Bifurcation Of Air – The Wonders of Science That Is The Vortex Tube

EXAIR has provided the benefits of vortex tube technology to the industrial world since 1983. Prior to that, French scientist George Ranque wrote about his discovery in 1928 calling it the tube tourbillion. But it wasn’t until German physicist Rudolf Hilsch’s research paper in 1945 on the wirbelrorhr or whirling tube, that the vortex tube entered the minds of commercial engineers. Nearly 60 years later, EXAIR is a leading provider for cooling products utilizing vortex tube technology.

More than 2,000 BTU/hr in the palm of your hand!

EXAIR Vortex Tubes produce a cold air stream down to -50° F and are a low cost, reliable, maintenance-free (there are no moving parts!) solution to a variety of spot cooling applications. These applications span a wide variety of industries and include cooling of electronic controls, soldered parts, machining operations, heat seals, environmental chambers, and gas samples. We’re always finding compelling new cooling opportunities for the vortex tubes.

How a Vortex Tube Works

So how does it produce the cooling stream? Compressed air is plumbed into the side port of the Vortex Tube where it is ejected tangentially into the internal chamber where the generator is located. The air begins flowing around the generator and spinning up to 1 million RPM toward the hot end (right side in the animation above) of the tube, where some hot air escapes through a control valve. Still spinning, the remaining air is forced back through the middle of the outer vortex. Through a process of conservation of angular momentum, the inner stream loses some kinetic energy in the form of HEAT to the outer stream and exits the vortex tube as COLD air on the other side.

The adjustable control valve adjusts what’s known as the cold fraction. Opening the valve reduces the cold air temperature and also the cold airflow volume. One can achieve the maximum refrigeration (an optimum combination of temperature and volume of flow) around an 80% cold fraction. EXAIR publishes performance charts in our catalog and online to help you dial into the right setting for your application, and you can always contact a real, live, Application Engineer to walk you through it.

EXAIR manufactures its vortex tubes of stainless steel for resistance to corrosion and oxidation. They come in small, medium and large sizes that consume from 2 to 150 SCFM and offer from 135 to 10,200 BTU/hr cooling capacity. Each size can generate several different flow rates, dictated by a small but key part called the generator. That generator can be changed out to increase or decrease the flow rate.

While operation and setup of an EXAIR Vortex Tube are easy, its performance will begin to  decrease with back pressure on the cold or hot air exhaust of over 3 PSIG. This is a key  when delivering the cold or hot airflow through tubes or pipes. They must be sized to minimize or eliminate back pressure.

The Vortex Tube is integrated into a variety of EXAIR products for specific applications, like the Adjustable Spot Cooler, the Mini Cooler, the Cold Gun Aircoolant System and our family of Cabinet Cooler Systems.

If you would like to discuss your next cooling application, please contact an Application Engineer directly and let our team lead you to the most efficient solution on the market.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

People of Interest: Rudolf Hilsch

Vortex Tubes

The EXAIR Vortex Tubes use compressed air to generate a cold air stream at one end and a hot air stream at the other end.  The history behind this phenomenon is rooted in the Ranque-Hilsch tube.

In 1931, a French physicist, Georges Ranque, tried to use a cyclone vortex to separate iron filings from the air.  He noticed that when he capped one end with a slight opening, the air would become very warm.  Being disappointed with the design flaw, he shelved his patented idea for several years.  In 1946, Rudolf Hilsch picked up this idea from Georges Ranque and refined the design.  This product has now become known as the Vortex Tube.  In this blog, I will cover Rudolf Hilsch as a person of interest.

Rudolf Hilsch was born in December 18th, 1903 in Hamburg, Germany and died on May26th, 1972.  In 1927, Rudolf received his doctorate at the age of 24.  In 1938, he worked with a colleague, Robert Pohl, to create one of the first working semiconductor amplifier.   From 1941 to 1953, Hilsch became a professor of physics at Erlangen, and in 1947, he published his paper on the Ranque-Hilsch tube which he called the “Wirbelrohr”, or whirl pipe.  This publication became well known and was the start of the Vortex Tube.

To expand a bit more into his publication, the design for spinning the air at a high rate of speed can produce a separation of temperatures.  It starts with a generator to help facilitate a vortex action.  As the vortex travels toward one end, a portion of that air will travel back through the center toward the opposite end.  (Reference picture below).  As these two vortices interact, conservation of momentum forces the inner vortex to give off energy in a form of heat to the outer vortex.  This separation of temperatures will give you a hot air stream and a cold air stream.  This type of device can do this without any moving parts or refrigerant.  You just have to supply a compressed gas.

To continue on with his career, in 1953, he became a full member of the Bavarian Academy of Sciences.  Also, at that same time, he started teaching physics at the Physics Institute of the Georg August University of Göttingen well into the 1960s.

EXAIR manufactures Vortex Tubes that utilizes this phenomenon with compressed air.  We stock units with cooling capacities up to 10,200 BTU/hr and can reach temperatures from -50oF to +260oF (-46oC to +127oC).  So, thank you Mr. Ranque and Mr. Hilsch for creating a product to generate hot and cold air in a single unit.  If you would like to discuss any applications where cooling or heating is needed, you can talk with one of our Application Engineers.  We will be happy to help.

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

Tried and True Products with Modern Performance and Safety Features

Over Labor Day I got the chance to take my dad and his friend climbing in Seneca Rocks West Virginia for the first time in a very long time. Seneca Rocks is a large Quartzite knife edge located in the Monongahela National forest on route 33. The majority of climbing there is what is known as Trad Climbing, which is just short for traditional climbing and is where one must place their own protection to clip the rope into (also pray it holds when you fall). Trad climbing requires a strong mental fortitude and precise physical movements as you jam different parts of your body into various sized cracks.

Me on the left and my Dad’s friend at the trail head for the hike to “the walls”.

In the ever-expanding world of new technology and advancements of outdoor adventure gear, all trad climbers stick with the same gear that was used some 30+ years ago. Although the materials and performance have improved the very principle and mechanics behind them has not. In this case the old saying “If it ain’t broke don’t fix it!” rings true. Sometimes when it comes to a solution, whether its hanging 200’ in the air or updating a process line, traditional is a great choice due to its simplicity and effectiveness.

Compressed air has been around since 1799 but the idea has been around since 3rd Century B.C. making it one of the oldest utilities next to running water. When it comes to manufacturing applications it’s about as tried and true as you can get, so why not look into our engineered products to help you solve your issues. Their simplicity and effectiveness remain, while their efficiency, safety and performance have been engineered to modern day needs.  These modern needs have insisted that products be safer and more efficient then they were 30+ years ago.  

One example of this is EXAIR’s Vortex Tube. Vortex tubes where discovered in 1931 and were exposed to industrial manufacturing in 1945. EXAIR improved upon them when the company began in 1983. Today they are still used for various cooling applications such as replacing mist coolant on CNC machines, cooling down plastic parts during ultrasonic welding, and keeping electrical cabinets cool so they don’t overheat.

Another example is air nozzles, nozzles are used for many different purposes like cleaning or cooling parts. If you are using nozzles from 30 years ago because they are effective, there is a good chance you can improve you r efficiency and increase safety for your personnel with EXAIR’s engineered Super Air Nozzles. They are designed in a variety of styles to fit your needs from tiny micro nozzles to massive cluster nozzles to blow off or cool  a multitude of parts and processes. 

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

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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Battling Heat Transfer

If you haven’t read many of my blogs then this may be a surprise. I like to use videos to embellish the typed word. I find this is an effective way and often gives better understanding when available.  Today’s discussion is nothing short of benefiting from a video.

We’ve shared before that there are three types of heat transfer, more if you go into sub-categories of each. These types are Convection,  Conduction, and Radiation. If you want a better understanding of those, feel free to check out Russ Bowman’s blog here.  Thanks to the US Navy’s nuclear power school, he is definitely one of the heat transfer experts at EXAIR.  If you are a visual learner like myself, check out the video below.

The Application Engineering team at EXAIR handles any call where customers may not understand what EXAIR product is best suited for their application. A good number of these applications revolve around cooling down a part, area, electrical cabinet, or preventing heat from entering those areas.  Understanding what type of heat transfer we are going to be combating is often helpful for us to best select an engineered solution for your needs.

Other variables that are helpful to know are:

Part / cabinet dimensions
Material of construction
External ambient temperature
If a cabinet, the internal air temperature
Maximum ambient temperature
Desired temperature
Amount of time available
Area to work with / installation area

Understanding several of these variables will often help us determine if we need to look more towards a spot cooler that is based on the vortex tube or if we can use the entrained ambient air to help mitigate the heat transfer you are seeing.

If you would like to discuss cooling your part, electrical cabinet, or processes, EXAIR is available. Or if you want help trying to determine the best product for your process contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Video Source: Heat Transfer: Crash Course Engineering #14, Aug 23, 2018 – via CrashCourse – Youtube – https://www.youtube.com/watch?v=YK7G6l_K6sA