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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EXAIR’s E-Vac Vacuum Generators & Accessories


EXAIR’s In-Line and Adjustable E-Vacs are powerful compressed air powered vacuum generators. They’re a low-cost way to create a vacuum for a variety of different applications: pick and place, clamping, chucking, lifting, surface mounting, and vacuum forming are just some of the possibilities. Both the In-Line and Adjustable E-Vacs are available in a variety of different sizes and flows and can accommodate a wide range of applications.

In addition to the vacuum generators themselves, EXAIR offers a variety of different accessories to help you build a complete system. To minimize the sound level and ensure you’re adhering to OSHA 29CFR 1910.95, we have Standard Mufflers as well as Straight Through Mufflers. The Straight Through Mufflers offer the best level of sound reduction, up to 26 dBA!!

Straight through mufflers are available from 1/4″-1″ MNPS

With no moving parts to wear out, EXAIR’s E-Vacs are virtually maintenance free when supplied with clean, dry compressed air. To maintain proper operation of your E-Vac, installation of an Automatic Drain Filter to remove any particulate and moisture from the air supply is necessary. In addition, oil removal filters are also available if your compressed air supply contains any oil as is common in many compressed air systems.

For pick and place or lifting applications, vacuum cups will be necessary. With a wide variety of different vacuum cups available: small round, large round, oval, and bellows, we can accommodate nearly any size or shape material. For heavier materials, round cups with cleats provide rigidity and ensure that the load remains stable. For applications on textured or uneven surfaces, bellows style cups have convolutions that allow for the cup to quickly decompress when it touches the surface of an uneven part or material.

EXAIR’s family of vacuum cups

The vacuum port of the E-Vac has an NPT thread, vacuum cups can be installed directly in this inlet. For applications where the vacuum cup(s) are remotely located, we offer polyurethane vacuum tubing as well as a variety of different fittings to connect them. Both 1/4” and 3/8” O.D. sizes are available in 10’ lengths up to 50’. Simply indicate the model number of the tubing and add the length with a “-“ at the suffix. For example, a 900795-30 would be 30′ of 1/4″ O.D. tubing. In addition to fittings and tubing, vacuum check valves are also available. These can be beneficial if there is potential for fluctuations in the compressed air pressure or supply. In the event that there is a significant drop in pressure or loss of compressed air supply, the check valve will ensure that the load remains held.

Push-in Swivel Tee Connector

With all of the different options making a selection can seem like a daunting task. A highly trained EXAIR Application Engineer is ready and available to help you!! With just a few quick details, we can help advise you about the proper size E-Vac generator for your application as well as recommend the most suitable cup and accessories. Give us a call, shoot us an e-mail, or reach out to us online via chat and we’ll make sure you have a complete vacuum solution ASAP with all parts ready to ship from stock!

Tyler Daniel
Application Engineer
Twitter: @EXAIR_TD

Threaded Line Vacs: Low Cost Conveyor Uses Ordinary Pipe!

EXAIR’s Threaded Line Vac air operated conveyor takes an ordinary pipe and converts it into a powerful conveying system.  A fast, low cost way to convey items such as pellets, scrap trim, bulk solids, chips, paper, small parts, sawdust, granules, and so much more. The Threaded Line Vac attached easily to plumbing pipe couplers, like PVC or iron, making it easy to build a complete system with parts readily available from your local supply house or hardware store.

The Threaded Line Vac are ideally suited for conveying large volumes of materials over long distances.  Like the standard, smooth bore ended Line Vacs, the unit works by ejecting a small amount of compressed air to produce a vacuum suction on the inlet side and a high output flow from the outlet side.  By using a pressure regulator to control the compressed air supply pressure, the rate of conveyance can be controlled to match the application needs, while minimizing the compressed air usage.


Models are available from 3/8 NPT to 3 NPT with materials of construction of aluminum and types 313 and 316 stainless steels (excellent corrosion resistance.)  High temperature versions of the stainless steel Threaded Line Vacs are available as well, for temperatures up to 900°F.

For those processes requiring the highest rates of conveyance over the longest distances and/or the most abrasive of materials, the Heavy Duty Threaded Line Vac is the right choice.  Designed with the most rugged industrial processes and applications in mind, the special hardened alloy construction helps prevent premature wear that could occur with standard aluminum or stainless steel models, under the harshest of conditions.  The performance has been boosted, to be able to convey more material, over longer distances and higher vertical rises.


To select the right model, information regarding these criteria is helpful-

  • Size of parts and bulk density of material being conveyed
  • What size hose, tube, or pipe is desired
  • Target conveyance rate
  • Distance of conveyance, both horizontal and vertical legs
  • Preferred material of construction

For another look, please see the video available that provides more details about the Line Vac family.

If you would like to talk about Line Vacs 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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Super Air Wipe Vs. Block Type Air Wipe

Air Wipes, which provide 360 degree blowoff, are typically used to remove heat, liquid, debris or static from wire, cable, pipe, tube, or extrusions.

We had a customer that was using a block type Air Wipe from a competitor to remove water from an extrusion.  These air wipes are built using a plastic material, typically with some additional ceramic insert to resist abrasion of the wire, the halves are hinged with air holes drilled into each half which carries air through the block and on to the wire. They were using these block air wipes on several lines. The interesting point of this blog is that it required 5 block type air wipes to equal the results of 1 EXAIR Super Air Wipe.

Since EXAIR’s Super Air Wipe equaled the performance of 5 of the competitors it consumed less air was less expensive and produced less noise.  Also in space sensitive applications the EXAIR Super Air Wipe is much thinner than the block type.  To highlight this the Super Air Wipe is 1.13″ thick on all 11 models that range from 3/8″ to 11″ throat diameter.   The performance of the block air wipe can only be changed by altering the inlet air pressure while the EXAIR Super Air Wipe can also be changed by adusting the inlet air pressure OR by adding an additional shim the force can be nearly doubled!

Many of these block type air wipes use a series of holes to direct the compressed air supply at an angle over the material that needs to be cleaned off.  EXAIR’s Super Air Wipe being an engineered compressed air product use’s fluid dynamic’s to create more force as demonstrated below. The air from EXAIR’s Super Air Wipes is a continuous 360 degrees, without the gaps a series of holes creates.

How The Air Wipe Works

Compressed air flows through the inlet (1) of the Air Wipe into the annular chamber (2).  It is then throttled through a small ring nozzle (3) at high velocity.  This primary airstream adheres to the Coanda profile (4), which directs down the angled surface of the Air Wipe.  A low pressure is created at the center (5) inducing a high volume flow of surrounding air into the primary airstream.  As the airflow leaves the wipe, it creates a conical 360° ring of air that attaches itself to the surface of the material running through it (6) uniformly wiping the entire surface with the high velocity airflow.

Block type air wipes are generally available in standard sizes up to 7″ in diameter while EXAIR’s Super Air Wipes are available in stock diameters up to 11″ and we also offer custom sizes to suit many other applications.

If you have any items that need to have a 360 degree blowing pattern, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer
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Sound Power Level and Sound Pressure

Energy…all day (and night) long, we humans are surrounded by – and bombarded by – all kinds of energy. Sometimes, the effects are pleasant; even beneficial: the warmth of the sun’s rays (solar energy) on a nice spring day is the sure-fire cure for Seasonal Affective Disorder, and is also the catalyst your body needs to produce vitamin D. Good things, both. And great reasons to get outside a little more often.

Sometimes, the effects aren’t so pleasant, and they can even be harmful. Lengthy, unprotected exposure to that same wonderful sun’s rays will give you a nasty sunburn. Which can lead to skin cancer. Not good things, either. And great reasons to regularly apply sunblock, and/or limit exposure if you can.

Sound is another constant source of energy that we’re exposed to, and one we can’t simply escape by going inside. Especially if “inside” is a factory, machine shop, or a concert arena. This brings me to the first point of today’s blog: sound power.

Strictly speaking, power is energy per unit time, and can be applied to energy generation (like how much HP an engine generates as it runs) or energy consumption (like how much HP a motor uses as it turns its shaft) For discussions of sound, though, sound power level is applied to the generation end. This is what we mean when we talk about how much sound is made by a punch press, a machine tool, or a rock band’s sound system.

Sound pressure, in contrast, is a measure of the sound power’s intensity at the target’s (e.g., your ear’s) distance from the source. The farther away you get from the sound’s generation, the lower the sound pressure will be. But the sound power didn’t change.

Just like the power made by an engine and used by a motor are both defined in the same units – usually horsepower or watts – sound power level (e.g. generation) and sound pressure (e.g. “use” by your ears) use the same unit of measure: the decibel.  The big difference, though, is that while power levels of machinery in motion are linear in scale, sound power level and pressure scales are logarithmic.  And that’s where the math can get kind of challenging.  But if you’re up for it, let’s look at how you calculate sound power level:

Sound Power Level Equation


Wis reference power (in Watts,) normally considered to be 10-12 W, which is the lowest sound perceptible to the human ear under ideal conditions, and

W is the published sound power of the device (in Watts.)

That’s going to give you the sound power level, in decibels, being generated by the sound source.  To calculate the sound pressure level:

Sound Power Level to Sound Pressure Equation


Lis the sound power level…see above, and

A is the surface area at a given distance.  If the sound is emitted equally in all directions, we can use the formula for hemispheric area, 2πrwhere r=distance from source to calculate the area.

These formulas ignore any effects from the acoustic qualities of the space in which the sound is occurring.  Many factors will affect this, such as how much sound energy the walls and ceiling will absorb or reflect.  This is determined by the material(s) of construction, the height of the ceiling, etc.

These formulas may help you get a “big picture” idea of the sound levels you might expect in applications where the input data is available.  Aside from that, they certainly put into perspective the importance of hearing protection when an analysis reveals higher levels.  OSHA puts the following limits on personnel exposure to certain noise levels:

Working in areas that exceed these levels will require hearing protection.

EXAIR’s line of Intelligent Compressed Air Products are engineered, designed, and manufactured with efficiency, safety, and noise reduction in mind.  If you’d like to talk about how we can help protect you and your folks’ hearing, call us.


EXAIR’s Unconditional 30 Day Guarantee = Success!

This week in Cincinnati we hit a record high 79°F. Since less than a week earlier it snowed all afternoon, let’s just say many people around here began to get excited. While I don’t mind a little snow here and there, once February begins to draw to a close I’m ready to bust out the shorts, tank tops and flip flops and bring on some warmer temperatures. It also means I’m right around the corner from opening up the pool. Let’s hope that goes much smoother than last year….


Another benefit to the warmer temperatures, especially here in Cincinnati, is the coming of the baseball season. With the Reds Spring Training also starting this week, optimism is in the air (albeit reserved after the last few years performance).

Unlike baseball where it’s 3 strikes and youuuu’rrrreeee out! EXAIR’s unconditional 30 day guarantee for all stock products allows you the opportunity to test out several different solutions to ensure you get the right product for your application.30dayguarantee

I recently worked with a customer that was interested in switching their current blowoff process with something that would reduce their sound levels but still allow them to complete the job in a similar time frame. The company makes aluminum castings and was using the air gun to remove residual sand leftover in the die after each cycle. Their current air gun was producing sound levels at 107 dBA, well above OSHA’s safe operating range for a full 8 hour shift of work according to OSHA 29 CFR 1910.95(a).

They didn’t want to commit to just one style of air gun, so he purchased a 1210SS-18 (Safety Air Gun w/ ¼ NPT Stainless Steel Nozzle and 18” extension) and a few different additional ¼ NPT nozzles to see which style his operators preferred. After some testing, they concluded that the air gun with an 1122SS 2” Flat Nozzle installed provided them with the best results. Having the added feature of changing out the shim to increase/decrease the force and flow was also welcomed. They’ll be returning the extra nozzles and applying the credit to the purchase of some new 1230SS-18 guns to outfit their other work stations.

Model 1230SS-18 Soft Grip Safety Air Gun

While we do have a highly trained team of Application Engineers ready and available to help you determine the most suitable product, sometimes testing it out at your facility is the best way to ensure a positive result. That is EXACTLY why we give you 30 days to test out any stock product. If for any reason at all you’re unsatisfied with the performance, give us a call and we’ll arrange for a return. Don’t be afraid to swing and miss!

Tyler Daniel
Application Engineer
Twitter: @EXAIR_TD

Reds photo courtesy of Keith via Creative Commons License

Oil Removal Filters – Keeping Compressed Air Clean

Compressed air filters help to keep the air clean and condensate free to protect equipment from dust, dirt, pipe scale, oil and water. Even though the compressed air system will typically have a main dryer, additional treatment is often necessary. For this discussion, we will focus on the oil removal process and filter type.

After the compressed air has passed through a particulate filter, the dirt, dust and water droplets have been removed.  Oil that is present is much smaller in size, and mostly passes though the particulate filter.  The installation of a coalescing filter will provide for the removal of the majority of the fine oil aerosols that remain. The coalescing filter works differently than the particulate filters. The compressed air flows from inside to outside through the coalescing filter media. The term ‘coalesce’ means to ‘come together’ or ‘form one mass.’  The process of coalescing filtration is a continuous process where the small aerosols of oil come in contact with fibers of the filter media. As other aerosols are collected, they will join up and ‘come together’ and grow to become an oil droplet, on the downstream or outside surface of the media.  Gravity will then cause the droplet to drain away and fall off the filter element.

Example of a 0.03 Micron Coalescing Oil Removal Filter

Some important information to keep in mind –

  • Change the filter regularly, not just when the differential pressures exceeds recommended limits, typically 5 PSI
  • Coalescing filters will remove solids too, at a higher capture rate due to the fine level of filtration, using a pre-filter for solids will extend the life
  • Oil free compressors do not provide oil free air, as the atmospheric air drawn in for compression contains oil vapors that will cool and condense in the compressed air system.

If you would like to talk about oil removal filters 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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