Thermodynamics is a branch of physics that focuses on heat and energy. It studies how these forms of energy move and change within a system. An isolated system is a key concept in thermodynamics; it is a space that does not interact with anything outside of it. This means that no heat or energy can enter or leave a system. Understanding these principles helps scientists and engineers design better machines and improve energy efficiency.
The unique physical phenomenon of the Vortex Tube principle generates cold air instantly, and for as long – or short – a time as needed.
Maxwell’s demon is a thought experiment created by the mathematician James Clerk Maxwell. This imaginary being has the ability to see fast and slow-moving molecules in a gas. By sorting these molecules, the demon could supposedly create a situation where one side of the container is hot, and the other side is cold, without using energy. This idea challenges the second law of thermodynamics, which states that systems tend to move towards disorder. Maxwell’s demon shows that there are limits to our understanding of energy and order in the universe.
How a Vortex Tube Works
Maxwell’s demon is a molecule-sized trapdoor that separates a box of gas into two sides. The demon observes molecules and only allows fast-moving molecules to pass through to one side, and only slow-moving molecules to pass through to the other side. This would cause the temperature inside the container to increase without any work being applied, which would violate the second law of thermodynamics.
The cold air from the Vortex Tube (dark blue arrow) is aimed directly at the inlet plenum of the Air Amplifier. As it draws in environmental air (at ambient temperature, pale curved arrows), the Air Amplifier discharges cool air (light blue arrow) at the desired temperature.
The Vortex Tube by EXAIR is a product that demonstrates this theory to its fullest extent. Using an ordinary supply of compressed air as a power source, Vortex Tubes create two streams of air, one hot and one cold, with no moving parts. Vortex Tubes offer a temperature range between -50F to +260F, with flow rates ranging from 1 to 150 SCFM. EXIARVortex Tubes are constructed of stainless steel, which offers resistance to corrosion and oxidation, and will provide years of reliable, maintenance-free operation.
If you would like to discuss the Vortex Tube, please do not hesitate to contact an Application Engineer. We are always happy to help!
If you’re a regular reader of the EXAIR Blog, you likely know that you can get cold (and hot) air from a Vortex Tube. You probably also know that there are ways to get more or less flow, and higher or lower temperatures. Today, I wanted to write about vortex tube operation. First, let’s recall the basics:
The unique physical phenomenon of the Vortex Tube principle generates cold air instantly, and for as long – or short – a time as needed.
To change the cold (or hot) air flow AND temperature (you can’t do one without the other), all you have to do is manipulate the Control Valve, or Hot Valve, as it’s oftentimes referred to because of its location at the ‘Hot’ end of the Vortex Tube. Essentially, as you open it, more hot air exits, meaning there’s less air to go to the ‘Cold’ end. By increasing the ‘Hot’ flow, more kinetic energy (in the form of heat) is carried away. And, since more energy (heat) is given off, the energy (heat) in the cold flow decreases as well, so you get colder air…and less of it as the hot flow increases. We can use the data in EXAIR’s Vortex Tube Specification and Performance Tables to calculate the cold (and hot) flows and temperatures at different positions of the Hot Valve. Let’s say we have a Model 3210 Vortex Tube that uses 10 SCFM when supplied at 100psig:
Let’s assume the compressed air supply temperature is 70°F and the Hot Valve is open wide enough to allow 40% of the Model 3210’s 10 SCFM (or 4 SCFM) worth of compressed air consumption out. That means that 60% (or 6 SCFM) are going to go out of the cold end. We call this condition a 60% Cold Fraction:
And, at that 60% Cold Fraction, the cold air is going to be 86°F colder than the supply of 70°F, which means that the 6 SCFM of cold flow is going to be -16°F. If the Hot Valve is opened further, to allow 5 SCFM out the hot end (and hence the other 5 SCFM will go out the cold end), that 5 SCFM of cold flow will now be 100°F colder than the 70°F supply, or -30°F. That’s as low as you can go with a 3200 Series Vortex Tube…they have a Cold Fraction range of 50-80%.
Now let’s say you want even COLDER air. You can simply replace the generator (shown to the left) in the Model 3210 to make it a 3400 Series Vortex Tube. If you replace its 10-R Generator with a 10-C Generator, you’ll now have a Model 3410, and you’ll be able to adjust your Vortex Tube to the 20-50% Cold Fraction range. The difference between R and C-style generators is the center hole size. The hole sets up proper internal pressure conditions to work better in each temperature range. In short, the generator type optimizes the temperature drop for each working condition.
You’re still working with a compressed air consumption of 10 SCFM, so, while the air gets colder, the flow decreases. At a 30% Cold Fraction, for example, you’ll get -48°F air (70°F – 118°F), but only 3 SCFM (30% of 10 SCFM) of the total flow going in.
If you need a -48°F net air temperature, but cannot accommodate such a reduction in flow, using a generator with a higher consumption rating is how you get around such an issue. If you were to replace that 10-C Generator with a 30-C, now it is a Model 3430 with triple the original flow of model 3410. Readjustment of the hot valve would be necessary to get back to a 30% Cold Fraction. That means the air flow will be the same temperature (-48°F) but it’s going to be 9 SCFM (instead of 3 SCFM.)
All you need to change the Cold Fraction of an EXAIR Vortex Tube is a flat-head screwdriver. If it’s something you’re going to be doing more frequently, our Adjustable Spot Coolers have a Temperature Control Knob that works the Hot Valve and may be a better choice for an application.
This is from the Vortex Tubes and Spot Cooling Products section of Catalog 35. The first graphic at the beginning of this blog is what you’ll find on page 200. You’re welcome.
The Adjustable Spot Coolers also come with three different generators, so you can get the different flows at the same temperature, or vice versa, as described above. If you have an application requiring cold (or hot) air flow, on demand, you’re looking for an EXAIR Vortex Tube. For help picking the right one, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
EXAIR’s Adjustable Spot Cooler is an ideal fit for those who need the ability to adjust the temperature of their spot cooling solution. This user-friendly tool is available right out of the box with the necessary accessories to allow you to quickly install and implement the solution. It can be great for dry-machining processes or applications where you’re looking to replace a standard coolant-based method of cooling.
If that sounds like something you’re looking for, then the Adjustable Spot Cooler could be an excellent product for optimizing your processes. EXAIR’s Adjustable Spot Cooler incorporates Vortex Tube technology to produce temperatures ranging from -30°F – +70°F. A Vortex Tube works by imparting a rapid spinning motion to the supplied compressed air. This airflow makes its way to the end of the tube where it is forced to abruptly change direction. It is during this change of direction that energy is given off in the form of heat. The hot air then exits the tube from the hot end, while cold air exits the other end of the tube. As the valve is opened to allow more air to exhaust from the hot end, the temperature at the cold end will decrease. At a sound level of just 73 dBA when operated at 100 psig and a stock generator installed, this compact cooler will keep your operation clean and dry without causing unnecessarily high noise levels.
When looking at a Vortex Tube based solution, the variety of options can sometimes be daunting. This is where the Adjustable Spot Cooler shines. Through a simple turn of the control knob, you can easily adjust the temperature and cold fraction of the unit. Additionally, the kits come with (2) extra generators (15-H and 30-H) that can be swapped out for the stock generator for more/less cooling power and air consumption. The 15-H generator will deliver up to 1,000 Btu/hr of cooling capacity and the 30-H will provide up to 2,000 Btu/hr of cooling capacity. We have (2) different kits available, the Model 3825 Single Point and the Model 3925 Dual Point Kit. The 3825 is recommended for use in applications where you’re cooling a small surface such as solder joints, hot melts, or drilled plastics. The 3925 system is better served when heat is generated over a larger surface area, such as saw blade cooling. The kits use a flexible Loc-Line hose to allow you to precisely position the cold airflow onto your target. The Adjustable Spot Cooler provides easy mounting with a swivel magnetic base, allowing you to position the cold air flow directly at the most critical point where heat is being generated.
If you’re tired of cleaning up your coolant or have an application that requires dry machining, get one of the Adjustable Spot Cooler systems on order today. They’re in stock ready to ship the same day with an order received by 2:00 ET!
I got a new cell phone a few months ago. It was my first ‘upgrade’ in quite some time, and while it has some neat features (along with a bunch of stuff I’ll NEVER use), there was one glaring omission: a 1/8″ port for the cord of my trusty earbuds. I even took the protective case off, looking for it. After just barely managing to get the case back on, I bought myself my first ever wireless earbuds. After scanning the ‘quick reference’ guide, I steeled my reserve for the long & arduous process of getting them up and running. To my pleasant surprise, they were fully charged, and, right out of the case, started pairing with my new cell phone. I was drowning out the sound of my lawnmower to 1970s Heavy Metal in no time!
You know what else is ready to go, right out of the box? EXAIR’s Adjustable Spot Cooler System, that’s what. OK; it doesn’t automatically connect itself to your compressed air system, but once you hook an air hose up to it, it makes a flow of cold air instantly. With the Temperature Control Valve, you can change the cold air flow and temperature just as instantly. If the 25 SCFM Generator that comes installed doesn’t make enough flow – or if it makes too much – the Adjustable Spot Cooler System comes with two more Generators (15 SCFM and 30 SCFM) that’ll put it into a whole new performance band.
The Adjustable Spot Cooler incorporates a vortex tube to convert an ordinary supply of compressed air (1) into two low pressure streams, one hot and one cold. With the turn of a knob, the temperature control valve (2) allows some hot air to flow through a muffling sleeve and out the hot air exhaust (3). The opposite end provides a cold airstream (4) that is muffled and discharged through the flexible hose, which directs it to the point of use. The swivel magnetic base (5) provides easy mounting and portability.
I was excited to hear that the Adjustable Spot Coolers were the focus of our latest Press Release. With their ease of installation and operation, they’re ideal for a wide variety of applications:
Adjusting thermostats
Cooling solder
Setting hot melts
Cooling welding horns, machined or molded plastics, gas samples, etc.
Your choice of a system with a one outlet, or two outlet Cold Air Hose.
If you need a blast of cold air that can be precisely controlled, right at the source, look no further than the Adjustable Spot Cooler. If you have an application you’d like to discuss, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
