EXAIR Corporation’s engineered Air Knife products have a number of uses in industry. The laminar, even flow is conducive to generating a stripping/sweeping action that is particularly effective for blowing off, cooling, cleaning, drying, etc. The way that they entrain enormous amounts of air from the surrounding environment makes them incredibly efficient. This entrainment also makes them very quiet, as it forms a boundary layer that attenuates the sound level of the high velocity flow of the compressed air exiting the Air Knife. These two features have a distinct benefit in a rather unique application in a decidedly non-industrial setting, though.
A company that services amusement parks & carnivals was making a “haunted house” type attraction. At one point, the victims visitors are to be surprised by animated figures “floating” in the air. Their idea was to project the animation on a wall/screen of smoke…spooky, right? They tried discharging the smoke through a series of holes, and even a thin slot, but could not get the effect they wanted, so they called EXAIR to talk about Air Knives.
Smoke escaping small holes or a thin slot doesn’t have much velocity, so it didn’t make a great ‘curtain’ for projection. It’s also turbulent in nature, so it tends to billow & plume (like the top graphic). Engineered compressed air products like EXAIR’s Air Knives generate a laminar flow (like the bottom graphic) whose velocity can be precisely controlled by regulating the air supply pressure.
They found their solution for this application in a Model 2836SS 36″ Stainless Steel Full Flow Air Knife Kit. The Full Flow Air Knife is the most compact design for any given length, and with rear ports for the compressed air supply, it was easy to conceal from the visitors’ sight. When smoke is introduced from behind, it gets pulled in (entrained), and discharges in a laminar, even curtain that the animated figures magically appear on. The extraordinarily low sound level contributes to the magic, as it can’t be heard over the din of eerie sound effects & music that are synonymous with the haunted house experience.
Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.
EXAIR Corporation has been in the business of providing quiet, safe, and efficient compressed air products for all kinds of applications for almost 39 years now. If you want to find out more about introducing more quietness, safety, efficiency…or magic…into your operation, give me a call.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
If you look at operating costs alone, compressed air can be just about the most inefficient method there is for cleaning parts. If you just look at the risks, it’s potentially very dangerous too. Don’t even get me started on the insufferable noise it can make.
For cleaning parts, most folks are familiar with the use of an air gun. You can find the simplest of these in many industrial settings: a valve (often in the form of a handheld trigger device) fitted with a nozzle of some sort (often in the form of an open ended tube, pipe, or fitting to focus or direct the air flow). These have all three of the “downsides” I opened this blog with. Of course, these concerns can be mitigated to a high degree by using the right tool for the job. That’s where engineered products like EXAIR Safety Air Guns come in. Let’s look at how we can address these three “downsides”:
Efficiency: This is all about compressed air consumption. In the simplest of air guns mentioned above, consumption is only limited by the passages in the valve (or trigger) and the discharge fitting…and those limits are usually negligible. Modifying the ends (see examples below) to focus the air flow usually has minimal effect, because you’re not appreciably changing the total cross sectional area of the discharge opening:
Here are a few modified thumb trigger air guns that were sent in for Efficiency Lab testing. Left to right, compressed air consumption at 80psig supply pressure was 34.2 SCFM, 30.9 SCFM, and 28.2 SCFM. For comparison (more on this later,) EXAIR Model 1210 Soft Grip Safety Air Gun uses only 14 SCFM and generates a very similar flow pattern.
Safety: Remember learning about kinetic and potential energy in grade school? Well, when you compress air to 100psig, fitting all that air into a much smaller space creates a TREMENDOUS amount of potential energy:
The block on the left represents a cubic foot of air at atmospheric pressure. The one on the right represents how much space the first one takes up when compressed to 100psig. The energy imparted by this process HAS to be handled with care.
One problem with the thumb guns above is, if you were to jam into the palm of your hand and pull the trigger, a large component of that potential energy (pressure) turns into kinetic energy (force)…more than enough to break the skin and cause a potentially fatal condition known as an air embolism. In the United States, OSHA (Occupational Safety and Health Administration) regulates compressed air devices used for cleaning purposes. All EXAIR Safety Air Guns comply with Standard 1910.242(b) by providing a relief path to ensure that it cannot be dead ended, and thus never create over 30psi measurable at the outlet)
EXAIR Super Air Nozzles cannot be dead ended, ensuring the outlet pressure won’t reach OSHA limits, regardless of supply pressure.
Noise: Another problem is, another component is turned into sound pressure…discharging air from a direct opening is quite loud. OSHA standards address these with limitations on outlet pressure and sound level. All EXAIR Safety Air Guns comply with Standard 1910.242(b), which limits the outlet pressure (by providing a relief path to ensure that it cannot be dead ended, and thus never create over 30psi measurable at the outlet) and all but our largest Super Blast Safety Air Guns comply with Standard 1910.95(a) limits for continuous 8 hour sound level exposure.
Which brings us to the topic of this blog: How exactly did THEY (our customer who used to use the thumb guns above) select the right Safety Air Gun, and how can we apply that to getting the right Safety Air Gun for YOU?
These steps aren’t all-inclusive, and they don’t necessarily need to be followed in order, but if you call an EXAIR Application Engineer about selecting a Safety Air Gun, here’s what we’re gonna talk about:
Ergonomics: We offer five distinctive styles of Safety Air Guns:
From small part cleaning by hand, to wide area blowoff, and all points in between, EXAIR has a Safety Air Gun for most any application.
Our thumb gun user (as I alluded to above) chose the Model 1210 Soft Grip Safety Air Guns (top right). They had a number of typical industrial applications where the operators had the parts or surfaces to be blown off right in front of them. They liked the integral storage hook and rubberized hand grip, but the VariBlast Compact (top middle) or Heavy Duty Safety Air Guns (bottom left) were also considered. The VariBlast Precision (top left) and Super Blast Safety Air Guns (bottom right) were too focused or more powerful, respectively, than needed.
Airflow pattern: Honestly, I could make a good case for this being the first consideration. Selection of any blowoff product – be it an Air Nozzle, Air Amplifier, Air Knife, Air Wipe, etc., will largely depend on the size and shape of the airflow.
variety of airflow patterns…and effective distances…are available from EXAIR’s comprehensive line of Super Air Nozzle products.
For the most precise, focused blowoff, our Atto Super Air Nozzle (top left) is a great choice. It’s available on:
Super Air Nozzle Clusters (bottom left) create higher force & flow, and still keep it in a more concentrated, tighter pattern. They can be installed on:
When stubborn, heavy, and/or LOTS of debris needs to be absolutely, positively blown off RIGHT NOW, our High Force Super Air Nozzles may be just what you need. Our largest; Model 1120 1-1/4 NPT Super Air Nozzle, is shown (above right). The High Force Super Air Nozzles are offered on:
Soft Grip or Heavy Duty Safety Air Gun (up to 3.3 pounds of force over a 6.3″ wide area @12″ away)
Application specific concerns: Everything we’ve discussed so far has involved aiming the blow off stream away from the operator, in the direction the device is aimed. In addition to wide variety of engineered Air Nozzles, EXAIR offers a number of options for these products:
If you’re looking for a portable, hand-held compressed air blow off product that’s quiet, safe, and efficient, look no further than EXAIR Corporation’s extensive line of Safety Air Guns. If you’d like to find out more, give me a call.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
In the pneumatic industry, there are two types of Air Amplifiers. One type will amplify the inlet air pressure to a higher compression. The other type uses the inlet air pressure to amplify the air volume. EXAIR manufactures the volume type called the Super Air Amplifiers™.
This change in air volume is called the amplification ratio. So, what does this mean? The definition of a ratio is the relation between two amounts showing the number of times one value is contained within the other. For the Super Air Amplifier, it is the value that shows the amount of ambient air that is contained within the compressed air. The higher the ratio, the more efficient the blowing device is. With the EXAIR Super Air Amplifiers, we can reach amplification ratios up to 25 to 1. This means that 25 parts of ambient “free” air is introduced for every 1 part of compressed air.
Air Amplifiers Are Great For blowing!
Why an EXAIR Super Air Amplifier? Like a fan, they are designed to move air. But fans use motors and blades to push the air toward the target. The fan blades “slap” the air which creates turbulent air flows and loud noises. The Super Air Amplifiers do not use any blades or motors to move the air. They just use a Coanda profile and a patented shim to create a low pressure to draw in the ambient air. In physics, it is much easier to pull than it is to push. The process of pulling air through the Super Air Amplifiers make them a more efficient, uniform, and quiet way to blow air.
Most people think that compressed air is free, but it is most certainly not. Because of the amount of electricity required, compressed air is considered to be the fourth utility in manufacturing plants. To save on utility costs, it is important to use compressed air as efficiently as possible. In reference, 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 properly using their compressed air system. These types of products generally only have between a 2:1 to 5:1 amplification ratio. The Super Air Amplifiers can reach a 25:1 ratio.
EXAIR manufactures and stocks five different sizes ranging from ¾” (19mm) up to 8” (203mm) in diameter. Some of the benefits that the Super Air Amplifiers have is the inlet and outlet can be ducted for remote positioning. They are very compact and can fit into tight places. They do not have any moving parts to wear or need electricity to run. They only need clean compressed air to operate; so, they are maintenance-free.
Another unique feature of the EXAIR Super Air Amplifier is the patented shim which optimizes the low-pressure to draw in more ambient air. With extracting welding smoke, increasing cooling capacities, and moving material from point A to point B; the more air that can be moved, the better the performance. And with the patented shim inside the EXAIR Super Air Amplifiers, it provides that. As an added bonus, they are OSHA safe and meet the standards for noise level and dead-end pressure.
Super Air Amplifier Patented Shims
To explain things in every day terms; the amplification ratio can be represented by gas mileage. Like your car, you want to get the most distance from a gallon of gasoline. Similarly, with your compressed air system, you want to get the most for your pneumatic equipment. An EXAIR Super Air Amplifier has a 25:1 amplification ratio.; so, in other words, you can get 25 mpg. If you use drilled pipes, open fittings, copper tubes, etc. for blowing, then you are only getting 2 to 5 mpg. If you want to get the most “distance” from your compressed air system, you should check the “gas mileage” of your blow-off components. If you need assistance, an Application Engineer at EXAIR can help you to “tune up” your compressed air system.
“You can’t manage what you don’t measure” is a well-known axiom in engineering & process improvement circles. We talk to callers every day who are keen on conserving compressed air use in their facilities by making a few tweaks, considering a complete overhaul, or more often, some point in between. Bottom line (literally) is, compressed air isn’t cheap, so small gains in efficiency can add up. And large gains can be complete game-changers…following our Six Steps To Optimizing Your Compressed Air System has resulted in users being able to shut down 50 and 100 HP air compressors, saving thousands of dollar A MONTH in operating costs.
Step #1 is measurement, and that’s where the EXAIR Digital Flowmeter comes in. They’re easy to install, highly accurate, extremely reliable, and available for just about any size pipe used for compressed air distribution. They can output a 4-20mA signal straight from their PCB board, or serial comms (RS485) through an optional control board. USB Data Loggers and Summing Remote Displays have proven to be value-added accessories for data management as well.
Summing Remote Display (left) for remote indication and totalizing data. USB Data Logger takes data from the Digital Flowmeter to your computer and outputs to its own software (shown above) or Microsoft Excel.
If you want to go wireless, we can do that too: using ZigBee mesh network protocol, a radio module is installed in the Digital Flowmeter with wireless gateway to transmit data to an Ethernet connected gateway. The transmitting range is 100 ft (30 meters,) and the data can be passed from one radio module to another, allowing for multiple Digital Flowmeter installations to extend the distance over which they can communicate with the computer you’re using for central monitoring. Advantages include:
