EXAIR Blog

Starting a Leak Prevention Program

Since all compressed air systems will have some amount of leakage, it is a good idea to set up a Leak Prevention Program.  Keeping the leakage losses to a minimum will save on compressed air… More

What Causes Static Electricity?

We’ve all been shocked before. And no, I’m not talking about the feeling we all here in Cincinnati felt when the Cincinnati Bengals finally fired Marvin Lewis… I’m referring to the discharge you’ve likely felt… More

Adjustable Air Amplifiers Aren’t Just About Adjustability

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… More

Super Air Wipe Overview

What do you do when you need to cool, blowoff, or dry extruded objects? How will you support the products to do these tasks, and how will you get your extrusions through them? Consider using engineered compressed air products air for these applications to provide instant on/off capability, fine tuning adjustment of the air flow, low noise levels and OSHA safety. The EXAIR Super Air Wipe is designed to work well with continuous production products like extrusions, wire and cable.

Super Air Wipe extrusion save
Implementing a Super Air Wipe salvaged a $30,000 job for this customer. Read all about it in our Case Study Library (registration required)

The Super Air Wipe is a highly efficient compressed air powered device that provides a uniform 360° air stream that is ideal for blowoff, drying, cleaning and/or cooling of pipe, cable, extruded shapes, hose, wire and more.

The clam shell design of EXAIR’s Super Air Wipe offers easy clamping around the surface of the material moving through it that eliminates the need for time-consuming and cumbersome threading.  All models utilize stainless steel screws and shims and for sizes up to 4″ (102mm) a Stainless Steel wire braided connecting hose is included.  Aluminum models are rated for temperatures up to 400°F (204°C) and stainless steel models for temperatures up to 800°F (427°C).

Mounting the EXAIR Super Air Wipe is very easy, it can be accomplished by using either the 1/4 – 20 tapped holes on the downstream side or by utilizing a hard pipe compressed air supply line.  Connecting the EXAIR Super Air Wipe to your compressed air supply is straightforward, there are (2) 1/4 FNPT compressed air inlets on throat sizes up to  7″ (178mm) diameter (one on each half), while the 9″ (229mm) & 11″ (279mm) diameters have a total of (4) 1/4 FNPT compressed air inlets (two per half) to ensure proper air volume for maximum performance.

Prior to the introduction of the Super Air Wipe, one way to blow off, dry, or clean extruded objects was to use a ring of air nozzles. The high air consumption and noise levels of the nozzles along with inconsistent air velocity often delivered poor results.

 

ring nozzle blow off

The Super Air Wipe, which is similar to the construction of EXAIR Super Air Knife provides a high volume, high velocity airflow that is uniformly ejected from the entire 360° of its inner diameter. The airstream adheres to the surface of the material running through it (Coanda Effect) to effectively wipe, clean or dry surfaces.

To further explain how the EXAIR Super Air Wipes work, reference the animation below: Compressed air flows through the inlet (1) of the Air Wipe into the annular chamber (2).  It is then throttled through a small ring nozzle (3) at high velocity.  This primary airstream adheres to the Coanda profile (4), which directs down the angled surface of the Air Wipe.  A low pressure is created at the center (5) inducing a high volume flow of surrounding air into the primary airstream.  As the airflow exits the slot, it creates a conical 360° ring of air that will attach to the surface of the material running through it (6) uniformly wiping the entire surface with the high velocity airflow.

sawworksani
How The Super Air Wipe Works

The EXAIR Super Air Wipe is 1.13″ (29mm) thick on all (11) Aluminum models that range in size from 3/8″ (10mm) to 11″ (279mm) throat diameter and all (5) Stainless Steel models that range in size from 1/2″ (50mm) to 4″ (102mm).   The performance can be altered by changing the inlet air pressure or by adding an additional shim, which will nearly double the force!

Super Air Wipe Family Photo
The Aluminum Super Air Wipe is available in 11 sizes 3/8″, 1/2″, 1″, 2″, 3″, 4″, 5″, 6″, 7″, 9″ & 11″; the Stainless Steel Super Air Wipe comes in 5 sizes, 1/2″, 1″, 2″, 3″ & 4″…all from stock!

So when you need to cool, blow off or dry extruded objects or are looking for expert advice on safe, quiet and efficient point of use compressed air products, give us a call.  We would enjoy hearing from you!

Steve Harrison
Application Engineer
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Choosing the Right Vortex Tube – Max Refrigeration vs. Max Cold Temperature

The Vortex Tube is a low cost, reliable, maintenance free way to provide cooling to a wide variety of industrial spot cooling problems.

VT_air2

There are two (2) popular uses for the Vortex Tubes.  One is to spot cool a warm item as fast as possible.  The other is to chill an item to as low a temperature as possible. Because these are very different requirements, different Vortex Tube configurations exist to handle each.

For those applications of spot cooling, we recommend the 3200 series of Vortex Tubes. They are designed to be most efficient at providing maximum refrigeration, which is a function of high cold air flow rate and moderate temperature differential of the cold air to the warm item.

And for those applications of chilling an item to a very low temperature at low flow rate , we recommend the 3400 series of Vortex Tubes.  They are designed to be most efficient at providing maximum cold air temperatures, but with a lower cold air flow rate.

An important parameter for the Vortex Tubes is the Cold Fraction.  By adjusting the hot valve on a vortex tube, the amount of air that is discharged through the cold end changes. When expressed as a percentage of the total compressed air that is supplied to the vortex tube, we get the Cold Fraction.  For example, if the hot valve is adjusted so that for every 10 parts of compressed air supplied, we get 7 parts of cold air, then we have a 70% Cold Fraction. When you know the Cold fraction setting and the compressed air supply pressure, you can use the Vortex Tube Performance tables and get the cold air discharge temperature.

Using the table below left, at 100 PSIG compressed air pressure and a 70% Cold Fraction, we can expect the cold air discharge temperature drop to be 71°F.  With 70 ° compressed air temperature, the cold air will be at -1°F.

Vortex Tube Charts
Vortex Tube Performance Tables

The 3200 series of Vortex Tubes are for use in the 50-80% Cold Fraction range, and the model 3400 series is designed for use in the 20-50% Cold Fraction ranges, to maximize the performance of each.

In summary, the selection of the Vortex Tube that best meets the application needs is based on the desired cold air flow rate, and the temperature of air desired. Once these are known, using the tables can provide the information needed to select the best option.

For those applications where we are unsure what will work best, we offer the EXAIR Cooling Kits, that include a Vortex Tube (small, medium, or large) and an array of Generators, to allow the configuration of the full range of Vortex Tubes within each size family.

  • Model 3908 – Small Vortex Tube Cooling Kit – build models 3202, 3204, 3208, and 3402, 3404, 3408
  • Model 3930 – Medium Vortex Tube Cooling Kit – build models 3210, 3215, 3225, 3230, 3240, and 3410, 3415, 3425, 3430, 3440
  • Model 3998 – Large Vortex Tube Cooling Kit – build models 3250, 3275, 3298, 3299, and models 3450, 3475, 3498, 3499

3930

If you have questions about Vortex Tubes or any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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People of Interest: Rudolf Hilsch

Vortex Tubes

The EXAIR Vortex Tubes use compressed air to generate a cold air stream at one end and a hot air stream at the other end.  The history behind this phenomenon is rooted in the Ranque-Hilsch tube.  In 1931, a French physicist, Georges Ranque, tried to use a cyclone vortex to separate iron filings from the air.  He noticed that when he capped one end with a slight opening, the air would become very warm.  Being disappointed with the separation, he shelved his patented idea for several years.  In 1946, Rudolf Hilsch picked up this idea from Georges Ranque and “tweaked” the design.  This product has now become known as the Vortex Tube.  In this blog, I will cover Rudolf Hilsch as a person of interest.

Rudolf Hilsch was born in December 18th, 1903 in Hamburg, Germany and died on May26th, 1972.  In 1927, Rudolf received his doctorate at the age of 24.  In 1938, he worked with a colleague, Robert Pohl, to create one of the first working semiconductor amplifier.   From 1941 to 1953, Hilsch was a professor of physics at Erlangen, and in 1947, he published his paper of the Ranque-Hilsch tube which he called the “Wirbelrohr”, or whirl pipe.  This publication became well known and was the start of the Vortex Tube.  To continue on with his career, in 1953, he became a full member of the Bavarian Academy of Sciences.  Also, at that same time, he started teaching physics at the Physics Institute of the Georg August University of Göttingen well into the 1960s.

Inside the Vortex Tube

To expand a bit more into his publication, the design for spinning the air at a high rate of speed can produce a separation of temperatures.  It starts with a generator to help facilitate a vortex.  As the vortex travels toward one end, a portion of that air will travel back through the center toward the opposite end.  (Reference animation above).  As these two vortices interact, conservation of momentum forces the inner vortex to give off energy in a form of heat to the outer vortex.  This separation of temperatures will give you a hot air stream and a cold air stream.  This type of device can do this without any moving parts or Freon.  You just have to supply a compressed gas.

EXAIR manufactures Vortex Tubes that utilize this phenomenon with compressed air.  We stock units with cooling capacities up to 10,200 BTU/hr and can reach temperatures from -50oF to +260oF (-46oC to +127oC).  So, thank you Mr. Ranque and Mr. Hilsch for creating a product to generate hot and cold air in a single unit.  If you would like to discuss any applications where cooling or heating is needed, you can talk with one of our Application Engineers.  We will be happy to help.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Super Ion Air Knife Removes Static from Flour Packaging Process

Static Eliminators
Static Eliminators

Recently I had the pleasure of working on an application with one of our South American distributors, AYRFUL. Their customer is an OEM manufacturer of packaging machines that deals with a variety of different industries in the region. They had a machine in the field operating in Argentina that was posing some issues for a company that processes flour.

Static was building up on the packaging material and was causing flour particles to stick to the outside of the package. If there was any residual flour stuck at the top of the bag after filling, it wouldn’t allow the package to seal properly. This would result in bags of flour that would be improperly sealed, this caused housekeeping issues as some would spill out, but also some of these bags have to be thrown out due to potential contamination.

SIAK web

They reached out to our distributor who was able to go see the application and confirmed that the static was causing the problem with a Model 7905 Static Meter. The web was 27” wide, making our Model 112030 30” Gen4 Super Ion Air Knife a near perfect fit. By placing the Super Ion Air Knife just prior to the filling operation, we were able to remove the static charge on the material and blow off any residual flour that was still stuck to the outside of the packaging. This immediately mitigated the static on the material and allowed for the packages to seal properly, resulting in a production improvement of almost 20%!!

We’re smack in the middle of winter here in the US with drier air causing an uptick in static problems across a wide variety of industrial processes. With a wide range of Static Eliminator solutions available from stock, EXAIR has the ability to solve your problem QUICKLY!

Get in touch with us via phone, chat, or e-mail and an Application Engineer will be happy to assist you in selecting the most suitable Static Eliminator based on the application.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Video Blog: EXAIR’s Efficiency Lab

If you’d like to know how efficient (or not,) quiet (or not,) and effective (or not) your current compressed air devices are, the EXAIR Efficiency Lab can help.  For more details, we hope you’ll enjoy this short video.

If you’d like to talk about getting the most out of your compressed air system, we’d love to hear from you.

Russ Bowman
Application Engineer
EXAIR Corporation
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Calculating Static Friction To Eject Parts with Air

2″ Flat Super Air Nozzle

In today’s fast-paced world, companies are always looking for ways to do things faster, cheaper, more efficiently without sacrificing safety.

A cereal company had a high-speed system to check the quality of each box of cereal.  When a box did not meet the quality criteria for visual and/or weight, the box would be rejected.  The rejection system that they used was a quick blast of compressed air to remove the box from the conveyor line into a non-conforming bin.  For their first attempt, they tried to use a ¼” copper tube with a solenoid valve attached to a reservoir tank.  When a “bad” box was detected, the solenoid would be triggered, and compressed air would “shoot” the box off the rubber conveyor belt.  The ¼” copper tube can be an inexpensive, common, and easy-to-use device; but they found that the copper tube was very loud (above OSHA limits for noise exposure) and not very effective.  As a note, this company had a safety committee, and they wanted to keep all blowing devices below 80 dBA in this department.  The ¼” copper tube was around 100 dBA.  So, they contacted EXAIR to get our expertise on this type of application.

The cereal company gave me some additional details of the operation.  The box weighed 26 oz. (740 grams) with a dimension of 7.5″  wide by  11″ tall by  2 3/4″ deep (19 cm X 28 cm X 7 cm respectively).  The issue with the ¼” copper tube was the small target area compared to the area of the box.  With any slight variation in the timing sequence, the force would miss the center of mass of the box.  The box could then spin and remain on the conveyor belt.  This would cause stoppage and disruption in the system.  They asked if EXAIR had a better way to remove the defective boxes.

I recommended a model 1122, 2” Flat Super Air Nozzle.  The reason for this style of nozzle was for a variety of reasons.  First, we needed a larger area to “hit” the box.  This Flat Super Air Nozzle has a width of 2” versus the ¼” copper tube.  This increased the target area by 8 times.  So, any small variations in time, we could still hit the center of mass and remove the box.  The second reason was the force rating.  The model 1122 has a force of 22 oz. (624 grams) at 80 PSIG (5.5 bar).  This is slightly under the 26 oz. (740 grams) weight of the cereal box, but we are just sliding the box and not lifting it.  If we can overcome the static friction, then the box can be easily removed.  With Equation 1, we can calculate the required force.

Equation 1:

Fs = ms * W

Fs – Static Force (grams)

m– Static Friction

W – Weight (grams)

From the “Engineering Toolbox”, the static friction between rubber and cardboard is between 0.5 to 0.8.  If I take the worse case condition, I can calculate the static force between the belt and cereal box using Equation 1:

Fs = 0.8 * 740 grams

Fs = 592 grams

The model 1122 has a force of 22 oz. (624 grams), so plenty enough force to move the box from the rubber conveyor belt.

The third reason for this nozzle is the noise level.  The noise level of the model 1122 is 77 dBA, well below the safety requirement for this company.  Noise levels are very important in industries to protect operators from hearing loss, and the model 1122 was able to easily meet that requirement.  I added an additional reason for recommending the 2” Flat Super Air Nozzle; compressed air savings.  Companies sometimes overlook the cost when using compressed air for blow-off devices.  In this comparison, the ¼” copper tube will use 33 SCFM (934 SLPM) at 80 PSIG (5.5 bar) while the model 1122 will only use 21.8 SCFM (622 SLPM).  This is a 33% reduction in compressed air; saving them money.

At the intro, I mentioned that companies are looking to do things faster, cheaper, more effective without sacrificing safety.  For this company, we were able to increase production rates by removing every cereal box from the conveyor belt.  We also saved them money by reducing the compressed air requirement as well as keeping it safe by reducing noise.

If you have an application that needs products to be moved by air, you can contact an Application Engineer at EXAIR to help you with a solution.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

“Go Green” in 2019 With EXAIR’s Super Air Nozzles & Jets!

If one of your New Year’s resolutions for 2019 is to help improve your impact on the environment, look no further than EXAIR’s Engineered Air Nozzles & Jets. By upgrading your blowoff, cooling, and drying operations to use one of our Super Air Nozzles or Jets you can save as much as 80% of your compressed air usage when compared with an inefficient solution.

open tubes
Example of a manifold of open pipes

An open copper pipe or tube, even if “flattened” as we’ll commonly see, wastes an excessive amount of compressed air. This wasted compressed air can create problems in the facility due to unnecessarily high energy costs and the pressure drop that can be experienced affecting other processes. In addition to simply using too much compressed air, an open pipe or tube will often produce sound levels in excess of 100 dBA. At these sound levels, according to OSHA, permanent hearing damage will occur in just 2 hours of exposure.

OSHA Chart

By simply replacing the open tubes and pipe with an EXAIR Super Air Nozzle, you can quickly reduce air consumption AND reduce the sound level. Sound level isn’t the only thing an OSHA inspector is going to be concerned about regarding an open pipe blowoff, in addition OSHA 1910.242(b) states that a compressed air nozzle used for blowoff or cleaning purposes cannot be dead-ended when using with pressures in excess of 30 psig. I don’t know if you’ve ever tried to use an air gun with 30 psig fed to it, but the effectiveness of it is dramatically reduced. This is why there needs to be a device installed that’ll prevent it from being dead-ended so that you can operate at a higher pressure.

nozzle_anim_twit800x320
EXAIR Super Air Nozzle entrainment

EXAIR’s Super Air Nozzles are designed with fins that serve two purposes. They help to entrain ambient air from the environment, allowing us to maximize the force and flow from the nozzle but keeping the compressed air consumption minimal. In addition, these fins are what prevents the nozzle openings from being completely blocked off. Using an OSHA compliant compressed air nozzle for all points where a blowoff operation is being performed should be a priority. Each individual infraction will result in a fine if you’re subject to an OSHA inspection. Inspections are typically unannounced, so it’s important to take a look around your shop and make sure you’re using approved products.

sag-osha-compliant
The fins along the outside of the Super Air Nozzle prevent it from being dead-ended

So, go ahead and make 2019 the year of energy savings, increased efficiency, and improving worker safety. You’ll find all of the tools you need in EXAIR’s 32nd edition of the catalog. Click here if you’d like a hard copy sent directly to you! Or, get in touch with us today to find out how you can get saving with an Intelligent Compressed Air Product.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

 

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