Tag: air knife nozzle

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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Banner image by Peter Fertig from Pixabay

Super Air Knife Positioning and Mounting

Published on by jasonkirbyLeave a comment

Super Air Knives are a versatile product for a wide variety of applications, including cleaning, drying, blow-off, and cooling. With no moving parts, the Super Air Knives provide a hard hitting curtain of air, with laminar and uniform airflow for your industrial application needs. The 40:1 air amplification is a great way to maximize the use of your compressed air supply, while maximizing efficiency at a surprisingly low decibel level.

While every application is different, there are a few essential standards and practices to consider when mounting. The primary airflow is provided by the compressed air, but the air amplification of 40:1 is provided by the designed ambient air entrainment. This means that the Super Air Knife will pull in the ambient air to increase the volume of your output airflow. For this to take place, you will need to allow spacing on both the top and bottom of the Super Air Knife. While there is not a minimum requirement, I would suggest not mounting your knife any closer than one half inch from any obstruction. This will allow the ambient air to be pulled through both the top and bottom of the knife to ensure proper air entrainment.

Gen4 Super Ion Air Knife

Another consideration you need to take into account when mounting the Super Air Knife is the compressed air inlet locations. The Super Air Knife has compressed air inlets at the opposite ends of the knife. Knives between 48″-59″ use 2 inlets at the opposite ends, plus 1 near the middle of the bottom of the knife. Knives 60″-83″ use 2 inlets at the opposite ends, plus 2 inlets equally spaced on the bottom of the knife. Knives 84″ and longer use 2 inlets at the opposite ends, plus 3 inlets equally spaced on the bottom of the knife. When mounting, be aware of the inlet requirements in order to allow enough space for your compressed air supply hoses.

Orientation of the Super Air Knife will depend on your application. Orientation of the knife will not affect performance, as long as proper spacing is allowed for compressed air supply and ambient air entrainment. While some applications will require a 90 degree placement of the knife to the target, most will benefit from increased contact time of the laminar airflow to the target. For example, when using the Super Air Knife for drying on a conveyor system, you will want to place the knife at as low an angle as possible, opposite to the oncoming material. This allows more contact time between the laminar airflow and the material, increasing the drying potential. This applies to blow-off and cooling applications as well.

Universal Mounting System

If you are unsure of where to mount your Super Air Knife for optimal performance, you may want to consider using EXAIR’s Universal Air Knife Mounting System. This mounting system is used to provide a secure, precise position for any of the EXAIR Air Knives. The Universal Air Knife Mounting System can quickly and easily be adjusted to move a connected Super Air Knife to be within close proximity of the part to improve blowing effectiveness. The Universal Mounting Mystem can also be used when testing different locations before permanently mounting your knife.

If you would like to discuss Super Air Knife mounting and positioning, please do not hesitate to contact an Application Engineer. We are always happy to help!

Jason Kirby
Application Engineer
Email: jasonkirby@exair.com
Twitter: @EXAIR_jk