Air entrainment is a term that we bring up quite often here at EXAIR. It’s this concept that allows many of our products to dramatically reduce compressed air consumption. The energy costs associated with producing compressed air make it an expensive utility for manufacturers. Utilizing engineered compressed air products that will entrain ambient air from the environment allow you to reduce the compressed air consumption without sacrificing force or flow.
Products such as the Super Air Knife, Super Air Nozzle, Air Amplifier, and Super Air Wipe all take advantage of “free” air that is entrained into the primary supplied airstream. This air entrainment occurs due to what is known as the Coanda effect. Named after renowned Romanian physicist, Henri Coanda, the Coanda effect is used in the design of airplane wings to produce lift. As air comes across the convex surface on the top, it slows down creating a higher pressure on the underside of the wing. This creates lift and is what allows an airplane to fly.
This is also the same principle which is allowing us to entrain ambient air. As the compressed air is ejected through a small orifice, a low-pressure area is created that draws in additional air. Our products are engineered to maximize this entrained air, creating greater force and flow without additional compressed air. Super Air Amplifiers and Super Air Nozzles are capable of up to a 25:1 air entrainment ratio, with just 1 part being the supplied air and up to 25 times entrained air for free!! The greatest air entrainment is achieved with the Super Air Knife at an incredible ratio of 40:1!
This air entrainment principle allows you to utilize any of these products efficiently for a wide variety of cooling, drying, cleaning, or general blowoff applications. In addition to reducing your compressed air consumption, replacing inefficient devices with engineered products will also dramatically lower your sound level in the plant. Sound level in some applications can even be reduced down to a point that would eliminate the need for hearing protection with the OSHA maximum allowable exposure limits set at 90 dBA for an 8-hour shift.
If you have inefficient blowoff devices in your facility, give us a call. An Application Engineer will be happy to help you select a product that will “quietly” reduce your compressed air consumption!
As Application Engineers, we help many customers with finding solutions with effective, safe, and efficient EXAIR products. But, in some instances, we get a request for an air amplifier to increase line pressures. EXAIR does not manufacture this type of Air Amplifier. In doing some research on the internet, I was able to find two different types of air amplifiers. In this blog, I will describe the difference between the pressure-type and volume-type.
The EXAIR Super Air Amplifiers are defined as a volume-type of an amplifier. They use compressed air to generate a large volume of air flow. The amplification ratio is the comparison between the inlet air flow and the outlet air flow. With the EXAIR Super Air Amplifiers, we can reach an amplification ratio of 25 to 1. They use a Coanda profile with a patented shim to create a low pressure to draw in a large volume of the surrounding air. EXAIR manufactures a variety of different sizes, materials, and types. But they all do the same thing, amplify the volume of air. To give an example, model 120024 Super Air Amplifier has a 25:1 amplification ratio. It uses 29.2 SCFM (826 SLPM) of compressed air at 80 PSIG (5.5 bar). So, the outlet air flow is amplified from 29.2 SCFM to 730 SCFM (20,659 SLPM) of air. This large volume of air works great for cooling, exhausting, and transferring. But, with any type of amplification, you have to lose something. With the volume type Air Amplifiers, the outlet pressure is reduced dramatically.
The pressure-type air amplifiers are different from the Super Air Amplifiers as this device will amplify the outlet air pressure, not the volume. It is an air pump that has a direct dual piston that uses two different diameters. The larger diameter uses the drive inlet pressure while the smaller diameter is used for the boost pressure. The amplification ratio is determined by the difference in volume from the drive piston to the boost piston. They also come in a variety of ranges and sizes. As an example, an amplification ratio of 15:1 will increase an inlet pressure from 100 PSI (7 bar) to an outlet pressure of 1,500 PSI (103 bar). Since the pressure-type air amplifier is an air pump, the system has to cycle. To do this, they use pilot valves to either add the inlet compressed air to the drive piston or to relieve the air pressure from the drive piston. This cycling portion of the operation does reduce the efficiency of the air amplifier. The pressure-type air amplifiers are used to generate high pressure for a specific application or area and eliminate the purchase of a high-pressure air compressor. The applications include air clamps and presses, pressure testing, air brakes, and also blow molding. Like stated above about losing something with amplifications, the volume of air is reduced dramatically. Generally, a reservoir tank and over-sizing will be needed for a good system.
The Application Engineers at EXAIR enjoy talking to customers about compressed air applications. If you need more information about Air Amplifiers, you can contact us directly. We can explain the volume-type that we manufacture or refer you to a company that makes the pressure-type. Either way, we will be happy to hear from you.
The EXAIR Super Air Amplifiers and Adjustable Air Amplifiers are used in 100’s if not 1000’s of applications and locations across the world. For cooling, drying, and cleaning of parts as well as venting and exhausting of smokes and fumes, or dust collection – the Air Amplifiers are sure to get the job done.
The Super Air Amplifiers are made of aluminum and are sized from 3/4″ to 8″ to cover a wide range of applications. Compact and lightweight, no electricity, no moving parts, and instant on/off are just a few of the features.
The Adjustable Air Amplifiers are made of aluminum or type 303 stainless steel and are sized from 3/4″ to 4″, and with adjustable output, provide a wide spectrum of performance. They have the same great features of the Super Air Amplifier with the added benefit of varying force and flow.
2″ Super Air Amplifier and 2″ Stainless Steel Adjustable Air Amplifier
Even with the wide variety of types, sizes, and materials of construction, a customer may have a special need and there are numerous ways that EXAIR can customize the Air Amplifiers. I’ll touch on several from the basics to the most complex.
The Super Air Amplifiers come with a stock shim that sets the performance seen in the catalog. There are other shim thicknesses available if more or less flow is preferred, and they can be installed at the factory if desired.
The Adjustable Air Amplifiers are designed for varying output by turning the plug further in to or out of the body. If there is a performance setting that is preferred, we can test, adjust and set it to meet that performance, allowing to be installed and ready for optimum results.
If the use of a special material will increase the benefit of the Air Amplifier, we can explore several options with you. One customer needed an Adjustable Air Amplifier with a PTFE plug to help draw a sticky material through a process and prevent the material from adhering to the surface of the Air Amplifier.
For those applications where the Air Amplifier is to be installed into a piping system, custom design with flanged ends can be done. Recent designs include stainless steel Adjustable Air Amplifiers with class 150 raised face flanges, and another with sanitary Tri-Clamp style.
Adjustable Air Amplifier with PTFE Plug, Class 150 Raised Face and Sanitary Tri-Clamp Flanges
A special High Temperature version was developed for moving hot air to surfaces requiring uniform heating while in a furnace or oven. This special design is rated for environments up to 700°F and its surface is protected from heat stress by a mil-spec coating process. This special High Temperature Air Air Amplifier was so popular, it became a standard offering and is in stock!
1-1/4″ High Temperature Air Amplifier
For over 35 years, EXAIR has been designing and manufacturing the best performing and highest quality products in the marketplace. If you have a special requirement and in need of a custom solution, we’ve got the experience and history to solve most problems.
If you have questions about Air Amplifiers, custom Air Amplifiers, or 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.
In general, the air amplifiers employ the Coanda effect – a basic principle of fluid flow – to create air motion in their surrounding. Through intelligent design, this surrounding fluid flow can be manipulated and exploited, creating an amplification of a small amount of compressed air.
How do they work? In the figure below – a small amount of compressed air flows into the unit (1) to an annular chamber (2). The air is then throttled through a small ring nozzle (3) at high velocity. This primary air stream adheres to the Coanda profile (4), which directs it towards the outlet. A low pressure area is created at the center (5), inducing a high volume flow of the surrounding air into the primary stream. At the exit, you have the combination of flows, resulting in a high volume, high velocity flow.
The amplification ratio – the outlet airflow compared to the compressed air flow is dependent upon the cross sectional area of the inlet, and the 3/4″ Super Air Amplifiers have 12:1 amplification ratios all the way up to the 4″ and 8″ Super Air Amplifiers with 25:1 amplification ratios! That is a lot of ‘free air’ to use for cooling, drying and cleaning. And a lot of air or smoke that can be drawn at the inlet and vented away from the area. For more on the amplification ratios, see this -blog-
Each Super Air Amplifier has a patented shim (patent#5402938) that precisely sets the compressed air flow, and shim sets are available to install to increase the force and flow as needed.
The balanced outflow of air minimizes wind shear to produce a very quiet, powerful flow at sound levels up to three (3) times quieter than other air movers. A 4″ Super Air Amplifier operated at 80 PSIG will have a Sound Level of just 73 dBA.
The video below shows the power of the Super Air Amplifier in inducing a high volume flow of surrounding air (for venting) into the primary air stream (for cooling/drying/cleaning)
Typical applications include venting weld smoke, cooling hot parts, drying wet parts, cleaning machined parts, distributing heat in mold & ovens, dust collection, and exhausting vent fumes.
If you have questions about the Super Air Amplifier or any of the 16 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.
Henri Coanda was a Romanian aeronautical engineer best known for his work on the fluid dynamic principle with his namesake, the Coanda effect. Before this, Henri patented what he labeled as a jet engine.
Henri’s patent (French patent No. 416,54, dated October 22, 1910) gives more information into how he envisioned the motor working. When air entered the front, it passed through different cavities that caused the air stream to first contract and then expand. In Henri’s opinion this contraction and expansion converted the air’s kinetic energy into potential energy. The air ultimately was channeled to a diffuser where it was discharged.
Henri stated that the efficiency of this engine could be improved by heating the air in the cavities, Henri’s logic was that this would increase the pressure of the air passing through.
What is obviously lacking in the patent (including identical ones taken out in England and the United States) is any mention of injecting fuel, which in a true jet engine would combust with the incoming air. Judging only by Henri’s patent, it was little more than a large ducted fan and it could not have flown. Throughout Henri’s career he changed his story many times on whether this plane actually flew or not.
Not to cast too much shade on Henri’s accomplishments he did discover the Coanda effect. The Coanda effect states that a fluid will adhere to the surface of a curved shape that it is flowing over. One might think that a stream of fluid would continue in a straight line as it flows over a surface, however the opposite is true. A moving stream of fluid will follow the curvature of the surface it is flowing over and not continue in a straight line. This effect is what causes an airplane wing to produce lift, and enhance lift when the ailerons are extended while at lower air speeds such as occurs during takeoff and landing.
EXAIR uses the Coanda effect to offer you highly engineered, intelligent and very efficient compressed air products. Our designs take a small amount of compressed air and actually entrain the surrounding ambient air with the high velocity exiting compressed air stream to amplify the volume of air hitting a surface.
When you are looking for expert advice on safe, quiet and efficient point of use compressed air products give us a call. We would enjoy hearing from you.
The EXAIRAir Amplifiers are a powerful, efficient and quiet air mover, whose power can be harnessed for blowoff, cooling and ventilation applications. Using a small amount of compressed air, air amplifiers pull in large amounts of surrounding air to produce a high volume, high velocity outlet flow. Quiet and efficient, output flows with amplification ratios of up to 25 times are possible. There are two types, the Super Air Amplifier and the Adjustable Air Amplifier.
The Super Air Amplifier, with sizes ranging from 3/4″ to 8″, has a patented design (patent #5402938) that uses a special shim to maintain critical position of the components parts. It is through this critical gap setting that a precise amount of compressed air is passed at exact intervals controlled by the shim toward the center of the of the Super Air Amplifier. The jets of air create a high velocity flow across the entire cross sectional area, which in turn pulls in large amounts surrounding air, resulting in the amplified outlet flow. Because the outlet flow remains balanced and minimizes wind shear, sound levels are typically three times lower than other types of air movers. The shims are available in thicknesses of 0.003″ (supplied as standard), 0.006″ and 0.009″, and changing to a larger shim will increase the force and flow of the outlet air. The 8″ Super Air Amplifier is supplied with a 0.009″ shim, with a 0.015″ shim available.
2″ Super Air Amplifier and Patented Shim Design
For high temperature applications (up to 700°F/374°C) a special 1-1/4″ High Temperature Air Amplifier is available, with performance equal to the 1-1/4″ Super Air Amplifier. Its surfaces are protected from heat stress by a mil-spec coating process. The High Temperature Air Amplifier is highly effective at pushing large amounts of hot air to areas that typically remain cool.
The Adjustable Air Amplifier, with sizes ranging from 3/4″ to 4″, does not use a shim, and has an infinitely adjustable air gap, which regulates the air consumption and outlet flow from a light breeze to a powerful blast. A highly effective air mover, it can be tailored to meet the exact air flow and force of your specific application. They are available in aluminum and in stainless steel (Type 303) for food service, higher temperatures (400°F/204°C) and corrosive environments.
Force and flow of the Adjustable Air Amplifier is changed by loosening the knurled lock ring and turning the exhaust end to open or close the gap. Once the desired force and flow is achieved, the knurled ring can be tightened to lock the device at the current setting. Typically, an air gap of 0.002″ to 0.004″ provides the required performance.
The table below summarizes the key features of the Super Air Amplifier and Adjustable Air Amplifier. Please contact an Application Engineer if you need assistance in making a selection.
Note that EXAIR can manufacture special Air Amplifiers to your specification including special flanged mounting style or with a PTFE plug to avoid sticky material build up.
To discuss your application and how a Super or Adjustable Air Amplifier or any EXAIR Intelligent Compressed Air Product can improve your process, feel free to contact EXAIR, myself, or one of our other Application Engineers. We can help you determine the best solution!
EXAIR Super Air Amplifiers and fans are designed to move air. Fans use motors and blades to push the air toward the target. There are two types, centrifugal fans and axial fans. Centrifugal fans are also called blowers or “squirrel” cages. The air enters into the side of the fan and is redirected 90 degrees to the outlet. The axial fans are box fans, ceiling fans, and industrial fans. The motor and spindle are attached to blades. The air enters from directly behind the fan, and the blades “slap” the air forward to the target. The EXAIR Super Air Amplifiers does not have any blades or motors to push the air. They use a Coanda profile with a patented shim to create a low pressure to draw in the air. (You can read more about it here: Intelligent Compressed Air: Utilization of the Coanda Effect.) I will expand a bit more in this blog about how each one performs in moving ambient air.
The reason to move air can vary by application from cooling, drying, cleaning, and conveying. The more air that can be moved, the better the performance for each of these functions. With the Super Air Amplifiers and fans, these products can move the air, but what affects air flow? Velocity, turbulence, and static or back pressure. As we look at each one, we can start to see the effectiveness within each application.
Velocity is air flow per unit area. This is the speed at which the air is traveling. Some fan designs can affect the velocity, like the motor and spindle in the center of the axial fan. Some of the area is removed from the middle of the flow region. So, the velocity is very weak in the center. (Reference diagram below). With the centrifugal fan, the air velocity has to be redirected and pushed out the exhaust. The velocity profile is very disoriented and will work against itself within the flow region. If we look at the EXAIR Super Air Amplifier, the center is open as shown above. There are no obstructions. Since we are drawing in the ambient air, the velocity profile is laminar meaning that the flow is even across the entire flow region. Laminar flow is optimum for a uniform force and effective blowing.
Turbulence is the “action” of the air flow. If the turbulence is high, the air flow pattern is interrupted and chaotic. It causes the velocity of the air to decrease quickly. By the time the air reaches the target, it has low energy and force. As a result of turbulence, noise levels can become very loud. With a centrifugal fan or blower, the air is forced to move at a right angle and pushed out through an exhaust port. This creates a very turbulent air flow. The axial fan has less turbulence than its counterpart, but the blades still “slap” the air to push it forward. This disruption in the flow pattern for both fans create turbulence and disarray. The EXAIR Super Air Amplifier draws the air into the device to generate very little turbulence on the exhaust end. The flow pattern is consistent, working together in the same direction. This will allow for more air to reach the target.
Static pressure is important as it relates to the amount of resistance or blockage. When blowing air through or around products, this resistance will determine the effectiveness and distance for efficient blowing. To find the maximum resistance, this would be considered at the dead-end pressure. When the exhaust is totally blocked, the maximum pressure is created. In an application, the higher the resistance, the less air that can flow through and around to be utilized. With fans, it is dependent on the blade types, motor size, and RPM. Since the EXAIR Super Air Amplifiers do not have motors or blades, it is determined by the inlet air pressure. So, the higher amount of static pressure, the more resistance that the blowing device can handle.
In comparison, I created a table below to show a model 120024 4” Super Air Amplifier against two different types of fans. The first thing that you notice is the small package area of the model 120024 as compared to the fans that create similar air flows. The centrifugal fan requires an addition electrical motor which increases the cost and generates a larger footprint. The reason for the smaller flow area is the laminar air flow that the Super Air Amplifiers generate. As stated above, the velocity pattern works together in the same direction. So, a smaller profile can produce a lot more air movement. In addition, this helps to create a larger static pressure. Also referenced above, it will move the air much further to do more work. With high turbulence, the air movement works against itself causing inefficiencies and louder noise levels.
In physics, it is much 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. Being powered by compressed air, there is no need for electric motors or blades to “push” the air ineffectively. 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. 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.