People of Interest: Henri Coanda June 7, 1886 – November 25, 1972

Henri Coanda was born in Bucharest, Romania on June 7 1886 in a large family with five brothers and two sisters. His father, Constantin M. Coanda, was a decorated Romanian soldier and following in his footsteps he also enlisted in the military. He finished his military education with high honors, but his keen interest in flying and his desire to achieve this sent him down a much different path.

Coanda attended a technical university in Germany and also attended the Superior Aeronautical School in Paris where he graduated at the top of his class with the highest of honors. In less than a year, he had partnered with Gianni Caproni, another known aviator, to construct what was called the Coanda-1910. This aircraft was displayed in Paris at the Second International Aeronautical Exhibition. But, unlike other planes of this time, Coanda’s aircraft did not have a propeller. The plane had an oddly shaped front with built-in rotary blades arranged in a swirling pattern. It was driven by an internal turbine screw that would suck air in through the turbine while the exhausting gases exited from the rear, driving the plane forward by propulsion.


As impressive as this jet engine was, no one believed that it could fly. It is not believed that it ever did achieve flight, despite some contradictory claims by Coanda himself, but was instead struck by disaster. It is rumored that as Coanda injected more fuel into the engine, he was surrounded by flames, thrown from the craft and was lucky to make it out alive. Coanda is not credited as the inventor of the first jet plane, but it is his technology that sky rocketed future aviation research and provided perspective into how jet engines should be built.

Coanda is most known today for his research into what is now known as the Coanda Effect, or propensity of a fluid to adhere to the walls of a convex surface. It is this principle that creates lift on an airplane wing and is also the driving force behind many of EXAIR’s Intelligent Compressed Air Products. If you’d like to discuss how the Coanda effect is utilized in a Super Air Knife, Super Air Amplifier, or Super Air Nozzle give us a call!

Tyler Daniel
Application Engineer
Twitter: @EXAIR_TD


Jet Engine image courtesy of Luke Healy via Creative Commons License

Fluidics, Boundary Layers, And Engineered Compressed Air Products

Fluidics is an interesting discipline of physics.  Air, in particular, can be made to behave quite peculiarly by flowing it across a solid surface.  Consider the EXAIR Standard and Full Flow Air Knives:

Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) 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 serve to optimize the entrainment of air (4) from the surrounding environment.

If you’ve ever used a leaf blower, or rolled down the car window while traveling at highway speed, you’re familiar with the power of a high velocity air flow.  Now consider that the Coanda effect can cause such a drastic redirection of this kind of air flow, and that’s a prime example of just how interesting the science of fluidics can be.

EXAIR Air Amplifiers, Air Wipes, and Super Air Nozzles also employ the Coanda effect to entrain air, and the Super Air Knife employs similar precision engineered surfaces to optimize entrainment, resulting in a 40:1 amplification ratio:

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

As fascinating as all that is, the entrainment of air that these products employ contributes to another principle of fluidics: the creation of a boundary layer.  In addition to the Coanda effect causing the fluid to follow the path of the surface it’s flowing past, the flow is also affected in direct proportion to its velocity, and inversely by its viscosity, in the formation of a boundary layer.

High velocity, low viscosity fluids (like air) are prone to develop a more laminar boundary layer, as depicted on the left.

This laminar, lower velocity boundary layer travels with the primary air stream as it discharges from the EXAIR products shown above.  In addition to amplifying the total developed flow, it also serves to attenuate the sound level of the higher velocity primary air stream.  This makes EXAIR Intelligent Compressed Air Products not only as efficient as possible in regard to their use of compressed air, but as quiet as possible as well.

If you’d like to find out more about how the science behind our products can improve your air consumption, give me a call.

Intelligent Compressed Air: Utilization of the Coanda Effect

Henri Coanda was a Romanian aeronautical engineer most known for his work developing what is today known as the Coanda effect. The Coanda effect is the propensity of a fluid to adhere to the walls of a curved surface. A moving stream of fluid will follow the curvature of the surface rather than continuing to travel in a straight line.  This effect is used in the design of an airplane wing to produce lift. The top of the wing is curved whereas the bottom of the wing remains straight. As the air comes across the wing, it adheres to the curved surface, causing it to slow down and create a higher pressure on the underside of the wing. This  is referred to as lift and is what allows an airplane to fly.


The Coanda effect is also the driving force behind many of EXAIR’s Intelligent Compressed Air Products. Throughout the catalog you’ll see us talking about air amplification ratios. EXAIR products are designed to take advantage of this phenomenon and entrain ambient air into the primary air stream. Compressed air is ejected through the small orifices creating air motion in their surroundings. Using just a small amount of compressed air as the power source, Super Air Knives, Air Nozzles, and Air Amplifiers all draw in “free” ambient air amplifying both the force and the volume of airflow.

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

Super Air Knives provide the greatest amount of air amplification at a rate of 40:1, one part being the compressed air supply and 40 parts ambient air from the environment. The design of the Super Air Knife allows air to be entrained at the top and bottom of the knife, maximizing the overall volume of air. Super Air Nozzles and Super Air Amplifiers also use this effect to provide air amplification ratios of up to 25:1, depending on the model.

Air Amplifiers use the Coanda Effect to generate high flow with low consumption.

The patented shim design of the Super Air Amplifier allows it to pull in dramatic amounts of free surrounding air while keeping sound levels as low as 69 dBA at 80 psig! The compressed air adheres to the Coanda profile of the plug and is directed at a high velocity through a ring-shaped nozzle. It adheres to the inside of the plug and is directed towards the outlet, inducing a high volume of surrounding air into the primary air stream. Take a look at this video below that demonstrates the air entrainment of a Super Air Amplifier with dry ice:

Utilizing the Coanda effect allows for massive compressed air savings. If you would like to discuss further how this effect is applied to our Super Air Knives, Air Amplifiers, and Air Nozzles give us a call. We’d be happy to help you replace an inefficient solution with an Engineered Intelligent Compressed Air Product.

Tyler Daniel
Application Engineer
Twitter: @EXAIR_TD

Custom Air Amplifiers To Meet Most Any Requirement

When I think of “special” in regard to Air Amplifiers, I’m more inclined to think of the applications they can be used in. I mean, the Air Amplifier itself is about as straight-forward as an engineered compressed air product can be:

Air Amplifiers use the Coanda Effect to generate high flow with low consumption.

Considering the simplicity of the product itself, they can be used for a large variety of “typical” applications:

  • Cooling
  • Drying
  • Cleaning
  • Ventilation
  • Fume Exhausting
  • Dust Collection

There are no shortage of “special” applications either.  They’re used successfully in Air Operated Conveyance applications (when the stronger vacuum head of a Line Vac isn’t required) and we’ve even got a customer who uses one instead of an E-Vac Vacuum Generator for a “pick & place” operation…they’re picking up small, porous fiber discs (sort of like a coffee filter) one at a time, and the E-Vac wanted to pick up a good part of the whole stack, no matter how low they turned the pressure.  And of course, I can’t think of anything more special about Air Amplifiers than this:

You have to read it to believe it.  Follow the link and click on “Case Study: Roaring Banana Breath”

With fifteen distinct models to choose from in a range of sizes (3/4″ to 8″,) materials (aluminum or Stainless Steel) and even a High Temperature model that’s rated to 700°F (374°C), we’ve still made a fair number of Custom Air Amplifiers too…thirty-four, to be exact, as of this writing.

I won’t bore you with all the details – I can’t, actually, because some of them are proprietary* – but here are some “regular” examples of “special” accommodations:

  • Connections: EXAIR Air Amplifiers have smooth bores on the inlet & outlet plenums that you can hose clamp a hose (or round duct) to if you need to get air flow from, or to, one place or another.  Sometimes, though, they’re going in to an existing system, so we’ve made them with flanges (150#RF and Sanitary Tri-Clamp, for example) or threads (NPT or BSPP.)  If you want to use something other than a standard hose or duct line, we can help.
  • Material of construction: Our durable, lightweight aluminum Super & Adjustable Air Amplifiers are just fine an awful lot of the time.  Our type 303 Stainless Steel Adjustable Air Amplifiers will hold up to heat and corrosives.  We’ve also in PTFE (Teflon™) as well as a range of metal alloys to meet specific corrosion or wear conditions.  If your environment calls for a little something extra, we can help.
  • Assembly: Super Air Amplifiers are fitted with a stock shim that gives you published performance.  We’ve got other thicknesses, though, if you need more (or less) flow, though.  Adjustable Air Amplifiers are, well, adjustable…you just thread the plug in/out of the body until you get the results you want.  Sometimes the user knows what shim they want in a Super Air Amplifier, or what gap their Adjustable Air Amplifier needs to be set to, and we can assemble it accordingly.  If you have a ‘tried-and-true’ performance setting and want it met right out of the box, we can help.
  • Assembly, part 2: Good engineering practices call for lubrication on O-rings and threaded connections, and we use high quality, general purpose compounds when assembling our Air Amplifiers.  These are detrimental, however, in certain situations (silicone exclusion areas, I’m looking at you.) If certain chemicals or compounds are prohibited by your application, we can help.

*Let’s say you’ve done the “heavy lifting” to call out one (or more) of these special design features.  If we make a custom product (and that’s not just Air Amplifiers, by the way) using directions based on your time and labor, we’ll treat that product as proprietary to you, and you alone.

EXAIR has 208 catalog pages worth of Intelligent Compressed Air Products on the shelf…8 of those pages are our Air Amplifiers.  If you want to talk about customizing one to meet your needs, give me a call.

Russ Bowman
Application Engineer
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What’s So “Super” About The Super Air Amplifier?

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

“Free air” from the surrounding environment?  You might think it’s too good to be true, and if you think you’re getting something for nothing, you’re right.  If you consider, though, that it’s oftentimes preferable to work smarter, not harder, then the use of engineered compressed air products is too good NOT to be true.  Case in point: the Super Air Amplifier.

The Coanda Effect is the “work smarter, not harder” part of the Super Air Amplifier

Simple and low cost, (hey, “engineered” doesn’t necessarily mean “complex and expensive”) the EXAIR Super Air Amplifier uses a small amount of compressed air to generate a tremendous amount of air flow through entrainment.  How much do they pull in?  Depending on the model, they entrain air at rates of 12:1 (for the 3/4″ Model 120020) to 25:1 (4″ & 8″ Models 120024 & 120028, respectively.)  The larger diameters mean there’s more cross sectional area to entrain air, so there is indeed efficiency to scale, size-wise.  There are a couple of great visuals in this video, if you want to see the entrainment in action (1:50) or the difference that the entrainment makes (1:30):


Where can you use a Super Air Amplifier?  The easy answer is, anyplace you want a consistent, reliable air flow.  The pressure supply can be regulated from a “blast to a breeze,” depending on the needs of your application.  The patented shim can be replaced for even higher performance, while maintaining the efficiency that makes it so valuable.  The balanced flow makes for incredibly quiet operation…no more noisy fans, blowers, or open-end compressed air pipes.  The body (3/4″ to 4″ sizes) is cast with a 2-hole flange for ease of installation.

When can you use a Super Air Amplifier?  Another easy answer: anytime you want.  If you need a continuous air flow, there are no moving parts to wear or electrical components to burn out.  Supply them clean, dry air, and they’ll run darn near indefinitely, maintenance free.

Alternately, if you need intermittent air flow, starting & stopping operation is as simple as opening & closing a valve in the compressed air supply line.  They produce rated flow immediately, and cut it off just as fast.

Some of the more popular applications are ventilation/exhaust, cooling, drying, cleaning, and dust collection.  There are five distinct models to choose from, and they’re all in stock.  We’re also happy to discuss special requirements that might lead to a custom product too.  Our Application Engineers work with Design & Production all the time to meet specific needs of particular situations.

If you’d like to find out more about letting the Super Air Amplifier, or any of EXAIR’s Intelligent Compressed Air Products work smarter for you, give me a call.

Russ Bowman
Application Engineer
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Video Blog: Which EXAIR Air Knife Is Right For You?

The following short video explains the differences between the 3 styles of Air Knives offered by EXAIR – The Super, Standard and Full-Flow. All of these Models are IN STOCK, ready to ship, with orders received by 3:00 PM Eastern.

If you need additional assistance choosing your EXAIR Air Knife, please contact an application engineer at 800-903-9247.

Justin Nicholl
Application Engineer



Principles of Operation

Last week, I wrote about frequently-asked-questions.  I really enjoy opportunities to engage in technical discussions with folks who want to know how a certain EXAIR product works, and, more importantly, how it will work for them.

Occasionally, we’ll get asked questions about the principle of operation, and, especially with our vacuum products, people will assume they operate on the Venturi principle (a constriction to fluid flow within a tube causes the velocity to increase and the pressure to fall), which is a very popular, tried-and-true method to create a vacuum.

Another way to do it, though, is to rely on the Coanda effect, which is the tendency of a stream of fluid flowing near a surface to follow the line of that surface, rather than its original course.  This is how our Air Knives turn a relatively small amount of compressed air into a tremendous amount of flow.  It’s also the way our Air Amplifiers work – when the compressed air leaves the internal nozzle and follows the internal surface (the Coanda profile) towards the outlet, it entrains a bunch of the existing air inside the product and takes it along, and a low pressure area (aka “vacuum”) is created.

Yet another way to do it is simply direct a high velocity of air towards the outlet.  The forceful exit of the air then entrains the air inside the item, creating a vacuum.  That’s how the Line Vacs, Chip Vacs, Heavy Duty Dry Vacs, and Vac-u-Guns work.  Fancy scientific principles aside, never underestimate the value of simple brute force!

That said, all of these products are quite similar in their basic construction.  The Air Amplifiers’ low pressure area allows it to pull an enormous amount of air through (albeit at a lower vacuum level), which is good for moving large quantities of air and airborne particulate.  The Line Vacs, Chip Vacs and Heavy Duty Dry Vacs don’t have as much vacuum flow, but are capable of pulling a pretty strong vacuum – as much as 144” H2O (-36 kPa), which is great if you’re vacuuming up, or conveying, solid materials.

For the record, our E-Vac Vacuum Generators use the Venturi principle to pull a strong vacuum of up to 27”Hg.  They’re ideally suited for a wide variety of applications such as: pick-and-place lifting, vacuum forming, mold evacuation, clamping/chucking, “hands-off” liquid sampling, and vacuum filling, just to name a few.

Strictly speaking, the Reversible Drum Vac operates on the Venturi principle as well, although the air path isn’t as straight forward as your plain old run-of-the-mill eductor type product.  That’s how it generates the vacuum to fill a drum with liquid.  Of course, to pump it out, with a simple turn of the knob, we’re back to good old brute force.

Regardless of the scientific principle behind the operation, if you have an application that requires pulling a vacuum, we can help…give us a call!

Russ Bowman
Application Engineer
EXAIR Corporation
(513)671-3322 local
(800)923-9247 toll free
(513)671-3363 fax