How To Make Compressed Air Get Cold…A Couple Of Different Ways

The Vortex Tube makes cold air for the same reason that a can of compressed air gets cold when I clean my computer keyboard, right?

That’s a common question, and since they both start with compress air and end up with cold(er) air, it’s not an unreasonable assumption.  But the answer is no; they’re not the same.   Both are curious physical phenomena, though:

Cans of compressed air get cold while they’re discharging because of a thermodynamic principle known as the adiabatic effect.  When you pressurize a gas by compressing it into a container, you’re putting all those molecules into a smaller volume of space…and you’re adding potential energy by the compression.  Then, when you release that gas back to atmospheric pressure, that energy has to go somewhere…so it’s given off in the form of heat – from the air inside the can, as the pressure inside the can decreases.  Now, the air that’s not under as much pressure as it was when you pushed the button on top of the can is going to start coming out of the can pretty soon.  I mean, there’s only so much air in there, right?  So, since it’s given off that energy immediately upon the drop in pressure, when it comes out of the can, it’s at a lower temperature than it was before you started spraying it out.

Vortex Tubes, on the other hand, generate a flow of cold air by a completely different phenomenon of physics called, maybe not so curiously, the Vortex Tube principle:

You can get a lot more cold air – and a much lower temperature – from a Vortex Tube than you can from a can of compressed air.

If you need a reliable and dependable flow of cold air, look no further than EXAIR’s comprehensive line of Vortex Tubes and Spot Cooling Equipment.  We’ve got 24 models of Vortex Tubes to choose from, as well as “out of the box” solutions for cooling applications like the Adjustable Spot Cooler, Mini CoolerCold Gun Aircoolant Systems. and, to protect your sensitive electrical and electronic enclosures from heat, Cabinet Cooler Systems.  If you’d like to find out more, give me a call.

Russ Bowman

Application Engineer
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Need to Cool Tooling but Limited On Compressed Air? Consider the Mini Cooler

I recently had a chat conversation with a customer who was looking to cool the tooling on his CNC router, mill and lathe in his small machine shop. During the machining process, as the tooling would begin to heat up, it would warp the bit, causing irregularities in the finished product. In some cases the tooling was getting so hot, it would actually break, creating a safety concern.

He had reviewed some of our cooling products and was thinking of using our Cold Gun in the application but was concerned with the air demand. The Cold Gun consumes 15 SCFM @ 100 PSIG and provides a 50°F temperature drop (from supply temperature) with 1,000 Btu/hr. of cooling capacity. The problem was that his compressor only produces a little over 9 SCFM. I explained that the existing compressor would in fact be undersized as it doesn’t produce enough volume to keep up with the demand of the Cold Gun.

Model 3808 Mini Cooler System with Single Point Hose Kit, includes swivel magnetic base and filter separator to remove moisture and particulate from the air supply.

Due to the limited amount of compressed air available, our Mini Cooler System, Model # 3808, would be the better solution. The Mini Cooler also provides a 50°F temperature drop with a little less cooling power, 550 Btu/hr., but this system only requires 8 SCFM @ 100 PSIG, falling within the existing compressor’s output capacity. The Mini Cooler also includes a magnetic base as well as flexible tubing to direct the cold air to the desired location, making it easy to move from machine to machine.

The Mini Cooler is the ideal solution for small tool or part cooling, with minimal air consumption.

If you are considering an EXAIR product for an application or have additional questions about performance, contact an application engineer for assistance in making the best selection.

Justin Nicholl
Application Engineer




Simplifying Plastics Machining Using The Cold Gun And Chip Vac

I was recently contacted by a plastics manufacturer who was needing some solutions for problem areas in their production processes. The company imports their machines from overseas and they are outfitted with a coolant based, quench system for the tooling. They were wanting to get away from using coolant as the parts were absorbing liquid, causing them to swell, not to mention the mess they were creating, requiring more time and labor to dry and clean the parts manually.

For the first application, replacing the messy misting system, I recommended the customer use our Cold Gun System, Model # 5215. The Cold Gun uses Vortex Tube technology to produce a cold air stream 50°F lower than the incoming compressed air supply temperature. For example, if your supply air was ambient 70°F, you would effectively see 20°F air at the exhaust. This clean, cold air stream can be easily directed to the needed area to prevent any warping or other damage related to heat, while also blowing away the machined fines.

Model # 5215 – includes the Cold Gun, Single Point Hose Kit, 3/8″ Cone Nozzle, 1-1/4″ Fan Nozzle and Filter Separator

The second part of the process involved the recovery of the plastic scrap and chips created during the machining process. Once again, EXAIR has the ideal solution with our Chip Vac, Industrial Vacuum. The Chip Vac creates a powerful vacuum, with no moving parts or motors to wear out, making them virtually maintenance free. The Chip Vac is designed to vacuum dry or wet chips and collect them in a standard, open-top steel drum. Systems are available in 5, 30, 55 or 110 gallon capacities.

From small area clean up to larger scale processes, the Chip Vac has you covered

To discuss how EXAIR products might help improve your machining process, give us a call at 800-903-9247.

Justin Nicholl
Application Engineer

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
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.

Vortex tube
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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Adjustable Spot Cooler: How Cold Can You Go?

I had the pleasure of discussing a spot cooling application with a customer this morning. He wanted to get more flow from his Adjustable Spot Cooler, but still keep the temperature very low.  He machines small plastic parts, and he’s got enough cold flow to properly cool the tooling (preventing melting of the plastic & shape deformation) but he wasn’t getting every last little chip or piece of debris off the part or the tool.

After determining that he had sufficient compressed air capacity, we found that he was using the 15 SCFM Generator. The Adjustable Spot Cooler comes with three Generators…any of the three will produce cold air at a specific temperature drop; this is determined only by the supply pressure (the higher your pressure, the colder your air) and the Cold Fraction (the percentage of the air supply that’s directed to the cold end…the lower the Cold Fraction, the colder the air.)

Anyway, the 15 SCFM Generator is the lowest capacity of the three, producing 1,000 Btu/hr of cooling. The other two are rated for 25 and 30 SCFM (1,700 and 2,000 Btu/hr, respectively.)

He decided to try and replace the 15 SCFM Generator with the 30 SCFM one…his thought was “go big or go home” – and found that he could get twice the flow, with the same temperature drop, as long as he maintained 100psig compressed air pressure at the inlet port.  This was more than enough to blow the part & tool clean, while keeping the cutting tool cool, and preventing the plastic part from melting.

Model 3925 Adjustable Spot Cooler System comes with a Dual Outlet Hose Kit, and three Generators for a wide range of cooling performance.

If you’d like to find out how to get the most from a Vortex Tube Spot Cooling Product, give me a call.

Russ Bowman
Application Engineer
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NEW Cold Gun Promotion – Order Today and Receive a FREE Dual Point Hose Kit!

Now through the end of 2017 if you purchase a Single-Point Cold Gun Kit with Model W5215 for the standard Cold Gun or W5230 for the High Power Cold Gun, we’ll include a free Model 5902 Dual Point Hose Kit, a $35.00 value!!

Model 5230 Cold Gun keeping a laser cut part cool

EXAIR’s Cold Gun was a Product of the Year finalist in 2007. By using only a source of compressed air, the Cold Gun and High Power Cold Gun produces a stream of clean, cold air 50° (28°C) below your compressed air supply temperature. The Cold Gun is very quiet at only 70dBA and has no moving parts to wear out. Just supply it with clean, dry compressed air and its maintenance free!


The Cold Gun is pre-set to an 80% Cold Fraction. In other words, 80% of the compressed air supplied to it will exhaust from the cold end of the tube, 20% from the hot end. This prevents the Cold Gun from freezing up during use and optimizes the gun’s cooling capacity. The Cold Gun is an ideal alternative to messy and expensive coolant mist systems. It eliminates the cost of purchase and disposal of cutting fluids as well as worker related health problems from breathing airborne coolant or slipping on wet floors. Replacing a coolant based system also eliminates the need for secondary cleaning operations after milling or drilling.

The Cold Gun is an invaluable tool for machining a wide range of plastics and other materials that may become contaminated when using traditional coolants or oils. The clean, cold air from the outlet of the Cold Gun keeps the part cool, clean, and dry. Take for example this application where an OEM for the plastics industry uses EXAIR Cold Guns in place of a coolant system.

EXAIR 5015 Cold Gun w/ Dual Point Hose Kit Installed

If you have an application that you believe would be better served by the use of an EXAIR Cold Gun, give us a call. Get one on order today and take advantage of receiving a FREE Dual Point Hose Kit!

Tyler Daniel
Application Engineer
Twitter: @EXAIR_TD


The Case For The Cold Gun

Albert Einstein famously said, “Nothing happens until something moves.” And unless it’s in a perfect vacuum when it moves, there’s gonna be friction. Especially if it’s in contact with something else besides air.  And where there’s friction, there’s heat. This pretty much applies to almost every single evolution in the manufacture of…well, just about everything.

I’m probably not telling you anything you don’t already know, but heat can be a BIG problem.  It can:

  • Shorten tool life. Not only do worn tools take longer to cut, they can also present safety issues.  You can get hurt WAY worse by a dull blade than a sharp one.
  • Cause thermal expansion. If you’re machining something to a precise tolerance, and friction heat causes it to grow, it won’t be the same size when it cools down.
  • Melt plastics. And even softer metals.  This isn’t good for the part…or the tool, either.

Those are just a few of the problems heat causes in manufacturing operations, and they’ve been traditionally addressed with mist (liquid) coolants.  And they work just fine…most of them are water-based, and if you want to get heat out of a solid piece of something, water will do the job VERY quickly.  Other additives in the coolant provide a measure of lubricity, corrosion control, emulsion prevention, etc.  It’s easy, well-known, and time-tested.  There are some drawbacks, however:

  • It can be messy.  When a part (or a tool) in motion gets sprayed down with liquid, it tends to fling that liquid all over the place.  That’s why most machines fitted with mist coolant have spray shields.
  • Not only is it a hassle to clean up, if you don’t stay on top of the clean-up, it can lead to slip hazards.
  • Speaking of hazards, if you can smell that mist (and you know you can,) that means you’re breathing it in too.  Remember the lubricants, corrosion inhibitors, emulsion preventers, etc., I mentioned above?  Yeah…they’re not all what you might call “good for you.”
  • Recirculation systems are common, which means the coolant sump is gathering solids, so the lines and/or spray nozzles can clog and be rendered useless.

EXAIR Cold Gun Aircoolant Systems not only address all of the above problems with heat, but eliminate all the problems associated with liquid coolant:

  • They incorporate EXAIR’s Vortex Tube technology to produce a stream of cold air.
  • They’re reliable.  There are no moving parts; if you supply them with clean, dry air, they’ll run darn near indefinitely, maintenance free.
  • They’re quick & easy.  With a built-in magnet for mounting and a flexible cold air hose, you can be be blowing cold air right where you want it as quickly as you can attach an air hose and open the valve.
  • Speaking of opening the valve, that’s all it takes to run a Cold Gun.  They’re producing cold air at rated flow and temperature, right away.  No “ramp up” time to get into operation.
  • They’re clean.  That cold air stream just becomes…well, air.  No mess.  No slip.  No clean up.  No smell.  No problem.

We’ve got four Models to choose from, depending on the nature of the application:

Both the standard and the High Power come with a Filter Separator, and are available with a one, or two, outlet cold air hose.

If you need to cool parts or tools down, and want it to be effective and clean, give me a call.

Russ Bowman
Application Engineer
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