Tag: venturi

The Case For Adjustable Air Amplifiers

Published on by Russ BowmanLeave a comment

EXAIR Air Amplifiers come in two designs:

  • Super Air Amplifiers come in sizes from 3/4″ to 8″ output flow, and have:
    • A 2-bolt mounting flange that is integral to the body (except the 8″ which has a cast-in handle and feet instead).
    • Replaceable shims to set the compressed air flow and hence, consistent performance.
    • Rugged, aluminum construction.
  • Adjustable Air Amplifiers come in sizes from 3/4″ to 4″ output flow and have:
    • Aluminum or 303SS construction.
    • Quick adjustment by turning the exhaust end into or out of the body to infinitely set compressed air flow and hence, performance.
Super Air Amplifiers (left) can be easily installed using the 2-bolt mounting flange. Adjustable Air Amplifiers are compact & light enough to be supported by supply piping, even using a Swivel Fitting if you like.

Strictly considering air flow performance, there aren’t really any applications where one design will work, and the other won’t. Once the right size is determined, selection comes down to material of construction, how it’ll be installed, where it’ll be installed, and whether it’ll need to be quickly adjusted for flow & force on the device, instead of by regulating the compressed air supply.

I had the pleasure of talking to a caller just this morning about a “textbook” application for an Air Amplifier: welding smoke ventilation.

Maybe instead of a “textbook”, I should call it a “catalog” application because it’s literally the first image you see when you get to the Air Amplifiers section of the EXAIR Catalog.

The caller had an existing 4″ ID hose to place at the point of suction and connect to the Air Amplifier. This narrowed the choices down to the two Air Amplifier products with a 4″ outside diameter on the inlet: Model 120024 4″ Super Air Amplifier, and Model 6043 (or 6033) 3″ Aluminum (or Stainless Steel) Adjustable Air Amplifier. It was to be used in a typical shop environment, so the higher temperature rating (400F or 204C) or superior corrosion resistance of the Stainless Steel construction wasn’t needed. They intended to support it with the suction hose, hose-clamped onto the Air Amplifier itself, so the Super Air Amplifier’s 2-bolt mounting flange wasn’t necessary…in fact, they thought it might even get in the way. So, the Model 6043 3″ Aluminum Adjustable Air Amplifier made it to the top of the list pretty quickly.

Another important consideration for the caller was maximizing the exhaust flow. Looking at the performance data for the 4″ Super Air Amplifier and the 3″ Adjustable Air Amplifier, the latter generates just a little higher total air volume at the outlet, which, when you subtract the compressed air consumption from it, gives you the total flow rate of entrained air (and welding smoke, in this case):

The 730 SCFM Air Volume at Outlet, minus the air consumption of 29.2 SCFM, means that it’s drawing in ~700 SCFM.
Which is not bad.
The 774 SCFM Air Volume at Outlet, minus the air consumption of 29.2 SCFM, means that it’s drawing in ~740 SCFM.
Which is even better.

In addition to ventilation/exhaust applications, Air Amplifiers can be used – just like our engineered Air Knives and Air Nozzles – in blow off, drying, cleaning, and cooling applications. If you’ve got questions about them (or any EXAIR Intelligent Compressed Air Products), give me a call.

Russ Bowman, CCASS

Application Engineer
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Draw Me A Picture

Published on by Brian FarnoLeave a comment

Here at EXAIR it has been said and said again, a picture is worth 1,000 words. This also doubles up on my favorite saying, you can’t teach experience. While I have been with EXAIR for nearly 14 years and in the metal cutting industry for 5 before that, then a student, before that, our other AE’s have diverse backgrounds as well. I grew up around cars and a family that was ingrained in a steel mill and many aspects of it, so seeing a multitude of processes is something I have done since I was little.

When I was a student in Mechanical Engineering Technology I would always try to get into the courses where I would learn more process and critical thinking focus. This led me to many factory visits and case studies where I got to sample many different aspects of many industries. How else am I supposed to know what I want to do when I grow up? Well, working here in the Application Engineer department, I draw on that knowledge and experience nearly every single day. Just this morning, I asked a customer to do a simple sketch of what their system layout would look like, so I could fully understand everything they were going to have in place for a new setup they wanted to try and were concerned with operating pressures/restrictions on their piping.

Now this sketch is quite elaborate from the amount of information it provides. The best part is, all these parts are critical pieces of information. It is also still missing some key parts of information, such as all the distances between system parts. Those items were all discussed and the longest run of the line was going to be the 3 feet of air piping shown. 

The customer and I then began to discuss all the size changes in the supply inlet to the system and how not only were the needle valves undersized, which they noted, but the entire piping seemed undersized and going to be an issue to really be able to operate anywhere near line pressure.

At the end of the conversation with the customer, we settled on using a 3/4″ Schedule 40 piping or equivalent, changing out their PRV-1 for a 3/4″ version as well as their filter. Then running that larger line size all the way to the needle valves. I strongly advised them to increase the needle valve sizes as well. We know the valves won’t feed the knives with enough volume as they noted in the sketch and 10 psig is a significant drop. At the same time, the application of keeping some lightweight debris off a surface as a final blowoff isn’t going to demand a full-line pressure blowoff. We also discussed that they could look into reducing the shim in the Super Air Knives like they did in the Air Amplifiers to reduce consumption and to be able to operate at a higher pressure if needed.

Sketches don’t have to be this detailed, it always helps, and the actual pictures are always great too. The point is that we will probably always ask more questions and the result will always be an answer that we feel confident in. We can often back up our selections with scientific data like flow through piping tables and equations for consumption at varying pressures.

If you have a new or existing setup that you would like to discuss with an Application Engineer to determine if it has a high success chance or not, reach out to us!

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

What is CE and How it Affects EXAIR

Published on by Jordan T ShouseLeave a comment

CE is short for the French words Conformité Européenne or European conformity. It means that a manufacturer has taken responsibility for compliance with a product meeting all European Health, Safety, performance, and Environmental requirements. This is a required (EU Legislation) certification for most products that are sold in the European Economic Area (EEA). The CE markings on a product assure that the product can be sold in any EU country, regardless of the country of origin. It has become an acceptable standard for much of the rest of the world as well, it just holds no weight other than in Europe.

CE Logo

The top left corner of the first product page in our catalog will show all the standards that a product is produced in compliance with. 

First page of the Intellistat Ion Air Nozzle

At EXAIR we go to great lengths to lead the way in standards compliance. Each of our products are engineered with the best technical knowledge, and perform at peak efficiency. All of our compressed air products comply with OSHA’s Safety Requirements (29 CFR1910.242(b), and the EU General Product Safety Directive 2001/95/EC, and they also meet the noise limitation requirements 29CFR-1910.95 (a), of the EU Machinery directive 2006/42/EC. Some EXAIR products display the CE mark where there are applicable directives. All sound level measurements are taken 3 feet from the product. On top of all this, you will get the best customer service anywhere. Myself and the other Application Engineers are here to assist you in choosing the best product for your application.

If you have any questions about how our products meet CE or other specifications, or you need assistance with any of EXAIR‘s products, please do not hesitate to reach out.

Jordan Shouse
Application Engineer

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

Published on by johnball2014Leave 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