Tag: air knife nozzle

Laminar Curtain of Air For Cleaning, Drying, Cooling, and Blowoff: EXAIR’s Super Air Knife

Published on by Tyler DanielLeave a comment

When a wide, even, laminar flow is necessary, there isn’t a better option available on the market than EXAIR’s Super Air Knife. We’ve been manufacturing Air Knives for 35 years now, with the Super Air Knife making its first appearance back in 1997. Since then, the Super Air Knife has undergone a few enhancements over the years as we’re constantly trying to not only introduce new products but also improve on the ones we have. We’ve added new materials, longer single piece knives, as well as additional accessories. But, by and large, the basic design has remained the same. As the saying goes “If it ain’t broke, don’t fix it!”.

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.

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 fans 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.

With lengths from 3” to 108” and (4) four different materials all available from stock, EXAIR has the right Super Air Knife for your application. In addition to shipping from stock, it’ll also come with our unconditional 30-day guarantee. Test one out for yourself to see just how effective the Super Air Knife is in a wide variety of cooling, cleaning, or drying applications.

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.

Tyler Daniel, CCASS

Application Engineer

E-mail: TylerDaniel@exair.com

Twitter: @EXAIR_TD

How EXAIR Uses Fluidics To Make Efficient, Quiet, and Safe Compressed Air Products

Published on by Russ BowmanLeave a comment

EXAIR Intelligent Compressed Air Products incorporate several distinct principles of fluidics into our engineered designs. To be clear, these principles aren’t exclusive to making quiet and efficient compressed air products. I personally have used them all for business and pleasure over the years. In the Navy, for example, the air ejectors that pulled vacuum on the main condensers where our turbines dumped their ‘used’ steam were basically great big Venturis – they restricted the diameter through which a fluid (steam, in this case) flowed, gradually increased that diameter, and doing so, changed the velocity so that a low pressure area (or vacuum) developed in the throat:

Graphic representation of the Venturi effect.

EXAIR E-Vac Vacuum Generators use the Venturi effect to draw vacuum of up to 27″Hg. They’re typically used with Vacuum Cups for pick-and-place material handling applications.

Here are a few examples of Mr. Venturi’s discovery, implemented in modern industry.

I first learned about the Bernoulli principle on a grade school field trip to the National Air Force Museum at Wright Patterson Air Force Base, about an hour from where I grew up. See, this Bernoulli guy discovered that when there is an increase in the speed of a fluid, a simultaneous decrease in fluid pressure occurs at the same time. That’s why airplane wings are shaped like they are – flat on the bottom and curved on top…when the air flowing that extra distance over the top speeds up to get to the back of the wing as fast as the air that’s simply flowing underneath the wing does, the decrease in pressure on top causes the wing (and the plane it’s attached to) rise in the air.

Bernoulli’s Equation: this is the math that proves it works.

The Bernoulli principle is incorporated in to the design & operation of EXAIR engineered Air Knives, Air Wipes, Air Amplifiers, and Air Nozzles.

The Coanda effect is the third fluidics principle that’s incorporated into the design & operation of many EXAIR engineered compressed air products. Its namesake, Henri Coanda, was an early 20th Century aeronautical engineer who discovered that if a jet of fluid exiting an orifice flows across a surface, it’ll tend to not only adhere to and follow that surface (even if it curves or bends), but also entrain fluid from the surrounding area.

EXAIR Intelligent Compressed Air Products such as (left to right) the Air Wipe, Super Air Knife, Super Air Nozzle, and Air Amplifier all use the Coanda effect to entrain enormous amounts of air from the surrounding environment.

There are a couple of easy – and interesting – experiments that demonstrate the Coanda effect, both of which I used when I was a Cub Scout leader and our Pack’s Webelos den was earning their Science Activity Pin:

Turn a faucet on and let the running water flow over the convex ‘bottom’ of a spoon. Everything we know about the laws of gravity say that when the water reaches the ‘bottom-most’ point on the spoon’s convex surface, it ought to fall straight down…but it doesn’t:

Another experiment that defies everything we think we know about gravity can be performed with a ball, and a source of air flow. Here’s a short video, showing how the air flow from an Air Amplifier ‘wraps’ around a ball and holds it in that jet of air:

The Webelos den did this with a leaf blower and a playground ball. Unlike a lot of things I’ve done, I DEFINITELY encourage you to try THAT at home.

For forty years now, EXAIR has been putting these principles of fluidics into practice by engineering & manufacturing the most efficient, quietest, and safest compressed air products on the market. If you’d like to find out how we can help you get the most out of our products – and your compressed air system – give me a call.

Russ Bowman, CCASS

Application Engineer
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Create a Custom Blowoff Solution With EXAIR’s Industry-Leading Super Air Knives

Published on by Tyler DanielLeave a comment

EXAIR’s Super Air Knife utilizes a source of compressed air to create a laminar sheet of high velocity air. This supplied compressed air mixes with ambient air that is entrained into the primary airstream. The Super Air Knife entrains ambient air at a rate of 40:1, making it VERY effective in a variety of drying, cleaning, and cooling applications. Available in lengths ranging from 3”-108” and in a variety of different materials of construction, there’s a Super Air Knife available for just about any application. Any time you have product moving along a conveyor that needs to be cleaned, dried, or cooled off, a Super Air Knife is the ideal fit.

The Super Air Knife is available in aluminum, Type 303 & Type 316 stainless steel, as well as in PVDF with Hastelloy bolts for extremely corrosive applications.  While there are numerous options available off the shelf ready to ship same day, not all applications can be served by a stock option. Since EXAIR handles all the manufacturing of these products in our facility in Cincinnati, Ohio, we have a great deal of control over the manufacturing process. If your application cannot accept something right off the shelf, we’re constantly producing special customized knives to fit most requirements.

Our knives can be manufactured in a special length if a stock length won’t fit in your application. We’ll use the same design and size profile and can build it to the precise length you require in order to fit perfectly onto your machine. If the dimensional profile of an existing knife isn’t suitable, we can change that too! The Super Air Knife shown below utilizes a very thin design and has been completely modified to achieve the smallest overall profile possible.

All Super Air Knives come stock with ¼ NPT air inlets and ¼-20 tapped holes along the bottom that can be used for mounting. Unfortunately, that isn’t always going to work for every application, so we also manufacture specials with custom air inlets as well as additional mounting holes to fit right onto any custom bracket. The photo below shows a modified stainless steel Super Air Knife with additional mounting holes machined onto either end.

We don’t just offer them in different shapes and sizes as a special, but we’ve also manufactured stock length knives out of entirely different materials. Shown below are two knives of different materials that aren’t already on the shelf. On the left-hand side is a knife manufactured from PVDF and on the right a glass filled PEEK material with brass hardware and a PTFE shim. In this application, the customer was noticing ground interference due to the aluminum knife construction. They specified this particular material, and we were able to machine a knife completely customized for this application.

Every year a new request comes across that is something we haven’t done before. Just because you don’t see it in the catalog doesn’t mean it isn’t possible when you deal with EXAIR. We’re here to make sure you get the most out of our products, and sometimes that isn’t possible right off the shelf. Contact an Application Engineer today if you’d like to discuss your application and begin the process of identifying your next custom solution!

Tyler Daniel, CCASS

Application Engineer

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD

Compressed Air Use In The Agriculture Industry

Published on by Russ BowmanLeave a comment

I didn’t grow up ON a farm, but more than a few of the kids I went to school with did. My wife’s grandpa had a farm, and one of her uncles still does. Farmers have always been the most diversely talented people I’ve ever known. They’re well versed in soil chemistry and plant biology. They have a keen understanding of climate & weather patterns which allows them to sow seed after the last frost in early spring, and gather their last harvest before the first frost of mid-to-late autumn. Most of them are also expert mechanics, welders, and plumbers as well, to avoid costly repair bills on equipment they operate in fairly harsh conditions. And the ones that raised livestock, I’d stack their veterinary knowledge & skills up against just about any vet’s office.

In my twelve years with EXAIR, I’ve had the pleasure of talking with many farmers & other folks in agricultural-type jobs, and a lot of the stuff they use our products for is downright fascinating. Here are two prime examples – one from an agricultural product provider, and one from an actual agricultural job:

*A company that makes irrigation drain pipe uses Model 2485 5″ Standard Air Wipe Kits to cool and dry their extruded 4″ pipe before cutting to length & packaging it for shipment. This replaced a blower operated setup that didn’t completely dry the corrugated outside diameter. The Air Wipe not only blew off almost all the water, all the time, but also allowed them to increase production speed by nearly 10%.

The turbulent air flow from the blower system (left) really just beats on the extruded surface, while the laminar flow of the EXAIR Super Air Wipe (right) strips & sweeps the surface clean & dry.

*Once fruit & vegetables are harvested, most of them go through some sort of cleaning process. EXAIR Super Air Knives are commonly used in conjunction with those processes. Sometimes they’re blowing loose dirt from, say, onions or potatoes, so they don’t turn the wash water into a mud bath. They’re also used to blow the wash & rinse water off, so they’re as dry as possible before packaging or processing. One particular customer uses Super Air Knives for the latter. By replacing blowers with a Model 110236SS 36″ Stainless Steel Super Air Knife Kit to dry freshly washed potatoes, they were able to increase the speed of conveyance…the laminar flow from the engineered Air Knife was better at blowing off the potatoes than the turbulent flow from the blower. Also, since the temperature of the Air Knife’s flow is the same as ambient temperature (because they entrain air from their surrounding at a rate of 40:1 to their compressed air consumption), this extended the time before spoilage. The warmer air from the blower (caused by friction in the rotating elements) was fostering the bacterial growth that leads to spoilage.

Increased potato production + longer shelf life = win/win.

Engineered compressed air products are widely used in agriculture (and, of course, many other industries) for their simplicity, durability, and reliability. If you’d like to find out how EXAIR products can make your life (or at least your job) easier, give me a call.

Russ Bowman, CCASS

Application Engineer
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