The Theory of the Vortex Tube

There are many theories regarding the dynamics of a vortex tube and how it works. Many a graduate student has studied them as part of their research requirements.

VT_air2

The Vortex Tube was invented by accident in 1928, by George Ranque, a French physics student. He was performing experiments on 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 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.

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.

Here is one widely accepted explanation of the physics and the phenomenon of the vortex tube.VT

Compressed air is supplied to vortex tube and passes through nozzles that are tangent to to an internal counterbore (1). As the air passes through it is set into a spiraling vortex motion (2) 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 (4) at the end allows some of the warmed air to escape (6) 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 the through the other end of as cold air (5).

It is thought that that both the hot and cold air streams rotate in the same direction at the same angular velocity, even though they are travelling in opposite directions. A particle of air in the inner stream completes one rotation in the same amount of time that an air particle in the outer stream. The principle of conservation of angular momentum would say that the rotational speed of the inner inner vortex should increase because the angular momentum of a rotating particle (L) is equal to the radius of rotation (r) times its 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 Coolers, Cabinet Coolers, and the Vortex Tube themselves.

Harnessing the cooling power of the vortex tube 

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.

Brian Bergmann
Application Engineer
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Cool Small Parts and Tools, with Clean, Cold Air

Do you need a proven way to reduce downtime and increase productivity on a variety of operations involving small parts where heat is a problem?  EXAIR‘s Mini Cooler produces a stream of 20°F (-7°C) cold air to prevent heat build up and blow away chips and debris.

Especially effective on high speed operations, the Mini Cooler helps to prevent burning, melting, and heat related breakage, and while doing so, at a quiet 76 dBA sound level. Better yet, all done with no moving parts to wear out.

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Mini Cooler Cooling a Small Mill Operation

Some popular applications for the Mini Cooler are – small tool cooling, needle cooling, blade cooling, and lens grinding.

There are several advantages to take note of – low cost, increased production rates, better tolerances, and quiet and compact.

minicoolerWFAM_500

The Mini Cooler Systems are available with One or Two Cold Outlets, and also include a 1″ wide Flare Nozzle Tip, and a Manual Drain Air Filter to clean the air, ensuring long, trouble free operation.

Using just 8 SCFM of 100 PSIG compressed air, the Mini Cooler will not tax your compressed air system.  Its small size allows it to fit in areas where larger systems could not fit.  The powerful magnetic base sticks to any ferrous surface and and provides up to 100 pounds of pull force.

If you have any questions about the Mini Cooler, the Adjustable Spot Cooler, Cold Gun or any EXAIR compressed air product, 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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Expand Flexibility of Cabinet Coolers with Side Mount Kits

Last week I wrote about the Thermostat Options for Smart Cooling utilizing the EXAIR Cabinet Cooler Systems.  You can see read that blog post here.  Today we will touch base on the Side Mount Kits as an option to expand the flexibility for the installation and operation.

Sometimes there isn’t room above an electrical panel to fit the Cabinet Cooler, even though it takes just 5″ to 7.25″ of space above. In these cases, the Side Mount Kit is available to handle any of the Cabinet Cooler sizes and NEMA ratings. EXAIR offers (6) models of Side Mount Kits –

  • Model 4909 – For NEMA 12 Cabinet Coolers up to 550 BTU.hr (139 Kcal/hr), Aluminum construction
  • Model 4910 – For NEMA 12 Cabinet Coolers , 650 BTU//hr (165 Kcal/hr) and higher, Aluminum construction
  • Model 4906 – For NEMA 4 and 4X Cabinet Coolers up to 550 BTU/hr (139 Kcal/hr), Type 303 Stainless Steel
  • Model 4907 – For NEMA 4 and 4X Cabinet Coolers, 650 BTU/hr (165 Kcal/hr) and higher, Type 303 Stainless Steel
  • Model 4906-316 – For NEMA 4 and 4X Cabinet Coolers up to 550 BTU/hr (139 Kcal/hr), Type 316 Stainless Steel
  • Model 4907-316 – For NEMA 4 and 4X Cabinet Coolers, 650 BTU/hr (165 Kcal/hr) and higher, Type 316 Stainless Steel

side_mounts_new

The NEMA 4 and 4X Cabinet Coolers must be mounted vertically for the unit to properly resist the ingress of liquids and maintain the integrity of the cabinet NEMA rating.

The Side Mount Kits install into a standard electrical knockout (1-1/2 NPS) for easy installation.

If you have any questions about the Side Mount Kits, Cabinet Coolers and/or Thermostat Options 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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EXAIR’s Cabinet Cooler System is Durable and Reliable

Any realtor will tell you that the three most important factors in selecting a property are location, location, and location. This simply means that houses with similar features – number of bedrooms, yard size, structure, garage (or not,) basement or not,) etc. – can be found in a lot of very different neighborhoods. Whether you want to live somewhere that’s convenient to the highway, close to (or not so close to) work, near your favorite activities, etc., odds are you can find a house that meets your material needs & wants within those geographical confines. Hence, location is your #1 consideration. And your #2 and your #3 as well…my lovely bride is a real estate professional, so I have this on good authority. And, so you know, #4 is price, and #5 is condition.

Electrical and electronics controls professionals will tell you that three of the most important things to protect their equipment from are heat, moisture, and dust. If you’re looking for a durable, reliable, and low cost method for that, we’ve got the solution: the EXAIR Cabinet Cooler System. Selection of the right system comes down to determining your heat load, and…the reason for today’s blog…the LOCATION in which it will be installed.

Let’s say it’s a control panel for one of the machines on a factory production line…indoors & dry.  Our NEMA 12 Cabinet Cooler Systems provide protection against dust and oil from entering the enclosure.

NEMA 12 Cabinet Cooler Systems are oil tight, dust tight, and rated for indoor duty. They can also be installed to the wall of an enclosure (instead of the top) with a Side Mount Kit.

If the enclosure is outdoors, or indoors but subject to water spray (like in a wash-down area,) our NEMA 4 Cabinet Cooler Systems are oil tight, dust tight, AND splash resistant.  They ensure the inside of the enclosure stays dry through the use of a low pressure relief valve that seals when the cooler is not operating, maintaining NEMA 4 integrity at all times.

EXAIR NEMA Cabinet Cooler Systems provide additional protection to keep the enclosure dry inside.

Our NEMA 4X Cabinet Cooler Systems are made of stainless steel, and are commonly specified for food service area installations, and in corrosive environments.  They’re also oil tight, dust tight, and splash resistant.  These are also available in Type 316 Stainless Steel construction, for especially harsh conditions, or when this is otherwise specified due to the nature of the installation, such as critical food grade or pharmaceutical areas.

EXAIR NEMA 4X Cabinet Cooler Systems are made of corrosion resistant stainless steel for corrosive environments, and are also available with Side Mount Kits.

Regardless of the NEMA rating called for by the location, all EXAIR Cabinet Cooler Systems are available with a Non-Hazardous Purge option, which provides a slight positive pressure through a low (1 SCFM) air flow when internal temperature is below the thermostat setpoint and the solenoid valve is closed.  This provides constant and reliable protection, even if the enclosure is not perfectly sealed, even in especially dirty or dusty environments.

All EXAIR Cabinet Cooler Systems are available with Non Hazardous Purge for constant, reliable protection from environmental contaminants.

High Temperature Cabinet Cooler Systems are also available when ambient temperatures can exceed 125F.  These are popular in foundries, glass production facilities, and even non-air conditioned spaces in particularly warm climates.

High Temperature Cabinet Cooler Systems provide reliable heat protection in areas where ambient temperatures reach 125-200F (52-93C)

If you’ve got sensitive, mission-critical electrical or electronic enclosures that need reliable heat protection, EXAIR has the solution you’re looking for.  If you know the required cooling capacity for your enclosure, you can select the right system directly from our website.  If you’d like help in calculating your heat load, you can use our Cabinet Cooler System Sizing Guide…just fill in the blanks and click “submit” – your request will be forwarded to an Application Engineer for immediate attention.  Or, if you’d rather, just give me a call.  We calculate heat loads over the phone all the time; it only takes a minute.

High Temperature Vortex Tube for Sensor Cooling

Last year I worked with a power company that was having issues with Position Feedback Sensors overheating causing erroneous readings and early failures.  The sensors were located above a steam turbine, and the ambient temperatures reached 128°F with spikes to 140-150°F.  The customer had called in looking for a way to keep the sensors cool, using minimal compressed air, and in a robust package.  After reviewing the details, we recommended the High Temperature Vortex Tube, model HT3210.  While using just 10 SCFM of 100 PSIG compressed air, the HT3210 provides 8 SCFM of cold air at a temperature drop of 54°F from the supply air temperature.  Bathing the sensor with this cool air keeps prevents it from heating up and has eliminated the bad readings and prevented the early failures.

The customer recently implemented the same fix for another set of sensors.

Plant Photo
Power Generation Process, with (3) Position Feedback Sensors
Sensor
Position Feedback Sensor

The High Temperature Vortex Tube is a special Vortex Tube offering from EXAIR that utilizes a brass generator and hi-temp seal for use in ambient temperatures up to 200°F.  Simply supply clean, dry compressed air, and get cold air starting at 50-54°F lower than the supply air temperature.  With sizes ranging from 2 to 150 SCFM, there is a Vortex Tube that will meet most applications.

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High Temperature Vortex Tube

If you have questions about the Vortex Tubes, or would like to talk about 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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Compressed Air Uses In Industry

From pneumatic hand tools like impact wrenches or nail guns to larger scale industrial applications like stamping presses, the use of compressed air can be found in almost any industry. In fact, it is often referred to as a “fourth utility” next to water, gas and electric.

Compressed air is used in virtually every industry!

 

Take for example in construction, workers will use a pneumatic riveter to join steel framing because of the power generated by the tool over an electrically powered device, not to mention it provides for a safer operation by removing an electrical hazard. Many companies use compressed air operated diaphragm pumps or air motor driven pumps to move expensive or viscous liquid from one location to another. These types of pumps are self priming drawing the liquid in and provide positive displacement meaning they fill and empty the liquid chamber with the same amount of liquid through a common inlet and outlet.

Amusement parks have used compressed air in some capacity in the operation of thrill rides like roller coasters or to enhance the effect of certain attractions. Compressed air can be found in hospitals where it is used for specialized breathing treatments or to power surgical instruments in an operating room. Educational facilities use compressed air for laboratory testing. You can even find compressed air in the tires on your car. Basically, when you think about it, compressed air is being used just about anywhere.

Here at EXAIR, we manufacture Intelligent Compressed Air Products to help improve the efficiency in a wide variety of industrial operations. Whether you are looking to coat a surface with an atomized mist of liquid, conserve compressed air use and energy, cool an electrical enclosure, convey parts or dry material from one location to another or clean a conveyor belt or web, chances are we have a product that will fit your specific need.

EXAIR has been providing engineered solutions since 1983.

 

To discuss your particular application or for help selecting the best product, contact an application engineer at 800-903-9247 for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Compressed Air Valves image courtesy of Shane Gorski via creative commons license.

Video Blog: Medium Vortex Tube Cooling Kit

EXAIR offers (3) Vortex Tube Cooling Kits, and the video below will provide an overview of the medium size offering, for refrigeration up to 2800 BTU/hr (706 Kcal/hr.)

If you have questions regarding Vortex Tube Cooling Kits or any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

Send me an email
Find us on the Web
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Twitter: @EXAIR_BB