EXAIR’s Super Air Amplifier Amplification Ratio’s, Explained

Much like the popular song from decades ago that was about “money for nothing”,  EXAIR can provide you with “air for free”.  What we mean by this is that when you choose to use our Super Air Amplifiers, you will produce a large volume of air while only requiring a small amount of compressed air. This is because Air Amplifiers amplify total output flow up to 25 times by entraining (pulling in) ambient air.

So just how does the EXAIR’s Super Air Amplifier do this?   By utilizing our patented design (Patent # 5402938) that incorporates a special shim to maintain the air slots precisely.  The compressed air is released toward the center of the Super Air Amplifier  which creates a constant, high velocity outlet flow across the entire cross sectional area.  This

SAA How It Works

The amplification occurs by entraining most of the ambient air from the back of the Super Air Amplifier. Another small volume of air is added again as the air exits the Super Air Amplifier further increasing the amplification.

SAA Blog 1Super Air Amplifiers that have outlet diameter’s of 3/4″ (19mm), 1 1/4″ (32mm), 2” (51mm) and 4” (102mm) are supplied with a .003” (0.08mm) shim which is ideal for most applications, however there is the optional .006” (.15mm) and .009” (.23mm) if more air volume and force is needed. The 8” (203mm) Super Air Amplifier comes standard with a .009” (.23mm) shim and for increased performance we offer an optional .015” (.39mm).  The chart below explains how to determine the total output flow and air consumption at different operating pressures for each Super Air Amplifier model.

SAA Blog 2

When you need “air for free” or more accurately stated, to get all you can from every SCFM of compressed air you produce, put the EXAIR Super Air Amplifier to work in your facility!

If you would like to discuss the EXAIR Super Air Amplifier or any of EXAIR’s Intelligent Compressed Air® products, give us a call as we would enjoy hearing from you.

Erik Kuhnash
Application Engineer
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Customizing Air Amplifiers

EXAIR’s line of Air Amplifiers can be found in a multitude of different applications across the world. They solve problems as simple as blowing debris off parts to exhausting fumes or circulating air. The Air Amplifier comes in two different styles either the Super Air Amplifier or the Adjustable Air Amplifier. Super Air Amplifiers come in a stock Aluminum Body with a diameter that ranges from ¾” to 8”. This differs from the Adjustable Air Amplifier which comes in either type 303 Stainless Steel or Aluminum and are Sized from ¾” to 4”.

The main difference between the Super Air Amplifier and the Adjustable Air Amplifier is the fact the Super Air Amplifier has a shim inside of it that sets the gap for the air flow. The standard shim thickness for the Super Air Amplifier in sizes of 3/4″ to the 4″ is 0.003” which is suitable for most applications. These shims can be exchanged for a thicker shim of thickness of either 0.006″ or 0.009″. The 8″ Super Air Amplifier is the only air amplifier that comes with a standard stock shim of 0.009″ and can be exchanged for a 0.015″ shim if needed.

Flanged Stainless Steel Adjustable Air Amplifier
Sanitary Flanged Adjustable Air Amplifier

Even though there is a wide variety of sizes and materials for the Stock Air Amplifiers they may not meet a customer’s specific application or need. Over the years EXAIR has produced many different custom Air Amplifiers for a customer’s specific need and the images throughout this blog are just a few of what we have done.

High Temp Air Amplifier

• Depending on the environment certain specific materials may be required like the food industry which requires specific Stainless Steel for various applications. One customer had a special PTFE plug made for the Adjustable Air Amplifier to help pull a sticky material through the process. The PTFE helped prevent the material form depositing on the Amplifier.
• For applications were mounting may be an issue, special attachments have been made to assist. For instances were an Amplifier may need to be mounted to a pipe a custom Stainless-Steel Adjustable Air Amplifier with a class 150 raised face flanges.
• Applications that are in a hot environment may require a special high temperature version which has be developed to operate in areas up to 700°F. The High Temperature Air Amplifier was so widely sought after that we turned it into a stock item. It is commonly used in large roto-molds and ovens to circulate air in order to maintain consistent temperatures.

Adjustable Air Amplifier with PTFE Plug Installed

No matter what your application needs are EXAIR will to work with you to create any custom Air Amplifier that fits your specific application needs.

If you have any questions about compressed air systems or want more information on any of EXAIR’s 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
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Laminar Flow Compared to Turbulent Flow

turbulent vs laminar

Fluid mechanics is the field that studies the properties of fluids in various states.  There are two main areas; fluid statics and fluid dynamics.  Fluid dynamics studies the forces on a fluid, either as a liquid or a gas, during motion.  Osborne Reynolds, an Irish innovator, popularized this dynamic with a dimensionless number, Re. This number determines the state in which the fluid is moving; either laminar flow, transitional flow, or turbulent flow.  Equation 1 below shows the relationship between the inertial forces of the fluid as compared to the viscous forces.

Equation 1:  Re = V * Dh/u

Re – Reynolds Number (no dimensions)

V – Velocity (feet/sec or meters/sec)

Dh – hydraulic diameter (feet or meters)

u – Kinematic Viscosity (feet^2/sec or meter^2/sec)

The value of Re will mark the region in which the fluid (liquid or gas) is moving.  If the Reynolds number, Re, is below 2300, then it is considered to be laminar (streamline and predictable).  If Re is greater than 4000, then it is considered to be turbulent (chaotic and violent).  The area between these two numbers is the transitional area where you can have eddy currents and some non-linear velocities.  To better show the differences between each state, I have a picture below that shows water flowing from a drain pipe into a channel.  The water is loud and disorderly; traveling in different directions, even upstream.  With the high velocity of water coming out of the drain pipe, the inertial forces are greater than the viscous forces of the water.  This indicates turbulent flow with a Reynolds number larger than 4000.  As the water flows into the mouth of the river, the waves transform from a disorderly mess into a more uniform stream.  This is the transitional region.  A bit further downstream, the stream becomes calm and quiet, flowing in the same direction.  This is laminar flow.  Air is also a fluid, and it will behave in a similar way depending on the Reynolds number.

Turbulent to Laminar Water

Why is this important to know?  In certain applications, one state may be better suited than the other.  For mixing, suspension and heat transfer; turbulent flows are better.  But, when it comes to effective blowing, lower pressure drops and reduced noise levels; laminar flows are better.  In many compressed air applications, the laminar region is the best method to generate a strong force efficiently and quietly.  EXAIR offers a large line of products, including the Super Air Knives, Super Air Amplifiers and Super Air Nozzles that utilizes that laminar flow for compressed air applications.  If you would like to discuss further how laminar flows could benefit your process, an EXAIR Application Engineer will be happy to help you.

John Ball
Application Engineer
Email: johnball@exair.com

Twitter: @EXAIR_jb

Calculating CFM of Air Needed for Cooling

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.

Heat Flow Equation
Using the standard heat equation above add in your variables for the item that needs to be cooled down. In the example I will be using a steel bar that is 25 kg in mass rate and cooling it down from 149 °C to 107 °C. We know that the specific heat of steel is 0.466 J/g°C therefore we have everything needed to calculate out the heat load using air temperature of 22 °C.
Calculating Joules/min
Using the heat rate, we can convert the value into watts of energy by multiplying the value by 0.0167 watts/(J/min) which gives us 16,537.18 watts. Furthermore, we can then convert our watts into Btu/hr which is a standard value used for cooling applications. Watts are converted into Btu/hr by multiplying by 3.41 Btu/hr/watt, giving us 56,391.77 Btu/hr.
Converting Joules to Btu/hr
Once you have Btu/hr you can plug the information into a re-arranged Cooling power formula to get the amount of CFM of air required for cooling.
Calculating CFM
As you can see in order to cool down this steel bar you only need to 343 CFM of air at 72°F. This can be done very easily and efficiently by using one of EXAIR’s Air Amplifiers or Air Knife. Sometimes you don’t need to use a vortex tube to cool down an object; sometimes simply blowing on it is good enough and its pretty simple to calculate out which product would fit your application the best.

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
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