Controlling Temperature and Flow on a Vortex Tube

Vortex Tube uses an ordinary supply of compressed air as a power source, creating two streams of air, one hot and one cold – resulting in a low cost, reliable, maintenance free source of cold air for spot cooling solutions.

One of the features of the Vortex Tube is that the temperature of the cold air and the cold air flow rate is changeable. The cold air flow and temperature are easily controlled by adjusting the slotted valve in the hot air outlet.

Vortex Tube Hot Valve Adjustment
Hot Plug Adjustment

Opening the valve (turning it counterclockwise) reduces the cold air flow rate and the lowers the cold air temperature.  Closing the valve (turning it clockwise) increases the cold air flow and raises the cold air temperature.

VT Adjustment Table

As with anything, there is a trade off – to get higher a cold air flow rate, a moderate cold air temperature is achieved, and to get a very cold air temperature, a moderate air flow rate is achieved.

An important term to know and understand is Cold Fraction, which is the percentage of the compressed air used by the Vortex Tube that is discharged through the Cold End.  In most applications, a Cold Fraction of 80% produces a combination of cold flow rate and and cold air temperature that results in the maximum refrigeration or cooling output form a Vortex Tube.

For most industrial applications – such as process cooling, part cooling, and chamber cooling, maximum refrigeration is best and the 32XX series of Vortex Tubes are preferred.  For those applications where ‘cryogenic’ cooling is needed, such as cooling lab samples, or circuit testing, the 34XX series of Vortex Tube is best.

To set a Vortex Tube to a specific temperature, simply insert a thermometer into the cold air exhaust and adjust the hot valve.  Maximum refrigeration, at 80% Cold Fraction, is achieved when the cold air temperature drop is 50°F (28°C) from the incoming compressed air temperature. See the video posted here for measuring and lowering and the cold air temperature.

For those cases when you may be unsure of the required cold air flow rate and cold air temperature to provide the needed cooling in an application, we would recommend an EXAIR Cooling Kit.  The Cooling Kit contains a Vortex Tube, Cold Air Muffler, Air Line Filter, and a set of Generators that will allow for experimentation of the full range of air flows and temperatures possible.

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EXAIR Vortex Tube Cooling Kit

To discuss your application and how a Vortex Tube or any EXAIR Intelligent Compressed Air Product can improve your process, feel free to contact EXAIR, myself, or one of our other Application Engineers. We can help you determine the best solution!

Jordan Shouse
Application Engineer

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The Scientific Legacy of James Clerk Maxwell

On June 13, 1831 at 14 India Street, in Edinburgh Scotland James Clerk Maxwell was born. From a young age his mother recognized the potential in James, so she took full responsibility of his early education. At the age of 8 is mother passed away from abdominal cancer, so his father enrolled him in the very prestigious Edinburgh Academy.

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James was fascinated by geometry at a early age, many times learning something before he was instructed. At the age of 13 he won the schools mathematical medal and first prize in both English and poetry. At the age of 16 he starting attending classes at the University of Edinburgh, and in 1850 he enrolled at the University of Cambridge.

 

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The largest impact he had on science were his discovery’s around the relationship between electricity, magnetism, and light. Even Albert Einstein credited him for laying the ground work for the Special Theory of Relativity. He said his work was “the most profound and the most fruitful that physics has experienced since the time of Newton.”

Maxwell also had a strong interest in color vision, he discovered how to take color photographs by experimenting with light filters.

But here at EXAIR we are very interested in his work on the theory that a “friendly little demon” could somehow separate gases into hot and cold flows, while unproven in his lifetime, did actually come to fruition by the development of the Vortex Tube.  Which does just that.

How A Vortex Tube Works

So here’s to you, James Clerk Maxwell…may we continue to recognize your brilliance, and be inspired by your drive to push forward in scientific developments.

Jordan Shouse
Application Engineer
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Photo credit to trailerfullofpix & dun_deagh

Applications for Vortex Tube Spot Cooling

The EXAIR Mini Cooler family is one of the many vortex tube based Spot Cooler products that EXAIR offers.  This is the smallest of the group coming in at 550 BTU/hr of cooling capacity.  The Mini Cooler Systems  are available in two options.

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EXAIR’s Mini Cooler is available with a single point hose kit or a dual point hose kit.

  • The Single Point Outlet option will give you ten inches of flexible cold outlet to easily position the cold air stream near the target point.
  • The Dual Point Outlet option gives ten inches of 1/4″ flexible outlet that then splits to two separate four inch lengths of 1/4″ flexible cold outlet hoses.
  • Both include point or flat fan tips for the cold air outlets
  • Both include a manual drain filter separator
  • both include the swivel magnetic base with 100 lb. pull magnet.

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The Single Point Mini Cooler with a Flat Fan Tip installed on a milling application where liquid coolant cannot be used due to material constraints.

The single point hose kit is ideal for small diameter milling or drilling applications where the cold air can cover the contact area of the cutter.  It can also be used on soldering, industrial sewing, ultrasonic welding, or even small punching applications to list just a few.

EXAIR’s Mini Cooler System w/ Dual Point Hose Kit keeping UHMW cool while being machined

The dual point hose kit is ideal for two separate small diameter cutters, one larger diameter cutter, rotary style knives where there material is being slit, or larger diameter multi-point ultrasonic welders/punches.

When using the Mini Cooler the adjustable cold outlet stays in place and can easily bend around fixtures, spindles, welding horns, or dye aligning pins.  The swivel magnetic base gives additional adjustment at the base of the cooler to aid in the versatility of this product.   To further the adjustability of the cooler the operating pressure can easily be adjusted to lower or raise the cooling capacity of the Mini Cooler to meet the demands of the precise application.

If you believe you have an application that would benefit from the use of a Mini Cooler, or you are unsure which product would be ideal for your application please contact an Application Engineer.  we are all here, willing to help however possible to get your application improved in both safety and efficiency.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

 

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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