Vortex Tubes can be Customized to Suit Your Application

Vortex tube

EXAIR’s Vortex Tubes are a low-cost, reliable, and maintenance-free solution to a variety of industrial spot cooling problems. With just an ordinary supply of compressed air, the Vortex Tube produces two streams of air: one hot and one cold. This is achieved without any moving parts or refrigerants!!

The Vortex Tube is capable of achieving a temperature drop/rise from your compressed air supply ranging from -50°F to +260°F (-46°C to +127°C). Flow rates range from 1-150 SCFM (28-4,248 SLPM) and refrigeration of up to 10,200 Btu/hr. With all Vortex Tubes constructed of stainless steel, they’re resistant to corrosion and oxidation ensuring you years of reliable, maintenance-free operation.

How A Vortex Tube Works

In addition to providing a range of different Vortex Tubes available to ship same-day from stock, EXAIR also has a few options available for cases where a stock Vortex Tube may not be the right solution. The standard Vortex Tube is suitable for use in environments with ambient temperatures up to 125°F (52°C) due to the plastic generator and Buna o-rings. For more extreme environments and ambient temperatures up to 200°F (93°C), we install a brass generator and replace the Buna o-rings with Viton seals.

All standard Vortex Tubes are adjustable. A small valve is located at the hot air exhaust end of the tube. Using a flat-tipped screwdriver, you can adjust the amount of air that is permitted to exhaust from the hot end. As more air is allowed to escape, the temperature at the cold end of the tube drops even further. The volume of air at the cold end as the temperature drops will also decrease. The percentage of air exhausting from the cold end relative to the total air consumption is referred to as the cold fraction percentage. Lower cold fractions will produce lower temperatures, but there won’t be as much volume. Finding the proper setting for your Vortex Tube can take some adjusting.

HT3240

As we all know, if there’s a knob to turn, button to press, or adjustment that can be made an operator is inevitably going to tinker with it. Day shift will blame the night shift, night shift blames the day shift, and it can present a problem when the Vortex Tube has been specifically tested and set to achieve the desired cold fraction. If you know the cold fraction you need, but would prefer to prevent it from being able to be adjusted, EXAIR can install a precisely drilled hot plug to set the cold fraction percentage to your specifications and eliminate any potential for it to be changed.

If you’d still prefer to keep the adjustability, but don’t have the capabilities to measure and set it yourself, we can also set any Vortex Tube to the desired cold fraction with the adjustable valve and send it to you ready to be installed. We’ll provide you with a special model number so you can rest assured that any time you need another it’ll come set to your specification.

At EXAIR, we’re committed to providing you with the best solution possible for your application. Sometimes that isn’t going to be achievable with a standard stock product. Just because you don’t see it in the catalog or on our website, doesn’t mean we can’t do it. If you have a unique application and would like more information on getting a special Vortex Tube, contact an Application Engineer today.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Vortex Tube Cold Fractions Explained

Simply put, a Vortex Tube’s Cold Fraction is the percentage of its supply air that gets directed to the cold end. The rest of the supply air goes out the hot end. Here’s how it works:

The Control Valve is operated by a flat head screwdriver.

No matter what the Cold Fraction is set to, the air coming out the cold end will be lower in temperature, and the air exiting the hot end will be higher in temperature, than the compressed air supply.  The Cold Fraction is set by the position of the Control Valve.    Opening the Control Valve (turning counterclockwise, see blue arrow on photo to right) lowers the Cold Fraction, resulting in lower flow – and a large temperature drop – in the cold air discharge.  Closing the Control Valve (turning clockwise, see red arrow) increases the cold air flow, but results in a smaller temperature drop.  This adjustability is key to the Vortex Tube’s versatility.  Some applications call for higher flows; others call for very low temperatures…more on that in a minute, though.

The Cold Fraction can be set as low as 20% – meaning a small amount (20% to be exact) of the supply air is directed to the cold end, with a large temperature drop.  Conversely, you can set it as high as 80% – meaning most of the supply air goes to the cold end, but the temperature drop isn’t as high.  Our 3400 Series Vortex Tubes are for 20-50% Cold Fractions, and the 3200 Series are for 50-80% Cold Fractions.  Both extremes, and all points in between, are used, depending on the nature of the applications.  Here are some examples:

EXAIR 3400 Series Vortex Tubes, for air as low as -50°F.

A candy maker needed to cool chocolate that had been poured into small molds to make bite-sized, fun-shaped, confections.  Keeping the air flow low was critical…they wanted a nice, smooth surface, not rippled by a blast of air.  A pair of Model 3408 Small Vortex Tubes set to a 40% Cold Fraction produce a 3.2 SCFM cold flow (feels a lot like when you blow on a spoonful of hot soup to cool it down) that’s 110°F colder than the compressed air supply…or about -30°F.  It doesn’t disturb the surface, but cools & sets it in a hurry.  They could turn the Cold Fraction down all the way to 20%, for a cold flow of only 1.6 SCFM (just a whisper, really,) but with a 123°F temperature drop.

Welding and brazing are examples of applications where higher flows are advantageous.  The lower temperature drop doesn’t make all that much difference…turns out, when you’re blowing air onto metal that’s been recently melted, it doesn’t seem to matter much if the air is 20°F or -20°F, as long as there’s a LOT of it.  Our Medium Vortex Tubes are especially popular for this.  An ultrasonic weld that seals the end of a toothpaste tube, for example, is done with a Model 3215 set to an 80% Cold Fraction (12 SCFM of cold flow with a 54°F drop,) while brazing copper pipe fittings needs the higher flow of a Model 3230: the same 80% cold fraction makes 24 SCFM cold flow, with the same 54°F temperature drop.

Regardless of which model you choose, the temperature drop of the cold air flow is determined by only two factors: Cold Fraction setting, and compressed air supply pressure.  If you were wondering where I got all the figures above, they’re all from the Specification & Performance charts published in our catalog:

3200 Series are for max cooling (50-80% Cold Fractions;) 3400’s are for max cold temperature (20-50% Cold Fractions.)
Chocolate cooling in brown; welding/brazing in blue.

EXAIR Vortex Tubes & Spot Cooling Products are a quick & easy way to supply a reliable, controllable flow of cold air, on demand.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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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
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Generators for the EXAIR Vortex Tubes

Vortex generator

The EXAIR Vortex Tubes use compressed air to generate cold air down to -50 deg. F (-46 deg. C) without any moving parts, freon, or electricity.  By design, it will produce hot air at one end and cold air at the other.  EXAIR offers different cooling capacities ranging from 135 BTU/hr (34 Kcal/hr) to 10,200 BTU/hr (2,570 Kcal/hr).  This cooling phenomenon begins by spinning the air at a high rate of speed inside the Vortex Tube.  The “separation” of temperatures starts at the generator.  In this blog, I will discuss the features of the generator and how our design allows for an efficient way to cool and heat the air flows.

Vortex Family

EXAIR stocks three different sizes of the Vortex Tubes; small, medium, and large.  Each Vortex Tube will use a generator to define the cooling capacity and compressed air usage.  When compressed air enters the Vortex Tube, it will have to pass through the generator first.  The generators are engineered with vane openings to initiate the spinning of the air and to control the amount of air that can pass through it.  As an example, for a medium-sized Vortex Tube, a model 10-R generator will only allow 10 SCFM (283 SLPM) of air at 100 PSIG (6.9 Bar).  While in that same size body, a model 40-R generator will allow 40 SCFM (1,133 SLPM) of air at 100 PSIG (6.9 Bar) to be used.  Precision in the design of the generators is what sets EXAIR apart with efficiency and effectiveness in cooling.

EXAIR Vortex Tube Performance Chart

EXAIR created a chart to show the temperature drop for the cold end and temperature rise for the hot end, relative to the incoming compressed air temperature.  Across the top of the chart, we have Cold Fraction and along the side, we have the inlet air pressure.  The Cold Fraction is the percentage of the inlet air that will blow out the cold end of the Vortex Tube.  This is adjustable with a Hot Exhaust Air Valve at the hot end.

As you can see from the chart, the temperature difference changes as the Cold Fraction and inlet air pressure changes.  You may notice that it is independent of the size of the generator.  So, no matter which size Vortex Tube or generator is used, the temperature drop and rise will follow the chart above.  But just remember, cooling capacity is different than cooling temperature.  At the same settings, a larger generator will give you more mass of air to cool faster.

Now, let’s look inside the Vortex Tube (reference photo above).  As the compressed air passes through the generator, the change in pressure will create a powerful vortex.  This spinning vortex will travel toward one end of the tube where there is an air control valve, or Hot Air Exhaust Valve.  This valve can be adjusted to increase or decrease the amount of hot air that leaves the Vortex Tube.  The remaining part of the air is redirected toward the opposite end as the cold flow, or Cold Fraction.

Now, what separates EXAIR Vortex Tubes from our competitors are the three different styles of generators and two different materials for each size.  These generators are engineered to optimize the compressed air usage across the entire Cold Fraction chart above.  With temperatures above 125 oF (52 oC), EXAIR offers a brass generator for the Vortex Tubes.  The same precision design is applied but for higher ambient temperatures.  With the wide range of Vortex Tubes and generators, we can tackle many types of cooling applications.

If you would like to discuss your cooling requirement with an Application Engineer at EXAIR, we will be happy to help.  This unique phenomenon to generate cold air with no moving, freon, or electricity could be a great product to use in your application.

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

Applying a Vortex Tube and Adjusting Temperature

Throughout my tenure with EXAIR there are may days where I have tested different operating pressure, volumetric flow rates, back pressures, lengths of discharge tubing, generator compression, and even some new inquiries with cold air distribution all on a vortex tube.  These all spawn from great conversations with existing customers or potential customers on different ways to apply and applications for vortex tubes.

Many of the conversations start in the same spot… How exactly does this vortex tube work, and how do I get the most out of it?  Well, the answer is never the same as every application has some variation.  I like to start with a good idea of the area, temperatures, and features of exactly what we are trying to cool down.  The next step is learning how fast this needs to be done.  That all helps determine whether we are going to be looking at a small, medium, or large vortex tube and which cooling capacity to choose.   After determining these factors the explanation on how to adjust the vortex tube to meet the needs of the application begins.

This video below is a great example of how a vortex tube is adjusted and what the effects of the cold fraction have and just how easy it is to adjust.  This adjustment combined with varying the air pressure gives great versatility within a single vortex tube.

The table below showcases the test points that we have cataloged for performance values.  As the video illustrates, by adjusting the cold fraction lower, meaning less volumetric flow of air is coming out of the cold side and more is exhausting out the hot side, the colder the temperature gets.

EXAIR Vortex Tube Performance Chart

This chart helps to determine the best case scenario of performance for the vortex tube.  Then the discussion leads to delivery of the cold or hot air onto the target.  That is where the material covered in these two blogs, Blog 1, Blog 2 comes into play and we get to start using some math.  (Yes I realize the blogs are from 2016, the good news is the math hasn’t changed and Thermodynamics hasn’t either.)  This then leads to a final decision on which model of vortex tube will best suit the application or maybe if a different products such as a Super Air Amplifier (See Tyler Daniel’s Air Amplifier Cooling Video here.)is all that is needed.

Where this all boils down to is, if you have any questions on how to apply a vortex tube or other spot cooling product, please contact us.  When we get to discuss applications that get extremely detailed it makes us appreciate all the testing and experience we have gained over the years.  Also, it helps to build on those experiences because no two applications are exactly the same.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

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.

minicoolerWFAM_500
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.
minicooler_appli400
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

 

 

Cold Guns for Spot Cooling or Replacing Mist Systems

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

How does it work, and what are the benefits?

  • The Cold Gun uses compressed air to produce a stream of clean, cold air at 50°F (28°C) below supply air temperature. Generally this will be 20°F-30°F outlet temperature.
  • They use Vortex Tube technology…no moving parts to wear out.

How A Vortex Tube WorksInstant cold air flow with no moving parts!

  • Cold flow and temperature are preset to optimize cooling capability, and are non-adjustable to prevent freeze-up during use.
  • Eliminates the expense of both the purchase & disposal of cutting fluids when replacing expensive mist systems.
  • Removes the potential for health problems associated with breathing mist & vapors, and the safety issue of slipping on a wet floor.

Cold Gun Aircoolant System selection is easy & straightforward…we offer a standard, and a High Power version to meet your specific needs.

CG
Four systems to choose from, to meet most any need.

We also offer Single & Dual Point Hose Kits, to further meet the needs of your application.

One of the best applications I have seen with our cold gun came from a customer in Peru. They are a gold mining operation and they were having trouble with the liquid they were using to cool a saw. Read all about it here!

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If you have an application that you believe would be better served by the use of an EXAIR Cold Gun, give us a call.

Jordan Shouse
Application Engineer
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