Today, I would like to discuss a question that comes up time and time again over the years. “What happens when I put water through a Super Air Knife?” That raised another question from myself of what about a Super Air Wipe?
The answer is quite simple, it will come out, just not as good as compressed air does. The engineering and design for Super Air Knives were all based around compressed air use. With any good product of course comes the question in time, how else can we use this? A number of applications for the Super Air Knife is blowing moisture off a part that has been applied through a series of wash/rinse nozzles. What if the knife could apply the liquid and then a second knife could remove the liquid. Below are some images from testing that was done on a Stainless Steel Super Air Knife at various gap sizes and various pressures. The “best” performance visually was from operating the air knife with .004″ gap and approximately a 17 PSIG inlet pressure (this is for a 12″ Super Air Knife).
As you can see in the photos, the water does flow fairly well immediately out of the knife, and becomes more turbulent as it gets further away from the knife. The stream actually begins to break up and thus the effective distance of the knife may be reduced when using it to flow liquids. This is not going to perform like a pressure washer, the maximum distance for the stream of liquid before it completely fell off was around 10′ from the discharge point. If this were to be used to remove loose debris or to cover a part in water to help cool the part the stream would be more than enough to perform.
As noted above the operating pressure was fairly low, and the gap was at a .004″ thickness. I recently tested a 1″ Stainless Steel Super Air Wipe as well. The shim gap was once again set to .004″ thick to permit a better flow and a low pressure, approximately 10-12 psig inlet pressure. As you can see the flow of water is not as smooth as the air flow out of a Super Air Wipe but if a light rinsing process was needed, or a water cooling process, this would work well.
So the answer to the main question at hand is yes, a Super Air Knife and Super Air Wipe will both operate with a pressurized liquid source under the correct circumstances. While they do not operate exactly like they do with compressed air, the results still prove useful in certain applications.
Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF