Last week, I had the opportunity to work with a customer who was trying to cool a thermoformed film from 85° C (185° F) down to room temperature, 21° C (69.8° F) or low enough for the package to be handled by an operator. This container was 270 mm X 170 mm X 100 mm (10.63″ x 6.69″ x 3.94″)
In applications like this, the customer often calls in with the idea of using a Vortex Tube to produce the cold air. There are two reasons to use a different product than a vortex tube in this application. First, a vortex tube is only going to cool a small area, so to cool anything this size would take several vortex tubes. Second, the cold air is going to mix with the ambient air very quickly. When the ambient air mixes with the cold air from the vortex tube, the air will lose the cold temperature generated by the vortex tube. To counter act this mixing, we have had customers create an insulated container to hold cold air from a vortex tube close to a product, similar to a cooling tunnel. This works in some applications, but my customer had a continuously moving line. He did not have time to stop the line and install insulation around each product. He also didn’t have the length of conveyor needed to put a cooling tunnel over the line.
Instead of using the vortex tube, I suggested that he use a 12” (305 mm) Super Air Knife to cool the thermoformed container. The 12” Super Air Knife moves significantly more air than a vortex tube over the surface of the part. Thanks to the 40:1 amplification ration of the Super Air Knife, it creates more cooling to the product and use less compressed air than a series of Vortex Tubes. By mixing a large volume of free ambient air, that is the same temperature he needs to cool the part to, and a small amount of compressed air over the product they can easily cool their part to close to ambient so the operator can handle the part. The best benefit for this customer was they would not need change their manufacturing line. The air knife is the best choice when cooling a very hot, fairly flat, large surface part to a temperature close to ambient. If you need to cool a product to a temperature lower than room temperature, then a vortex tube would be a great product to do the job.