A manufacturer of both residential and commercial steel doors used in the construction industry recently contacted me for help with an application in their manufacturing process. They make a wide variety of exterior and interior doors as well as some custom doors that are sold to builders across the country.
The raw material for the doors is formed, assembled, and welded together before it is then taken to a finishing step that involves grinding down the welds and sanding any rough spots on the door down to a smooth finish. This smooth finish creates a clean look and also helps with the application of paint at the end of the process.
After finishing, the doors are hung on an overhead conveyor where they pass through a machine that cleans off all of the surfaces and remain hanging until they dry. This air drying prevented them from continuously operating as they’d have to wait at least 10 minutes until the doors dried before they could apply any paint. In the summer, humid conditions in their plant further increased the time the doors took to air dry.
Rather than waiting to dry, they wanted to blow off any remaining water from both sides of the door just after the washing operation. The solution was to install (2) Model 110048PKI Super Air Knives on either side of the door to blow off residual water as it moved along the conveyor. Since the spacing in between doors was 12’, they didn’t want to have to operate the knives continuously and waste unnecessary compressed air.
With the doors traveling slowly at about 30 ft/min and a significant space in between them, they also went with a Model 9064 Electronic Flow Controller to keep the air on only when necessary. A standard door height is just under 7′. At the speed they were traveling, it would take roughly 14 seconds for each door to pass through the flow of the knives while 24 seconds pass with no door.
With a minimum 10 minute dry time without the Super Air Knives, the overall drying time was reduced to 38 seconds. That’s a 93.6% improvement in the overall time of their drying process! By improving the drying process, they were able to increase their production to 100 doors per 8-hr shift.
(2) 48″ Super Air Knives operating continuously at 80 PSIG would require 278.4 SCFM of compressed air. The average cost of compressed air is $0.25/1000 SCF. So what did this cost when operating continuously with a 38 second blowoff time?
0.633 min x 278.4 SCFM = 176 SCF/door
176 SCF x 100 doors per shift = 17,600 SCF
17600 SCF x ($0.25/ 1000 SCF) = $4.40/ 8 hr shift
Over the course of a year that equates to $1,144 in operating costs. With the EFC implemented, the blowoff time was reduced to just 14 seconds per door.
0.233 min x 278.4 SCFM = 65 SCF/door
65 SCF x 100 doors per shift = 6500 SCF
6500 SCF x ($0.25/1000 SCF) = $1.63/ 8 hr shift
Not only were they able to increase their production rate by implementing the Super Air Knife, but by taking it one step further with the EFC they reduced the overall operating costs for a full year to just $423.80.
If you have a similar application in the construction industry and would like to speak to an Application Engineer please give us a call!
I was recently contacted by an automobile manufacturer that was looking for a quote for a system of Super Air Knives for a current process they were replicating at a new facility. The customer had an existing application where they’re using the Super Air Knife to dry the body of the car after a washing operation and before it enters into an oven. Any large water droplets remaining when the body enters the oven cause water spots that must then be cleaned off, adding an additional step in their process.
The solution was working well to dry the bodies, they just needed a quote so that they could implement the very same process in the new plant. As this was an installation that had been in place for many years, they had an older style of Long Super Air Knife that consisted of two shorter knives coupled together. In 2014, EXAIR began manufacturing our Long Super Air Knives in one single piece (available from stock up to 108”!!).
So, now, rather than having two individually coupled knives they could order (1) single 84” knife with a consistent flow all the way across and no dead spots. They ordered one for the top, one for each side and replicated the already successful application.
EXAIR’s industry leading Super Air Knife dramatically reduces compressed air usage and noise when compared to other blowoff methods. The Super Air Knife is available in lengths ranging from 3”-108” and in Aluminum, 303 Stainless Steel, 316 Stainless Steel, and PVDF for corrosive applications. Even at high pressures of 80 psig, the Super Air Knife is able to maintain a sound level of just 69 dBA for most applications! Air is entrained from the ambient environment at a rate of 40:1, maximizing the force and flow from the Super Air Knife. In addition, these knives meet or exceed OSHA maximum dead-end pressure and noise requirements.
Adjustability of both the force and flow from the Super Air Knife is infinitely adjustable. Right out of the box from the factory the Super Air Knife comes stock with a .002” thick shim installed. This sets the gap between the body and cap of the knife and determines how much compressed air can flow through the precise, slotted orifice.
An accessory that EXAIR has available for the Super Air Knife is the shim set. For the aluminum knives, a .001”, .003”, and .004” plastic shims come in the shim set. To reduce the flow and force, a .001” can be used. If more force is required, a thicker shim can be installed. For the stainless steel and PVDF knives, (3) .002” shims are included in the set. Stainless steel shims for the stainless knives and a PTFE shim for the PVDF. These, as well as the plastic shims, can be stacked on top of one another to create an even larger gap. One thing that is important to keep in mind however, the larger the air gap the greater the air consumption. Installing a .004” shim in a Super Air Knife will double the force, flow, and consumption of the knife when compared to the stock .002” shim.
If you have a new application (or need to replicate an existing one) for the Super Air Knife, don’t hesitate to reach out to an EXAIR Application Engineer for assistance. With a highly-trained team coming from multiple different industry backgrounds, we’re ready to help.
Air entrainment is the phenomenon that occurs when air (or any gas) under pressure is released from a device in such a way that a low pressure is generated in the immediate area of the air (or gas) discharge. Air (or gas) from the surrounding environment is then pulled (or entrained) into the discharged air stream, increasing its volumetric flow rate. EXAIR Corporation has been engineering & manufacturing compressed air products to take maximum advantage of this phenomena since 1983…and we’ve gotten better & better at it over the past 36 years.
Obviously, the first thing that’s so great about air entrainment is…free air flow. Every cubic foot that’s entrained means that’s a cubic foot that your compressor didn’t have to spend energy compressing. Considering the EXAIR Super Air Knife’s entrainment ratio of 40:1, that makes for a VERY efficient use of your compressed air.
Another thing that’s so great about air entrainment is…it’s quiet. As you can see from the graphic at the top of this blog, the Super Air Knife entrains air (the lighter, curved blue arrows) into the primary compressed air stream (the darker, straight blue arrows) from above and below. The outer layers of the total developed flow are lower in velocity, and serve as a sound-attenuating boundary layer. The sound level of a Super Air Knife (any length…here’s why) is only 69dBA. That means if you’re talking with someone and a Super Air Knife is running right next to you, you can still use your “inside voice” and continue your conversation, unaffected by the sound of the air flow.
I always thought it would be helpful to have more than just a graphic with blue arrows to show the effect & magnitude of air entrainment. A while back, I accidentally stumbled across a stunning visual depiction of just that, using a Super Air Knife. I had the pleasure of talking with a caller about how effective a Super Air Knife might be in blowing light gauge paperboard pieces. So I set one up in the EXAIR Demo Room, blowing straight upwards, and tossed paper plates into the air flow. It worked just as expected, until one of the paper plates got a little closer to the Super Air Knife than I had planned:
As you can see, the tremendous amount of air flow being entrained…from both sides…was sufficient to pull in lightweight objects and ‘stick’ them to the surface that the entrained air was being drawn past. While it doesn’t empirically prove the 40:1 ratio, it indisputably demonstrates that an awful lot of air is moving there.
If you’re looking for a quiet, efficient, and OSHA compliant solution for cleaning, blow off, drying, cooling…anything you need an even, consistent curtain of air flow for – look no further than the EXAIR Super Air Knife. If you’d like to discuss a particular application and/or product selection, give me a call.
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In a recent blog “EXAIR Super Air Knives: Overview”, I shared the features and benefits that puts the “Super” in the Super Air Knives. But, let’s not define ourselves by our widest range of lengths and materials that we stock. EXAIR can also customize the Super Air Knives to fit your requirements. Many manufacturers like to make their standard items and expect the customers to adapt to their design. But at EXAIR, customer service is our primary focus.
EXAIR manufactures our products at one location in Cincinnati, Ohio. So, this gives us the flexibility to do many things like making adaptive configurations with our Super Air Knives. Here are some examples that our customers requested.
Special lengths: EXAIR stocks standard incremental lengths from 3” (76mm) up to 108” (2.74 meters) in aluminum, 303SS, and 316SS materials; or 3” (76mm) to 54” (1,372mm) for PDVF Super Air Knives. But sometimes, the Super Air Knife has to fit into a specific area where a standard length will not work. This is where EXAIR exceeds, and we can make any length metric or imperial between the ranges above.
Other materials: There isn’t a single material that is inert to all chemicals. In some rare cases, the environment can chemically attack our Stainless Steel or PVDF Super Air Knives. So, a different material may have to be used. For the customer above, they required a PVC material for a phosphorous environment.
Critical Dimensions: When the Super Air Knives have to adapt inside machines or in tight areas, we can modify the profile. We have two special applications (reference above) that needed a design change for fit and function. A curved Super Air Knife was used to hold tubes on a rotary table; and a thin Super Air Knife that was only 11/16” (17.5mm) thick cleaned a mold for circuit chips.
Add-ons: EXAIR understands the importance of connecting to our Super Air Knives to get the greatest performance. Our stock product has ¼” NPT inlet air ports along the bottom and one at each end. We have ¼” – 20 threaded holes for mounting along the bottom as well. But if you want threaded holes in a specific location for mounting or need the inlet air ports to be metric threads, EXAIR can accommodate these features.
Situational Applications: Super Air Knives can have complex or simple changes depending on the application. As an example, EXAIR created a design for a double-sided Super Air Knife to blow a laminar stream of air 180 degrees apart (reference photo above). A simpler proposal was to replace the cap screws in a 316SS Super Air Knife with hygienic screws for food applications to remove crevices for bacterial growth.
OE Protection: In today’s market, it is important to protect your business. At EXAIR, we can make a special Super Air Knife to blow, dry, or cool in your custom machines. With a unique model number, EXAIR can help support and protect your business for future and replacement business.
Remember, your imagination is the beginning of creation. If you cannot find a specific design to be used in your compressed air application, don’t give up. Contact an Application Engineer at EXAIR to see if we can help you. We have a team of engineers that can evaluate the fit and function to create a “Super” blow-off solution. For the customers above, we were able to propose a unique Super Air Knife to work in their application; not the other way around.
Any time you’re considering a new purchase your return on investment is a critical aspect of the decision-making process. A recent case for me this past year was the purchase of a new riding lawn mower. What used to take me 2-hours to mow my entire yard, now only takes 45 minutes. Mowing 1 time per week throughout the growing season, I was able to save over an hour of my time each week! Considering that I’ll mow the lawn approximately 25 times per year, that’s more than a full day’s worth of time saved over the course of a year.
Some products, however, provide a monetary value due to reduced operating costs. For example, an LED light bulb may cost more initially but will use less energy to operate as well as have a longer lifespan than an incandescent bulb. You can calculate, down to the day, when you’ll recoup the costs difference from buying the more expensive bulb.
The same can be said for EXAIR’s Intelligent Compressed Air Products. An extrusion company had a line where they were using (3) modular-hose style flat nozzles. (1) was placed just before a water bath to remove some of the initial heat, (2) were then placed as the material exited the bath to dry the material after it was cooled. While they did work, they had begun to notice pressure drops in their compressed air system that was causing issues for other processes in the facility.
The (3) nozzles were all operated at 50 PSIG consuming 17 SCFM per nozzle for a total consumption of 51 SCFM. They were operated for one full 8-hour shift, 5 days per week.
51 SCFM x 60 mins x 8-hours = 24,480 SCF/day
Since they had a range of different sizes of material they process with the widest up to 2.5”, we recommended replacing the modular style hose flat nozzles with EXAIR’s 3” Super Air Knife. At a pressure of 50 PSIG, (3) Model 110003 Super Air Knives consumes just 17.1 SCFM.
17.1 SCFM x 60 mins x 8-hours = 8,208 SCF/day
By implementing the Super Air Knife, they reduced their compressed air consumption for this particular application by 66.4%!! But, just how quickly will that air savings provide them with a return on their investment? Let’s calculate the savings:
The average cost for compressed air is $0.25/1000 SCF. Before the installation of the Super Air Knives, the total consumption was 24,480 SCF/day.
24,480 SCF x $0.25/1000 SCF = $6.12/ day
With the Super Air Knives, this was reduced to just 8,208 SCF/ day:
8,208 SCF x $0.25/1000 SCF = $2.05/ day
Total Savings – $4.07 each day!!!
The 2019 list price on the Model 110003 is $206.00. Since they bought (3) their total investment was $618.00.
$618.00/$4.07 = 151.84 (152 days)
On the 152nd day, the customer will have saved enough money from the reduced air consumption to account for the initial purchase price of the Super Air Knives. Once they’re paid for, it isn’t like you just stop saving money. These knives will continue to save money, each shift, day in and day out. If there’s a process in your facility that you can improve upon, give us a call. We’re also able to test it out here at EXAIR and report back to you on the savings through our free Efficiency Lab!
The cheapest and easiest solution isn’t always necessarily the best. The best example I like to use to highlight this is the incandescent light bulb. They’re definitely the cheapest to buy, but over the useful life it will cost more in electricity to operate and it won’t last nearly as long as an LED light bulb. When you compare the costs of electricity as well as the lifespan of an incandescent bulb, it becomes quite clear that the initial price difference between the two will be quickly recouped over the lifetime of the LED bulb. Once it pays for itself, it doesn’t just stop saving you electricity. These savings continue to compound.
The same can be said when comparing the Super Air Knife to a commonly seen homemade alternative, drilled pipe. While it only takes a matter of minutes to drill a few holes into a section of pipe, the operating costs (electricity required to generate the compressed air) are significantly higher than that of the Super Air Knife. In addition, it’s not nearly as effective and is considered unsafe under OSHA 29 CFR 1910.242 (b) and depending on operating pressure is likely also considered dangerous due to the high sound levels as outlined in OSHA 29 CFR 1910.95(a).
Air exiting out of drilled holes in a pipe will create a turbulent airstream. This turbulence not only contributes to the high sound level but it’s ability to entrain surrounding ambient air is minuscule. The air entrainment ratio of a compressed air solution refers to the relationship between supplied compressed air and the free ambient air that is brought into the primary airstream. The higher the amplification ratio, the less compressed air necessary to complete a similar task. For a drilled pipe, the amplification ratio is generally around 3:1. With the Super Air Knife, this is dramatically increased with an amplification ratio of 40:1.
The Super Air Knife has a precisely set air gap across the full length of the knife, allowing for an efficient and quiet laminar airstream. When compared to a drilled pipe, the air consumption is dramatically reduced as is the sound level. For example, let’s take an 18” section of drilled pipe, with 1/16” diameter holes spaced out every ½”. At 80 PSIG, each hole consumes 3.8 SCFM. With a total of 37 holes, this equates to a total of 140.6 SCFM.
3.8 SCFM x 37 = 140.6 SCFM
A Super Air Knife, operated at 80 PSIG with .002” stock shim installed will consume a total of 2.9 SCFM per inch of knife. An 18” SAK would then consume just 52.2 SCFM.
2.9 SCFM x 18 = 52.2 SCFM
140.6 SCFM – 52.2 SCFM = 88.4 SCFM saved
Replacing an 18” drilled pipe with a Super Air Knife represents a total reduction in compressed air consumption of 63%! How much does this equate to in $$$? A reasonable average of cost to generate compressed air is about $0.25/ 1000 SCF. Let’s assume just a 40hr workweek:
88.4 SCFM x 60 mins x $0.25/1000 SCF = $1.33/hr
$1.33 x 40hr workweek = $53.20 USD
$53.20 x 52 weeks/year = $2,766.40 USD in yearly savings
The 2019 list price on a Model 110018 Super Air Knife is $397.00. By replacing the homemade solution with an 18” Super Air Knife, the return on investment is just over 38 working days of an 8-hr shift. If your plant runs multiple shifts, or works on weekends, it pays for itself even quicker.
Once the knife has paid for itself, it doesn’t just simply stop saving you money. That savings continues to compound and add to your bottom line. Don’t waste unnecessary air (and money) by using solutions that aren’t engineered to do the job in a safe and efficient manner. Reach out to an Application Engineer and get yourself an Intelligent Compressed Air Product that’s Built to Last.
EXAIR has been manufacturing Intelligent Compressed Air® products since 1983. In the beginning, the Standard Air Knives and Full Flow Air Knives were very effective at that time. But as leaders in this market, EXAIR did not want to stop there. We were able to engineer a more efficient, more powerful, and much safer air knife, the Super Air Knife. In this blog, I will discuss the features and benefits that the Super Air Knives can offer.
Bernoulli’s principle explains how a high velocity fluid can generate a low pressure. The EXAIR Super Air Knife creates a high velocity air stream to produce a low pressure to entrain ambient air. What does this mean for you? It will save you much money by using less compressed air. The mass of the ambient air is added into the air stream to give a strong blowing force. The Super Air Knife has an amplification ratio of 40:1. For every 1 part of compressed air, 40 parts of ambient air is drawn into the blowing air stream. Ambient air is free, and compressed air is expensive. EXAIR was able to engineer a design to use the Bernoulli’s principle to make one of the most efficient air knives in the market place.
What else makes EXAIR unchallenged? We manufacture and stock the widest range in lengths and materials. To start, EXAIR has Super Air Knives ranging from 3” to 108” (76mm to 2,743mm) in three different materials; aluminum, 303 stainless steel, and 316/316L stainless steel. There is no-one else in this industry that can manufacture to those lengths. EXAIR also offers Super Air Knives in PVDF material with Hastelloy hardware for chemical resistant applications from 3” to 54” (76mm to 1,372mm). Depending on the temperature requirement, chemical resistance, OSHA and FDA regulations, or application details, we probably will have one on the shelf for you. If EXAIR does not have it, we can make special air knives in different lengths and materials to best fit your application.
Some interesting features for the Super Air Knives are as follows. They have a compact design that can fit into tight places for blowing and cooling. The footprint is very small compared to blower-air knife system. They do not have any moving parts to wear or maintenance to do. They only need clean compressed air to work. They blow a laminar air stream which reduces noise levels and create a consistent force along the entire length. An even force will give you tighter control for blowing applications which will cut compressed air usage unlike the inconsistent and turbulent air flows caused by drilled pipes.
To adjust the force and air usage, this can be easily controlled with a regulator. The advantage that EXAIR Super Air Knives have is the replaceable shims. So, you can increase or decrease the gap to get a variety of force ratings. The Aluminum version uses colored plastic shims for visual verification. They come stock with a 0.002” (0.05mm) red shim installed. We have other thicknesses in our Shim Sets which includes a 0.001” (0.03mm), 0.003” (0.08mm), and a 0.004” (0.10mm) colored as amber, green, and tan respectively. The Stainless Steel Super Air Knives come with a stainless steel shim for higher temperatures and chemical resistance. Stock units have the 0.002” (0.05mm) thickness as well. The Shim Sets come with three additional 0.002” (0.05mm) shims to stack. Similarly, the PVDF Super Air Knives use a PTFE shim for maximum chemical resistance. It is also 0.002” (0.05mm) thick, and there are three more shims in the Shim Set. This unique feature of using shims allows for the most flexibility in creating forces for different applications ranging from a blast to remove rocks from a conveyor to a breeze for light duty work.
We also offer the Super Air Knives in kits as a more complete system. The kit includes a filter, regulator and the above-mentioned Shim Set. The filter removes the debris and water from the compressed air line to optimize the performance of the air knife as well as keeping your product clean. The regulator is used to make the “fine” adjustment to the blowing force while the shim set is used as the “coarse” adjustment. EXAIR sells this kit as one model number for simple ordering, and the accessories are properly sized to not hinder the performance of the Super Air Knife.
To optimize the system even more, EXAIR offers a Deluxe Kit for the Aluminum and Stainless Steel models. This includes the accessories in the kit above, plus an Electronic Flow Control, or EFC. This exclusive instrument uses a photoelectric eye to start a timing sequence to control a solenoid valve. So, when a part is not in front of the Super Air Knife for cleaning or cooling, the compressed air is turned off. This will save you even more money and maximize your efficiency to only blow air when needed.
For the longer Super Air Knives, EXAIR can install a Plumbing Kit, or PKI, to help attach your compressed air to the Air Knife. They are designed to help lessen the time for install as well as to properly supply compressed air equally along the entire length, specifically for 24” (610mm) and longer. We can offer the Plumbing Kit separately if you find that it could benefit your fabricators during installation. EXAIR also offers a Coupling Kit for the Aluminum and Stainless Steel versions. If you need to extend past the 108” (2,743 mm) width, the Coupling Kit is designed to mount Super Air Knives together at the ends. You will still get that consistent blowing force along the multiple of Air Knives. Another helpful accessory is the Universal Air Knife Mounting System. It has a bracket and an articulated arm that can reach up to 30” (762mm). With this system, you can position your air knife securely and precisely in any orientation. It attaches easily to your Super Air Knife and gives you the flexibility to maximize the blowing effect at your target.
With the today’s cost in making compressed air, it is important to use it as efficiently as possible. The Standard and Full Flow Air Knives would be good options to use. But the best way to conserve is with the Super Air Knife. If you have any questions about the Super Air Knife or if you would like to discuss an application, you can contact an Application Engineer at EXAIR. We will be glad to help you.