Georges J Ranque: Father of the Vortex Tube

Georges J. Ranque is known as the inventor and father of the Ranque-Hilsch Vortex tube. The vortex tube is device that takes a compressed gas and generates hot and cold streams from a source of compressed gas. George accidentally discovered the phenomenon on accident while studying physics at Ecole Polytechnique in Paris France. Ranque was looking was performing an experiment on a vortex-based pump to vacuum up iron fittings; during the experiment he noticed that warm air was being expelled out of one side and cold air out of the other when he inserted a cone into one end of the vortex. In 1931 Ranque filed for a patent for the vortex tube and two years later presented a paper on it.

Georges vortex tube was all but lost and forgot about until 1945 when the German physicist Rudolph Hilsch published a paper on the device. This paper became widely read and exposed the vortex tube to the industrial manufacturing environment. This paper revived what was thought to be lost and led the vortex tube into what we see today.

How an EXAIR Vortex Tube operates

During World War 2 Georges Ranque started to develop different steels that would be used in military aviation efforts. He later went on to work at Aubert et Duval Steelworks as the Director of Metallurgical Laboratory. While at Duval he would continue to developing alloys for the aviation industry.

Interestingly, in 1972 he went on to publish a book on the search for the Philosophers Stone, a mythological chemical substance that Alchemist’s thought could be used to turn base metals into Gold. The following year in 1973 he passed away in his home just outside of Paris.

Here at EXAIR we have expanded the uses of Ranque’s original vortex tubes for various different cooling uses. The vortex tube can be found in our Cold Guns, Spot Coolers, and Cabinet Coolers. In many cases EXAIR’s spot coolers and cold guns have been used to replace coolant in simple milling and grinding applications. Also, EXAIR’s Cabinet Coolers have been keeping control cabinets from overheating for many decades. 

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
Visit us on the Web
Follow me on Twitter
Like us on Facebook

Adjustable Spot Cooler Removes Tackiness from Plastic Tubes

Black PVC Tube

A manufacturing plant contacted EXAIR to help them with a “sticky” situation.  This company extruded PVC tubes that would be used as fuel lines on small engines.  Plasticizers are typically used to add flexibility to plastic materials.  For the PVC material above, a plasticizer was added to make it softer and more elastic.  The issue that they saw was the outer surface of the tubes were tacky from the plasticizer and heat which made it difficult to handle in packaging the tubes.

This company extruded many different diameters, but they wanted to target their most difficult size, the smallest tube.  The dimensions were given as 0.187″ (4.7mm) O.D. by .0934″ (2.4mm) I.D., and the feed rate was close to 4 feet/min (1.2 meter/min).  The problem area that they explained was at the end of the production line where the extruded tubes were cut by a blade cutter into 12” (305mm) lengths.  The tubes would then fall into a collection bin for batch processing.  Since the collection bin was setup at a slight upward angle, they wanted the tubes to gather toward one end of the bin.  Since the tubes were still hot and sticking to each other, the operators had to individually handle each tube which was counterproductive and time-consuming.  After our discussions, I suggested that cold air could harden the PVC tube enough by removing heat and help to “set”  the platicizer.  Since they manufactured different sizes and feed rates, we needed to have adjustability as well in our cold air device.

How the Adjustable Spot Cooler Works

One of our most versatile spot cooling instruments is the EXAIR Adjustable Spot Cooler.  This system uses the Vortex Tube technology to convert compressed air into a cold air stream without any moving parts, refrigerants, or motors.  The Adjustable Spot Cooler is a low-cost, reliable, maintenance-free way to give spot cooling for a myriad of industrial applications.  For this customer, this product gave them the versatility that they were needing.

EXAIR stocks these units with either a single or dual point hose kit, a magnetic base, a filter separator, and two additional generators.  The control valve at the end of the unit adjusts the output temperature down to -30 oF (-34 oC) with a turn of a knob.  The generators are specifically engineered to control the amount of compressed air that is used.  Both types of controls will allow this customer to “dial in” the correct cooling capacity for the operation.  The filter separator included with the system will clean the compressed air to keep the unit and the product free of dirt and debris.  The magnetic base which this customer really liked makes the Adjustable Spot Cooler portable for use in different areas.

3925 Adjustable Spot Cooler

I recommended the model 3925 Adjustable Spot Cooler because it had the dual point hose kit to blow cold air on both sides of the tubes.  Since this company had different tube diameters and thicknesses, adjustability was very critical.  If the tubes got too cold, cracks could occur from the blade cutting machine; and, if the tubes were too warm, the tackiness on the surface of the tube would remain.   Once they installed the Adjustable Spot Cooler, this company was able to increase their packaging line for the different size PVC tubes.  Now the operators could reach into the collection bin and grab many aligned tubes instead of individually separating and sorting.

If you have a “sticky” situation, the EXAIR Adjustable Spot Cooler may be a product for you.  The company above was able to have their tubes slide together in the collection bin.  Many applications could be improved by adding cold air.  And, if you have a similar situation, an Application Engineer at EXAIR will be happy to discuss a solution.

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

 

Photo: Black tube by NIMR LondonCC License 2.0

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
Visit us on the Web
Follow me on Twitter
Like us on Facebook

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
Visit us on the Web
Follow me on Twitter
Like us on Facebook