From pneumatic hand tools like impact wrenches or nail guns to larger scale industrial applications like stamping presses, the use of compressed air can be found in almost any industry. In fact, it is often referred to as a “fourth utility” next to water, gas and electric.
Take for example in construction, workers will use a pneumatic riveter to join steel framing because of the power generated by the tool over an electrically powered device, not to mention it provides for a safer operation by removing an electrical hazard. Many companies use compressed air operated diaphragm pumps or air motor driven pumps to move expensive or viscous liquid from one location to another. These types of pumps are self priming drawing the liquid in and provide positive displacement meaning they fill and empty the liquid chamber with the same amount of liquid through a common inlet and outlet.
Amusement parks have used compressed air in some capacity in the operation of thrill rides like roller coasters or to enhance the effect of certain attractions. Compressed air can be found in hospitals where it is used for specialized breathing treatments or to power surgical instruments in an operating room. Educational facilities use compressed air for laboratory testing. You can even find compressed air in the tires on your car. Basically, when you think about it, compressed air is being used just about anywhere.
Here at EXAIR, we manufacture Intelligent Compressed Air Products to help improve the efficiency in a wide variety of industrial operations. Whether you are looking to coat a surface with an atomized mist of liquid, conserve compressed air use and energy, cool an electrical enclosure, convey parts or dry material from one location to another or clean a conveyor belt or web, chances are we have a product that will fit your specific need.
To discuss your particular application or for help selecting the best product, contact an application engineer at 800-903-9247 for assistance.
A company had a small converting machine that was winding a plastic film onto a roll. The width of the plastic film was only 3” across, and the amount of tension required for a consistent roll was small. The maximum amount of tension without damaging the plastic film was 16 ounces of force. In converting media onto rolls, it is very important to control the tension on the web to reduce defects like wrinkles, out-of-round rolls, or stretching.
They explained the setup that they were trying. They had a 4” manifold with two 2” wide “duck-foot” nozzles attached. They sent a hand drawing to better describe what they were using. (See below). The issue that they were seeing was too much variation in the blowing force being applied to the film. To get near the correct blowing force, they had to start at an air pressure of about 18 PSIG. As they ran the process, the operator would have to adjust the pressure continuously to evenly roll the film onto the core. The process was out of control, and they wondered if EXAIR had a better way to evenly exert this force.
In analyzing the drawing and their setup, I noticed a couple of things that could cause the variations. I modified his drawing to better explain the situation (Reference below). As compressed air leaves the two flat nozzles, the center section will overlap. This overlap will cause turbulence in the air flow pattern. In order to get an even distribution of forces across the width of the product, turbulence cannot exist. Turbulence is a mixing pattern where the velocity is not linear; thus, causing high and low pressure points on the target. The other thing that I noticed was the low air pressure that they could not go above. This limited the precision of the incremental forces. Because of the fixed openings of the two nozzles, they had to have a ceiling with the air pressure at 18 PSIG for 16 ounces of force. If they had to “bump” the force level, the change was difficult to hit exactly. If we divided the 16 ounces of force between 0 – 18 PSIG, we would get roughly 0.9 ounce of force per PSIG. You lose the accuracy to make fine adjustments.
I recommended our model 110003, 3” Super Air Knife and a model 110303 Shim Set. The Super Air Knife blows compressed air across the entire length. Without any overlap, the flow is laminar, and the velocity profile is moving in the same direction. Thus, an even force across the entire 3 inches. The Shim Set comes with additional shim thicknesses of 0.001”, 0.003”, and 0.004” thick (the standard thickness of 0.002” is installed in the Super Air Knife). In working with such a precise force requirement, they needed additional options for more control. They could change the shims as a coarse adjustment and adjust their pressure regulator as a fine adjustment. This combination gave them the best results to accurately dial in the correct force and not damage the material. With the maximum requirement of 16 ounces across 3 inches of film, they were able to change the shim to the 0.004” thickness. For the model 110003 Super Air Knife, it put them at a maximum pressure of 86 PSIG, not 18 PSIG. Thus the increment was now 0 – 86 PSIG for 16 ounces of force, or 0.19 ounces per PSIG. There was much more resolution to make smaller changes to the force levels thus optimizing their adjustment range.
In replacing the competitor’s product with a Super Air Knife, our customer had all the necessary control to wrap rolls of film without issue. The setup with the nozzles on a manifold design resulted in turbulence, which was noisy and produced inconsistent results. It also restricted their adjustment resolution in changing forces, as they do not use shims. If you would like to exert a greater degree of precision blowing with products like the Super Air Knife, please contact us. We would be happy to discuss your application and help you meet such goals.
I recently spoke with one of my colleagues at our Finland distribution partner, Projecta Oy. He had an application for static elimination on a large paper producing machine. He has applied our Ion Bar to paper machines in the past to eliminate static. In this case though, the line speed was more than double that of his previous application at about 1450 meters per minute. He was not sure if he could apply EXAIR Static Eliminator to the affected machine or not, simply due to the line speed.
Actually, use of a Super Ion Air Knife, or rather a few of them (due to machine width) is right in line with what is recommended. When the application involves a high-speed, moving web there is the issue of a boundary layer of air that moves along adjacent to the web which can affect the static elimination result if not approached properly. The boundary layer can prevent static eliminating ions from reaching the surface of the statically charged web and must be overcome to be effective.
A Super Ion Air Knife, with it’s powerful laminar air flow, is the right choice on a web-based application like this one. Setting the unit up so that it blows parallel to the web but in the direction opposite the web travel creates a counter airflow which disrupts the boundary layer and allows the static eliminating ions to come into contact with the moving web to neutralize the charges present.
There is also a secondary benefit in that the Super Ion Air Knife, by being mounted in such a way, enables a much longer time in contact between the ions and the charged surface. This has the net effect of being able to reduce the static charge down to a much lower level before the web passes this area. Since slowing the web speed down is not an option in these cases, the only way you can effectively create dwell time within the ionized airflow is to extend the distance over which the web is treated and using the Super Ion Air Knives in this way allows the user to do that.