Where Can’t I Use An EXAIR Super Air Knife?

Considering the material options available, there are very few places you CAN’T use a Super Air Knife. Most often, we find those to be due to extreme elevated temperature, like this one:

A caller from a glass manufacturing company wanted to replace a drilled pipe in a cooling application. Thing is, glass makers deal with their product in molten form, which is HOT…the ambient temperature that this drilled pipe is exposed to reaches 800°C, or 1,472°F.  Because of the temperature, and corrosive atmospheric elements (SO2 is also present, as if the heat wasn’t bad enough,) they have to replace the drilled pipe every so often, and wanted to explore other solutions.

Now, this was a rare case where a Super Air Knife would not have necessarily offered an improvement over a drilled pipe:

  • The air flow from the drilled pipe is primarily straight from their compressed air system.  Since the Super Air Knife entrains air from the surrounding environment at a rate of 40:1, the resultant flow would be very close to the 800°C ambient temperature…and not as effective at cooling as the much cooler compressed air supply temperature.  It wouldn’t have helped to reduce consumption if it simply didn’t work.
The Super Air Knife takes a supply of compressed air (1), discharges it through a gap that runs the length of the Air Knife (2,) and entrains an enormous amount of “free” air from the surrounding environment (3.)
  • Another great thing about the Super Air Knife is that it’s dramatically quieter than any other method of compressed air blowing.  Of course, if you find yourself in a 800°C sulfur dioxide environment, hearing protection is the least of your concerns.

    When supplied at 80psig, the EXAIR Super Air Knife produces a hard hitting, powerful curtain of air, with a sound level of only 69dBA.
  • EXAIR Super Air Knives (and all of our Intelligent Compressed Air Products) are compliant with OSHA Standard 1910.242(b) which limits the outlet pressure of a compressed air blowing device used for cleaning to 30psi…this protects personnel from high velocity debris and air embolisms.  Again, not a concern in an unoccupied (and uninhabitable) space.

Again, that’s a rare case…a very specific exception to a broadly inclusive rule, in light of the options EXAIR offers.  Consider:

  • Aluminum Super Air Knives are durable, lightweight, and suitable for most any installation in a typical industrial/commercial environment.  They’re good to 180°F (82°C) and are fitted with stainless steel fasteners to eliminate corrosion in damp environments.  The polyester shim can be replaced with a custom stainless steel shim, increasing the temperature rating to 400°F (204°C) if needed.
  • Type 303 Stainless Steel Super Air Knives offer higher tensile strength, and are good to 800°F (427°C.)  They are popular in applications with factors like high heat, corrosive environments, frequent spray down cleaning, outdoor installations, etc.
  • Type 316 Stainless Steel Super Air Knives are often specified in food and pharmaceutical applications, due to their even higher resistance to chemical attack and pitting.  They’re also rated to 800°F (427°C) and have the same high tensile strength as the Type 303 Stainless Steel models.
  • Some situations call for better corrosion resistance than these high grades of austenitic stainless steels – and that’s where EXAIR’s PVDF Super Air Knife comes in.  Fitted with PTFE shims and Hastelloy© C-276 hardware, they are especially well suited for processes involving the harshest of corrosive agents, such as electroplating, solar cell manufacturing, and lithium ion battery production, just to mention a few.  They would, in fact, be ideal for the SOenvironment at the glass factory, if it weren’t for the temperature…they’re rated to 275°F (135°C.)

Performance is identical, regardless of construction materials, and all EXAIR Super Air Knives come in lengths from 3″ to 108″ (except PVDF…those go up to 54″ lengths) and ship quickly from our well maintained inventory.  Aluminum and Stainless Steel models can be coupled together for even longer flow lengths.  Plumbing Kits and Universal Air Knife Mounting Systems make for easy and quick installation, and all Super Air Knife Kits come with an Automatic Drain Filter Separator, a Pressure Regulator, and a Shim Set for reliability, clean air flow, and total performance control.

If you need a reliable, cost effective, safe, quiet, and efficient curtain of air, EXAIR’s Super Air Knives are what you’re looking for.  If you’d like to discuss a particular application and/or product selection, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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What’s In My Air, And Why Is It Important?

Everyone knows there’s oxygen in our air – if there wasn’t oxygen in the air you’re breathing right now, reading this blog would be the least of your concerns. Most people know that oxygen, in fact, makes up about 20% of the earth’s atmosphere at sea level, and that almost all the rest is nitrogen. There’s an impressive list of other gases in the air we breathe, but what’s more impressive (to me, anyway) is the technology behind the instrumentation needed to measure some of these values:

Reference: CRC Handbook of Chemistry and Physics, edited by David R. Lide, 1997.

We can consider, for practical purposes, that air is made up of five gases: nitrogen, oxygen, argon, carbon dioxide, and water vapor (more on that in a minute.)  The other gases are so low in concentration that there is over 10 times as much carbon dioxide as all the others below it, combined.

About the water vapor: because it’s a variable, this table omits it, water vapor generally makes up 1-3% of atmospheric air, by volume, and can be as high as 5%.  Which means that, even on a ‘dry’ day, it pushes argon out of the #3 slot.

There are numerous reasons why the volumetric concentrations of these gases are important.  If oxygen level drops in the air we’re breathing, human activity is impaired.  Exhaustion without physical exertion will occur at 12-15%.  Your lips turn blue at 10%.  Exposure to oxygen levels of 8% or below are fatal within minutes.

Likewise, too much of other gases can be bad.  Carbon monoxide, for example, is a lethal poison.  It’ll kill you at concentrations as low as 0.04%…about the normal amount of carbon dioxide in the atmosphere.

For the purposes of this blog, and how the makeup of our air is important to the function of EXAIR Intelligent Compressed Air Products, we’re going to stick with the top three: nitrogen, oxygen, and water vapor.

Any of our products are capable of discharging a fluid, but they’re specifically designed for use with compressed air – in basic grade school science terms, they convert the potential energy of air under compression into kinetic energy in such a way as to entrain a large amount of air from the surrounding environment.  This is important to consider for a couple of reasons:

  • Anything that’s in your compressed air supply is going to get on the part you’re blowing off with that Super Air Nozzle, the material you’re conveying with that Line Vac, or the electronics you’re cooling with that Cabinet Cooler System.  That includes water…which can condense from the water vapor at several points along the way from your compressor’s intake, through its filtration and drying systems, to the discharge from the product itself.
  • Sometimes, a user is interested in blowing a purge gas (commonly nitrogen or argon) –  but unless it’s in a isolated environment (like a closed chamber) purged with the same gas, most of the developed flow will simply be room air.

Another consideration of air make up involves EXAIR Gen4 Static Eliminators.  They work on the Corona discharge principle: a high voltage is applied to a sharp point, and any gas in the vicinity of that point is subject to ionization – loss or gain of electrons in their molecules’ outer valences, resulting in a charged particle.  The charge is positive if they lose an electron, and negative if they gain one.  Of the two gases that make up almost all of our air, oxygen has the lowest ionization energy in its outer valence, making it the easier of the two to ionize.  You can certainly supply a Gen4 Static Eliminator with pure nitrogen if you wish, but the static dissipation rate may be hampered to a finite (although probably very small) degree.

At EXAIR Corporation, we want to be the ones you think of when you think of compressed air.  If you’ve got questions about it, give us a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Air photo courtesy of Bruno Creative Commons License

Great Stuff About Jets

There are a number of fascinating facts about jets…both the aircraft engines and the EXAIR Intelligent Compressed Air Products:

  • Because they don’t require dense air to engage spinning blades (like their propeller driven counterparts,) they can operate at much higher altitudes. (Jet aircraft engines only)
  • They provide a high thrust, directed airstream, which makes them great for part ejection, chip removal, and part drying. (EXAIR Air Jets only)
  • With few or no moving parts, they are extremely reliable, durable, and safe. (Both jet aircraft engines and EXAIR Air Jets)
  • They use the Coanda effect (a principle of fluidics whereby a fluid flow tends to attach itself to a nearby surface, and follow that surface regardless of the flow’s initial direction) to do what they do.
    • EXAIR Air Jets use this principle to generate a vacuum in their throat, pulling in a large amount of “free” air from the surround environment, making their use of compressed air very, very efficient.
    • Jet (and propeller driven) aircraft wings employ the Coanda effect to create aerodynamic lift, enabling the plane to fly.

Now, since I’m not a pilot, nor do I particularly like to fly, but I AM a fluid dynamics nerd, the rest of this blog will be about the Air Jets that EXAIR makes.

All of our Air Jet products operate on the same principle…using the Coanda effect (as described above) to generate a high volume air flow while minimizing compressed air consumption:

(1) Compressed air enters and is distributed through an annular ring, and directed towards the discharge via the Coanda effect.
(2) This causes entrainment of surrounding air, both through the throat, and at the discharge.
(3) The total developed flow has tremendous force and velocity, for a minimal consumption of valuable compressed air.(1) Compressed air enters and is distributed through an annular ring, and directed towards the discharge via the Coanda effect.
(2) This causes entrainment of surrounding air, both through the throat, and at the discharge.
(3) The total developed flow has tremendous force and velocity, for a minimal consumption of valuable compressed air.

There are four distinct models of the EXAIR Air Jet:

  • Model 6013 High Velocity Air Jet is made of brass for economy and durability.  The annular ring gap (see 1, above) is fixed by a 0.015″ thick shim.  Performance can be modified by changing to a 0.006″ or 0.009″ thick shim, which come in the Model 6313 Shim Set.
  • Model 6013SS is a Type 303 Stainless Steel version, for higher temperatures – good to 400°F (204°C) – and superior corrosion resistance.
  • Model 6019 Adjustable Air Jet is brass construction, and dimensionally identical to the Model 6103.  Instead of a shim that sets the annular ring gap, though, it has a threaded plug, with a micrometer-style indicator, to “fine tune” the gap.
  • Model 6019SS is the Type 303 Stainless Steel version…fine tuning adjustability, good for high heat and/or corrosive elements.
Four distinct models to meet the needs of your air blowing application.

If you’d like to find out more about EXAIR’s quiet, efficient, and safe Air Jets, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Super Air Knives Provide Dry Surface for Printing

I’ve always liked Halloween.  My friends and I got to go trick-or-treating together around the neighborhood, under the supervision of a parent or two, until one year when we were deemed old enough to go around the immediate neighborhood (gasp) by OURSELVES!!!

You need to know that, for any of our Moms, that was a HUGE investment in trust they were putting in us. One that, I’m afraid was undeserved. See, we’d all heard rumors of “tricks” from some cool older kids, and were eager to try our hands at it. Now, we were a relatively mild mannered bunch. We certainly weren’t going to break anything or hurt anyone. But the tales of soaping windows had an irresistible appeal…so, after we donned our costumes that evening, we all sneaked a bar of hand soap out of the house, and set about on our great adventure. Which was not so great, for a couple of reasons:

First, Halloween that year fell on a particularly drizzly night.  We weren’t in danger of a rain-out, but there was a layer of “wet” on everything…especially the windows on which we planned to display our art. That didn’t stop us from trying, though…it just wasn’t near as effective, or fun, as we’d hoped.  Basically, we got some weak smudges here and there.

Second, our parents & neighbors were a lot more savvy than we’d expected. I’m not even sure what happened first…the discovery of the missing bars of soap, or the neighbors calling our parents to tell them what we were up to. We were all punished according to our respective families’ customs, and the next year, we were the oldest trick-or-treaters out there under adult supervision.

I think about that night whenever I see one of those “World’s Dumbest Criminals” shows, but it popped into my head recently while discussing a Super Air Knife application with a customer.  The caller worked in facility that produced pizza dough, and had recently implemented a quality tracking system that applied a temporary code to the rims of the plastic trays that carried the loaves of dough along a conveyor.   Thing is, the trays could still be wet from the wash/rinse cycle, and the ink (which is water soluble and is supposed to be removed by the washer anyway) really, really needs a pretty dry surface, or it’s just going to be a weak, smudgy mess, much like the great Window Soap Fail of 1970-something.

They purchased two Model 110003SS 3″ Stainless Steel Super Air Knives and installed one on each side of the conveyor, just after the rinse tunnel.  The Super Air Knives blow off the rims of the trays, leaving a clean, dry surface for the printer.

EXAIR Super Air Knives come in a wide variety of lengths to suit a wide range of applications.

EXAIR Super Air Knives come in a variety of materials, lengths from 3 inches to 9 feet, and are the quietest & most efficient compressed air operated blow off products on the market today.  If you’d like to find out more about they can help you, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Is It Safe To Use Compressed Air?

Think about it…compressed air is, by definition, gas under pressure: potential (stored) energy.  This energy is intended to do work, like operation of pneumatic tools, actuation of pneumatic cylinders, debris removal with an air gun or blow off device, and (even though I haven’t done it in a while) my personal favorite:

High pressure compressed air is meticulously made, prepared, and stored to ensure the number of surfaces equals the number of dives.

Uncontrolled, unplanned, or accidental releases of stored energy (regardless of the source) are inherently dangerous, and great care must be taken to guard against such incidents.  This is accomplished, primarily, in three areas:

*Operation.  This might be the most prevalent, because it involves the greatest number of personnel (e.g., everyone) as well as the ways compressed air is used (e.g., all of them.)  It’s also the area where the most involved people (the operators) have the most control:

  • Personal protection.  Don’t even think about operating a compressed air device without eye protection.  Ever.  Hard stop.  Also, if the operation involves flying debris, a full face shield, long sleeves, gloves, etc. might be called for.  Hearing protection may be required as well…keep in mind, even if an engineered device (like any of EXAIR’s Intelligent Compressed Air Products) generates a relatively low sound level, the impingement noise of the air flow hitting the object can reach dangerous levels.
  •  Personnel cleaning is prohibited.  The risk of injury to the eyes, respiratory system, and other parts is just too great to rely on personal protective equipment that’s designed for use while discharging compressed air AWAY from the body.  While this is expressly prohibited in certain situations, OSHA has long recognized it as good practice for all industries.
  • No horseplay.  ’nuff said.  Plenty of better ways to have fun at work.

*Design.  This one usually has the advantage of being traceable to a small number of people, and is also the one that’s most likely to be documented.  This is where it starts…if the system is designed to fail, it doesn’t matter how much care the operators take:

  • Supply lines, fittings, and hoses must be rated for use with compressed air, up to and exceeding the maximum discharge pressure of the air compressor.
  • This goes for any tools, blow off devices, components, etc., serviced by the air system.  The only thing worse than a component failing is a component failing in your hand.
  • Shut off valves should be located as close as practical to point(s) of operation.  This allows you to quickly secure the flow of compressed air to a failed component, hose, etc., and prevent further damage or risk of injury.
  • Hoses shouldn’t be run across the floor, where they can become a trip hazard or subject to damage from stepping on them.   This is a surefire way to find out the value of shut off valves (see above.)

*Product specification.  Or, more simply put, using the right tool for the job.  A broader discussion could include efficiency and performance, but we’ll stay within the confines of safety for the purposes of this blog:

  • Be mindful of dead end pressure.  Blow off devices, especially hand held ones like air guns, are oftentimes fitted with a simple open-end discharge.  If this is pushed into a part of the body, the pressurized air can break the skin and cause an air embolism.  This is a serious injury, and can be fatal if it reaches the heart, lungs, or brain.
    • This is a key consideration to OSHA Standard 1910.242(b), which limits the downstream pressure when compressed air is used for cleaning to 30psi.
    • EXAIR products are compliant with this Standard by design…there’s always a relief path for the air pressure; they can’t be dead ended.
Because the compressed air exits through a series of holes, recessed between a ring of fins, any attempt to block the air flow will simply send it in another direction.
  • Harmful sound levels are a consideration as well.  As stated above, hearing protection is required in many cases, but sound levels can be mitigated through the use of engineered products.  EXAIR Intelligent Compressed Air Products, as a result of their high entrainment, generate a boundary layer of air flow that leads to dramatically lower sound levels than a similar-sized open end blow off device.

If you’d like to explore ways to make your compressed air system safer, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Standards, Compliance, And You. And EXAIR.

I’m pretty impressed with the number of safety features my car has. Aside from the literal lifesaving functions like seat belts and air bags, it’s got anti-lock brakes…if you’ve ever had to counter-steer out of a skid on an icy road, you will appreciate the value of this for sure.  Those are just some of the ones I’m keenly aware of – the Federal Motor Vehicle Safety Standards comprise dozens of regulations in three categories: crash avoidance, crashworthiness, and post-crash survivability.  None of these prevent me from operating my vehicle at an unsafe rate of speed…an expensive reality that an Ohio State Highway Patrolman dutifully reminded me of last Sunday afternoon.

Likewise, there are many regulations to ensure safety and prevent hazards of all kinds in industry, administered by a host of agencies that are either subordinates of, or accountable to, the federal government.  When you manufacture products that are used with high energy sources (compressed air or high voltage electricity,) a strong commitment to safety is not negotiable.  So, at EXAIR, we commit considerable resources towards the best engineering and manufacturing practices to make our products as safe as possible.  That includes compliance with a number of standards and certifications:

The Occupational Safety and Health Administration (OSHA) is an agency of the U.S. Department of Labor.  Their mission is to “assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance.”  They are a regulatory body in the truest sense, in that they don’t offer certification or approval of products, processes, etc.; they publish guidelines and standards for manufacturers and users to comply with.  OSHA Standard 1910.242(b), for instance, limits the downstream pressure of a compressed air operated device used for cleaning purposes to 30psi. Now, you can regulate the supply pressure to meet this, but that also limits the effectiveness of the air flow generated.  EXAIR Intelligent Compressed Air Products are all designed and manufactured to be in compliance with this standard, at any supply pressure.  Take, for example, our Super Air Nozzles:

Because none of our products can be dead-ended, there’s always a relief path preventing the downstream pressure from exceeding that level.

OSHA also has Standard 1910.95(a), that sets limits for maximum allowable noise exposure.  All EXAIR Intelligent Compressed Air Products, with the exception of some our largest and most power Super Air Nozzles (which aren’t normally used in areas that don’t already require hearing protection anyway) meet the 8-hour exposure limits of this standard.

Hearing loss is the best known, but not the only, ill effect of harmful noise exposure. It can also cause physical and psychological stress, impair concentration, and contribute to workplace accidents or injuries.

CE marking indicates conformity with health, safety, and environmental protection standards for products sold withing the European Economic Area.  Unlike OSHA standards, responsibility for CE marking falls solely with the seller of the product – a CE marked product has been tested and certified to have been made in such a way to meet safety & quality benchmarks specified for that type of product.  All EXAIR products that are defined under applicable directives have been tested according to these standards, and carry the CE mark.

The Restriction of Hazardous Substances Directive, or RoHS, is another standard borne from the European Union, and is geared towards public & workplace safety by restricting the use of hazardous materials in the manufacture of electronic & electrical equipment.  Since its inception in 2006, similar standards have been vigorously adopted around the globe.  Electrical portions of EXAIR’s Static Eliminators, EFC Electronic Flow Controls, ETC Electronic Temperature Controls, Digital Flowmeters, Solenoid Valves, and Thermostats all comply with the RoHS Directive.

Section 1502 of the Dodd-Frank Wall Street Reform and Consumer Protection Act doesn’t address a concern for product users, but rather a particularly troubling human rights issue – Conflict Minerals.  For almost two decades, trade in tin, tantalum, tungsten and gold in the Democratic Republic of the Congo (DRC) has been used by some very bad people to finance violent campaigns against their neighbors.  EXAIR thoroughly and systematically documents our supply chain compliance with this act.  We are proudly committed to our support for this effort to the world a better place for everyone…especially those in desperate circumstances beyond their control.

EXAIR Intelligent Compressed Air Products have been successfully implemented into a variety of uses where application- or industry-specific standards are in force.  We’re happy to work with you to determine if our products meet those standards…or can be made to meet them.  If you’ve got such an application, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Heat Transfer – 3 Types

When you have two objects and they are of different temperatures, we know from experience that the hotter object will warm up the cooler one, or conversely, the colder object will cool down the hotter one.  We see this everyday, such as ice cooling a drink, or a fan cooling a person on a hot day.

The Second Law of Thermodynamics says that heat (energy) transfers from an object of a higher temperature to an object of a lower temperature. The higher temperature object has atoms with higher energy levels and they will move toward the lower energy atoms in order to establish an equilibrium. This movement of heat and energy is called heat transfer. There are three common types of heat transfer.13580963114_f222b3cdd9_z

Heat Transfer by Conduction

When two materials are in direct contact, heat transfers by means of conduction. The atoms of higher energy vibrate against the adjacent atoms of lower energy, which transfers energy to the lower energy atoms, cooling the hotter object and warming the cooler object. Fluids and gases are less heat conductive than solids (metals are the best heat conductors) because there are larger distances between atoms.  Solids have atoms that are closer together.

Heat Transfer by Convection

Convection describes heat transfer between a surface and a liquid or gas in motion. The faster the fluid or gas travels, the more convective heat transfer that occurs. There are two types of convection:  natural convection and forced convection. In natural convection, the motion of the fluid results from the hot atoms in the fluid moving upwards and the cooler atoms in the air flowing down to replace it, with the fluid moving under the influence of gravity. Example, a radiator puts out warm air from the top, drawing in cool air through the bottom. In forced convection, the fluid, air or a liquid, is forced to travel over the surface by a fan or pump or some other external source. Larger amounts of heat transfer are possible utilizing forced convection.

Heat Transfer by Radiation

Radiation refers to the transfer of heat through empty space. This form of heat transfer does not require a material or even air to be between the two objects; radiation heat transfer works inside of and through a vacuum, such as space. Example, the radiation energy from the sun travels through the great distance through the vacuum of space until the transfer of heat warms the Earth.

EXAIR‘s engineered compressed air products are used every day to force air over hot surfaces to cool, as well as dry and/or blow off hot materials. Let us help you to understand and solve your heat transfer situations.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can improve your process, feel free to contact EXAIR, myself, or one of our other Application Engineers. We can help you determine the best solution!

Brian Bergmann
Application Engineer

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The picture “Energy Transfer – Heat” by Siyavula Education is licensed under CC BY 2.0