Discovery of The Vortex Tube

There are many theories regarding the dynamics of a vortex tube and how it works. Many students have studied them in hopes of advancing the physics or as part of their undergrad studies. The man that started it all was not intentionally researching it, however.

The Vortex Tube was invented by accident in 1928, by George Ranque, a French physics student. He was performing experiments on a vortex-type pump that he had developed and noticed that warm air exhausted from one end and cold air from the other. Ranque quickly changed his focus from the pump to start a company taking advantage of the commercial possibilities for this odd little device that produced both hot and cold air, using only compressed air, with no moving parts. The company was not successful, and the vortex tube was forgotten until 1945 when Rudolph Hilsch, a German physicist, published a widely read paper on the device.

A vortex tube uses compressed air as a power source, has no moving parts, and produces hot air from one end and cold air from the other. The volume and temperature of the two air streams is adjustable with a valve built into the hot air exhaust.  Temperatures as low as -50°F (-46°C) and as high as 260°F (127°C) are possible.

Compressed air is supplied to a vortex tube and passes through nozzles that are tangent to an internal counterbore. As the air passes through it is set into a spiraling vortex motion at up to 1,000,000 rpm. The spinning stream of air flows down the hot tube in the form of a spinning shell, like a tornado (in red). The control valve at the end allows some of the warmed air to escape and what does not escape reverses direction and heads back down the tube as a second vortex (in blue) inside of the low-pressure area of the larger warm air vortex. The inner vortex loses heat and exits through the other end of as cold air.

It is thought that both the hot and cold air streams rotate in the same direction at the same angular velocity, even though they are traveling in opposite directions. A particle of air in the inner stream completes one rotation in the same time of an air particle in the outer stream. The principle of conservation of angular momentum would say that the rotational speed of the inner vortex should increase because the angular momentum of a rotating particle (L) is equal to the radius of rotation (r) times it’s mass (m) times its velocity (v).  L = r•m•v.  When an air particle moves from the outer stream to the inner stream, both its radius (r) and velocity (v) decrease, resulting in a lower angular momentum. To maintain an energy balance for the system, the energy that is lost from the inner stream is taken in by the outer stream as heat. Therefore, the outer vortex becomes warm and the inner vortex is cooled.

At EXAIR, we have harnessed the cooling power of the vortex tube, and it can be found and utilized in such products as Spot CoolersCabinet Coolers, and Vortex Tubes themselves. 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 us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Cabinet Cooler Systems – Around The Clock (And Calendar) Heat Protection

So it was 19°F (-7°C) when I walked outside this morning. The layer of ice on my windshield was thin, but particularly stubborn, and I muttered under my breath. I have no business complaining about the cold…see, I moved to Ohio (on purpose) from Florida, in 1991. In November, to be exact. I still remember where I surrendered my “complain-about-the-cold” card:

If you’re headed north on I95, the next sign you’ll see is in Georgia. And if you’re not careful, you can end up “Up North.”

Why am I writing a blog about solutions to heat problems when, even though I do have a really nice pair of gloves, my fingers still aren’t even really thawed from ice removal duty this morning? Well, I’ve got three reasons:

1. Outside temperature doesn’t necessarily have any bearing at all on the temperature inside. Sure; there’s a reason we call July and August “Cabinet Cooler Season” – summer heat will do a number on sensitive electronic & control panels in spaces with no climate controls, but the problem goes away as winter approaches. In fact, there’s even such as thing as a cabinet HEATER, if the equipment in question is exposed to the elements.   Sometimes, though, heat is an issue year ’round…think blast furnaces, boiler rooms, foundries, chemical plants.  If your process generates heat, it’ll affect a control panel in the dead of winter just the same as on the dog days of summer.  We can quickly and easily specify the right Cabinet Cooler System for you with just a few key pieces of data…here’s a link to our Cabinet Cooler Sizing Guide if you want to find out.

2. It’s not winter all over the world.  Here in the Midwest United States, I full well realize we’re just gearing up for windshield scraping, snow shoveling, slipping-on-the-ice (some people call it skating and do it intentionally) season.  But right now, our friends in the Southern Hemisphere are getting ready for heat waves, sunscreen, and (hopefully) air conditioning.  So, in essence, they’re moving towards what we call “Cabinet Cooler Season.”

3. Our Cabinet Cooler Systems are so great, the 316SS Cabinet Cooler Systems with Electronic Temperature Control are actually up for Plant Engineering’s Product of the Year Award.  Because of their 316SS construction, they’re optimally suited for installation in harsh or demanding locations.  The Electronic Temperature Control offers continuous indication of internal temperature, and the ability to change the thermostat setpoint with the push of a button.  If you’re a current user, and you agree that they’re great, we’d appreciate your vote.  If not, I’m reluctant to encourage you to vote for it, but I suppose I can’t stop you from taking my word for it…

EXAIR NEMA 4X 316SS Cabinet Cooler System with Electronic Temperature Control installed on control panel in a pharmaceutical plant.

If you’d like to talk about protecting sensitive electronics from the heat, or from the environment, or both, I’d love to hear from you…give me a call.

How Could EXAIR Help With The Olympics?

With the Winder Olympics now officially underway I have been trying to figure out just how EXAIR could be a part of the process.  Maybe not in the forefront, but what are some applications that are there and have potential for being done by or improved by an EXAIR product.

The first even/ sport I thought of was Hockey.  When a skate is sharpened they generally do a dry grinding stone.  This can heat up the blade and cause it to become brittle.   The best way EXAIR can help is to offer a Cold Gun or a Mini Spot Cooler to apply a cold dry air to the grinding point and keep both the material and the stone cool to offer maximum tool life as well as a finer finish on the blade.  (This could probably be used in figure skating too but we’ll stick to hockey for this example.)

Skate Sharpening

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The second point was during any of the celebratory events where confetti is dispensed an EXAIR Line Vac or a Super Air Amplifier to help dispense the confetti.  We showcase how well this works in one of the Professor Penurious videos.

willitlaunch

The final would be the best in my opinion which is to use a Line Vac for a T-Shirt Cannon.  Which would help to spread the promotional items in the common areas. We have customers who build awesome t-shirt cannons used at sporting events, I’m just not sure they get the crowd that hyped up within the curling stadium.

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So whether you are in the Olympics or simply trying to make some parts for a customer we probably have a product that can help.  Feel free to contact us and find out how.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Is The Polar Vortex Responsible for Creating an EXAIR Application?

IAJ

It’s a new year, and with it comes new opportunities and new applications.  With the recent cold spell that’s taken hold of the U.S., and the Midwest especially, the applications susceptible to static have spiked.  Yesterday I spoke with an end-user in Texas experiencing the coldest temperatures on record, and with those low temps came low humidity and the perfect environment for static accumulation.

The process in the application was to feed a pill filling machine (machine fills gelcaps with small beads of XYZ) from a hopper a short distance away.  Typically, the feed from one to the other is accomplished with gravity.  The hopper sits about 5 feet higher than the pill filler and when more material is needed, a valve is opened and viola!

But the transfer of the material had slowed to a creep and then to a fully unacceptable rate.  The end-user decided to install an EXAIR Ion Air Jet, and to their surprise, there was no change.  So, they called in and sought guidance on how to move forward.

The first step in such a situation is to make sure the unit is properly installed.  Most often, when an EXAIR device doesn’t function as intended out of the box it is due to improper installation.  When asked what the pressure at the device was, the end-user said “Probably pretty low.  There’s about 30 feet of ¼” line and at least two quick disconnects feeding the unit.”  When asked what the airflow through the Ion Air Jet felt like, they again replied that it was low and we traced this to the poor plumbing.

But what about neutralizing the static?  Poor plumbing can account for a portion of that but we should still see some achievable results even with low airflow.  (In fact, low airflow is common in a static application because once the static is removed, any process disturbance or dust adhered to the product blows away with relative ease.)  We went through the steps to connect the Ion Air Jet to the power supply, and found that the ground was not connected to the power supply!  The end-user connected the ground, and reset the Ion Air Jet to meet the desired results.

EXAIR static eliminators are designed for ease of use and if they ever become problematic, Application Engineers are on staff to get the product, and the application back on track.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

Side note:  With the A4 running (and DESTROYING the snow) I’ve been cruising the local ads to see what’s out there.  (I blame @EXAIR_BF for asking me to help him find a car.  Ok, he didn’t ask, but he wants something German and I don’t need much of an impetus.)  I ran across an E36 3 series BMW that blew the head gasket and the owner tried to repair.  Halfway through the job they realized they were in over there head, put the top half of the engine in the trunk, and threw it up for sale cheap (just how I like ’em :) ).  Can I take boxes of engine parts tossed into a trunk and make a car run again?  Let’s find out!  I’ll update the 3 series progress and post a few pics when the weather breaks.