EXAIR’s Vortex Tubes are a great product for many cooling applications. When supplied with a clean and moisture-free source of compressed air, they will generate two streams of airflow, one hot and one cold. They are a low-cost and reliable solution, capable of producing temperatures ranging from -50°F to +260°F. We have flow rates from 2 SCFM to 150 SCFM, producing refrigeration over 10,000btu/hr.
We also have several other product lines that are great for cooling, like our Air Knives or Air Amplifiers. So, why would you choose a Vortex Tube? Our Air Knives and Amplifiers cool primarily by moving large volumes of ambient air. If you have a 400°F part that needs cooling to under 100°F, then hitting it with large amounts of 70°F ambient air is going to rapidly bring the temperature down. This does mean that there is a limit to how low of a temperature you can achieve with these products; our Air Knives and Amplifiers won’t be able to cool below ambient temperatures. Our Vortex Tubes, on the other hand, with temperatures as low as -50°F, can provide much more powerful cooling and targeted cooling.
Now you have determined that a Vortex Tube is right for you, you’ll need to decide between our two different series: 32XX and 34XX. The difference between the two model types comes down to the Cold Fraction, which is determined by where the Control Valve is positioned. When you open the Control Valve (by turning it counterclockwise, as shown by the blue arrow in the photo to the right), it decreases the Cold Fraction, which leads to a reduced flow and a significant drop in temperature in the cold air discharge. Conversely, closing the Control Valve (by turning it clockwise, indicated by the red arrow) boosts the cold air flow, but causes a smaller temperature drop. This ability to adjust is crucial for the Vortex Tube’s flexibility.
You can set the Cold Fraction as low as 20%, which means that a small portion (20% to be precise) of the supply air is sent to the cold end, resulting in a significant temperature drop. On the flip side, you can crank it up to 80%, meaning that most of the supply air heads to the cold end, but the temperature drop won’t be as drastic. Our 34XX Series Vortex Tubes are designed for cold fractions between 20–50 %, while the 32XX Series caters to 50–80 % Cold Fractions.
So how do you select the right model for you? To determine this, you need to know what temperature and flow will best serve your application. For most situations, the ~20°F produced by an 80% cold fraction is sufficiently cold. At this cold fraction, you will get the most flow (80% of the inlet supplied). Applications like welding or brazing benefit from higher flows. When your starting temperature is hundreds of degrees Fahrenheit, there is little difference in blowing -20°F air vs +20°F. What you need is more volume to strip away the heat as quickly as possible. In this instance, a 32XX series is the way to go.
If you need lower flow, or to achieve freezing temperatures, then the 34XX series would be the best choice. A chocolate maker took advantage of the lower flow rates offered by this type of Vortex Tube as they didn’t want the airflow to disturb the surface of the chocolate as it cooled, affecting the finish. The greater temperature drop allowed for rapid cooling without reducing quality.
Vortex Tubes can produce higher levels of noise than our Knives and Amplifiers, so we would always recommend using hot and cold mufflers with them. This will ensure they stay within OSHA sound standards. And just like with all EXAIR products, it’s a good idea to use a pressure regulator with a gauge right where you’re using it. This is especially crucial for Vortex Tubes if you want to get an accurate temperature.
Whatever your cooling application, our Vortex Tubes will likely be able to help. If you would like to discuss it, please give us a call!
Al Wooffitt
Application Engineer
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