Heavy Duty Line Vac Solves Alumina Spillage Problem

Spilled alumina material which needs to be vacuumed and returned to the main hopper.

The image above shows spillage of small alumina particles at an aluminum manufacturing plant in South America.  This customer needed a method to vacuum the spilled material and return it to the main hopper.  The ideal solution needed to be compact, simple, and provide repeatable results.  All of these are key aspects of EXAIR Line Vacs, so we began discussing application variables to make a solution recommendation.

Whenever we consider Line Vac applications we always explore the following variables:

  •      Bulk density of the material
  •      Size of the material
  •      Conveyance height
  •      Conveyance distance
  •      Required conveyance rate
  •      Available compressed air supply

The spilled alumina in this application has a bulk density of 1.1 g/cm³ (~68.7 pounds/ft³) which needs to be conveyed to a height of 3.3m (~11ft.).  The conveyance rate is not mandated, but the alumina particles are rather small in diameter and the customer wanted to move as much material as possible in as little time as possible.  Compressed air is readily available at proper pressures and flows, so we were left to determine whether a Line Vac could be a viable solution.  Fortunately we’ve found success in transferring alumina with our Line Vacs in multiple applications before, so we were confident we could find a solution here as well.

The height of this application is 3308mm (~11ft.) – an easy conveyance height for an EXAIR Line Vac.

After exploring the specifics of this application we determined the best solution to be the 2” Heavy Duty Line Vac model 150200.  The 150200 Heavy Duty Line Vac can easily move the alumina to a height of 3.3m at an estimated conveyance rate of 11kg/minute (25 pounds/minute).  There are no moving parts to wear out, which means little to no maintenance and reliable performance each time the Line Vac is used.

Our local distributor assisted with product procurement and in-country technical support.  So even though this customer was in a different continent, we were able to quickly get them the assistance and products they needed to solve their problems.

If you have an application and would like to work with an EXAIR Application Engineer, give us a call and we’ll be happy to help.  1-800-903-9247.

EXAIR Corporation Application Engineers
Techelp@EXAIR.com

Heat Transfer – How Energy Can Move

Heat. One word can bring to mind so many different things from cooking to sun tanning. But what is heat and how does it move. Heat is essentially a form of energy that flows in the form of changing temperatures; this form of energy will flow from high to low. When you describe something as being hot, you are actually describing that the item in question has a higher temperature than your hand thus the thermal (heat) energy is flowing from that object to your hand. This phenomenon is what is referred to as heat transfer. Heat transfer can be observed all the way down to the atomic scale with the property known as specific heat. Every molecule and atom can carry a set amount of energy which is denoted by specific heat; this value is the ration of energy (usually in Joules) divided by the mass multiplied by the temperature (J/g°C).

Energy moving through atoms in an object

But how does this heat move from object to object? On the atomic scale, the atoms are storing the energy which will cause electrons to enter into an excited state and rapidly switch between shells. When the electron returns back to a lower shell (closer to the nucleus) energy is released; the energy released is then absorbed by atoms at a lower energy state and will continue until the thermal energy is equal between the two objects. Heat has four fundamental modes of transferring energy from surface to surface and they are as follows:

Advection
Advection is the physical transport of a fluid from point A to point B, which includes all internal thermal energy stored inside. Advection can be seen as one of the simpler ways of heat transfer.

Conduction
Conduction can also be referred to as diffusion and is the transfer of energy between two objects that have made physical contact. When the two objects come into contact with each other thermal energy will flow from the object with the higher temp to the object with the lower temp. A good example of this is placing ice in a glass of water. The temperature is much lower than the room temperature therefore the thermal energy will flow from the water to the ice.

Convection
Convection is the transfer of thermal energy between an object and a fluid in motion. The faster the fluid moves the faster heat is transferred. This relies on the specific heat property of a molecule in order to determine the rate at which heat will be transferred. The low the specific heat of a molecule the faster and more volume of the fluid will need to move in order to get full affect of convection. Convection is used in modern ovens in order to get a more even heat through out the food while cooking.

Radiation
Radiation is the transfer of thermal energy through empty space and does require a material between the two objects. Going back to the how thermal energy is released from atoms; when the electron returns to a lower energy shell the energy is released in the form of light ranging from infrared light to UV light. Energy in the form of light can then be absorbed by an object in the form of heat. Everyone experiences radiation transfer every day when you walk outside; the light from the sun’s radiation is what keeps this planet habitable.

EXAIR’s engineered compressed air products are used every day to force air over hot surfaces to cool, as well as dry and/or blow off hot materials. Let us help you to understand and solve your heat transfer situations.

If you have any questions about compressed air systems or want more information on any of EXAIR’s products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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The picture “Energy Transfer – Heat” by Siyavula Education is licensed under CC BY 2.0

Efficiency Lab Leads To Big Savings

EXAIR Corporation manufactures quiet, safe, and efficient compressed air products for industry. We want our customers to get the most out of our products, and, in turn, their compressed air systems. To do that, we offer a unique service called the EXAIR Efficiency Lab. Here’s how it works:

  • An Application Engineer can arrange to have your existing compressed air device(s) sent in to our facility.
  • We’ll use our calibrated test equipment to measure the compressed air consumption, sound level, and force applied of those devices.
  • You’ll receive a detailed test report, along with our recommendations to implement an efficient, quiet, and safety compliant solution.
  • We’ll even send your tested device(s) back to you, at no charge, if you wish.

I recently had the pleasure of conducting just such a test on some air guns.  The caller was the Environmental Health & Safety Director for a plastics manufacturer.  The main concern was safety compliance…a recent audit had shown that some workstations were using handheld blowoff devices that did not comply with OSHA standard 1910.242(b), which limits dead end pressure of compressed air products used for cleaning to 30psi.

After discussing their typical uses for these (and other) air guns, they sent in a couple for testing.  Here’s what we found out:

“Thumb guns” are especially popular for blowoff because of their compact size, ergonomic design. and low price.

The air gun with the 7″ straight extension (top) is a “textbook” example of non-compliance with OSHA standard 1910.242(b).  Because it has an open-end discharge with no relief path, this one could cause an air embolism if it were inadvertently dead-ended into the operator’s skin – a potentially fatal condition.  It also uses a considerable amount of compressed air, and is quite loud.  At 80psig supply pressure:

  • Compressed air consumption is 40.7 SCFM
  • Noise level is 95.5dBA
  • Force applied, at a distance of 12″, is 13oz

For comparison’s sake, EXAIR Model 1210-6 Soft Grip Safety Air Gun is fitted with our Super Air Nozzle, on the end of a 6″ rigid extension:

  • Compressed air consumption is 14 SCFM
  • Sound level is 74dBA
  • Force applied, at a distance of 12″, is 13oz…same as theirs.
Model 1210 Soft Grip Safety Air is fitted with an EXAIR Super Air Nozzle. We can also supply it with a Rigid Extension and Chip Shield (right).

The other one is OSHA compliant (it can’t be dead-ended…the cross-drilled hole provides a relief path, but it was still pretty inefficient and loud.  At our standard test pressure of 80psig:

  • Compressed air consumption is 30.8 SCFM
  • Noise level is 94.8dBA
  • Force applied, at a distance of 12″, is 16.9oz

Although the force generated by the Model 1210 Soft Grip Safety Air Gun isn’t quite as high as theirs, it’s still our recommendation here.  Oftentimes, the flow and velocity generated by the engineered Super Air Nozzle is more than capable of meeting the needs of the typical blow off applications these types of air guns are used in.

EXAIR Efficiency Lab testing proves that replacing these air guns with our Soft Grip Safety Air Guns (or at least replacing the tips with EXAIR Super Air Nozzles…we also have adapters for that) will result in compressed air savings of 66% and 55%, respectively, and lower sound levels to within OSHA standard 1910.95(a) limits:

All EXAIR Soft Grip Safety Air Guns comply with these limits for 8 hour exposure.

If you’d like to know more about the efficiency & safety (or lack thereof) of your current air blow off devices, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Ion Air Cannon Keeps Paper Recycling Baler Working

One of the cruelest pranks I’ve ever been party to happened during my time in the United States Navy. All it took was:

  • A cigar box
  • A rubber band
  • The scrap “dots” from every 3-hole punch we could find

We cut the lid off the cigar box, filled it with the “dots,” used the lid and the rubber band to make a wind-up flapper that we stretched across the open top of the box, and carefully placed it in our Leading Petty Officer’s (LPO’s) desk drawer.  Then we waited for hilarity to ensue the next time he opened that drawer.

Unbeknownst to us, he was going to a pretty important meeting that morning, so he was wearing his Service Dress Blues (also known as “crackerjacks” – the dark wool one; not the white one on the popular snack mix box).  When he opened his desk drawer, the rubber band-powered flapper flung those little white paper dots all over him.  It was wintertime, in an office space with electric baseboard heat, so the static cling was heinous.  It took several of us with makeshift lint brushes fashioned from duct tape to get his uniform “shipshape” and presentable for the meeting.

I was reminded of this incident recently when I had the pleasure of helping a caller from a paper recycling plant, who was having a static problem in a baler, with, basically, large confetti-like pieces of shredded paper.  These shreds are pneumatically conveyed through a long 8-inch duct, where they picked up enough static to cling to the inside of the baler chute, and built up to a point where they covered the sensors that opened the chute.  This caused the chute doors to cycle without the chute being full, which triggered the baler to activate with nothing there.  The result from the operators was a lot of slamming, frustration, and cursing…which further reminded me of my LPO’s reaction to getting covered in paper dots.

While lint brushes (and duct tape, in a pinch) work just fine for removing statically charged debris from one’s clothing, the baler required a different solution…in the form of a pair of EXAIR Gen4 Ion Air Cannons.  These were installed to blow into the baler, from opposite walls just above the chute, and aimed slightly down towards the sensors.  This keeps the sensors clear until paper shred actually DOES fill the chute, allowing it to dump a whole bale’s worth of scrap, keeping the baler (and the operators) happy.

Whatever you needs, EXAIR has a Gen4 Static Eliminator product to solve your static problem.

Many industrial static charge problems have similarities to “real world” experiences that most of us are familiar with.  If you want to talk about static control, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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