Using EXAIRSUniversal Air Knife Mounting System greatly ease’s the installation of all Air Knives (Except PVDF). It will save you the time and expense of designing and fabricating your own mounting system which will maximize your uptime and keep your staff focused on key plant tasks!
Henri Coanda was a Romanian aeronautical engineer most known for his work developing what is today known as the Coanda effect. The Coanda effect is the propensity of a fluid to adhere to the walls of a curved surface. A moving stream of fluid will follow the curvature of the surface rather than continuing to travel in a straight line. This effect is used in the design of an airplane wing to produce lift. The top of the wing is curved whereas the bottom of the wing remains straight. As the air comes across the wing, it adheres to the curved surface, causing it to slow down and create a higher pressure on the underside of the wing. This is referred to as lift and is what allows an airplane to fly.
The Coanda effect is also the driving force behind many of EXAIR’s Intelligent Compressed Air Products. Throughout the catalog you’ll see us talking about air amplification ratios. EXAIR products are designed to take advantage of this phenomenon and entrain ambient air into the primary air stream. Compressed air is ejected through the small orifices creating air motion in their surroundings. Using just a small amount of compressed air as the power source, Super Air Knives, Air Nozzles, and Air Amplifiers all draw in “free” ambient air amplifying both the force and the volume of airflow.
Super Air Knives provide the greatest amount of air amplification at a rate of 40:1, one part being the compressed air supply and 40 parts ambient air from the environment. The design of the Super Air Knife allows air to be entrained at the top and bottom of the knife, maximizing the overall volume of air. Super Air Nozzles and Super Air Amplifiers also use this effect to provide air amplification ratios of up to 25:1, depending on the model.
The patented shim design of the Super Air Amplifier allows it to pull in dramatic amounts of free surrounding air while keeping sound levels as low as 69 dBA at 80 psig! The compressed air adheres to the Coanda profile of the plug and is directed at a high velocity through a ring-shaped nozzle. It adheres to the inside of the plug and is directed towards the outlet, inducing a high volume of surrounding air into the primary air stream. Take a look at this video below that demonstrates the air entrainment of a Super Air Amplifier with dry ice:
Utilizing the Coanda effect allows for massive compressed air savings. If you would like to discuss further how this effect is applied to our Super Air Knives, Air Amplifiers, and Air Nozzles give us a call. We’d be happy to help you replace an inefficient solution with an Engineered Intelligent Compressed Air Product.
As proud as we are of being able to ship most any catalog product, same day, from stock (99.9831% of the time for on-time shipping in 2017…22 years straight for 99.9% or better,) we take a certain amount of pride in our ability to offer custom solutions for challenging applications as well. Our Engineering and Production teams have a deep well of resources (knowledge, experience, and capability) to draw from, which allows us to meet those challenging applications head-on, in short order.
The one I’m writing about today isn’t exactly one of those challenging ones…
A machine fabricator had a special need for an Air Knife. It had to be Stainless Steel, and it had to be 30″ long. No problem so far…that’s a Model 110030SS 30″ Stainless Steel Air Knife, and it’s on the shelf. Thing is, they only needed 26″ worth of air flow; a full 30″ width was going to disturb, and maybe damage, the edges of the sheet of material that the air was being blown onto.
So we made a custom shim for the Air Knife. Now, we make these all the time, in all kinds of configurations…hence the term “custom.” Since this one was blowing onto a web where they didn’t want to disturb the material on the far edges, we made this shim to provide 26″ of flow, on center. We could just as easily made it to provide 26″ of flow starting at one end or the other, or a specified distance from one end or the other. Or 13″ of flow on both ends, with 4″ of no flow in the middle, for a total of 26″.
Regardless of how challenging (or not) your compressed air product application is, we’re here to discuss, any time you’re ready. Call us.
EXAIR commonly works with plastic injection molding companies. They produce top quality plastic parts from both commodity and engineering-grade resins for many diverse industries. The customer reached out to us with a problem. A mold that they were running was having some issues. The parts were not releasing and ejecting properly, causing the need to use a mold release, which was slowing down the process by a manual operation to the process. Also, the parts were seeing push pin marks, causing cosmetic issues with the parts. The customer wanted to explore using compressed air to blow the parts free.
Based on the mold size and layout, a pair of 12″ Super Air Knives was installed. The knives are oriented to blow straight down along the face of the mold, one knife per part tree. The strong laminar flow of air hits the parts causing them to release and drop without the use of release agents. Also, the push pin marks are within normal standards, eliminating the the cosmetic concerns.
This is just one example of how intelligently using compressed air can help improve a process. By using air knives for wide areas or using a 1″ Flat Super Air Nozzle for very small parts, or anywhere in between, we can help to solve your part ejection issues and make your process run better, faster, and with higher quality.
If you would like to talk about Super Air Knives, Flat Nozzles or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
“I’ll get you my pretty, and your little dog too!”
“This EXAIR 42 inch Super Air Knife has ¼ NPT ports, but the Installation and Operation Instructions recommend feeding it with, at a minimum, a ¾ inch pipe…”
If you’re a movie buff like me, you probably recognize 75% of those quotes from famous movies. The OTHER one, dear reader, is from a production that strikes at the heart of this blog, and we’ll watch it soon enough. But first…
It is indeed a common question, especially with our Air Knives: if they have 1/4 NPT ports, why is such a large infeed supply pipe needed? It all comes down to friction, which slows the velocity of the fluid all by itself, and also causes turbulence, which further hampers the flow. This means you won’t have as much pressure at the end of the line as you do at the start, and the longer the line, the greater this drop will be.
If you want to do the math, here’s the empirical formula. Like all good scientific work, it’s in metric units, so you may have to use some unit conversions, which I’ve put below, in blue (you’re welcome):
dp = 7.57 q1.85 L 104 / (d5 p)
dp = pressure drop (kg/cm2)1 kg/cm2=14.22psi
q = air volume flow at atmospheric conditions (FAD, or ‘free air delivery’) (m3/min)1 m3/min = 35.31 CFM
Let’s solve a problem: What’s the pressure drop going to be from a header @80psig, through 10ft of 1″ pipe, feeding a Model 110084 84″ Aluminum Super Air Knife(243.6 SCFM compressed air consumption @80psig)…so…
q = 243.6 SCFM, or 6.9 m3/min
L = 10ft, or 3.0 m
d = 1″, or 25.6 mm
p = 80psig, or 94.7psia, or 6.7 kg/cm2
1.5 psi is a perfectly acceptable drop…but what if the pipe was actually 50 feet long?
Again, 1.5 psi isn’t bad at all. 8.2 psi, however, is going to be noticeable. That’s why we’re going to recommend a 1-1/4″ pipe for this length (d=1.25″, or 32.1 mm):
I’m feeling much better now! Oh, I said we were going to watch a movie earlier…here it is:
If you have questions about compressed air, we’re eager to hear them. Call us.
Of the 3 styles of Air Knife offered by EXAIR, the Super, Standard and Full-Flow, the Super Air Knife is our most efficient, in regards to compressed air usage. Using a 40:1 amplification rate of entrained ambient air to compressed air consumed, it uses only 2.9 SCFM per inch of knife length when operated at 80 PSIG, while producing a low sound level of only 69 decibels (the quietest on the market today). The Super Air Knife provides an even laminar flow of air across the length of the knife and is available in single piece lengths from 3″ up to 108″ in aluminum, 303 stainless and 316 stainless as well as up to 54″ in PVDF (Polyvinylidene Flouride) construction for applications where aggressive chemicals may be present. 1/4″ FNPT air inlets are available on each end as well as on the bottom of the knife.
For Super Air Knives 24″ and longer, you need to plumb air to multiple inlets to maintain an even airflow. Our available Plumbing Kits includes the properly sized hose or pipe and fittings, to not only save valuable time looking for these parts yourself but also eliminates the potential of using undersized lines which will reduce the performance of the Super Air Knives.
For Super Air Knives in aluminum construction, the Plumbing Kits include cut to length PVC compressed air hose and the required brass fittings.
The Plumbing Kits for our stainless steel and PVDF Super Air Knives, include 316ss cut to length pipe as well as 316ss fittings.
The Super Air Knife is the ideal choice when looking to treat wide-area applications, like cleaning a conveyor or drying parts after a wash process. For help selecting the best product to fit your process, contact one of our application engineers for assistance.
An Argentine food manufacturer recently reached out to our distributor in Buenos Aires (AYRFUL) to discuss a potential application for EXAIR products. The need became clear when a packaging line for soon-to-be-frozen food began experiencing problems with excessive water on the surface of the packages. In this process, the packages are rinsed to remove any unwanted debris, and then sent into a large freezer before distribution to local groceries.
The excessive water on the packages would become ice, which would fuse the packages together when stacked in boxes for transporting to retail centers. This fusing caused rips in the packaging when they were separated, thereby creating unsellable goods, ultimately leading to returns for this manufacturer. And, the residual water also increased the total weight of the packed packages, enough to increase the actual weight when bulk packed. This increase in actual weight led to an increase in freight costs from their courier. So, this manufacturer needed a way to remove the residual water, reduce defects and returns, and simultaneously lessen the freight cost.
The solution they found was a 48” EXAIR Super Air Knife, model 110048, mounted using (2) Universal Air Knife Mounting Kits. The Super Air Knife in this application provided a precision airflow to blow off the water from the top of the packages, after rinsing and before freezing. Removing the water at this stage, as shown above, eliminated the problem of fused packages, rejected products, returns, and increased freight. And, the Super Air Knife was able to do this at a low operating pressure, fed from a single compressed air inlet.
(Note – EXAIR recommends plumbing multiple compressed air inlets for Air Knives longer than 18”. For this model, 110048, we recommend compressed air be supplied to (3) compressed air inlets. Plumbing less inlets will reduce the compressed air flow into the knife, which reduces possible operating pressure. In this case, the lower operating pressure was acceptable, however, we still recommend to plumb (3) compressed air inlets on a 48” Super Air Knife.)
Plumbing specifics aside, this solution still brought tremendous value for the customer. They were able to solve the root cause of a multi-faceted problem with an engineered solution. If you have an application in need of an engineered solution, contact an EXAIR Application Engineer.