reach out. I can’t promise you that we will be able to make it for you, but I can promise you that we will look at it and give it our best shot.

Thank you for stopping by,

Brian Wages

Application Engineer EXAIR Corporation
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NIOSH Hierarchy of Controls

Last year I hosted a Webinar about the NIOSH Hierarchy of Controls and compressed air safety! You can watch that here on our website!

The hierarchy of controls is a strategy that originates from NIOSH (National Institute for Occupational Safety and Health). NIOSH is the federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. This hierarchy is their recommendation for increasing safety for personnel by taking specific steps and how each step increases safety moving from bottom to top of the pyramid. In this blog I will explain the main elements of the HIERARCHY OF CONTROLS and illustrate how to reach the highest level of control with important compressed air safety standards.

The least effective methods are Administrative Controls and Personal Protective Equipment (PPE). Administrative Controls involve making changes to the way people perform the work and promoting safe practices through training. The training could be related to correct operating procedures, keeping the workplace clean, emergency response to incidents, and personal hygiene practices, such as proper hand washing after handling hazardous materials. PPE is the least effective method because the personnel themselves make the choice to wear them or not wear them in any particular situation. They can be trained on the risks of not using PPE equipment (ear plugs, gloves, respirators, etc.) but we all know it does not always get used. PPE can also become damaged, may be uncomfortable and not used, or used incorrectly.

In the middle range of effectiveness is Engineering Controls. These controls are implemented by design changes to the equipment or process to reduce or eliminate the hazard. Good engineering controls can be very effective in protecting people regardless of the the actions and behaviors of the workers. While higher in initial cost than Administrative controls or PPE, typically operating costs are lower, and a cost saving may be realized in the long run.

The final two, Elimination and Substitution are the most effective but can be the most difficult to integrate into an existing process. If the process is still in the design phase, it may be easier and less expensive to eliminate or substitute the hazard. Elimination of the hazard would be the ultimate and most effective method, either by removing the hazard altogether, or changing the work process so the hazard is no longer part of the process.

EXAIR can help your company follow the Hierarchy of Controls, and eliminate, or substitute the hazards of compressed air use with relative ease. 

Home of Intelligent Compressed Air Products

Engineers can eliminate loud and unsafe pressure nozzles with designs that utilize quiet and intelligent compressed air products such as Air NozzlesAir Knives and Air Amplifiers. Also, unsafe existing products such as air guns, can be substituted with EXAIR engineered solutions that meet the OSHA standards 29 CFR 1910.242(b) and 29 CFR 1910.95(a).

Elimination and Substitution are the most effective methods and should be used whenever possible to reduce or eliminate the hazard and keep people safe in the workplace. EXAIR products can be easily substituted for existing, unsafe compressed air products in many cases. And to avoid the hazard altogether, remember EXAIR when designing products  or processes which require compressed air use for cooling, cleaning, ejection, and more. 

If you have questions about the Hierarchy of Controls and safe compressed air usage from any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution

Jordan Shouse
Application Engineer

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Hierarchy of Controls Image:  used from  Public Domain

Understanding Air Entrainment

EXAIR uses the word entrainment a lot, all of our blowoff products use the principle to amplify the air stream and increase efficiency. But, what is entrainment and what causes the phenomenon? Entrainment can be defined as a fluid that is swept along into an existing moving fluid. This brings Bernoulli’s equation into the picture. When looking at specific situations and conditions Bernoulli’s equation can show some interesting significance with gases.

Bernoulli’s Equation

Bernoulli’s equation takes into account four main variables which are Pressure (P), Density (r), Velocity (v), and a height difference (z); along with a single constant for gravity. you can see the relationship between the velocity squared and the pressure from the equation above.  Being that this relationship is a constant along the streamline; when the velocity increases; the pressure has to come down. Now we have to look at how fluids like to behave. Fluids within a system like to be at a constant pressure when at the same height and reach a state of equilibrium. This means that fluids will always flow towards a low pressure area, which means that if you create a constant low pressure area you can amplify the air stream. This is the same principle as to why airplanes can fly.

EXAIR Super Air Nozzle entrainment

Since compressed air can be an expensive utility, it is good to minimize it and maximize the surrounding entrained air. Therefore we have designed our products to use this entrainment principle to amplify the air blast while using less compressed air and more entrained ambient air. Products like our Super Air Knife can see an amplification ratio (ambient air to compressed air) of up to 40:1; this means for every 1 SCFM of compressed air used we are entraining 40 SCFM of ambient air.

EXAIR’s Super Air Knife

We use this principle for our Air Amplifiers, Air Knifes, Air Nozzles and Jets, Safety Air Guns, and our Gen4 Static Eliminators. Our goal is to save you money and give you better results in the process.  

If you have questions about any of our engineered Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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Henri Coanda: June 7, 1886 – November 25, 1972

Compressed air flows through the inlet (1) to the Standard Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

How did a past inventor help generate efficient compressed air products for EXAIR?  In the early 20th century, Henri Coanda who was a Romanian aeronautical engineer built an experimental Coanda-1910 airplane.  There are some debates if the airplane actually flew, but he invented a curved surface for a wing to generate a Coanda effect. The Coanda effect is the “tendency of a fluid jet to stay attached to a convex surface”1.   Thus, a moving stream of fluid will follow the curvature of the surface rather than continuing to travel in a straight line.  The Wright Brothers who flew the first airplane in the state where EXAIR is located, Ohio, used the Coanda effect to create lift.  With a curved profile, the air will adhere to the surface, causing a low pressure which makes the airplane fly.

EXAIR also uses this Coanda profile to make some of our Intelligent Compressed Air Products™.  Like an airplane wing, our curved surface will create a low pressure.  How does this help?  Well, higher pressure will always travel to lower pressure.  Instead of lift, we use the low air pressure to entrain ambient air.  This ratio of entrained air to compressed air is what we call the amplification ratio.  The higher the amplification ratio, the higher the efficiency for a blowing device. Two main compressed air products that EXAIR manufactures use this type of profile; Air Knives and Air Amplifiers.  I will cover both below. 

The Air Knives that use the Coanda profile blows air along the length of the knife at a 90o angle from the exit.  We offer two types; the Standard Air Knife and the Full Flow Air Knife.  The Standard Air Knives are made in Aluminum or Stainless Steel with blowing widths up to 48” (1219mm).  The inlet ports are at each end; so, the overall length is 1” (25.4mm) longer than the blowing length.  The Full Flow Air Knives have a port, or ports, on the backside.  Like the name states, the air blows out the entire length of the air knife.  The maximum length is 36” (914mm).  Both types use the Coanda profile to generate a low pressure as the air exits the gap and “hugs” the curve (reference photo above).  This low pressure draws ambient air into the air stream at a 30:1 amplification ratio for both the Standard Air Knife and Full Flow Air Knife.  So, for every one part of compressed air, we entrain 30 parts of ambient air.  Besides efficiency, it also adds mass to the air stream for a hard-hitting force.  With the engineered profile, the airstream is laminar which gives a consistent force across the entire length and makes them quiet.  Not only will they save you money by using less compressed air, but they are also OSHA safe.    

Super Air Amplifier – flow region

The Air Amplifiers use the Coanda profile in a circular form to pull in large amounts of free surrounding air.  The Coanda effect is able to generate a low pressure in the center to blow air for cooling, cleaning or removing welding smoke and debris efficiently and quietly.  The Air Knives above will blow a flat stream of air while the Air Amplifiers will blow a conical air stream.  They can reach amplification ratios up to 25:1. The Super Air Amplifiers use a patented shim to increase efficiency.  Unlike fans, they blow a laminar air stream for quick cooling.  They do not have any moving parts or motors to wear, so they are very quiet.  EXAIR manufactures five different sizes from ¾” (19mm) to 8” (203mm).  The Adjustable Air Amplifiers have a plug that can be adjusted to control the blowing from a breeze to a blast.  For cleaning surfaces, this is a nice feature to “dial” in the correct amount of blowing force.  We also manufacture five different sizes ranging from ¾” (19mm) to 4” (102mm).  Both types can be ducted to remove debris, heat or smoke. 

Utilizing the Coanda effect allows for massive compressed air savings. Whether it is a flat or round air stream, EXAIR can do this with high amplification ratios.  If you would like to discuss further how our Air Knives or Air Amplifiers can help you in your application, please contact us. An Application Engineer will be happy to help you replace your inefficient blowing devices.  History has given us a way to increase efficiency for blowing compressed air.  Thank you, Henry Coanda. 

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

1note – Wikipedia – Coanda effect