Factors in Selecting an Air Knife – Size, Materials, Stock Levels, Accessories

Super Air Knife Family

EXAIR has been manufacturing Intelligent Compressed Air® products since 1983.  In the beginning, the Standard Air Knives and Full Flow Air Knives were very effective at that time.  But as leaders in this market, EXAIR did not want to stop there.  We were able to engineer a more efficient, more powerful, and much safer air knife, the Super Air Knife.  In this blog, I will discuss the features and benefits that the Super Air Knives can offer.

Bernoulli’s principle explains how a high velocity fluid can generate a low pressure.  The EXAIR Super Air Knife creates a high velocity air stream to produce a low pressure to entrain ambient air.   What does this mean for you?  It will save you much money by using less compressed air.  The mass of the ambient air is added into the air stream to give a strong blowing force.  The Super Air Knife has an amplification ratio of 40:1. For every 1 part of compressed air, 40 parts of ambient air is drawn into the blowing air stream.  Ambient air is free, and compressed air is expensive.  EXAIR was able to engineer a design to use the Bernoulli’s principle to make one of the most efficient air knives in the market place.

EXAIR Super Air Knife model 1100108

What else makes EXAIR unchallenged?  We manufacture and stock the widest range in lengths and materials.  To start, EXAIR has Super Air Knives ranging from 3” to 108” (76mm to 2,743mm) in three different materials; aluminum, 303 stainless steel, and 316/316L stainless steel.  There is no-one else in this industry that can manufacture to those lengths.  EXAIR also offers Super Air Knives in PVDF material with Hastelloy hardware for chemical resistant applications from 3” to 54” (76mm to 1,372mm).  Depending on the temperature requirement, chemical resistance, OSHA and FDA regulations, or application details, we probably will have one on the shelf for you.  If EXAIR does not have it, we can make special air knives in different lengths and materials to best fit your application.

Some interesting features for the Super Air Knives are as follows.  They have a compact design that can fit into tight places for blowing and cooling.  The footprint is very small compared to blower-air knife system.  They do not have any moving parts to wear or maintenance to do.  They only need clean compressed air to work.  They blow a laminar air stream which reduces noise levels and create a consistent force along the entire length.  An even force will give you tighter control for blowing applications which will cut compressed air usage unlike the inconsistent and turbulent air flows caused by drilled pipes.

To adjust the force and air usage, this can be easily controlled with a regulator.  The advantage that EXAIR Super Air Knives have is the replaceable shims.  So, you can increase or decrease the gap to get a variety of force ratings.  The Aluminum version uses colored plastic shims for visual verification.  They come stock with a 0.002” (0.05mm) red shim installed.  We have other thicknesses in our Shim Sets which includes a 0.001” (0.03mm), 0.003” (0.08mm), and a 0.004” (0.10mm) colored as amber, green, and tan respectively.  The Stainless Steel Super Air Knives come with a stainless steel shim for higher temperatures and chemical resistance.  Stock units have the 0.002” (0.05mm) thickness as well.  The Shim Sets come with three additional 0.002” (0.05mm) shims to stack.  Similarly, the PVDF Super Air Knives use a PTFE shim for maximum chemical resistance.  It is also 0.002” (0.05mm) thick, and there are three more shims in the Shim Set.  This unique feature of using shims allows for the most flexibility in creating forces for different applications ranging from a blast to remove rocks from a conveyor to a breeze for light duty work.

Super Air Knife Kit

We also offer the Super Air Knives in kits as a more complete system.  The kit includes a filter, regulator and the above-mentioned Shim Set.  The filter removes the debris and water from the compressed air line to optimize the performance of the air knife as well as keeping your product clean.  The regulator is used to make the “fine” adjustment to the blowing force while the shim set is used as the “coarse” adjustment.  EXAIR sells this kit as one model number for simple ordering, and the accessories are properly sized to not hinder the performance of the Super Air Knife.

To optimize the system even more, EXAIR offers a Deluxe Kit for the Aluminum and Stainless Steel models.  This includes the accessories in the kit above, plus an Electronic Flow Control, or EFC.  This exclusive instrument uses a photoelectric eye to start a timing sequence to control a solenoid valve.  So, when a part is not in front of the Super Air Knife for cleaning or cooling, the compressed air is turned off.  This will save you even more money and maximize your efficiency to only blow air when needed.

Plumbing Kits

For the longer Super Air Knives, EXAIR can install a Plumbing Kit, or PKI, to help attach your compressed air to the Air Knife.  They are designed to help lessen the time for install as well as to properly supply compressed air equally along the entire length, specifically for 24” (610mm) and longer.  We can offer the Plumbing Kit separately if you find that it could benefit your fabricators during installation.  EXAIR also offers a Coupling Kit for the Aluminum and Stainless Steel versions.  If you need to extend past the 108” (2,743 mm) width, the Coupling Kit is designed to mount Super Air Knives together at the ends.  You will still get that consistent blowing force along the multiple of Air Knives.  Another helpful accessory is the Universal Air Knife Mounting System.  It has a bracket and an articulated arm that can reach up to 30” (762mm).  With this system, you can position your air knife securely and precisely in any orientation.  It attaches easily to your Super Air Knife and gives you the flexibility to maximize the blowing effect at your target.

Universal Mounting System

With the today’s cost in making compressed air, it is important to use it as efficiently as possible.  The Standard and Full Flow Air Knives would be good options to use.  But the best way to conserve is with the Super Air Knife.  If you have any questions about the Super Air Knife or if you would like to discuss an application, you can contact an Application Engineer at EXAIR.   We will be glad to help you.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

 

Mounting Options for EXAIR’s Super Air Knife

 

Super Air Knife installed using the Universal Air Knife Mounting system.

The key towards a successful Super Air Knife  application is making sure it’s installed properly. Using the chart on the installation & maintenance guide to ensure your plumbing is properly sized is the first step. This ensures that an adequate volume of compressed air is able to reach the knife, without causing an unnecessary pressure drop.

super air knife pipe size

Once you’ve planned out the distribution of compressed air to the Super Air Knife you must consider how to mount it in your application. Across the bottom of the knife are ¼-20 tapped holes spaced out evenly every 2” along the knife. A 30” Model 110030 will have (15) holes, a 60” 110060 (30), and so on. These holes are tapped through to allow you to mount the knife to best suit the application.

If you’d rather have a more “out of the box” solution, EXAIR offers our Universal Mounting System. It gives you the ability to mount onto a conveyor rail or machine frame and provide precise positioning for all of EXAIR’s Super Air Knives, Standard Air Knives, Full-Flow Air Knives, as well as the Standard and Super Ion Air Knives. Each system comes with (2) 1/2-13 x 5” long bolts, 2’ long stainless steel rod, mounting hardware, angle bracket, and adjustable swivel clamps. Check out the video below for a demonstration of the adjustability you can achieve with the Model 9060 Universal Mounting System.

Another critical factor to consider is the mounting position of the knife. If the material is moving along a conveyor, the knife should be positioned as closely as possible with the airflow oriented against the direction of travel of the material. By doing so, we increase the amount of time that the material is in contact with the airflow. We call this term counter-flow. Maximizing the time in contact with the laminar airflow from the Super Air Knife gives us the best chance at a successful result. Whether we’re talking about cooling, drying, or cleaning, the longer that the material is in contact with the laminar airflow the better the results will be.

air knife counter flow

In this photo, the Super Air Knife is positioned upside down at an angle above a conveyor belt, against the direction of travel. We recommend installing the Super Air Knife in this orientation as it allows the airflow to get closest to the material being blown off. They’ve used their own brackets to allow the knife to be adjusted when blowing residual dust off of a conveyor for a mining application. The dust on the belt would build up over time and was difficult to remove. By installing a Super Air Knife, they’re able to continuously remove the dust from the conveyor belt before it becomes a problem.

If you have an application that would be better served with one of EXAIR’s Super Air Knives, give us a call. An Application Engineer is ready to assist you in selecting the proper material, length, and mounting method.

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

Super Air Knife Coupling Kit Helps Customer Save Money and Increase Productivity!

I was recently contacted by a manufacturer of specialty food products that was looking to increase productivity on one of their packaging lines. In order to do so, they needed a longer Super Air Knife.

SS SAK cheese.jpg cropped
Model 110012SS-316 Super Air Knife

They manufacture a variety of different products, but this application was involving small snack-size blocks of cheese. They’re placed into individual plastic containers and before they seal the packaging any residual particles must be blown off or it will affect the seal. Any residual particles of cheese around the container would allow air to come into contact with the product and affect shelf-life.

In the current setup, they were using EXAIR’s Model 110012SS-316 a 12” 316 grade Stainless Steel Super Air Knife and the Model 9060 Universal Mounting System. They wanted to add in an additional two rows of cheese to help increase throughput. To do so, he needed an overall width of 18”. We do have an 18” available from stock, but rather than having a spare 12” model lying around he wanted to try and utilize what he had without having to purchase an entirely new knife.

uakmb
Model 9060 Universal Mounting System

Fortunately, EXAIR’s Super Air Knives can be coupled together to create a wide variety of different lengths. From stock, the Super Air Knife is available from 3”-108”. With the help of a Super Air Knife Coupling kit, we can achieve much longer lengths. In this case, although we did have an 18” knife available, we could also couple the existing 110012SS-316 (12”) with our Model 110006SS-316 (6”). This option was a bit cheaper than going with a new knife, and still allowed them to utilize the 12” that they already had.

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Coupling Kit for Aluminum Super Air Knives

While this isn’t the typical place we’d recommend a coupling kit, it was an option that allowed the customer to save a bit of money but still get the same effect that they’d achieve with the 18” single piece knife. We also manufacture a wide variety of custom knives per customer specifications. If you’ve got an odd application that you don’t think is best served by a stock offering, give us a call. An Application Engineer will be happy to take a look at your application and help recommend the most suitable product.

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