How to Best Apply Vortex Tube Cooling

So, you have found yourself with a little bit of a conundrum. You need to cool a part but don’t know where to start and there are so many different options to choose from. In most cases when it comes to cooling with compressed air there are two different paths you can take. First is using a large volume of air at room temperature to blow across the surface area of the product. The other option is to use cold air from a vortex tube to drop the part’s temperature. In most case a large volume of air can be used to cool things down to relatively cooler temperatures; think cooling a cup of coffee using your breath. The issue you run into is when the temperature of the room air gets closer to the temperature you want to achieve in the end. In other words, when the temperature difference between your cooling air and your desired end temperature is small there is less cooling taking place with that same volume of air.

Mini Spot Cooler cooling down a bit used in milling plastic

This can be explained by looking at the cooling power formula:

Btu/hr = 1.0746*(CFM)*(Delta T)

In this case the Delta T is the difference between the temperature that you want to cool the product down to and the temperature of the air. This means the smaller the delta T is the higher the CFM flow will need to be to counteract the effect of the temperatures are so close to one another. Here are some examples of cooling a product and you are providing 1000 CFM of air to cool it.

Btu/hr = 1.0746*(1000 CFM)*(150F – 130F)

                Btu/hr = 21,492 Btu/hr

Btu/hr = 1.0746*(1000 CFM)*(150F – 100F)

                Btu/hr = 53,730 Btu/hr

As you can see the closer the Delta T is to 0 the less Btu/hr you get. Getting this kind of CFM flow is easy if you use something like EXAIR’s Super Air Knife or Super Air Amplifier. These systems take a small amount of compressed air and entrain the surrounding ambient air to increase the volume to a large blast. Take a look at model number 120022 which is the 2” Super Air Amplifier, this unit can produce 1,023 CFM while only using 15.5 CFM at 80 psig. But when you get close to cooling the temperature down to that room temperature or below it gets much harder; which only means that the temperature of the air being used to cool needs to be dropped. Dropping the air temperature can only be accomplished by using outside means like air coolers or in this case EXAIR’s Vortex Tubes and Spot Coolers.

EXAIR Air Amplifiers use a small amount of compressed air to create a tremendous amount of air flow.

Vortex Tubes and Spot coolers have some limitations. Generally they are not thought of products that produce large volumes of air (even though we make them up to 150 SCFM). And they are best suited for smaller areas of cooling, spot cooling, if you will. However, EXAIR Vortex Tubes do have one key feature that can help compensate for the lack of volume. LOW TEMPERATURE! The vortex tube can produce temperatures lower than 0F while stile retaining a good portion of air volume from the inlet.

Sub-zero air flow with no moving parts. 3400 Series Vortex Tubes from EXAIR.

For example, lets look at model number 3240 running at 100 psig with 70% of the air from the inlet exiting the cold side. At 100 psig the 3240 will use 40 SCFM at the air inlet and will have a temperature drop of 71F. If the compressed air has a temperature of 70F that means you will be seeing a temperature of -1F. Also, when using the 70% cold fraction you will see only 28 SCFM flow out of the vortex tubes cold side. Now let’s plug those numbers into the cooling power formula.

 Btu/hr = 1.0746*(28 CFM)*(150F + 1F)

                Btu/hr = 4543 Btu/hr

As you can see, using a small amount of compressed air you can still net you a good amount of cooling if the temperature is lower. All in all, the best option for cooling products down to temperatures that are above ambient temperatures is something that can produce a large volume of air. For anything that requires cooling the product down to temperatures around ambient temperature and below, use a vortex tube.

If you have questions about our Air Amplifiers and Vortex Tubes, or would like to talk about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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The Battle of Cooling: Fans Vs. Air Amplifiers

So, you have a cooling application and don’t know what to choose; do you go with the age-old fan or something different. Fans are probably one of the most common items used for cooling in everyday life and chances are you have a few that are always cooling. These fans can be found in cars, at your home, in your computer, and many other places.

But there may be other items that might just blow away the competition (pun intended). This is where EXAIR’s Air Amplifiers step onto the scene. Air Amplifiers use a little bit of compressed air to entrain the surrounding ambient air to turn it into a large volume of air.

Axial Fan being used to cool down an electrical cabinet

When it comes to cooling with air, volume is key. Air cannot hold a lot of thermal energy (heat) so in order to cool something down you need a lot of it. This means that the unit that can produce the largest volume of air is going to produce more cooling. So, what is the difference between a fan and the air amplifiers and which is better?

Fans have been in use since late B.C.E. and are still in use today. Many of the fans used for cooling are centrifugal style fans which are also known as blowers. These systems use an impeller that consists of a central shaft with blades that form a circle around a central opening. Blowers produce a high volume of air at a high velocity and low pressure. Not only do blowers require significant space to install, they also require noticeable maintenance and will eventually need to be replaced. Another, and perhaps more important downside, is that a blower will increase the temperature of the outlet air which further reduces the air’s ability to absorb additional heat and effectively cool.

Super Air Amplifier Family

On the other hand, Air Amplifiers use a source of compressed air to form a thin stream of high velocity laminar flow of air to entrain the surrounding ambient air. By doing so you can create a focused blast of air for cooling. So the downside in this case is that if you do not have a source of compressed air, the Air Amplifier will not function for you. With a small amount of compressed air, Air Amplifiers will multiply the volume of air up to 25 times to produce the large volume of air needed to cool parts, films, castings and more.

Air Amplifiers are extremely inexpensive when compared to blower systems and can out perform a blower in many applications.

If you have questions about our Air Amplifiers, or would like to talk about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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Super Air Amplifiers: Evacuation of Smoke or Fumes

Air Amplifiers Are Great For many things!

In the pneumatic industry, there are two types of Air Amplifiers.  One type will amplify the inlet air pressure to a higher pressure.  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 ratio is the relation between two amounts showing the number of times one value is contained within the other.  For the EXAIR Super Air Amplifiers, the ratio is the value that shows the amount of ambient air that is drawn within the compressed air.  The higher the ratio, the more efficient the blowing device is.  The EXAIR Super Air Amplifiers 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.    

Super Air Amplifier – flow region

To show the power of the Super Air Amplifier, we have a video of a model 120022.  In the video, oil is being heated to generate smoke, and the Super Air Amplifier is placed in the center of an exhaust pipe.  This demonstration was for a customer that was looking to evacuate vapors from an enclosed area.  Other applications would include welding smoke, ventilation, exhaust tank fumes, and dust collection.  You can see when the Super Air Amplifier is turned on and in operation in the video below. 

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 like the exhaust pipe above.  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.   As an added bonus, they are OSHA safe and meet the standards for noise level and dead-end pressure. 

With the today’s cost to make compressed air, it is important to use it as efficiently as possible.  The EXAIR Super Air Amplifiers have the ability to give effective blowing to remove debris, dry parts, transport material, cool objects, and clear smoke without using a large amount of compressed air.  EXAIR has the Super Air Amplifiers in stock and as always, EXAIR offers a 30-day unconditional guarantee for our customers in the U.S. and Canada to try them out.  If you have any questions about the Super Air Amplifiers or if you would like to discuss your application, an Application Engineer at EXAIR will be happy to help you.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Thinking Outside of the Box

Over the years of working at EXAIR, I have spoken to thousands of customers. The applications we discuss can run the full range that is showcased in the Solutions section of our website. It is always fun to approach applications when we have to think outside of the box for a solution. Throughout the Application Engineering department, our level of experience here combined with the customer’s knowledge of their setup, sometimes results in a solution that is not straightforward. Sometimes, we have to think outside of the box.

What kind of application may we have encountered where the obvious solution wasn’t the one that worked? One of the best applications that came to mind for me is when a customer was attempting to lift/pick up a very porous piece of filter media like the pre-filter from a Heavy Duty HEPA Vac. This material is extremely lightweight and porous. When hearing from a customer, I want to pick this material up, my mind quickly goes to the E-Vac Vacuum generators which are used to generate vacuum to operate suction cups.

In-Line E Vac picking up a block of cut extrusion.

With this material however, the vacuum flow needed is quite extensive and there is another product which is going to be a more efficient use of compressed air. That product, the Super Air Amplifier. As you can see in the photo below, a 2″ Super Air Amplifier easily lifts the porous material and because the suction side is a nominal hose size a hose can easily be attached if needed. The image shows a single amplifier lifting a larger sheet from a bench, these could be organized in an array like suction cups to pick materials up.

Model 120022 – 2″ Super Air Amplifier picking up a porous pre-filter material.

The moral of the story is to keep an open mind for solutions, while one path will always work other paths may become a more efficient manner. These solutions don’t always fit inside a box nice and neat. The Super Air Amplifier fit this because the amount of air entrained is tremendous and can easily be utilized to pull low vacuum force/high flow applications. This is very similar to fume evacuation which would be a “normal” application for the Super Air Amplifier.

If you want to discuss any point of use compressed air application with us, contact an Application Engineer and let us help you determine the solution your job needs.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF