Have A Blast (Of Cold Air) With EXAIR Vortex Tubes & Spot Cooling Products

The operation of a Vortex Tube is one of the more peculiar phenomena in fluidics, and a particularly unique method of producing cold air. Since they don’t perform “heat transfer” in the classical sense (see below), there’s no RATE of heat transfer…they’re generating cold air, at rated flow and temperature, instantly.

Compressed air enters the Vortex Tube (blue arrow) where the Generator imparts a spinning motion to the flow, which continues towards the “hot end” (red ribbon). The flow is forced to change directions and continue spinning, flowing in the opposite direction (blue ribbon). It’s at this point that the flow gives up energy in the form of heat, which is exhausted through the Hot Valve (red arrows) while the cold flow makes its way to the opposite end, where it exits at temperatures up to 129F colder than the compressed air supply.

EXAIR Corporation’s Vortex Tubes come in a range of sizes & cooling capacities, and are integrated into a number of Spot Cooling Products which add convenience and flexibility to their operation. Consider:

  • Vortex Tubes themselves are perfect for the most basic of installations. Small and Medium models weigh only a few ounces; you can thread them directly onto an existing 1/8 NPT (Small) or 1/4 NPT (Medium) fitting, if you have one (or can get one) adjacent to where you want to blow the cold air. Hot and Cold Mufflers can be added for sound attenuation, and the Cold Caps have 1/4 NPT (Small) or 3/8 NPT (Medium) female threads if you want to use a short pipe or hose to direct the cold flow.
  • Most spot cooling applications are best handled with the higher air flows and moderate temperature drops associated with a Vortex Tube product set to a high cold fraction. We have three distinct products that have a pre-set, non-adjustable cold fraction, aimed at these situations:
    • Mini Cooler Systems are quiet, compact, and ready to install in minutes via a Swivel Magnetic Base. They’re ideal for cooling small tools, needles in industrial sewing machines, saw blades, or lens grinders, just to name a few of the more popular applications. These come with built-in hot muffler, and are available with a Single or Dual Outlet Cold Air Hose Kit.
    • For applications that call for a higher cooling capacity, we offer the Cold Gun Aircoolant Systems. These have a bar magnet built in to the Cold Gun itself, integral Hot and Cold Mufflers, and, like the Mini Coolers, come with Single or Dual Outlet Cold Air Hose Kits. They’re most popularly specified to replace mist coolant in machine tools, but are also used on routers, grinders, drills, larger saws, and even some non-machining applications like chill rolls and setting hot melt adhesives.
    • For even higher cooling capacities than that, the High Power Cold Gun can be used. Size-wise, it’s identical to the Cold Gun, but it generates twice the Cold Gun’s flow of cold air.
Mini Cooler (left) and Cold Gun (right).

One of the main advantages of using these Vortex Tube products with the pre-set higher cold fractions is the prevention of freeze-up…while the cold air generated is usually just a little below 32F (0C), ambient conditions in the areas where they’re used typically add enough heat to prevent mass freezing of any moisture condensed in the cooling process. A number of applications, however, do indeed call for much colder air flow than this, and for those, we’ve got the Adjustable Spot Cooler:

EXAIR Adjustable Spot Coolers can generate temperatures as low as -30°F (-34°C) instantly, and on demand.

Their versatility makes them a great “utility player” – when very cold air (well below zero) is needed, the Temperature Control Knob is turned counterclockwise. If another application calls for higher flow (like the Mini Coolers or Cold Guns), it can be turned clockwise for instant adjustment of flow and temperature.

Adjustable Spot Cooler Systems are available with Single or Dual Point Cold Air Hose Kits, and come with three Generators: 15 SCFM (installed), 25 SCFM, and 30 SCFM, to select the compressed air consumption, and hence, the overall flow range.

If you’ve got a spot cooling application, EXAIR Corporation has a Vortex Tube solution for you. Give me a call; let’s talk cold air!.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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How to Best Apply Vortex Tube Cooling

So, you have found yourself with a little bit of a conundrum. You need to cool a part but don’t know where to start and there are so many different options to choose from. In most cases when it comes to cooling with compressed air there are two different paths you can take. First is using a large volume of air at room temperature to blow across the surface area of the product. The other option is to use cold air from a vortex tube to drop the part’s temperature. In most case a large volume of air can be used to cool things down to relatively cooler temperatures; think cooling a cup of coffee using your breath. The issue you run into is when the temperature of the room air gets closer to the temperature you want to achieve in the end. In other words, when the temperature difference between your cooling air and your desired end temperature is small there is less cooling taking place with that same volume of air.

Mini Spot Cooler cooling down a bit used in milling plastic

This can be explained by looking at the cooling power formula:

Btu/hr = 1.0746*(CFM)*(Delta T)

In this case the Delta T is the difference between the temperature that you want to cool the product down to and the temperature of the air. This means the smaller the delta T is the higher the CFM flow will need to be to counteract the effect of the temperatures are so close to one another. Here are some examples of cooling a product and you are providing 1000 CFM of air to cool it.

Btu/hr = 1.0746*(1000 CFM)*(150F – 130F)

                Btu/hr = 21,492 Btu/hr

Btu/hr = 1.0746*(1000 CFM)*(150F – 100F)

                Btu/hr = 53,730 Btu/hr

As you can see the closer the Delta T is to 0 the less Btu/hr you get. Getting this kind of CFM flow is easy if you use something like EXAIR’s Super Air Knife or Super Air Amplifier. These systems take a small amount of compressed air and entrain the surrounding ambient air to increase the volume to a large blast. Take a look at model number 120022 which is the 2” Super Air Amplifier, this unit can produce 1,023 CFM while only using 15.5 CFM at 80 psig. But when you get close to cooling the temperature down to that room temperature or below it gets much harder; which only means that the temperature of the air being used to cool needs to be dropped. Dropping the air temperature can only be accomplished by using outside means like air coolers or in this case EXAIR’s Vortex Tubes and Spot Coolers.

EXAIR Air Amplifiers use a small amount of compressed air to create a tremendous amount of air flow.

Vortex Tubes and Spot coolers have some limitations. Generally they are not thought of products that produce large volumes of air (even though we make them up to 150 SCFM). And they are best suited for smaller areas of cooling, spot cooling, if you will. However, EXAIR Vortex Tubes do have one key feature that can help compensate for the lack of volume. LOW TEMPERATURE! The vortex tube can produce temperatures lower than 0F while stile retaining a good portion of air volume from the inlet.

Sub-zero air flow with no moving parts. 3400 Series Vortex Tubes from EXAIR.

For example, let’s look at model number 3240 running at 100 psig with 70% of the air from the inlet exiting the cold side (aka 70% cold fraction). At 100 psig the 3240 will use 40 SCFM at the air inlet and will have a temperature drop of 71F. If the compressed air has a temperature of 70F that means you will be seeing a temperature of -1F. Also, when using the 70% cold fraction you will see 28 SCFM of cold air flow. Now let’s plug those numbers into the cooling power formula.

 Btu/hr = 1.0746*(28 CFM)*(150F + 1F)

                Btu/hr = 4543 Btu/hr

As you can see, using a small amount of compressed air you can still net you a good amount of cooling if the temperature is lower. All in all, the best option for cooling products down to temperatures that are above ambient temperatures is something that can produce a large volume of air. For small areas that require cooling the product down to temperatures to ambient temperature and below, use EXAIR’s Vortex Tube.

If you have questions about our Air Amplifiers and Vortex Tubes, or would like to talk about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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EXAIR Cold Gun, Different Application, Problem Solved!

Recently I was working with a customer on sizing a EXAIR Cabinet Cooler when I found out they would be best suited by another EXAIR product! They wanted to cool some analyzer panel fins (heat sinks) while keeping dust off of them. This application said Cold Gun all the way!

I recommended our Model # 5315 Cold Gun Aircoolant System with two cold outlets. The Cold Gun produces a 50°F temperature drop from compressed air supply temperature and provides 1,000 Btu/hr. of cooling capacity. For example, if your compressed air supply temperature is 70°F you would effectively see 20°F air being discharged from the cold exhaust. The Dual Point Hose Kit splits the cold airflow into 2 separate streams, providing for a wider coverage area.

5315_SCGdual
Model # 5315 Cold Gun System with dual point hose kit

The customer decided to order a single unit and after a week of testing replied back…

“We tried one a week ago with excellent results! We are installing three more today. 

Thank you so much for your help! Our analyzer is running 31°F cooler than it had been with no more overtemp failures!”

It goes without mentioning, but this is the type of positive feedback we are thrilled to hear! It feels incredible when a customer takes time out of their busy schedule to acknowledge how EXAIR products provided the perfect solution for their needs!

BUT the story doesn’t end there… just last week, over 2 months since our last correspondence, the customer sent me another email that read…

“Just a follow up on the effectiveness of the cold air guns. We have not experienced a single failure of our TOC analyzers since the guns were installed two months ago.

The cold air solved the problem of our analyzer overheating — even during the hottest part of the summer.

Thank you for your excellent recommendation!”

I let the customer know how much we appreciated the awesome news and how happy we were to be able to solve their problem. At the end of the day, that’s what we strive for, to provide the best and largest selection of Intelligent Compressed Air Products on the market today.

Jordan Shouse
Application Engineer

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Hazardous Location AND Overheating Electronics? We Have You Covered!

Here in Ohio, we like to think we know a lot about the weather. Did you know there are more than 4 seasons? Heck, we have at least two Winters, and then a Pre-Summer, Spring, Summer, Heat is still coming – make it stop season, and Fall. Don’t forget the construction season where the lovely orange cones and barrels bloom on every major roadway, and then we also like to throw in brood weeks for the cicadas every now and then. Yeah, we get a full gambit of weather and the past week has brought out some heat. I know this isn’t just Ohio, we get calls from around the globe of atmospheric conditions that have caused issues within control panels. Some of these panels are in areas where the No Smoking sign is more than just a suggestion to better your health.

1 – Dust Explosion

That’s right, there are areas in manufacturing facilities that are governed by the standard due to a variety of conditions resulting in what is known as Hazardous Locations. NFPA and UL have a list of standards breaking these down into separate Classes, Divisions, and Temperature Classes. If you want all the details, the NFPA code is around 908 pages, cover to cover. The Classified UL mark shown below is one way of knowing that a product has been tested to these stringent standards and is okay to use in clearly marked environments.

UL Classified Markings

EXAIR offers Cabinet Cooler Systems that will meet these stringent standards and keep your enclosures cool in order to keep your production up and running. The top three tiers that we meet are:

  • Class I Div 1, Groups A, B, C and D
  • Class II Div 1, Groups E, F and G
  • Class III

The HazLoc Cabinet Cooler Systems are available in 8 different cooling capacities from 1,000 Btu/hr to 5,600 Btu/hr. and are manufactured to work in conjunction with a purged and pressurized control system. As well as with or without thermostatic control.

EXAIR’s Hazarous Location Cabinet Cooler Systems maintain Type NEMA 4/4X Integrity and are CE Compliant.

If you would like help sizing the correct system for your electrical panels, feel free to use the link, or contact an Application Engineer to discuss the applications and get one sized while on the phone with us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Dust explosion 05.jpg, Hans-Peter Scholz, October 7, 2009, retrieved from https://commons.wikimedia.org/wiki/File:Dust_explosion_05.jpg