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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People of Interest: Daniel Bernoulli (2/8/1700-3/17/1782)

Daniel BernoulliDaniel Bernoulli was born in the Netherlands in February of 1700. Mathematics was in his bloodline as the son of renowned Swiss mathematician, Johann Bernoulli. He and Johann’s brother, Jakob, both took jobs as professors at a university in Basel, Switzerland. Fittingly, Johann taught Daniel mathematics at a very young age. Daniel Bernoulli spent some time studying a variety of topics including philosophy, logic, and medicine. Daniel obtained his Bachelor’s Degree at the age of just 15, earning his Master’s Degree just one year later.

Daniel was well-known and was highly regarded among scholars throughout Europe. After spending some time teaching Botany, he switched to physiology topics in 1743. This continued for several years when in 1750 he was appointed to the chair of physics where he taught at Basel for 26 years. During this time, he also received a total of 10 grand prizes from the Paris Academy of Sciences for work he completed in astronomy, a variety of nautical topics, and magnetism.

Daniel is most commonly known for his work in developing what is now called Bernoulli’s Principle, which discusses the relationship between fluid speed and pressure. An increase in the speed of a fluid will occur simultaneously with a decrease in the fluid’s pressure or potential energy.

Entrainment
EXAIR Intelligent Compressed Air Products such as (left to right) the Air Wipe, Super Air Knife, Super Air Nozzle, and Air Amplifier are engineered to entrain enormous amounts of air from the surrounding environment.

The air entrainment properties of some of EXAIR’s Intelligent Compressed Air Products can be explained through Bernoulli’s Principle. As high-velocity air exits the nozzle of a Super Air Knife, for example, a low-pressure area is created that speeds up and draws in ambient air at an astonishing rate of 40:1. The same also occurs with the Super Air AmplifiersAdjustable Air Amplifiers, and Air Nozzles. To find out how you can utilize this advantage to save compressed air in your processes, give us a call. An Application Engineer will be happy to help assist you in determining the most suitable products for your application.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

 

Intelligent Compressed Air: Avoid Pressure Drop

A critical component to optimal performance of any compressed air operated product is ensuring sufficient compressed air flow. Simply put, inadequate air flow won’t allow you to get the job done.

As compressed air moves through the distribution system, it encounters friction inside of the walls of the pipe, tube, hose, etc. The diameter of the pipe, length, number of direction changes, and finish surface of the inner wall all play a part in this. A drop in air pressure will occur as a result of this friction. In addition to pressure drops experienced due to the distribution system, they can also occur at the point of use.

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Common analog pressure gauge

When designing and maintaining your compressed air system, pressure measurements should be taken across varying points to identify (and fix) any issues before they create a greater problem down the road. According to the Compressed Air Challenge, these are the places you should take regular pressure measurements to determine your system operating pressure:

  • Inlet to compressor (to monitor inlet air filter) vs. atmospheric pressure
  • Differential across air/lubricant separator
  • Interstage on multistage compressors
  • Aftercooler
  • At treatment equipment (dryers, filters, etc.)
  • Various points across the distribution system
  • Check pressure differentials against manufacturers’ specifications, if high pressure drops are noticed this indicates a need for service

*More recent compressors will measure pressure at the package discharge, which would include the separator and aftercooler.

Once you’ve taken these measurements, simply add the pressure drops measured and subtract that value from the operating range of your compressor. That figure is your true operating pressure at the point of use.

If your distribution system is properly sized and the pressure drops measured across your various equipment are within specifications, any pressure drop noticed at the point of use is indicative of an inadequate volume of air. This could be due to restrictive fittings, undersized air lines, hose, or tube, or an undersized air compressor. Check that the point of use product is properly plumbed to compressed air per the manufacturer’s specifications.

EXAIR Products are designed to minimize this pressure drop by restricting the flow of compressed air at the point of use. The more energy (pressure) that we’re able to bring to the point of use, the more efficient and effective that energy will be. The photo below shows two common examples of inefficient compressed air usage. With an open-ended blow off, a pressure drop occurs upstream inside of the supply line. If you were to measure the pressure directly at the point of use, while in operation, you’d find that the pressure is significantly lower than it is at the compressor or further up the line. In the other photo with modular style hose, some pressure is able to be built up but if it gets too high the hose will blow apart. These types of modular style hose are not designed to be used with compressed gases.

open end blow offs
They may be inefficient, but they sure are loud…

EXAIR’s Super Air Nozzles, on the other hand, keep the compressed air pressure right up to the point of discharge and minimize the pressure drop. This, in addition to the air entrained, allows for a high force while maximizing efficiency. If you’d like to talk about how an EXAIR Intelligent Compressed Air Product could help to minimize pressure drop in your processes give us a call.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Pressure gauge photo courtesy of Cliff Johnson via Flickr Creative Commons License

Super Air Nozzles and Stay Set Hoses to Replace Open Tubes

I recently worked with an company that performs energy audits and they were working with a food company to review and propose ways to reduce the energy consumption throughout the plant. One area where we were able to help was on an onion peeling machine, shown below:

Vegetable Peeler Wide
Onion Peeler With Screw Conveyor and Blow off Tubes

The area of machine in question used a screw conveyor and friction source to help loosen the peels and fifteen (15) 1/4″ O.D. open ended tubes, which were noisy and unsafe, to blow the peels completely off and away form the onion. The auditor was able to install an air flow meter on the system and found that the machine was consuming 220 SCFM of compressed air for this operation.

Vegetable Peeler Detail
(15) Total, 1/4″ Tubes Used to Blow Air and Help Remove the Peels

We proposed to replace the tubes with a 6″ Stay Set Hose and the model 1103 Mini Super Air Nozzle.  Each model 1103 Mini Super Air Nozzle will consume just 10 SCFM of 80 PSIG compressed air. Attached to the 6″ Stay Set Hose, the nozzle can be placed exactly where needed and aimed appropriately. A strong blast of air rated at 0.56 lbs (9 ozs.), and ultra quiet at 71 dBA, the Mini Super Air Nozzle delivers the results needed.

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Model 1103 – Mini Super Air Nozzle

1103 Performance

1103 Pattern

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Model 9256 6″ Stay Set Hose

The Stay Set Hose has “memory” and will not creep or bend, simply install the 1/4 NPT fitting into the compressed air supply side, an thread the 1/8 NPT Mini Super Air Nozzle into the other end and position as needed!

Fifteen (15) of the Mini Super Air Nozzles will pass 150 SCFM of compressed air compared to the current usage of 220 SCFM, resulting in a 70 SCFM drop, or a 31.8 % reduction.  At a typical cost of $0.25 per 1000 Cubic Feet of Compressed Air, the nozzles would save $1.05 per hour of operation. Rate of Return yields a full pay-off in just 43 days of operation (24 hours per day operation)!

If you are looking for ways to save on compressed air usage in your facility that is safe to operate and quiet to use, we will have a solution for you.

If you have questions about any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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EXAIR Safety Air Gun Promotion

From August 1st to September 30th, 2018, EXAIR will be giving away a 1” Flat Super Air Nozzle with the purchase of any promotional VariBlast, Soft Grip, or Heavy Duty Safety Air Gun.  EXAIR is stressing the importance of safety in the workplace with the EXAIR Safety Air Guns as well as the versatility of the different types of EXAIR Super Air Nozzles.

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This promotional item, the model 1126 1″ Flat Super Air Nozzle, has a patented shim to blow a 1” wide stream of air to clean surfaces quickly and efficiently and is a $45.00 USD value. For more details on the Promotion, click on the photo/link above. For more information about the Flat Super Air Nozzles, click HERE.

Inexpensive air guns can be purchased just about anywhere- online, via catalogs, and through industrial supply companies. Typical quality is less than ideal – broken triggers, leaky valves – a short lifespan in an industrial setting are merely a few of the issues observed.  Most are loud and inefficient – they just blow large amounts of compressed air, and at noise levels that violate OSHA requirements.  Some may even generate dangerous dead end pressure situations that that can result in serious or fatal injuries if blocked.

EXAIR’s Safety Air Guns have been engineered and designed to eliminate these issues. They are durable for use in industrial situations and comfortable to use for extended periods of time.  With an EXAIR engineered air nozzle, each model provides top performance by entraining large volumes of surrounding air into the air-stream. Operation is assured to be safe along with low compressed air consumption and noise levels.  Due to the design, the airflow that exits the nozzle cannot be blocked, as required by OSHA Standard 29 CPR 1910.242(b).

Safety Air Guns
The EXAIR VariBlast, Soft Grip and Heavy Duty Safety Air Guns

The VariBlast style of safety air gun offers variable force based on the range of trigger pull. Force can be varies, form a light breeze, to full force maximum output. This cast aluminum air gun can be fitted with any of the EXAIR 1/8 NPT engineered air nozzles.

The Soft Grip style of safety air gun  has a durable cats aluminum body suited for rugged, industrial use. The ergonomic design has a soft vinyl cover, a large trigger for easy operation, and a hanger hook for easy storage.

The Heavy Duty style of safety air gun is powerful with a durable aluminum cast body and ergonomic composite rubber grip, best suited for rugged industrial environments. Hours of fatigue free operation are possible.

With all of the Safety Air Guns styles, Chip Shields and Extension Pipes are available, from 6″ to 72″ in length.

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Soft Grip Safety Air Gun, with Chip Shield and 12″ Extension

With many nozzle options, from a whisper quiet 58 dBA and 2.5 SCFM of flow up to 60 SCFM and 87 dBA (still below the OSHA 8 hour noise level threshold) there is a model that will fit practically any application. Application Engineers are available by phone, email, and chat to review your specific blow off needs, and help to select the best possible solution available.

We invite to you to try out an EXAIR Safety Air Gun, and get the free 1″ Wide Flat Super Air Nozzle as a bonus.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can improve your process, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Small, Precise Blowoff at Your Fingertips

For many blowoff applications, stronger isn’t necessarily better.  For applications and processes where a light, but effective blast of air is needed for cleaning and drying, the VariBlast Compact Safety Air Gun with the Atto, Pico, or Nano nozzle fits the bill. The smallest of the EXAIR engineered Super Air Nozzle family, the Atto, Pico, and Nano have been designed to provide the smallest, most precise blowoff possible. The focused airflow pattern allows for very accurate control and placement of the air stream.  The nozzles are available in both Type 316 Stainless Steel and PEEK plastic (useful for harsh environments, and is non-marring)

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The Atto, Pico, and Nano Super Air Nozzles (Scale is in Inches)

The new VariBlast Compact Safety Air Gun is a great choice for putting the power and performance of the nozzle into a small and lightweight air gun. Designed with a variable flow trigger, the airflow can be throttled from a whisper to full force, simply by varying the trigger pull distance.

1698SS
VariBlast Model 1698SS, with Stainless Steel Nano Super Air Nozzle

The Atto, Pico, and Nano nozzles use very little compressed air and are extremely quiet, easily meeting OSHA Standard 29 CFR 1910.95(a) for Noise Exposure.  The design incorporates engineered solutions for safety and can be supplied with higher pressure compressed air and meet OSHA Standard 29 CFR 1910.242(b), relating to dead end pressure requirements.

The table below provides performance data, including the compressed air consumption, force, and sound level for the various configurations.

VariBlast With Small Nozzles

Note that the VariBlast air guns can be had with extensions from 6″ to 72″ and chip shields to meet the performance and safety needs of any application.

The Atto, Pico and Nano Nozzles can also be configured to work with the Soft Grip style of Safety Air Gun.  Consult an Application Engineer for assistance in choosing.

If you have any questions about the Atto, Pico, or Nano nozzles, the VariBlast Compact Safety Air Gun, or any EXAIR compressed air product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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EXAIR Flat Super Air Nozzles – Adjustable, Flexible and Powerful

As an Application Engineer here at EXAIR, we get calls from customers looking for an air knife, but shorter than our typical 3″ stocked size.  We can make an air knife to any length needed, but we will look at the 1″ and 2″ Flat Super Air Nozzles as a possible solution.

Like an air knife, the Flat Nozzles provide a wedge shaped pattern of air that maintains the width of the nozzle, to create a concentrated, powerful air flow.  Thus, a 1″ Flat Super Air Nozzle has air stream 1″ wide, and the 2″ Flat Super Air Nozzle has one 2″ wide.

The Flat Super Air Nozzles are available in zinc aluminum alloy or type 316 stainless steel construction, to meet environmental conditions of the process.  Both the 1″ and 2″ nozzles contain a changeable, patented shim that maintains the critical air gap, which allows the release of a precise amount of air through the thin slot, across a flat surface. The result is a wide, forceful stream of high velocity, laminar airflow, with minimal air consumption and noise.

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1″ and 2″ Flat Nozzles, in Zinc aluminum Alloy and Type 316 Stainless Steel

Shims are available in thicknesses of 0.005″, 0.010″, 0.015″, 0.020″, 0.025″, and 0.030″.  Shim Sets with either 2 or 3 shims are available for both sizes to allow for adjustment of the performance to best meet the application need.

1fsanshim
Patented, Interchangeable Shims

Table below shows the stock offerings of 1″ and 2″ Flat Super Air Nozzles, along with Air Consumption, Force and Sound Level data for your review.

Flat Nozzle Table

If you have any questions about the Flat Super Air Nozzles, or any EXAIR nozzle or other compressed air product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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