Georges J. Ranque and the Vortex Tube

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 for vacuuming iron filings and noticed that warm air exhausted from one end and cold air from the other when he inserted a cone at one end of the tube! Ranque quickly stopped work on the pump, and started a company to take 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.

How A Vortex Tube Works

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.

During the second world war Georges J. Ranque started developing steels that would be used in military aviation efforts. After the war he took a job at  Aubert et Duval steelworks as director of metallurgical laboratory where he continued developing alloys for use in the aviation industry.

In 1972 he published a book on the search for the Philosophers stone, a legendary chemical substance capable of turning base metals such as mercury into gold. And in 1973 he passed away in his home just outside of Paris.

If you have any questions of want more information on how we use our vortex tubes to better 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.

Jordan Shouse
Application Engineer
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Robert Boyle And The Scientific Method

How do we know something is true? In grade school, you may remember being taught a process by which an observation elicits a question, from which a hypothesis can be derived, which leads to a prediction that can be tested, and proven…or not) These steps are commonly known as the Scientific Method, and they’ve been successfully used for thousands of years, by such legendary people of science as Aristotle (384 – 322 BC,) Roger Bacon (1219 – 1292,) Johannes Kepler (1571-1630,) Galileo Galilei (1564-1642) and right up to today’s scientists who run the CERN Large Hadron Collider.  The collider is the largest machine in the world, and its very purpose is the testing and proving (or not) of hypotheses based on questions that come from observations (often made in the LHC itself) in ongoing efforts to answer amazingly complex questions regarding space, time, quantum mechanics, and general relativity.

The Scientific Method is actually the reason (more on this in a minute) for the name of a fundamental law of physics: Boyle’s Law.  It states:

“For a fixed amount of an ideal gas kept at fixed temperature, pressure and volume are inversely proportional.”

And can be mathematically represented:

PV=k, where:

  • P = is the pressure of a gas
  • V = is the volume of that gas, and
  • k = is a constant

So, if “k” is held constant, no matter how pressure changes, volume will change in inverse proportion.  Or, if volume changes, pressure will change in inverse proportion.  In other words, when one goes up, the other goes down.  It’s also quite useful in another formulaic representation, which allows us to calculate the resultant volume (or pressure,) assuming the initial volume & pressure and resultant pressure (or volume) is known:

P1V1=P2V2, where:

  • P1  and P2 are the initial, and resultant, pressures (respectively) and
  • V1  and V2 are the initial, and resultant, volumes (respectively)

This is in fact, what happens when compressed air is generated, so this formula is instrumental in many aspects of air system design, such as determining compressor output, reservoir storage, pneumatic cylinder performance, etc.

Back to the reason it’s called “Boyle’s Law” – it’s not because he discovered this particular phenomenon.  See, in April of 1661, two of Robert Boyle’s contemporaries, Richard Towneley and Henry Power, actually discovered the relationship between the pressure and volume of a gas when they took a barometer up & down a large hill with them.  Richard Towneley discussed his finding with Robert Boyle, who was sufficiently intrigued to perform the formal experiments based on what he called “Mr Towneley’s hypothesis.”  So, for completing the steps of Scientific Method on this phenomenon – going from hypothesis to law –  students, scientists, and engineers remember Robert Boyle.

Russ Bowman
Application Engineer
EXAIR Corporation
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IMGP6394 image courtesy of Matt Buck, Creative Commons License

People of Interest: Robert Boyle – January 25, 1627 – December 31, 1691

Robert Boyle was born on January 25, 1627 in Lismore Castle, County of Waterford, Ireland.  He was an Anglo-Irish natural philosopher, chemist, physicist and dabbled in many other areas of study. He published the book The Sceptical Chymist in 1661, and many consider him and his work as the foundation of modern chemistry.  He was a very devout Anglican, and published numerous works in this area as well.

Robert Boyle

One of Boyle’s most famous discoveries was to become the first of the gas laws, relating the pressure of a gas to its volume. With Robert Hooke, a young university student as his laboratory assistant, Boyle began experimenting with air.  Together they made their first great discovery, now known as Boyle’s Law.

J-Tube 2
Boyle used a ‘J’ Tube – Sealed on the Short End, and Open at the Long End

The experiment was performed using a ‘J’ shaped glass tube sealed on the shorter leg, and open to atmosphere on the longer leg.  Quicksilver (mercury) was poured into the tube, such that the level was equal on each side. The volume of the trapped air was noted. Additional mercury was poured into the tube and it was observed that the mercury did not stay level, and measurements of the heights on each tube leg were recorded.  The height difference of the mercury is effectively a measure of the pressure of the trapped air. Boyle, through the experiment and the data,  discovered a relationship between the volume and the pressure of air.  The data as published, is shown below.

Boyle's Data

Boyle noticed the pressure times the volume of air for the initial condition equaled the pressure times the volume at any other mercury height.

Known as Boyle’s Law – P ∝ 1/V,      pressure is proportional to the inverse of the volume

Alternately, PV = k,       pressure times volume is equal to a constant

For comparing the same substance under two different sets of conditions, the law can be expressed as P1V1 = P2V2

Of note is that Boyle’s Law, combined with Charles’s law and Gay-Lussac’s Law formed the combined gas law, and in combination with Avogadro’s law is the basis for the ideal gas law – PV=nRT, which include temperature, the amount of the substance, and the ideal gas constant to the mix.

It is noted that Boyle credited fellow scientist Richard Towneley for making the connection between the pressure of a gas and volume, but Boyle’s experiments and observations using the ‘J’ tube confirmed Towneley’s predictions, and the rest as they say is history.

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

Brian Bergmann
Application Engineer

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Experiment Data from the book New Experiments Physico-Mechanicall, Touching the Spring of the Air, and Its Effects (1660)