Super Air Knife Prevents Errant Failure Readings On Vision Testing Of Parts

“False Positives” have been in the news a lot recently regarding COVID19 testing. We’re all hoping for better news on that soon, but all I have to offer about that, right now, are my hopes that you and yours are well and safe…and that we’re all in this together, and I’m pulling for you (us).

Manufacturers of precision products often use an automated vision system to inspect parts for defects. These systems can operate at a high rate of speed, and the sensors are capable of reading a very fine resolution, so even very slight blemishes on the surface of a critical part can be detected, allowing for instantaneous rejection of that part…a process that EXAIR Super Air Nozzles are commonly used for.

Model 1104 High Force Super Air Nozzle ejects a rejected package from a high speed conveyor line.

The ejection part of the process, however, is only as effective as the detection operation.  I recently had the pleasure of assisting a caller whose sensor was mounted at the outlet of a wash/rinse tank.  Some moisture carryover (and, at times, just the humidity) would cause moisture to collect or condense on the sensor lens, giving a “false positive” defect signal for a (presumably) perfectly fine part.

The sensor lens itself is 4.5″ in diameter and slightly convex.  They bought a Model 110206 6″ Aluminum Super Air Knife Kit:

  • The Air Knife itself is installed to blow a curtain of air across the lens at all times to keep it clean and free of moisture & condensation.
  • The Automatic Drain Filter Separator keeps the air supply clean & moisture free…remember, whatever’s in your air supply will get on whatever you’re blowing it onto.
  • The Pressure Regulator allows them to dial in the flow & force of the air curtain.  They really only need a good, stiff breeze running across this, so hitting it with full line pressure would just be a waste of perfectly good compressed air.
  • They can even use the 0.001″ thick shim from the Shim Set to dial down their consumption even more, if desired (and why wouldn’t that be desired?)
Super Air Knife Kits include a Shim Set, Filter Separator, and Pressure Regulator.

The EXAIR Super Air Knife is the most efficient, and quietest, compressed air blow off product on the market today.  They’re on the shelf in lengths from 3 inches to 9 feet.  Our 30 Day Unconditional Guarantee allows you to try one out, risk free, for up to a month.  What’s stopping you from saving money on compressed air, lowering your noise levels, and (very likely) improving the performance of your air blowing application?  Call me; let’s talk.

Russ Bowman
Application Engineer
EXAIR Corporation
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Customizing Blow-off Applications

EXAIR Blowoff Systems are a combination of EXAIR air Nozzles, mag bases and Stay Set hoses. They are available in single or dual outlets and can change the length of the Stay Set Hose and/or the type of nozzle. The flexibility of this product comes in handy when an application require multiple point blowoff or requires different force values from each nozzle. Customizing allows you to fit the nozzles directly to the need of the application.

Example of an EXAIR Blowoff System – these can be customized with different nozzles or length of hose to suit your application best.

One example of this came from a customer who was running a 1950’s era Benchmaster OBI press to stamp out copper lamination and spring steel. There current set-up which can be seen bellow was not really that effective, was loose/floppy, and had been glued together. All of this made it hard for the Technician to line everything up to eject the parts. The technician reached out to us to see if we could substitute some nozzles on our dual Blow-off system with the stay set hose and dual port magnetic base (as seen above). We were able to piece together a special kit for them to swap out one of the 1103 Mini Super Air Nozzles with a 1126 1″ Flat Super Air Nozzle to match the current set-up.

The Customer’s current ejection set-up in the punch press

Customizing the nozzles in Blow-off systems can allow for better coverage on awkwardly shaped parts that might have a mix of both smooth surfaces and crevices. Also changing out the length of the Stay Set hoses that come with the kits can allow you to reach all sides when centrally located mounting is not applicable. Using two different length stay set hoses can also allow for two different blow off points to share the same mounting and air line; this means your maintenance team wont have to bring in multiple drops which I’m sure they will appreciate.

Not only can we customize blowoff systems for you, since we manufacture the products here in Cincinnati, OH, we can provide custom features and performance characteristics for you. Our wonderful team of Engineers (just don’t tell them I said that) can design special air knives, nozzles, and even air amplifiers to fit your needs. The image below shows custom Air Amplifiers (with customer specified flanges) that we have built. We can customize our products to fit your needs.

Custom Stainless Steel Sanitary Flange Air Amplifier
Special Curved Super Air Knife

If you have any questions about compressed air systems or want more information on any of EXAIR’s products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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Cooling With Compressed Air: Air Knife vs. Vortex Tube Products

One of the popular applications for the EXAIR Super Air Knife is cooling. When mounted so that the air flow sweeps across the surface of a product, the laminar nature of the air flow works to maximize the contact time with the surface, which also maximizes the heat transfer…which means better product cooling than, say the turbulent air flow from a fan or blower.

Still, it’s common for us to get questions about how to provide even faster cooling.  Well, the two main variables in heat transfer are the time the air is in contact with the product, and the difference in temperature between the product surface and the air.

We’ve already touched on “time in contact”…sweeping the laminar flow across the surface at as low of an angle as you can, against the direction of travel, is ideal.  Combine that with the extraordinarily high air flow due to the entrainment level of the Super Air Knife, and you get an awful lot of air in contact with the surface, for a (relatively) long time.

Super Air Knives cool steel casting from 1,725°F (940°C) to 200°F (93°C) in under 20 minutes.

The difference in temperature, though, is a little trickier to deal with.  Because the developed flow from the Super Air Knife is mostly entrained ambient temperature air from the surrounding environment, you’re at the mercy of that ambient temperature.  One of the most common question – of the common questions about faster cooling – is, can you feed a Super Air Knife with cold air from a Vortex Tube?  The answer is no, for two big reasons:

  • The Vortex Tube’s cold flow can’t be back pressured, which would happen if you fed it through the plenum of a Super Air Knife and tried to make it come out the 0.002″ gap.
  • Even if it did work, the entrained air which, remember, makes up most of the flow, is still room temperature…meaning the total developed flow is a lot closer to room temperature than however cold the air you fed the Super Air Knife would be.

If the surface area to be blown on, to effect the desired cooling, is suitably sized, a Vortex Tube can be installed at a low angle to sweep its flow across.  The cold air flow from a Vortex Tube can also be distributed to more than one point, to cover more surface area.  That’s exactly what we do with our Dual Point Hose Kits for our Adjustable Spot Coolers, Mini Coolers, and Cold Gun Aircoolant Systems:

Dual Point Hose Kits can distribute air to both sides of a part, or onto a wider surface, than a single point discharge.

In fact, both the Single and Dual Point Hose Kits have a variety of tips they can be fitted with for tighter, or broader, flow patterns:

In some cases, multiple Vortex Tube products can be used, and, in other situations, the cold air can be directed through a manifold of some sort:

There are numerous methods to distribute the cold air flow from a lone, or a series of, Vortex Tubes.

Applications like the two on the right above (setting molten chocolate in molds, and keeping those white plastic parts during ultrasonic welding, respectively,) commonly start out as Air Knife inquiries, but the need for refrigerated air leads to creative Vortex Tube solutions.

If you’d like to discuss whether your application is best served by a Super Air Knife or a Vortex Tube Spot Cooling Product, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Video Blog: Importance of Point-of-Use Filtration

When operating any of your Intelligent Compressed Air Products, something that often gets overlooked is the importance of delivering clean, dry air to those point-of-use products. Many of our products have very tight orifices to help reduce the volume of compressed air they consume. In addition, most have no moving parts to wear out and require no maintenance. That is, unless you’re using unfiltered compressed air.

Rust and scale are commonly found within the distribution system inside your facility. Old iron pipe and receiver tanks are the common culprits. A common misconception is that the air is already filtered as it exits the compressor. While this may be true, there’s still places in the distribution system that can cause issues downstream.

To eliminate the hassle of taking things apart to periodically clean, EXAIR recommends installing a point-of-use filter for all of our Intelligent Compressed Air Products. Kits are available for purchase that come with a properly sized filter to ensure your air is sufficiently clean. To see how quickly debris can clog your products, check out my video below demonstrating the difference between dirty and clean air with a Model 110006 6″ Super Air Knife.

If you’ve already purchased and installed products without filters, it’s never to late to go back and install one. Contact an EXAIR Application Engineer today and we’ll be happy to help you determine the proper size for the volume of air you’re products need.

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