A Cold Winter’s Chill and Vortex Tubes

Two weekends ago I had the pleasure of flying out to meet my friend in Colorado Springs and ski the weekend at Breckenridge. As an avid skier Breckenridge has been one of the resorts I have been wanting to ski since I started skiing out west. The weather was amazing and I couldn’t ask for better; the Saturday blue skies and cool breeze followed up by a Sunday of snow fall. The Trip was a dream come true. Breckenridge is specifically known for having high winds that howl across the peaks that stand at a max of 12,998 ft. above sea level. These chilling winds would freeze just about anyone if you aren’t dressed prepared for them as they blow right in your face on the lift. As I was sitting on the lift with these cold winds blowing in my face it brought to mind EXAIR’s Vortex Tubes, Cold Guns, and Cabinet Coolers.

EXAIR’s Vortex Tubes and similar products provide everything from a cool blast of air to a frigid breeze to cool off various parts and products. In a lot of smaller milling and grinding applications the Cold Gun has been used as a replacement to costly coolant-based alternatives. Vortex tubes have been used in cooling applications since 1945 and assist in everything from stress testing electronics to cooling down plastic parts during ultrasonic welding.

 Vortex tubes use a source of compressed air to create a hot and cold stream of air coming out on opposite ends of the device. This means that not only can the vortex tube be used for cooling but also heating applications. In one case a vortex tube was used to heat up an adhesive before it was sealed to get a better adhesion. Although the vortex tube can be used for heating purposes those applications are few and far between as usually a heating element or other heating source is more applicable.
Vortex tubes are quickly adjustable, just as the winds of Breckenridge can change from being a breeze to almost blowing you off of the mountain. Weather in the mountains is always varying and so are EXAIR’s Vortex Tubes.

If you have any questions or want more information on how we use our vortex tubes to improve processes all over industry. 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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How it Works: Theory Behind the Vortex Tube

What is a vortex tube and how does it work? A vortex tube is a device used to separate compressed air into a cold and hot stream of air; but the main question that many people have theorized is how does this device work.

In 1928 George Ranque, a French physics student stumbled upon this phenomenon on accident while he was performing experiments on a vortex type pump. During the experiment George noticed that hot air was being exhausted from one side and the other side was producing cold air. Eventually the device was forgotten about until 1945 when the German physicist, Rudolph Hilsch published a paper describing the device, eventually causing it to gain popularity and find applications in the industrial world.

EXAIR’s Vortex Tube uses compressed air as the supply and contains no moving parts to create a cold and hot stream of air from either end of the device. Using the valve located on the hot stream the vortex tube can achieve temperatures as low as -50°F (-46°C) and temperatures as high as 260°F (127°C).

The diagram bellow is one of the widely accepted explanations for the vortex tube phenomenon.

When the vortex tube is supplied with compressed air the air flow is directed into the generator that causes spin into a spiraling vortex at around 1,000,000 rpm. This spinning vortex flows down the neck of the hot tube denoted in the diagram as red. The control valve located on the end of the hot tube allows a fraction of the hot air to escape and what does not escape reverses direction and travels back down the tube in a second vortex denoted in blue. Inside of the low-pressure area of the larger outer warm air vortex, the inner vortex loses heat as it flows back to the front of the vortex and as it exits the vortex expels cold air.

The phenomenon is theorized to occur because both the hot and cold streams rotate at the same velocity and direction. This means that a particle of air in the inner vortex makes a complete revolution in the same time that a particle in the outer vortex takes to make a complete revolution. This effect is known as the principle of conservation of momentum and is the main driving force behind the vortex tube. In order for the system to stay in equilibrium air particles lose energy, in the form of heat, as they move from the outer stream to the inner stream, creating the cold air vortex that gets expelled.

At EXAIR we have harnessed many uses of vortex tubes for your cooling needs. Both our Cabinet Coolers and our Adjustable Spot Coolers utilize the vortex tube to either cool down an overheated cabinet or provide spot cooling for many different applications including to replace a messy coolant system for small grinding and machining applications.              

If you have questions about Vortex Tubes, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.   

Cody Biehle
Application Engineer
EXAIR Corporation
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Adjustable Spot Cooler Keeps Rollers Rolling

A manufacturer of automotive power transmission shafts was experiencing frequent failure of high pressure plastic rollers on their spin tester.  There are four rollers in a 90° array that center the shaft during spin testing.  They exert a pressure of around 1,500psi onto the shaft while it’s rotating at 1,000rpm.  This generates enough heat to actually melt the rubber coating on rollers, which means stopping testing (which holds up production) while they change out the rollers.  Just for it to start all over again.

This, of course, was an ideal application for a Vortex Tube cooling solution.  They wanted to aim the cold air flow from the dual points of two Model 3925 Adjustable Spot Cooler Systems at four points of the shaft, right where it starts to contact the rollers.

Model 3925 Adjustable Spot Cooler System has a Dual Outlet Hose Kit for distribution of cold air flow to two points.

Thing was, they wanted to mount the Adjustable Spot Coolers where they could have access to the Temperature Control Valve, but the cold air Hose Kit wouldn’t reach the shaft.  So they got a couple of extra sections of the cold air hose…they needed one section of the ‘main’ (shown circled in blue, below) to reach into the test rig’s shroud, and two sections of the ‘branch’ (circled in green) to reach to each roller.

If you need a little extra reach from an Adjustable Spot Cooler or a Cold Gun, the cold air hose segments snap together, and apart, for any length you need.

Now, adding too much hose length will start to put line loss on the cold air flow, and it will pick up heat from the environment.  But if you just need that extra foot of hose to get the job done, this generally works just fine.  The extra foot or so they’ve added (5″ to the main and 6″ to each branch) has solved their problem…they haven’t had to replace a roller since the Adjustable Spot Cooler Systems were installed.

If you’d like to find out more about how EXAIR Vortex Tubes & Spot Cooling Products can prevent heat damage in your operation, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Real Heroes of Science: Rudolf Hilsch

Rudolf Hilsch helped to advance vortex tube technology into what it is today.

If you look into the history or even the definition of a vortex tube, you’re likely to find mention of a physicist named Rudolf Hilsch.  Born December 18th, 1903, Hilsch was a German physicist, professor, and manager of the Physics Institute of the George August University of Göttingen.  He received a doctorate degree by the age of 24 and spent his career furthering the advancement and understanding of numerous phenomena of physics.

Although Hilsch didn’t invent the Vortex Tube (the original inventor was a physicist by the name of Georges J. Ranque), he is entwined with their history thanks to a paper he published in 1947.  According to lore, this paper significantly changed the understanding and performance capabilities of the vortex tube, eventually being marked as the precursor for identifying a vortex tube as a real potential cooling device. (I’ve made attempts to find this 1947 publication properly translated into English, but to no avail.  If you have it or find it, please email it to me at LeeEvans@EXAIR.com! (Original publication in German can be found here.)

Given that vortex tubes are a known EXAIR solution, it seems reasonable that today, on Hilsch’s birthday, we give recognition to this influential physicist and his mark on thermodynamic fluid flow technology.  And, although we at EXAIR are connected to Hilsch through vortex tubes, everyone alive has been influenced by his work.  This is because Hilsch and a partner (physicist Robert Wichard Pohl) constructed the first semiconductor amplifier in 1938, prompting Hilsch to prove (in 1939) that solid-state electronics are possible.  This work paved the way for transistor and solid-state electronics technology as we know it today.  Without Hilsch and his life’s work, not only would we not have vortex tubes, we likely would have any electronic devices we use every day.

Here’s to you Rudolf Hilsch.  Thank you for your work, your discoveries, and your achievements.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

 

 

Our Only Priority

Vortex Tubes

I know I’ve written on the topic before, but customer service isn’t just a department at EXAIR, it’s a priority.  And it’s not just a top priority, it’s our only priority.

I’m reminded of the distance between a company like ours and those in other industries whenever I’m required to interact with their service departments.  Rather than sound off about a bad experience, I think it’s more fitting, and becoming of our company culture, to give an example of our standard service level.

I fielded a call today from a manufacturer in Georgia.  They’ve used a series of Vortex Tubes to cool their product as it moves down a conveyor line for quite some time.  Process changes have resulted in greater temperatures and greater throughput, so there is a need to extend the cooling capacity to keep products up to quality.  Essentially what was needed was the same product that has worked in the past, just a few more pieces.  The only problem was that the model number was unknown.

After a search in our system turned up empty, it came to light that the company has changed names (perhaps more than once), and the most accurate way to determine the model number in question would be through a roll-stamped marking on the generator of the Vortex Tube.

The shop foreman and I walked through the disassembly over the phone, and realized that the Vortex Tubes have been in service for so long, that the roll-stamp had worn off.  So, we took it a step further and took measurements of critical dimensions on the generator.  I then cross referenced to our CAD files, and determined the unit was a 2 SCFM model 3200 series Vortex Tube.  A quick email to the shop foreman gave confirmed model number, pricing, and availability.

Situations like this are a regular occurrence for everyone at EXAIR.  If you’re having application difficulties and need a helping hand, we’ll be happy to add you to our list of success stories.

Lee Evans
Application Engineer
leeevans@exair.com
@EXAIR_LE