It’s easy to know that EXAIR’s vortex tubes can be used to cool down parts and other items, but did you know that our air knifes can be used to cool down these same things? It’s the same process that we do every day to cool down hot food by blowing on it. Every molecule and atom can carry a set amount of energy which is denoted by physical property called Specific Heat (Cp); this value is the ration of energy usually in Joules divided by the mass multiplied by the temperature (J/g°C). Knowing this value for one can calculate the amount of air required to cool down the object.
Starting out you should note a few standard values for this rough calculation; these values are the specific heat of Air and the specific heat of the material. Using these values and the basic heat equation we can figure out what the amount of energy is required to cool. The specific heat for dry air at sea level is going to be 1.05 J/g*C which is a good starting point for a rough calculation; as for the specific heat of the material will vary depending on the material used and the composition of the material.
If you have any questions about compressed air systems or want more information on any EXAIR’s of our products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.
Cody Biehle Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
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 that 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 uses this Coanda profile to make some of our Intelligent Compressed Air Products™. Like the airplane wing, our curved surface will also create a low pressure. How does this help? Well, high pressure will always travel to low pressure. Instead of lift, we use the low air pressure to entrain ambient air. This ratio 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” (25mm) longer. The Full Flow Air Knives have the port or ports on the back. The air blows out the entire length of the air knife. The maximum length is 36” (914mm).
Both types of air knives 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 this engineered profile, the air stream is laminar which gives a consistent force across the entire length and reduces noise levels. Not only will they save you money, but they are also OSHA safe.
The Air Amplifiers use the Coanda profile in a circular form to pull in dramatic amounts of free surrounding air. The Coanda effect is able to generate a low pressure to blow air for cooling, cleaning or removing smoke and debris efficiently and quietly. The Air Knives above 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 force from a breeze to a blast. For cleaning surfaces, this is a nice feature to “dial” in to exactly what you need. We also manufacture five different sizes in aluminum and stainless steel ranging from ¾” (19mm) to 4” (102mm). Both Air Amplifiers can be attached to ducts to remove debris, heat or smoke from the area.
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 applications, please contact us. An Application Engineer will be happy to help you. History has shown us a way to increase efficiency when using compressed air. And you can take advantage of it with the Coanda profile. Thank you Mr. Henri Coanda.
In the pneumatic industry, there are two types of Air Amplifiers. One type will amplify the inlet air pressure to a higher compression. The other type uses the inlet air pressure to amplify the air volume. EXAIR manufactures the volume type called the Super Air Amplifiers™.
This change in air volume is called the amplification ratio. So, what does this mean? The definition of a ratio is the relation between two amounts showing the number of times one value is contained within the other. For the Super Air Amplifier, it is the value that shows the amount of ambient air that is contained within the compressed air. The higher the ratio, the more efficient the blowing device is. With the EXAIR Super Air Amplifiers, we can reach amplification ratios up to 25 to 1. This means that 25 parts of ambient “free” air is introduced for every 1 part of compressed air.
Why an EXAIR Super Air Amplifier? Like a fan, they are designed to move air. But fans use motors and blades to push the air toward the target. The fan blades “slap” the air which creates turbulent air flows and loud noises. The Super Air Amplifiers do not use any blades or motors to move the air. They just use a Coanda profile and a patented shim to create a low pressure to draw in the ambient air. In physics, it is much easier to pull than it is to push. The process of pulling air through the Super Air Amplifiers make them a more efficient, uniform, and quiet way to blow air.
Most people think that compressed air is free, but it is most certainly not. Because of the amount of electricity required, compressed air is considered to be the fourth utility in manufacturing plants. To save on utility costs, it is important to use compressed air as efficiently as possible. In reference, the higher the amplification ratio, the more efficient the compressed air product. Manufacturing plants that use open fittings, copper tubes, and drilled pipes for blowing are not properly using their compressed air system. These types of products generally only have between a 2:1 to 5:1 amplification ratio. The Super Air Amplifiers can reach a 25:1 ratio.
EXAIR manufactures and stocks five different sizes ranging from ¾” (19mm) up to 8” (203mm) in diameter. Some of the benefits that the Super Air Amplifiers have is the inlet and outlet can be ducted for remote positioning. They are very compact and can fit into tight places. They do not have any moving parts to wear or need electricity to run. They only need clean compressed air to operate; so, they are maintenance-free.
Another unique feature of the EXAIR Super Air Amplifier is the patented shim which optimizes the low-pressure to draw in more ambient air. With extracting welding smoke, increasing cooling capacities, and moving material from point A to point B; the more air that can be moved, the better the performance. And with the patented shim inside the EXAIR Super Air Amplifiers, it provides that. As an added bonus, they are OSHA safe and meet the standards for noise level and dead-end pressure.
To explain things in every day terms; the amplification ratio can be represented by gas mileage. Like your car, you want to get the most distance from a gallon of gasoline. Similarly, with your compressed air system, you want to get the most for your pneumatic equipment. An EXAIR Super Air Amplifier has a 25:1 amplification ratio.; so, in other words, you can get 25 mpg. If you use drilled pipes, open fittings, copper tubes, etc. for blowing, then you are only getting 2 to 5 mpg. If you want to get the most “distance” from your compressed air system, you should check the “gas mileage” of your blow-off components. If you need assistance, an Application Engineer at EXAIR can help you to “tune up” your compressed air system.
In the compressed air world, when we talk about an “air amplifier” it can mean one of two things: either a pressure air amplifier, or a volume air amplifier. How do we differentiate the two and what types of applications does each serve?
A pressure air amplifier works as an air pump to increase the pressure of the supplied air, generating pressures ranging from 30 psi up to as much as 1500 psi in some specialized types of pressure amplifiers. Pressure air amplifiers operate only off of the supplied compressed air and do not require a source of electricity to drive the piston amplifying the pressure. They are available in both single-acting and double-acting varieties with the double-acting being the most efficient.
Pressure-type air amplifiers are used in applications where a specific product or process must have a higher pressure than the compressor system can deliver. This includes applications such as: air clamps, presses, pressure testing, air brakes, and also blow molding. The drawback to these products is that the increase in pressure does result in a reduction in volume of air. A point of use receiver tank and over-sizing of the overall system is generally a good practice to ensure sufficient operation.
On the other side of the amplifier spectrum lies EXAIR with our volume amplifying amplifiers. EXAIR manufactures two different styles of volume air amplifier: The Super Air Amplifier and Adjustable Air Amplifier. These products utilize Bernoulli’s Principle and the coanda effect to draw in large amounts of ambient air that mixes with the supplied compressed to project a hard hitting force of laminar airflow, much greater than what is supplied.
EXAIR’s Adjustable Air Amplifiers are available in both Stainless Steel and Aluminum from sizes ranging from ¾”-4” on the air outlet. The outlet can be ducted or it can be used as-is. The air gap of the Adjustable Air Amplifier is infinitely adjustable, allowing you to regulate both the air consumption and outlet flow from a “breeze” to a “blast”. In addition to the standard Adjustable Air Amplifiers, we also have a High Temperature Air Amplifier available that is capable of withstanding temperatures as high as 700°F.
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.
Volume air amplifiers can be used in a variety of blowoff, conveying, drying, cooling, and venting applications. With a range of different sized Super Air Amplifiers and Adjustable Air Amplifiers, EXAIR has a solution for you if you need to move A LOT of air for a variety of reasons. Reach out to an Application Engineer today if you have an application that you believe could be served with a low-cost, simple solution!