Tag: Coanda effect

People of Interest: Henri Coanda 1886 – 1972

Published on by John BallLeave a comment
In each of these EXAIR engineered compressed air products, the primary air stream following the curved surface causes entrainment. And efficiency.

Being in the compressed air industry for over 35 years, you come across many interesting people from the past that have created laws that we are still using today.  Henri Coanda is one of those people. 

Henri Coanda was a prominent Romanian inventor and aerodynamics pioneer.   In 1910, Henri and his Italian counterpart, Gianni Caproni, began a partnership to construct an experimental aircraft which was later called the Coanda-1910. The Coanda-1910 was unlike any other aircraft of its time as it had no propeller; instead, it sported an oddly shaped front end with built-in rotary blades arranged in a swirl pattern. These blades were driven by an internal turbine screw that would suck air in through the turbine while exhausting the gases out of the rear, propelling the plane forward. This initial jet engine was quite impressive for the time, but sadly nobody believed it would ever fly, and it is believed that it never did achieve flight. Coanda is not credited with the invention of the jet engine, but his technology spurred the future of aviation into the future.

Henri spent his time developing the turbo-propeller drive system of his 1910 Biplane during World War 2.  After it ended, Henri began furthering his research on the Coanda Effect which would become the basis for several investigations into entrained and augmented flow of fluids.  It states that a fluid adheres to and follows a contour which creates low pressure.  Later, in 1969, Henri would spend the last of his days in Romania serving as Director of the Institute for Scientific and Technical Creation.  Henri died on November 25, 1972, in his hometown of Bucharest.

Henri Coanda passed away on November 25, 1972, in his hometown of Bucharest.  Here at EXAIR, we have used the Coanda Effect to apply it to several of our products.  This helps to amplify total airflow by using less compressed air.  Thus, saving you money.  The most notable products are our Air Amplifiers, Air Wipes, Standard Air Knives, and Full-Flow Air Knives, which are some of the most efficient products of their kind.  If you would like to speak more about how EXAIR can benefit your pneumatic system, one of our Application Engineers can help you determine the best solution.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Entrainment: How it Works and Why EXAIR Products are Engineered to Use it.

Published on by John BallLeave a comment
EXAIR Super Air Nozzle entrainment

Because of the large amount of energy required to run an air compressor, the pneumatic system is considered the fourth utility in a manufacturing plant.  And saving this commodity and using it as efficiently as you can, should be a priority.  EXAIR has many products that can save energy by using less compressed air.  And the story behind this is entrainment explained by Bernoulli’s equation. 

Bernoulli’s principle explains how a high velocity fluid can generate a low pressure.  (You can read more about Bernoulli’s principle HERE.)  Let’s start by looking at Equation 1.

Equation 1:

P + d * V2/2 = C 

P – pressure

d – density of the fluid

V – velocity

C – a constant

As you can see from Equation 1, when the velocity goes up, the pressure must go down.  When we have a lower pressure, then the surrounding fluid will fill that void.  Since air is a fluid, we can use high velocity to entrain the surrounding ambient air.  The free air will add to the compressed air to give the airstream mass for a hard-hitting force.  This ratio of ambient air to compressed air is called entrainment.  The higher the entrainment, the more efficient the product.  Bernoulli’s Principle can be applied in two ways; as a Coanda and as a Venturi.  EXAIR uses both methods in our products for creating low-pressure effects. 

Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

The first way is from a Coanda profile.  Coanda, named after Henri Coanda, noticed that a fluid would “hug” a curved surface.  (You can read more about Henri Coanda HERE.)  The high velocity air going around the curved surface will generate a low pressure above it.  You can imagine an airplane wing generating that low pressure to fly.  We use this with our FullFlow and Standard Air Knives, our Air Wipes, and our Air Amplifiers.  With a Coanda profile, we can get an amplification ratio up to 30:1, which means that for every 1 part of compressed air, 30 parts of ambient air is entrained.  We are able to create an efficient blow-off device by using the Coada profile. 

To generate even lower pressure, this can be done by a Venturi.  This phenomenon is named after Giovanni Venturi, who discovered that by increasing the velocity through an orifice, the surrounding fluid will move with it, generating a lower pressure.  (You can read more about Giovanni Venturi HERE.)  Remember the higher the velocity, the lower the pressure from Equation 1 above.  We use the Venturi effect on our Super Air Knives, E-Vacs, Line Vacs, and Super Air Nozzles.  As compared to our FullFlow and Standard Air Knives, the Super Air Knives can generate an amplification ratio of 40:1.  As an engineered product, we were able to increase efficiency even further. 

EXAIR has been manufacturing Intelligent Compressed Air® products since 1983.  We can provide solutions that are efficient, effective, and safe for blow-off systems.  In comparison, the other blow-off devices are like incandescent light bulbs, while EXAIR products are like LED light bulbs.  Entrainment of free ambient air can save you a lot of money when using your compressed air system.  If you would like to discuss solutions to use less compressed air and improve your bottom dollar, an Application Engineer at EXAIR is available to help.   

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Entrainment: How It Works, and Why EXAIR Products Use It.

Published on by John BallLeave a comment
EXAIR Super Air Nozzle entrainment

Because of the large amount of energy required to run an air compressor, the pneumatic system is considered the fourth utility in a manufacturing plant.  And saving this commodity and using it as efficiently as you can, should be a priority.  EXAIR has many products that can save this energy safely and effectively.  And the story behind the efficiency of EXAIR products is Bernoulli’s equation. 

Bernoulli’s principle explains how a high velocity fluid can generate a low pressure.  (You can read more about Bernoulli’s principle HERE.)  Let’s start by looking at Equation 1.

Equation 1:

P + p * V2/2 = C 

P – pressure

p – density of the fluid

V – velocity

C – a constant

As you can see from Equation 1, when the velocity goes up, the pressure must go down.  When we have a lower pressure, then the surrounding fluid will have to fill that void.  Since air is a fluid, this is how we can entrain the free ambient air while only using a small amount of compressed air.  Bernoulli’s Principle can be applied in two ways; as a Coanda and as a Venturi.  EXAIR uses both methods in our products for creating low-pressure effects. 

Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

The first way is from a Coanda profile.  Coanda, named after Henri Coanda, noticed that a fluid would “hug” a curved surface.  (You can read more about Henri Coanda HERE.)  The high velocity air going around the curved surface will generate a low pressure above it.  We use this with our Full Flow and Standard Air Knives, our Air Wipes, and our Air Amplifiers.  With a Coanda profile, the low pressure will entrain the surrounding air to add mass to the air stream.  We can get an amplification ratio up to 30:1, which means that for every 1 part of compressed, 30 parts of ambient air are entrained.  We are able to create an efficient air moving (blow-off) device by using the Coanda profile. 

Generating even lower pressures can be accomplished with a Venturi.  This phenomenon is named after Giovanni Venturi, who discovered that by increasing the velocity through an orifice, the surrounding fluid will move with it, generating a lower pressure.  (You can read more about Giovanni Venturi HERE.)  Remember the higher the velocity, the lower the pressure.  We use the Venturi effect on our Super Air Knives, E-Vacs, Line Vacs, and Super Air Nozzles.  When compared to our Full Flow and Standard Air Knives, the Super Air Knives can generate an amplification ratio of 40:1.  We were able to engineer the product to increase the air entrainment efficiency even further. 

EXAIR has been manufacturing Intelligent Compressed Air® products since 1983.  We provide solutions that are efficient, effective, and safe for air moving and blow-off systems.  Consider the following analogy; homemade air movers and blow-off devices are the equivalent to incandescent light bulbs. EXAIR products are the equivalent to LED light bulbs.  More efficient design leads to lower operating cost, higher efficiency and a higher level of effectiveness. Entrainment of free ambient air can save you a lot of money and increase your mass flow with your compressed air use to generate higher forces on your targets.  If you would like to discuss solutions to use less compressed air, an Application Engineer is available to help.    

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

EXAIR Solenoid Valves and Ball Valves

Published on by John BallLeave a comment

EXAIR has been a pioneer in compressed air products for efficiency, safety, and quality.  We have designed our products using some interesting inventors from the past; like Henri Coanda and Giovanni Venturi.  These fluid dynamic engineers found a way to entrain ambient air.  We use these phenomena to increase the efficiency of our products by adding free ambient air to the airstream.  This will create a hard-hitting force without using a lot of compressed air.  Since compressed air is very expensive to produce, it will save you much money when using our blow-off devices.  To save even more money, EXAIR does offer valves to turn off the compressed air supply when not in use.  In this blog, I will go over the types of valves that we have.

The Manual Valves allow operators to turn on and off their system by hand. The full-flow ball valves range from ¼” NPT to 1 1/4” NPT in size and will not restrict flows.  EXAIR also offers a manual foot pedal valve for hands-free operations.  This ¼” NPT foot valve has a 3-way operation and works great if the operator has to use both hands in their process.

EXAIR also offers Solenoid Valves to turn on and off the supply of compressed air electrically for automated systems. We offer Solenoid Valves in three different voltages; 110Vac, 240Vac, and 24Vdc.  They have a large range of flows with ports ranging from ¼” NPT to 1” NPT.  All models are UL listed and are CE and RoHS compliant.

In more elaborate situations, EXAIR has attached these solenoid valves to a miniature PLC-like controller.  It is called the Electronic Flow Control, or EFC.  It uses a photoelectric eye to detect the part and trigger a timing sequence.  We have eight different timing operations to best combine the trigger mechanism with the blow-off device.  This is the next step in optimization, which will keep the compressed air usage to a minimum. 

EXAIR created a chart that shows “Six Steps to Optimizing Your Compressed Air System.”  Even though EXAIR has the most efficient products on the market for pneumatic systems, we still want to help our customers save even more money.  When not in use, the compressed air should be turned off, according to the fourth step.  In this blog, I discussed some products that can assist you with this.  If you wish to discuss further how to optimize your compressed air system, an Application Engineer at EXAIR will be happy to assist you. 

John Ball
Application Engineer


Email: johnball@exair.com
Twitter: @EXAIR_jb