November’s Promo Features Cool Products

That’s right, with the start of November this year we also start our Cold Gun promotion. This promotion runs from the start of November until December 31, 2022. The best part is that Cold Guns have a long history of providing spot cooling solutions for industry. Cold Guns have been cooling product and processes for over 35 years! Take advantage of the current promotion today!

The EXAIR Cold Gun promo is a great way to receive an additional tool to extend the use of the Cold Gun. With the purchase of a promotional Cold Gun System w/ Single Point Hose Kit or promotional High Power Cold Gun System w/ Single Point Hose Kit you will receive a Dual Point Hose Kit for free. This is a $48.00 USD value. The Cold Gun will drop your compressed air temperature by 54°F when operating at 100 psig inlet pressure. Choose the standard point tip or the 1″ fan tip to blow the cold air. The total length of the flexible discharge hose is around 11″. If more coverage is needed, the promotional Dual Point Hose Kit gives around 5-6″ of straight hose before splitting into two smaller lines that offer both point or fan tip nozzles as well. This dual point can be used to reach both sides of larger diameter cutters and components that need a blast of cool air.

The Cold Gun is easily setup in any machine that has a ferrous metal surface thanks to its integrated magnetic base that will hold the unit in place even when the machine is moving or vibrating. If you do not have ferrous metal available for the magnetic base, using rigid piping or even something like u-bolts to hold the unit into place is a common practice of customers who need the cooling and know the Cold Gun will perform.

Lastly, if you aren’t certain whether the Cold Gun is the solution, we have an entire team of Application Engineers here to discuss the application, and it is also backed by our 30-day guarantee so our US and Canadian based customers can order one, test it in their facility for 30 days. If they are not pleased with the performance for any reason, the item can be returned to EXAIR. If you want to discuss your application, contact us today!

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

The Vortex Tube, Maxwell’s Demon, Hilsch Tube, Ranque Tube: What Exactly is this Device? How Does it Work?

If I were to tell you that I can take a supply of ordinary compressed air and drop its temperature by 50°F with no moving parts and without any type of refrigerant or electrical connection, you might be scratching your head a bit. That is of course unless you’ve been introduced to the wild world of Vortex Tubes. My favorite product among the EXAIR Product Line, the Vortex Tube, does just that. With an ordinary supply of compressed air as the sole power source, and no moving parts, the Vortex Tube converts that airstream into a hot and cold flow that exits from opposite ends of the tube. No magic, witchcraft, or wizardry involved here. Just physics!

The theory all began in the 19th century with the famous physicist and mathematician James Clerk Maxwell. He suggested that since heat involves the movement of molecules, it could be possible to create a device that could distribute hot and cold air with no moving parts with the help of a “friendly little demon” that would sort and separate the hot and cold molecules of air. Not much was done with regard to this or any further advancement until about 61 years later.

In 1928, a French physics student by the name of George Ranque was conducting some testing on a vortex-type pump he had developed. In this testing, he noticed that warm air was exhausting from one end, while cold air was coming out of the other. He dropped his plans for the pump and begin an attempt to exploit this phenomenon commercially. His business ultimately failed, along with the Vortex Tube theory, until 1945 when a German physicist named Rudolph Hilsch published a scientific paper based on the Vortex Tube.

With so many involved, the tube became known by a variety of different names: “Ranque Vortex Tube”, the “Hilsch Tube”, the “Ranque-Hilsch Tube”, and (my personal favorite) “Maxwell’s Demon”. Over the years, it has gained a reputation as a low cost, reliable, and highly effective method for industrial spot cooling and panel cooling applications. While using the tube as a PC cooler isn’t generally recommended, here’s a great video demonstrating the tube in operation from Linus Tech Tips on YouTube:

So how exactly does this thing work? The truth is no one knows for certain, but there is one commonly accepted theory that explains the phenomenon:

Compressed air is supplied into the tube where it passes through a set of nozzles that are tangent to the internal counterbore. The design of the nozzles force the air to spin in a vortex motion at speeds up to 1,000,000 RPM. The spinning air turns 90° where a valve at one end allows some of the warmed air to escape. What does not escape, heads back down the tube in the inner stream where it loses heat and exhausts through the other end as cold air.

Both streams rotate in the same direction and at the same angular velocity. Due to the principle of conservation of angular momentum, the rotational speed of the inner vortex should increase. However that’s not the case with the Vortex Tube. The best way to illustrate this is in Olympic Figure Skating. As the skater is wider, the spinning motion is much slower. As she decreases her overall radius, the velocity picks up dramatically and she spins much quicker. In a Vortex Tube, the speed of the inner vortex remains the same as it has lost angular momentum. The energy that is lost in this process is given off in the form of heat that has exhausted from the hot side of the tube. This loss of heat allows the inner vortex to be cooled, where it can be ducted and applied for a variety of industrial applications.

This Vortex Tube theory is utilized in basic Vortex Tubes, along with a variety of other products that have additional features specific for your application. EXAIR’s line of Cabinet Coolers, Cold Guns, Adjustable Spot Coolers, Mini Coolers, and Vortex Tubes all operate off of this same principle.

If you’re fascinated by this product and want to give it a try, EXAIR offers an unconditional 30 day guarantee. We have them all in stock and ready to ship as well, same day with an order received by 2:00 ET. Feel free to get in contact with us if you’d like to discuss how a vortex-based product could help you in your processes.

Tyler Daniel, CCASS

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

Vortex Tube Cold Fraction and how it Affects Flow and Temperature Control

Vortex Tubes are the perfect solution when dealing with a variety of spot cooling applications. They use compressed air to produce a cold air stream and a hot air stream, with temperatures ranging from as low as -50°F  up to +260°F (based on ambient supply temperature) and providing as much as 10,200 Btu/hr. of cooling capacity. By simply adjusting the valve in the hot end of the Vortex Tube, you are able to control the “cold fraction” which is the percentage of air consumed by the vortex tube that is exhausted as cold air versus the amount of air exhausted as hot air. Our small, medium and large Vortex Tubes provide the same temperature drop and rise, it’s the volume of air that changes with the various sizes.

The unique physical phenomenon of the Vortex Tube principle generates cold air instantly, and for as long – or short – a time as needed.

When looking at the below performance chart, you will see that “Pressure Supply” and “Cold Fraction %” setting all play a part in changing the performance of the Vortex Tubes. Take for example, an operating pressure of 100 PSIG and cold fraction setting of 20%, you will see a 123°F drop on the cold side versus a 26°F temperature rise on the hot side. By the using the same Vortex Tube and keeping the operating pressure at 100 PSIG but changing the cold fraction to 80%, you will now see a 54°F temperature drop on the cold side and a 191° rise at the hot end.

Vortex Tube Performance Data
Vortex Tube Performance Chart

We’ve looked at how the cold fraction changes the temperature, but how does it change the flow for the various Models?

Say you are using a Model # 3240 Medium Vortex Tube which consumes 40 SCFM @ 100 PSIG. Again with the cold fraction set at 80% (80% of the consumed compressed air out of the cold end), you would flow 32 SCFM at the cold air exhaust.

40 SCFM x 0.8 (80% CF) = 32 SCFM

Using the same Model # 3240 Medium Vortex Tube but now with a 20% cold fraction (20% of consumed compressed air out of the cold end), you would flow 8 SCFM at the cold exhaust.

40 SCFM x 0.20 (20% CF) = 8 SCFM

As you can see, to achieve the colder air temperatures, the volume of cold air being exhausted is reduced as well. This is important to consider when making a Model selection. Some other considerations include the operating pressure which also has a significant effect on performance. The compressed air supply temperature is important because the above temperatures are temperature differentials, so in the example of the 80% cold fraction there is a 115F temperature drop from your inlet compressed air temperature.

If you need additional assistance, you can always contact myself or another application engineer and we would be happy to make the best selection to fit your specific need.

Jordan Shouse
Application Engineer

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Twitter: @EXAIR_JS

EXAIR Cold Gun Overview

In any machining operation, tool wear is an inevitability. Cutting tools heat up due to friction and this heat contributes to premature tool wear. As tooling wears, poor tolerances and dimensional inaccuracy are common. Additionally, as the cutting edge dulls increased cutting force is required which further increases the amount of heat generated.

Coolants can be used to reduce friction and help mitigate some of the wear, but then you’re left with the mess that coolant brings along with it both on the part and in the machine itself. What if I were to tell you that there’s a way to mimic the effects of coolant, but without all of the mess? All of this can be achieved with just a supply of compressed air and one of EXAIR’s Cold Gun Systems.

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 it’s maintenance free!

Cold Guns Systems

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.

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 our limited time promotion and receive a FREE Dual Point Hose Kit upgrade!

Tyler Daniel, Application Engineer

E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD
Ph. 1-800-903-9247 or 1-513-671-3322