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.
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.
A couple days ago I took a call from an extrusion company who was looking to increase the airflow in their plating operation. They manufacture several different shapes and styles of aluminum extrusions by the way of 8 large extrusion presses. On one of the presses they make a specialty line of products that are sent to a finishing operation to be anodized.
Above the anodizing process tanks they use a vacuum hood to capture fumes and send them to a scrubber system so the air can be cleaned before being exhausted. They were starting to see an increase in the level of VOC (Volatile Organic Compound) gases in the area and, after some internal testing, determined the existing system wasn’t moving enough air through the system for the gases to be adequately delivered to the scrubber tank.
After further discussion, the customer ordered our Model # 120022 2″ Super Air Amplifier to test under our Unconditional 30 Day Guarantee. Air Amplifiers are one of the most efficient products in the EXAIR catalog. Using a patented internal shim, they use a small amount of compressed air that passes through an internal chamber where it is exhausted through a thin gap at high velocity. This directed airflow creates a lower pressure at the intake side which draws in a large amount of free air. The 2 combining air flows result in a large volume of “amplified”, high velocity exhausting airflow, making them ideal for increased air movement.
If you have an application where you need to increase airflow or if you’re looking to vent or exhaust noxious fumes, an Air Amplifier is the ideal choice. For help selecting the best Model or to discuss a particular process, please contact an application engineer for assistance.
There is rarely a day that goes by that I don’t receive a call from someone who has a need for a compressed air product and when I state the SCFM requirements of the device they respond back with the psi rating of their air compressor. Many technicians simply do not understand the difference between the two. Simply put psi (pounds square inch) is force and CFM (cubic feet per minute) is flow.
A simple illustration would be to contrast a 12 VDC powered air compressor that many people carry in their trunks to inflate car tires. They will inflate your car tire to 35 psi in a matter of minutes. While the air compressor at a tire shop can inflate a car tire in a minute or less. What is the difference?
Simply put, the flow. Both inflate the tire to the desired pressure but the one with largest flow (volume) does it much faster. In the case of a compressed air product such as an air nozzle, the pressure required to operate is only one part of what is necessary to operate the device effectively, you need to have enough flow or CFM.
Let us now consider an EXAIR 1100 Super Air Nozzle, its rated performance of 13 ounces of force at 12″ distance from the nozzle is derived from supplying 14 SCFM @ 80 psi. The typical home use air compressor that runs on 110 VAC (Generally 2 HP maximum) will not generate the flow (volume /CFM) at 80 psi to run the nozzle at peak force, just as it would not generate enough flow to fill the tire as quickly as the industrial compressor at a tire shop.
When an open tube, pipe or inefficient nozzle is placed at the end of an air line to provide blow off for cooling or cleaning it demands much greater volume from the compressor. If the compressor cannot keep up the force (pressure) of the system will decline. Replacing an open tube or pipe with an EXAIR engineered nozzle will require less compressed air volume which, in turn, will give the compressor more ability to provide full pressure and force upon your application.
If you would like to discuss air consumption of any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.
Essentially compressed air technology was first used with the knowledge of how to start a fire. Humans learned that to get the fire started, blowing helped the process, healthy human lungs can generate approximately .02 to .08 bar or .3 to 1.2 PSI.
At the beginning of the metallurgical age (approximately 3000 B.C.) a higher volume of air than what human lungs could produce was required to the reach the temperatures required to melt and form metals such as copper, tin, lead, etc. This need lead to the hand-operated bellows, the first mechanical air compressor. Approximately 1500 years later the more efficient foot powered bellows was developed.
The foot powered bellows was followed by water powered bellows and was the mainstay for more than 2000 years. However as blast furnaces came into being the need for compressed air increased. This lead John Smeaton in 1762 to design a water wheel that powered a blowing cylinder and this began to replace bellows. In 1776 John Wilkinson developed an efficient blasting machine and this was the beginning for mechanically powered air compressors.
As time progressed the idea of transmitting energy via compressed air became acceptable. This idea was demonstrated around 1800 when the newly invented pneumatic rock drill was used to tunnel 80 miles under Mt. Cenis to connect Italy & France by rail. This was an extraordinary feat for the time and garnered global interest. This event perpetuated great interest into pneumatic powered devices and brought us the air powered motors, clocks and even beer dispensers!
While compressed air is capable of transmitting energy long distances and performing tremendous work it also referred to as the 4th utility in industrial plants due to its cost. We at EXAIR have been promoting compressed air conservation and safety using highly engineered products for 35 years! Our products wring the maximum of energy out of every SCFM fed to them by using air entrainment and the Coanda effect. Not only are we conserving your compressed air we offer products that are quiet and can’t be dead ended which prevents air embolisms.
If you are interested in discussing conserving compressed air and/or compressed air safety, I would enjoy hearing from you.
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.
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.
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.