Pneumatic vortex tubes, also known as Ranque-Hilsch vortex tubes, are used in electronics and machining industries to provide inexpensive cool air to electronic equipment, such as electrical cabinets, and for cooling machining and other equipment. The vortex tube provides this cool air by converting compressed air into a stream of cold air, which can reach temperatures as low as −50 °C (−58 °F). Due to the process within the tube, the opposite end of the vortex tube produces hot air which can reach temperatures of up to 200 °C (392 °F), depending on the model. Vortex tubes do not require any electrical current or additional coolant materials.
Vortex tubes convert factory compressed air into two streams of hot and cold air without any moving parts. A vortex of air in created within the tube as compressed air is pumped into a swirl chamber, allowing the air to rapidly accelerate to a high rate of rotation within the tube and increase in temperature. A conical nozzle at one end of the tube only allows the air on the outer rotations to escape as incredibly hot air, whereas the rest is forced backwards in an inner vortex, rapidly cooling on its way back to the other end, where it is expelled as incredibly cold air.
As pneumatic vortex tubes only require compressed air, they are an inexpensive cooling method used in the machining and electronics industries, especially as compressed air is usually already available within machining and tooling factories. While not the most efficient cooling method for tools and enclosures, vortex tubes remove the need for liquid coolant, which is messy, expensive and environmentally hazardous.
Vortex tubes are often positioned on top of electronic cabinets and enclosures, with the cold air directed to flow into the cabinet to displace any hot air generated by the electronic components, keeping them from overheating. In machining, pneumatic vortex tubes are used to cool cutting tools, such as lathes and mills in both manual and CNC-operated machines. The jet of cold air not only cools the tools but additionally removes any debris or 'chips' produced by the tool.