A Super Air Knife Benefits Aerospace Manufacturing

The aerospace industry has a high demand for high quality materials and can often be the leading users of high-quality materials. Since these sort of materials are typically very expensive it should be no surprise that manufacturers of aerospace parts are always looking for ways to gain efficiency within their processes. Today’s blog offers insight into how one aerospace company optimized its performance.

1 – Airplane Interior

A manufacturer of passenger plane interiors contacted us looking to improve their feed of material in and out of presses. They manufactured aircraft plywood and struggled with a hands-free way to help “float” the sheets during loading and unloading. They also spent a good amount of time waiting for the sheet to cool enough to handle for removal. These presses opened a minimal amount and were pressing the layers of the sheet together and then needed to be slid out of the press and moved on to the next process. The operators would use a handheld blowgun to try and blow under the sheet to move and adjust its positioning however they were then left with only one hand to do the positioning which became cumbersome. After the sheet was pressed they would blow with the same gun again and attempt to cool down the handling location and then drag it back out of the press. This was not a safe or efficient method to handle these sheets.

To improve the process this manufacturer installed a Super Air Knife. The opening on the press was 6′ wide, so they used a 72″ Super Air Knife w/ Plumbing Kit Installed Kit on one press as a test run. The knife was fed from a line that was outfitted with a solenoid valve that tied into a sensor already existing on their press so the air would only be fired when called for by the operator. While the knife did consume more air per minute of operation they were able to reduce the overall time air was being used for loading because the operator now had both hands to work with the sheet.

A 72″ Super Air Knife w/ Plumbing Kit Installed blowing debris off a part being laser cut.

Once the process was completed and the press opened the knife would turn on again to cool the sheet, then within a few seconds, the operator would reach in and again be able to easily float the sheet out. This was all made possible by the low profile design of the Super Air Knife not inhibiting the range of motion the operators had and not having to block the limited work envelope they had at the machine.

With this test machine improving production time, operator satisfaction, and enabling safer machine operation the company elected to implement a program installing the 72″ Super Air Knives on each one of their presses. If you would like to discuss any point of use compressed air application that needs improvement or isn’t as safe or efficient as you would like in your facility, contact an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Timofejev, Aleksandrs – Turkish Airlines, TK015, Instanbul- Sao Paulo- Buenos Aires – 16 June 2013, retrieved from commons.wikimedia.org/wiki/File:Turkish_Airlines,TK015,_Istanbul-_Sao_Paulo-_Buenos_Aires-_panoramio.jpg

The Bernoulli Principle

What do baseball, airplanes, and your favorite singer have in common? If you guessed that it has something to do with the title of this blog, dear reader, you are correct.  We’ll unpack all that, but first, let’s talk about this Bernoulli guy:

Jacob Bernoulli was a prominent mathematician in the late 17th century.  We can blame calculus on him to some degree; he worked closely with Gottfried Wilhelm Leibniz who (despite vicious accusations of plagiarism from Isaac Newton) appears to have developed the same mathematical methods independently from the more famous Newton.  He also developed the mathematical constant e (base of the natural logarithm) and a law of large numbers which was foundational to the field of statistics, especially probability theory.  But he’s not the Bernoulli we’re talking about.

Johann Bernoulli was Jacob’s younger brother.  He shared his brother’s passion for the advancement of calculus, and was among the first to demonstrate practical applications in various fields.  So for engineers especially, he can share the blame for calculus with his brother.  But he’s not the Bernoulli we’re talking about either.

Johann’s son, Daniel, clearly got his father’s math smarts as well as his enthusiasm for practical applications, especially in the field of fluid mechanics.  His kinetic theory of gases is widely known as the textbook (literally) explanation of Boyle’s law.  And the principle that bears his name (yes, THIS is the Bernoulli we’re talking about) is central to our understanding of curveballs, airplane wings, and vocal range.

Bernoulli’s Principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure (e.g., the fluid’s potential energy.)

  • In baseball, pitchers love it, and batters hate it.  When the ball is thrown, friction (mainly from the particular stitched pattern of a baseball) causes a thin layer of air to surround the ball, and the spin that a skilled pitcher puts on it creates higher air pressure on one side and lower air pressure on the other.  According to Bernoulli, that increases the air speed on the lower pressure side, and the baseball moves in that direction.  Since a well-thrown curveball’s axis of rotation is parallel to the ground, that means the ball drops as it approaches the plate, leaving the batter swinging above it, or awkwardly trying to “dig it out” of the plate.
  • The particular shape of an airplane wing (flat on the bottom, curved on the top) means that when the wing (along with the rest of the plane) is in motion, the air travelling over the curved top has to move faster than the air moving under the flat bottom.  This means the air pressure is lower on top, allowing the wing (again, along with the rest of the plane) to rise.
  • The anatomy inside your neck that facilitates speech is often called a voice box or vocal chords.  It’s actually a set of folds of tissue that vibrate and make sound when air (being expelled by the lungs when your diaphragm contracts) passes through.  When you sing different notes, you’re actually manipulating the area of air passage.  If you narrow that area, the air speed increases, making the pressure drop, skewing the shape of those folds so that they vibrate at a higher frequency, creating the high notes.  Opening up that area lowers the air speed, and the resultant increase in pressure lowers the vocal folds’ vibration frequency, making the low notes.
  • Bonus (because I work for EXAIR) Bernoulli’s Principle application: many EXAIR Intelligent Compressed Air Products are engineered to take advantage of this phenomenon to optimize efficiency:

The high speed of the air exiting the (left to right) the Air Wipe, Super Air Knife, Super Air Nozzle, and Air Amplifier creates a low pressure (just like Daniel Bernoulli said) that causes entrainment of an enormous amount of air from the surrounding environment.  This maximizes flow while minimizing consumption of your compressed air.

If you’d like to discuss Bernoulli, baseball, singing, or a potential compressed air application, give me a call.  If you want to talk airplane stuff, perhaps one of the other Application Engineers can help…I don’t really like to fly, but that’s a subject for another blog.

Russ Bowman
Application Engineer
EXAIR Corporation
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