Tag: Air Knives

How Do You Mount An EXAIR Super Air Knife?

Published on by Russ BowmanLeave a comment

This is a fairly common question for the Application Engineering team. The quick (and fairly accurate) answer is: “Any way you want.”

Let’s unpack that a little, though. We’re obviously constrained by the laws of physics, so the method of mounting it has to be structurally sound enough to support the Super Air Knife’s weight, and the reaction force of the compressed air discharge. 3″ Super Air Knives can actually be mounted (and supplied with compressed air) using Stay Set Hoses, if you have an air line ‘drop’ nearby. If not, you can use a Magnetic Base to hold the Stay Set Hose and the Super Air Knife:

Compact, efficient and quiet, the EXAIR 3″ Super Air Knife is an ideal blow-off solution for a variety of applications. Installation is quick & easy with a Stay Set Hose and a Magnetic Base.

Longer Super Air Knives can be installed just about as easily with Universal Air Knife Mounting Systems. Air Knives up to 18″ long use one Model 9060 Mounting System. Longer Air Knives need multiple Mounting Systems for proper support.

The 72″ Super Air Knife w/ Plumbing Kit Installed shown here will use four Model 9060 Universal Air Knife Mounting Systems for proper support.

Because of their design, though, there are a number of other ways to mount a Super Air Knife. If you’re using hard pipe to supply compressed air, a shorter-length Super Air Knife will essentially be as well-supported as the pipe itself. I’ve talked to users who have successfully installed 6″ and 9″ Aluminum Super Air Knives in this manner. We wouldn’t recommend doing that with anything longer than that, due to concerns about overhung loading. The exception to that would be a Super Air Knife installed vertically…and even then, I’m unaware of anyone doing that with any Super Air Knife longer than 12″.

Curiously, though, you can use the supply piping for longer models. A Super Air Knife over 18″ in length will need to be supplied with compressed air to both ends. A properly supported pipe holding up either side offers a great deal of stability.

This Model 110054 54″ Aluminum Super Air Knife is well supported by its black iron supply pipe.

Super Air Knives also have 1/4-20 threaded holes along the bottom of the body. These are the ‘leftover’ threads below the cap screw ends that hold the cap to the body. Those cap screws can also be replaced with longer 1/4-20 hardware. That allows you to use a bracket of your choosing to mount it. We have customers who have gotten downright creative with those:

Yes, that’s a door hinge. No, it wasn’t my idea, but I kind of wish it was.

No matter which Super Air Knife you’re using, and what you’re using it for, there are always options for mounting. If you’d like help in determining which one(s) is best for you, give me a call.

Russ Bowman, CCASS

Application Engineer
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Amplification Ratio: Super Air Knives

Published on by John BallLeave a comment
Super Air Knife

Earlier, I wrote a blog about how entrainment works with EXAIR products by using two phenomena, Coanda Profile and the Venturi Effect.  You can find it here, “Entrainment: how it works and why EXAIR products use it.”  In this blog, I will cover the Super Air Knife specifically and how it uses the Venturi Effect to entrain the surrounding air. 

This Venturi Effect 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.  The higher the velocity, the lower the pressure.  When you have a low pressure, the surrounding air will fill that void and move into the airstream.  The amount of ambient air that gets “pulled” into the airstream is the entrainment, and this amount as compared to the inlet flow is the Amplification Ratio. 

So, what does this mean?  The definition of a ratio is the relationship between two amounts showing the number of times one value is contained within the other.  For the Super Air Knife, it is a value that shows the amount of ambient air that is drawn in along with the primary, compressed air flow.  With an amplification ratio of 40:1, that means that there are 40 parts of ambient air for every 1 part of compressed air, which helps make them the most efficient compressed air operated Air Knives available on the market.  By adding mass, the Super Air Knife will give a hard-hitting force to do more “work”. 

Most people think that compressed air is free, but it is most certainly not.  Because of the amount of electricity required to produce compressed air, it is considered to be a fourth utility for manufacturing plants.  To save on utility costs, it is important to use compressed air as efficiently as possible.  So, the higher the amplification ratio, the more efficient the compressed air product.  Manufacturing plants that use open fittings, copper tubes, and drilled pipes for blowing are not efficient.  These types of products generally have a very low amplification ratio, somewhere between 2:1 to 5:1.  When EXAIR began manufacturing in 1983, we knew that there was a better way of saving compressed air by increasing the amplification ratios of our various air moving products.

I like to explain things in everyday terms.  For this analogy, we can use the amplification ratio as represented by gas mileage.  Like your car, you want to get the most distance from a gallon of gas.  With your compressed air system, you want to get the most utilization for the compressed air being expended.  With an EXAIR Super Air Knife, it has a 40:1 amplification ratio; or, in other words, you can get 40 MPG.  But, if you use drilled pipes, copper tubes, etc. for blowing, then you are only getting 2 to 5 MPG, so to say.  If you want to get the most “mileage” for the money you spend on creating compressed air, you want to check the “fuel efficiency” of your blow-off components.

EXAIR manufactures many blow-off items with high amplification ratios to save compressed air. EXAIR can help “tune up” your blow-off systems to make them efficient and safe by contacting an Application Engineer.  We will be happy to help you.  

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

Super Air Knife and Laminar Air Flow

Published on by Jordan T ShouseLeave a comment

What sets EXAIR’s Super Air Knife above the competition is the ability to maintain a consistent laminar flow across the full length of the knife, particularly when compared against blower-operated knives or even fans. A fan “slaps” the air, resulting in a turbulent airflow where the airflow particles are irregular and will interfere with each other. A laminar airflow, by contrast, will maintain smooth paths that will never interfere with one another.

Top: 108″ Super Air Knife is supported & aimed via an array of Model 9060 Universal Air Knife Mounting Systems. Bottom: mounting systems can be ‘overkill’ for some smaller applications, especially when the user is creative. Yes, those are door hinges. No, it wasn’t my idea, but I kind of wish it was.

The effectiveness of a laminar airflow vs turbulent airflow is particularly evident in the case of a cooling application. The chart below shows the time to cool computers to ambient temperatures for an automotive electronics manufacturer. They used a total of (32) 6” axial fans, (16) across the top and (16) across the bottom as the computers traveled along a conveyor. The computers needed to be cooled down before they could begin the testing process. By replacing the fans with just (3) Model 110012 Super Air Knives at a pressure of just 40 psig, the computers were cooled from 194 °F down to 81°F in just 90 seconds. The fans, even after 300 seconds, still couldn’t remove enough heat to allow the customer to test them.

Utilizing a laminar airflow is also critical when the airflow is being used to carry static-eliminating ions further to the surface. Static charges can be both positive or negative. In order to eliminate them, we need to deliver an ion of the opposite charge to neutralize it. Since opposite charges attract, having a product that produces a laminar airflow to carry the ions makes the static reduction dramatically more effective. As you can see from the graphic above showing a turbulent airflow pattern vs a laminar one, a turbulent airflow is going to cause these ions to come into contact with one another. This neutralizes them before they’re even delivered to the surface needing to be treated. With a product such as the Super Ion Air Knife, we’re using a laminar airflow pattern to deliver the positive and negative ions. Since the flow is laminar, the total quantity of ions that we’re able to deliver to the surface of the material remains greater. This allows the charge to be neutralized more quickly, rather than having to sit and “dwell” under the ionized airflow.

EXAIR Super Air Knives are the most efficient compressed air knife on the market, and for a limited time, you will receive a FREE Safety Air Gun when you purchase any EXAIR Super Air Knife! Learn more over on our site. (Until December 31, 2024)

Jordan Shouse
Application Engineer

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Saving Money with our Super Air Knives

Published on by Al WooffittLeave a comment

Here at EXAIR we are confident that there is a lot to gain from using our products. Two of the biggest benefits of our Intelligent Compressed Air Products are a reduction in noise, and a reduction in Compressed Air usage. The latter will often lead to big money savings. Many times the savings our products offer will pay for the product itself! What is my Return on Investment going to be?

So, how do you calculate your ROI? The easy answer is that you don’t have to! You can use our Air Savings Calculator to calculate your savings for you. If you know your current air consumption (in SCFM), the new air consumption (SCFM) and the cost of the product, our calculator will turn that into monetary savings, as well as the calculated payback time in days.

Another option if you would rather not do the calculations yourself, is that you can send the item in question to our Efficiency Lab Testing. The Efficiency Lab Testing is a free service that we offer to show you the possible savings by switching to one of our products. We will calculate the savings for you and send you the results of our findings.
The final option – my favorite by the way – is that we can do the math right here:

For a simple example, I’m going to show the ROI of replacing a drilled copper pipe with an EXAIR Super Air Knife for a blowoff application. The calculations will be as follows:

Copper Pipe (1/4”): 3x 3/32” diameter drilled holes uses 9.4scfm per hole (28.2scfm total) at 80psig.

3” Super Air Knife: uses 8.7scfm at 80psig

Calculation:

For the yearly consumption, we need to find how many minutes in a year the blowoff will be operated:

For the Copper Pipe:

For 3” Super Air Knife

The difference between these two:

At this point, if you know your facilities cost to generate 1,000scf, you can use that to calculate how much you would save. For this example, we will use $0.25 to generate 1,000scf, which is used by the U.S. Department of Energy to estimate costs. This gives the following yearly savings:

With an investment of $273.00 (at the time of publishing), you can calculate the time it would take to pay off the unit:

From these numbers you can see that after 117 days, the 3” Super Air Knife will have paid for itself.

As you can see, it doesn’t have to take long for the knife to pay for itself, and then continue to contribute toward your bottom line. 

Al Wooffitt
Application Engineer

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