With Valentine’s Day coming up in the U.S. many of us will be buying chocolates for our significant other. My wife (somehow) doesn’t particularly care for chocolate, so I buy some for her anyway knowing… More
360° Air Wipe Comparison for Extrusion, Hose, Cable, Pipe and Wire Blowoff or Cooling
When it comes to blowing off extrusions, cables, pipe, tubing, hose, or wire, the EXAIR Super Air Wipe is an ideal product that often stands alone in this field. From time to time I will receive a call asking about a block style blowoff for wire or cabling, maybe even small extrusion, and the Super Air Wipe is always there to provide a true 360° blowoff compared to what the customer is used to.
See, the block style blowoffs are similar to the SAW in they both offer a clamshell design that will open and close into place around the product to prevent the user from having to “thread the needle”. Also, they both operate off compressed air. The means by which they deliver the air is where the stark contrast in performance begins.
First, let us take a look at how these block style blowoffs deliver the air to the product being blown off. Generally, inside of these, there are a couple holes on each half of the block that are drilled at an angle to deliver the air onto the surface of the product. These block style products have to be kept fairly close in diameter to the product so that the air contacts the surfaces and they are for the most part offered in smaller sizes only.
Now, how does the Super Air Wipe deliver the air to the product being blown off? The air enters (1) into an internal chamber that fills (2) and then dispurses through a continuous gap (3) on each half of the wipe that is set by a shim. The shim can be interchanged with different thicknesses to give a course adjustment to the volumetric flow of air. The air then follows the Coanda profile (4) of the Super Air Wipe to maximize entrained air (5) and exits at a 60° included angle (6) to impact the surface of the part at a full 360°.
Stock Super Air Wipe Product OfferingBlock Style air wipes also have a tendency to operate very loudly, often exceeding 90 dBA and more. This will affects personnel directly and can also affect their communication when attending to a processing line. Super Air Wipes operate at 82 dBA with 5″ and smaller diameters. Up to 89 dBA for diameterss from 6″-11″.
The Super Air Wipe is available in eleven sizes from stock in aluminum (up to 11″ dia.) while the stainless steel configurations are available in five sizes from stock (up to 4″ dia.). If aluminum or stainless steel don’t fit the requirements of an application, custom sizes and materials are always available with short lead times.
If you notice that the block style air blowoff is leaving streaks or maybe the physical space requirements of the block are too much to fit into your production line, please contact an Application Engineer and let us help you determine which Super Air Wipe is going to be right for your needs.
Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF
Entrainment: What is it?
By definition, entrainment is a form of the verb, entrain, which is fluid that is swept along into an existing moving flow. Whenever there is a discussion about fluid dynamics, the Bernoulli’s equation generally comes up. This equation is unique as it relates flow energy with kinetic energy and potential energy. The formula was mainly linked to incompressible fluids, but under certain conditions, it can be significant for gas flows as well. I would like to discuss how EXAIR uses the Bernoulli’s equation for entrainment to maximize efficiency within your compressed air system.
This relationship between pressure as compared to flow and velocity came to be known as the Bernoulli’s principle. “In fluid dynamics, Bernoulli’s principle states that an increase in the speed of fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluids potential energy”1. Bernoulli realized that the sum of kinetic energy, flow energy, and potential energy is a constant during steady flow. He wrote the equation like this:
Equation 1:
P/r + V2/2 + gz = constant
P – Pressure
r – density
V – velocity
g – gravitational constant
z – height difference
Not to get too technical, but you can see the relationship between the velocity squared and the pressure from the equation above. Being that this relationship is a constant along the streamline; when the velocity increases; the pressure has to come down. An example of this is an airplane wing. When the air velocity increases over the top of the wing, the pressure becomes less. Thus, lift is created and the airplane flies.
Since we know the criteria to apply the Bernoulli’s equation with compressed air, let’s look at some EXAIR products. Blowing compressed air to cool, clean, and dry, EXAIR can do it very efficiently as we use the Bernoulli’s principle to entrain the surrounding air. Remember from the equation above, as the velocity increases, the pressure has to decrease. When the pressure decreases, the surrounding air will move toward the low pressure. That low pressure will sweep the ambient air into the air stream; called entrainment.
Compressed air is expensive, but the ambient air is free. The more ambient air we can entrain, the more efficient the blowing device is. As an example, we engineer the Super Air Knife to maximize this phenomenon to give an amplification ratio of 40:1. So, for every 1 part of compressed air, the Super Air Knife will bring into the air streamline 40 parts of ambient “free” air. This makes the Super Air Knife one of the most efficient blowing devices on the market. By adding mass to the flow stream, it will reduce the compressed air usage, saving you money, and allow for better cooling and a stronger blowing force. For a drilled pipe, the amplification ratio is generally only two to three times.
We use this principle for many of our products like the Air Amplifiers, Safety Air Guns, Air Nozzles, Air Knives, and Gen4 Static Eliminators. Daniel Bernoulli was able to find a relationship between velocities and pressures, and EXAIR was able to use this to create efficient, safe, and effective compressed air products. To find out how you can use this advantage to save compressed air in your processes, you can contact an Application Engineer at EXAIR. We will be happy to help you.
John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb
EXAIR’s Gen4 Power Supplies, the Foundation of Gen4 Static Eliminators
In the fall and winter seasons, the air becomes much drier. You may be familiar with the unpleasant shock you get from the door knob after walking across a carpeted surface. While this type of shock doesn’t generally cause any sort of problems, in many industrial processes this static electricity can cause a wide range of issues. These may manifest as nuisance shocks to an operator – similar to the door knob example, but it can also cause problems with the finish quality of coatings and paint. It will make ink jetted codes unreadable, cause blemishes in printing processes, and short out sensors being relied upon for counts and quality inspections…just to name a few.
The reason that you experience static shocks more frequently during winter is due to the relative humidity. At colder temperatures air does not hold as much water as it does when it’s warm, and since water conducts electricity, higher humidity keeps static at lower levels. Even though you’re heating your house to a similar temperature, the air that is being drawn into your home and heated is still the dry cold air containing less moisture.
So how do we tackle this static problem that’s running rampant in your processes? EXAIR has a wide range of Static Eliminators available to ship same-day from stock. Each of which is designed to handle different types of applications. At the heart of these Static Eliminators is the EXAIR Power Supply. Available with either 2 or 4 ports, the Gen4 Power Supply is suitable for use with either 115V or 230V via the selector switch on the back. A 6’ modular power cord and lighted power switch are included. The modular cable protects sensitive electronics against electromagnetic interference while easing connections and routing. An integrated fuse (spare fuse is also included) on the primary protects against voltage spikes.
Two shielded cables are included with both styles of Power Supply. A standard 3-prong outlet for North American customers, and another that allows you to install your own plug to accommodate any style of electrical outlet. The integrated ground connection on the high voltage side allows for complete connection using just the bayonet connector. A grounding post on the front-face of the Power Supply is available for bonding of the Power Supply to machine frames. Shunting circuitry designed into the Power Supply protects the user against any short circuit on the secondary side.
The Power Supply includes an integrated flange for easy mounting in any orientation. Rugged and durable stainless steel connections are present at the high voltage side vs the plastic connectors of the competition. This facilitates the integrated ground and shockless design of all of our Static Eliminator products. The Power Supply is both RoHS and CE compliant, as well as UR Listed.
Here at EXAIR we’ve helped customers in a wide range of industries solve their static issues within their processes. If you would like to discuss the best option for dealing with your static, give us a call. An Application Engineer is ready on the other line to help diagnose your issue and make a suitable recommendation.
Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD
Bifurcation Of Air – The Wonders of Science That Is The Vortex Tube
EXAIR has provided the benefits of vortex tube technology to the industrial world since 1983. Prior to that, French scientist George Ranque wrote about his discovery in 1928 calling it the tube tourbillion. But it wasn’t until German physicist Rudolf Hilsch’s research paper in 1945 on the wirbelrorhr or whirling tube, that the vortex tube entered the minds of commercial engineers. Nearly 60 years later, EXAIR is a leading provider for cooling products utilizing vortex tube technology.
EXAIR Vortex Tubes produce a cold air stream down to -50° F and are a low cost, reliable, maintenance-free (there are no moving parts!) solution to a variety of spot cooling applications. These applications span a wide variety of industries and include cooling of electronic controls, soldered parts, machining operations, heat seals, environmental chambers, and gas samples. We’re always finding compelling new cooling opportunities for the vortex tubes.
So how does it produce the cooling stream? Compressed air is plumbed into the side port of the Vortex Tube where it is ejected tangentially into the internal chamber where the generator is located. The air begins flowing around the generator and spinning up to 1 million RPM toward the hot end (right side in the animation above) of the tube, where some hot air escapes through a control valve. Still spinning, the remaining air is forced back through the middle of the outer vortex. Through a process of conservation of angular momentum, the inner stream loses some kinetic energy in the form of HEAT to the outer stream and exits the vortex tube as COLD air on the other side.
The adjustable control valve adjusts what’s known as the cold fraction. Opening the valve reduces the cold air temperature and also the cold airflow volume. One can achieve the maximum refrigeration (an optimum combination of temperature and volume of flow) around an 80% cold fraction. EXAIR publishes performance charts in our catalog and online to help you dial into the right setting for your application, and you can always contact a real, live, Application Engineer to walk you through it.
EXAIR manufactures its vortex tubes of stainless steel for resistance to corrosion and oxidation. They come in small, medium and large sizes that consume from 2 to 150 SCFM and offer from 135 to 10,200 BTU/hr cooling capacity. Each size can generate several different flow rates, dictated by a small but key part called the generator. That generator can be changed out to increase or decrease the flow rate.
While operation and setup of an EXAIR Vortex Tube are easy, its performance will begin to decrease with back pressure on the cold or hot air exhaust of over 3 PSIG. This is a key when delivering the cold or hot airflow through tubes or pipes. They must be sized to minimize or eliminate back pressure.
The Vortex Tube is integrated into a variety of EXAIR products for specific applications, like the Adjustable Spot Cooler, the Mini Cooler, the Cold Gun Aircoolant System and our family of Cabinet Cooler Systems.
If you would like to discuss your next cooling application, please contact an Application Engineer directly and let our team lead you to the most efficient solution on the market.
Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF
