There are a great many applications that require a spray (as opposed to a stream) of liquid. Certain droplet sizes, and flow rates, are beneficial for certain applications. For example, if you’re fighting a fire, you want as high of a flow rate as possible – the more water you douse the fire with, the quicker it goes out. You also want a fairly large droplet size, since a mist would tend to evaporate instead of extinguishing the flames.
Pressure washers also benefit from higher (though not near as high as fire hose) flow rates, and droplet sizes. You want an appreciable flow rate, because that means high velocity, and good sized droplets combine that velocity with their relative mass to “blast” away dirt and detritus from the surface.
Medicine delivery devices, like asthma inhalers, are designed to produce mid-sized droplets, but pretty low (and controlled) flows. The droplets need to be small enough to efficiently spread the medicine through the breathing passages, but large enough to where they won’t evaporate before they ‘plant’ on the nasal & bronchial membranes to get absorbed.
These are examples of “liquid-only” nozzles…no other media or means of force are used to effect the spraying action. Most of the time, the droplet sizes in these applications are measured in hundreds of microns, which “liquid-only” nozzles are ideally suited to generate. Other applications, however, call for much smaller droplet sizes…such as those only attainable through atomization.
Small droplet size is key to cost effectiveness in many applications:
Think about expensive coatings…the smaller the droplet size, the better and more even the coverage, and the less you have to spray (and pay) out.
Or humidification…smaller droplet size means more stays airborne, for longer, and in a larger space.
Petroleum based lubricants, by their nature, only require a thin layer for best results. Smaller droplets make as even and thin of a layer as possible.
Dust control is much more effective with smaller droplet sizes, since the longer the mist lingers in the air, the more dust particles the individual droplets will adhere to…and then drop with them to the surface. This also prevents getting the surface of the material any wetter than it has to be.
If you’d like to discuss a liquid spraying application, I’d love to hear from you. Call me.
Russ Bowman Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
Adjustability is a key feature for a great many devices:
An adjustable wrench – or as I like to call it, the trusty “all 16ths” – is my go-to for work around the house involving anything with a hex…fittings under the sink when I’m cleaning out a drain, nuts & bolts on furniture or household items needing some tightening (or loosening,) etc. I don’t get out my combination-end wrenches for much except automobile maintenance.
Speaking of sinks, my kitchen faucet lets me adjust water flow (and temperature) which is important because I use different flow rates (and temperatures) if I’m getting a tablespoon of water, or if I’m rinsing my hands, or if I’m filling the sink to do dishes.
Speaking of tablespoons, I’ve even got an adjustable measuring spoon that lets me get a full tablespoon, a half a teaspoon, or anywhere in between, by moving a lever block back & forth in the spoon head.
Adjustability is a key feature for several EXAIR Intelligent Compressed Air Products too…like our Adjustable Air Amplifiers. The ‘adjustable’ part has to do with setting the air flow:
You can get an amazing range of flow from a little twist*:
A gap of about 0.010″ is about the max for 80psig supply pressure. Above that, the air flow overwhelms the Coanda profile, creating a turbulent ‘storm’ in the throat, hampering the efficiency and effectiveness. The proper “adjustment” for that is to select the next larger Air Amplifier!
While the range of air flow is certainly impressive, their versatility is another major factor in their selection. I reviewed our Application Database (registration required) for real-life details on Adjustable Air Amplifiers “in the field” and found a litany of other benefits that made them better suited to particular installations than a Super Air Amplifier:
A customer who builds automated equipment incorporates the Model 6031 1-1/4″ SS Adjustable Air Amplifier to blow open bags with a puff of air as they move into position on an automated filling machine. They use it because it’s available in stainless steel construction, and it’s still compact & lightweight.
A mattress manufacturer uses Model 6043 3″ Aluminum Adjustable Air Amplifiers to cool mattress springs. They’re lightweight, the perfect size to match the springs’ profile, and they can “dial them out” for high heat removal before putting springs on a rubber conveyor.
A tier 1 automotive supplier has Model 6234 4″ SS Adjustable Air Amplifier Kits installed on their robotic paint line to blow off moisture from parts to prevent water spotting between the wash cycle and the oven. They use them because the stainless steel construction holds up to high heat due to the proximity to the ovens.
A food plant uses Model 6031 1-1/4″ SS Adjustable Air Amplifiers to improve the drying time of 3,000 liter mixers that must be washed between batches of different products. The stainless steel construction holds up to the rigors of the frequent washdown in this area.
A bedding manufacturer replaced a regenerative blower with a Model 6041 1-1/4″ Aluminum Adjustable Air Amplifier for trim removal on stitched fabric at bedding manufacturer. The blower was prone to failure from lint & dust; the Air Amplifier, with no moving parts, is not. It’s also compact, lightweight, and virtually maintenance free.
A light bulb manufacturer installed Model 6030 3/4″ SS Adjustable Air Amplifiers on the ends of open pipes that were used to cool mercury lamp wicks. This reduced noise levels significantly while providing the same cooling rate, and the stainless steel construction holds up to the heat of the operation.
Because of the simplicity of their design, Adjustable Air Amplifiers are also extremely adaptable to custom applications. We’ve added threads or flanges to the inlets and outlets of several different sizes, to accommodate ease of mounting & installation:
Adjustable Air Amplifiers are available in both aluminum and 303SS construction, to meet most any environmental requirements…except extreme high heat. In those cases, the Model 121021 High Temperature Air Amplifier is rated to 700°F (374°C) – significantly higher than the Aluminum – 275°F (135°C) or the Stainless Steel – 400°F (204°C). They’re commonly used to circulate hot air inside furnaces, ovens, refractories, etc.
Adjustability. Versatility. Durability. If you’d like to know more about the Adjustable Air Amplifier, or any of EXAIR’s Intelligent Compressed Air Products, give me a call.
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For me, one of the first signs that winter is here takes place at the grocery store. I’ll stop on the way home to pick up a thing or two, and proceed to the automated self-scan…not because I don’t like people, but because they’re the closest to the exit and, while I DO actually like a LOT of people, I REALLY like dinner. Anyway, the drop in humidity that comes with colder temperatures outside leads to what the buried-wire pet containment folks call a “mild correction” when I touch the self-scan terminal.
I won’t rehash my disdain of cold weather (like I did here, here, here, or here) and while those nuisance static shocks aren’t at the top of the list of reasons why, they actually can be quite severe in other cases. For example, the minor jolt you get from touching a grounded terminal after pushing a rubber-wheeled shopping cart over the vinyl-tiled floor of the produce aisle isn’t near as bad as the shock that a plastic extrusion machine operator gets when he touches a conveyor duct carrying hundreds of pounds of plastic pellets per hour.
Why one is so much worse than the other? To fully understand the answer to that question, we’ll need to better understand how static charge is generated. Scientists have been studying the phenomenon since at least the 17th Century, and studies continue to this day of its creation (mainly at universities) and control (right here at EXAIR Corporation.) Simply put, when two solid surfaces touch each other, the contact can result in electrons in the outer valences of atoms on one surface to “jump ship” and end up in the outer valences of atoms on the other surface.
It’s called the triboelectric effect. The prefix “tribo” comes from the Greek word “to rub,” and while many common demonstrations of static charge involve rubbing…for example, rubbing a balloon on a wool sweater sleeve and ‘sticking’ it to the wall…mere contact is all it takes – and that’s where we’ll start:
Separation of material – lifting the top sheet from a stack, peeling off a protective layer, or unrolling plastic film, for example – can also cause those weaker-held electrons to leave one surface for another.
Some processes involve surface contact, and separation. And more contact, and separation. And oftentimes, one surface is in relative motion with the other…and that’s what REALLY puts the “tribo” (“to rub,” remember?) in “triboelectric effect.
I once worked in an equipment repair shop with a small and simple compressed air system…just a 5HP single acting piston compressor that sat atop a 50 gallon tank, in the corner by “The Big Truck”. The majority of our work was field service, and management was big on maintaining our service trucks, so we checked tire pressures every Monday morning as we rolled out, and kept a tire chuck handy to ensure proper inflation. It was also used to supply a couple of air guns that were used at our drill press and soldering/assembly station. One morning, I noticed the air compressor was running when I arrived…I thought it was odd, because I knew for a fact it hadn’t been used in at least 16 hours, but that compressed air went someplace, right? We had a leak. Well, at least one.
This was mid-December, and the week between Christmas and New Year’s Day was characteristically slow, and typically devoted to a thorough shop cleaning. We also took the opportunity to get some bottles of soapy water and check for leaks at the handful of pipe fittings that comprised the system…for the uninitiated, if you have a leaky fitting, the escaping air blows bubbles in the soapy water (a cheap, messy way in other words). We found some bubbling, undid those fittings, cleaned them, and applied fresh pipe thread sealant (I don’t want to start any arguments, but I was taught that tape is more of a thread protectant than an effective sealing agent) and, in addition to replacing a couple of well-worn hoses, we were up and running. And we never heard the compressor running first thing in the morning again.
Not all compressed air systems are as simple as that, though. Many go from a room with several large & sophisticated air compressors, to corners of every building on the grounds. Through valves & manifolds, to cylinders, machinery and blow offs, with more connections than you could soap-and-water check in a month.
In those cases, the EXAIR Model 9061 Ultrasonic Leak Detector makes short(er) work of finding the leaks. With both visual (LED’s on the face) and audible (headphones) indications, even very small leaks are easy to detect with the parabola installed. The precise location can then be found with the tubular extension.
You’ll still have to fix the leaks yourself, but finding them is oftentimes more than half the battle. And, once fixed, it can be worth a million (cubic feet of compressed air, that is.)
EXAIR’s Ultrasonic Leak Detectors are not only useful for finding compressed air leaks; they’re popular in a variety of other areas:
Additionally, they can be used to identify faulty bearings, brake systems, tire & tube leaks, engine seals, radiators, electrical relay arcing…anything that generates an ultrasonic sound wave. If you’d like to find out more, give me a call.
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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.
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.
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.
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.
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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:
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.
The word “accessory” can come with some baggage… it’s become synonymous with “add-on” and “up-sell,” and cost-mindful consumers may see them as just another way for a slick salesperson to make an extra buck. And frankly, they wouldn’t have that reputation if there wasn’t some truth to it. The server at your favorite restaurant will offer appetizers, or recommend side dishes to go with your entree. If you go to buy a new car, you’ll get a pitch for a variety of aftermarket add-ons. The paint counter folks at the hardware store always tell me what specific brush and/or rollers I should use with the paint I’m buying…and it’s never the 10-pack of economy brushes that costs less than the single, premium quality brush they recommend. In all of these cases, these employees are trained, constantly encouraged, and hopefully rewarded on the success of these “up-sell” strategies.
Of course, my boys and I can devour even the largest plate of chili cheese nachos long before the rest of meal comes out. My wife absolutely loves the remote starter function that the dealership installed on the new car she bought last year. And, if you’ve ever painted a well-lit room, you know the difference between a $1 paint brush and a $10 paint brush. So if my server gets a little bigger tip, my car dealer salesperson gets a little more commission, or the paint counter folks get a bonus, then it’s a win-win, as far as I’m concerned.
EXAIR carries a variety of accessories for our Intelligent Compressed Air Products. Some aid in mounting & installation:
Others make it easy to ensure adequate supply conditions:
The performance of many EXAIR Intelligent Compressed Air Products can be altered by replacing the shim:
In addition to these product-specific accessories, EXAIR carries a complete line of:
*Filter Separators to remove water, dirt, and rust from your compressed air system. Our Automatic Drain Filter Separators have a 5 micron particulate element, and a centrifugal vane to remove moisture.
*Oil Removal Filters with coalescing elements that remove any trace of oil, and also provide additional particulate filtration to 0.03 microns.
*Pressure Regulators, so you can “dial in” the performance you need, so you don’t overpower the application, or waste compressed air. They come in sizes from 1/4 NPT to 1-1/4 NPT, and are rated for flows up to 700 SCFM. A pressure gauge provides accurate indication of outlet pressure, and the adjustment cap can be removed to prevent tampering.
*Silencing Mufflers to reduce work area noise from compressed air exhausting from pneumatic cylinders, valves, etc. There are several styles to choose from, depending on your needs:
Sintered Bronze Mufflers are simple in design, with minimal back pressure restriction, and come in sizes from #10-32 thread to 1-1/2 NPT.
Straight-Through Mufflers offer noise reduction up to 20 dB, and come in sizes from 1/4 NPT (up to 22 SCFM) to 3/4 NPT (up to 73 SCFM.)
Heavy Duty Mufflers have an internal stainless steel screen that not only protects the exhausting components from environmental contamination, but also keeps air system contaminants from being ejected at high speed into the work area.
Reclassifying Mufflers are an upgrade to the Sintered Bronze Mufflers and provide the highest level of noise reduction – up to 35 dB. They also trap oil mist, eliminating breathing hazards to personnel.
*12 ft Coiled Hoses (1/4″ or 3/8″ ID) and Compressed Air Hose (3/8″ or 1/2″ ID; up to 50ft lengths) can be provided with any Intelligent Compressed Air Product. We also have a full supply of fittings (tees, elbows, nipples, couplers, reducers, etc.) and adapters to fit our Super Air Nozzles to your existing air guns or blow off devices.
*Receiver Tanks are used to store a ready supply of compressed air. If you have an intermittent demand of sufficient size, it can cause a pressure transient in your system, which can drag down the ability to supply other points of use. Installed near the point of intermittent demand, they prevent pressure & volume fluctuations, keeping the operators at all points of use happy. Model 9500-60 Receiver Tank has a capacity of 60 gallons, is rated to 200psig, and meets ASME pressure vessel code.
In closing, let me offer the following advice that’s served me well over the years:
*Be mindful of the valued added by the accessories & add-ons you’re presented during a purchase of capital equipment…or anything else, really. Don’t buy something you don’t need, but if you need it…well…it’s OK to buy it.
*Don’t skimp on quality. Odds are, if an accessory is offered by the manufacturer of the product, it’s going to work well for you. They should be able to tell you if it will or won’t if you discuss your needs with them. I know I will if you call me to discuss a compressed air product application.
*Get the big plate of nachos, especially if you’re dining with teenagers.
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