Aluminum Smelting: Cooling the Hot Spots!

Aluminum smelting is an important process to change alumina ore into aluminum, a lightweight metal.  This process uses high heat for a period of time to separate the oxygen from the alumina.  The temperature can reach over 1000oF (538oC) to cause this separation.  As a reference, two pounds (0.9 Kg) of alumina ore is needed to make one pound (0.45 Kg) of aluminum.  Inside the ovens and exhaust ducts, they are lined with a cement brick to contain the heat and fumes.  Over time, the brick can get weak and have hot spots.  Once the brick is compromised, the system has to be shut down for days to replace the brick.  This is an expensive process and time-consuming.  To help reduce the hot spots and extend the life of the brick, the smelting company was using ¼” copper tubes to blow compressed air to reduce the heat.  This was costing the company a lot of money to operate; so, they contacted EXAIR for a better solution.     

They may be inefficient, but they sure are loud…

EXAIR has been manufacturing intelligent compressed air products since 1983.  And one thing that we know how to do is to save money on compressed air blow-off applications.  For this company above, they had 90 open pipes throughout their plant.  I was able to do a quick calculation for this customer to compare the copper tube to a Super Air Nozzle.  A ¼” copper tube will use roughly 33 SCFM (935 SLPM) of compressed air at 80 PSIG (5.5 bar).  As a replacement nozzle in a hot area, EXAIR recommended a model 1100SS Super Air Nozzle which will use 14 SCFM (396 SLPM) at 80 PSIG (5.5 bar).  With a simple connection, they could mount the ¼” NPT Super Air Nozzle at the end of each tube.  With the cost to make compressed air at $0.25/1,000 ft3, we can calculate the air savings.    

33 SCFM (copper tube) – 14 SCFM (Model 1100) = 19 SCFM savings

The operation for the smelting plant was 24 hours and 7 days a week.  The amount of savings is as follows:

19 ft3/min * 60 min/hr * 24 hr/day * 7 days/week * $0.25/1,000 ft3 = $47.88 savings per week per nozzle.

Since they have 90 nozzles, this would save them $4,309.20 each week! 

How can we do this?  With cooling capacities, it is dependent on the mass of air that can be moved.  With our Super Air Nozzles, we are near an amplification ratio of 25:1.  This means that for every one part of compressed air, we can entrain 25 parts of ambient air.  Also, with our Super Air Nozzles, we can generate a laminar air flow which has a velocity profile that has the air moving in the same direction.  An open pipe has turbulent flow, which means that the velocity is traveling in different directions and not working together.  And the amplification ratio is very low.  I did a demonstration to illustrate this effect here: Video Blog: Laminar and Turbulent Flows.  The large volume of air creates good cooling without using too much compressed air to reduce the hot spot temperatures.  In keeping the temperature under control, they could continue operations and lessen the concern for untimely shut-downs and costly maintenance.

By using air to cool, you can do it safely and efficiently.  As a benefit, the Super Air Nozzles reduced the noise level as well.  Saving a lot of money; having an effective way to reduce stress on the cement bricks; and reducing the noise nuisance were great replacements for this company.  If you would like to speak about cooling applications, you can contact an Application Engineer; even something as large as a smelting oven.

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

EXAIR’s Calculator Library

If there is one thing you can always count on it’s a good calculator, and EXAIR offers you 3 — right on our website!!! The calculator library consists of an Air Savings Calculator, an EFC Calculator, and a Cabinet Cooler sizing calculator. All 3 of these add exceptional value and insight into our products. Let’s take a minute and look at each of these calculators in a little more detail.

The Air Saving Calculator allows you to compare a current product, to one of our products based upon overall cost. In order to make this effective for you, you will need to know the SCFM that your current solution is using. With that information, we can factor in the cost of our product and the SCFM consumption of this new solution, and give you an Air and Cost savings number. For example, if you are using a 1/4″ open pipe for blow off, you would be using @ 40 SCFM (not going to mention the OSHA violations – that’s for another blog). By placing one of our Super Air Nozzles on this open pipe, we will save you so much air (SCFM) that you can quickly see (above) that this one nozzle, can save you up to $1350 per year… One Nozzle!!!

The next calculator is the EFC calculator. An EFC is an Electronic Flow Control that can help you quickly automate your process. The EFC will allow you to use air only when it’s necessary and cut down on consumption. For example, if your conveyor has dead space between products, the EFC will shut the air flow off during the dead space. The calculator will tell you how much money you can save by installing the EFC. This will even tell you how long it will take to pay off the initial cost of the EFC unit. To use this calculator you will need the SCFM being consumed, the % of time that the product needs to be on, the purchase price of the EFC (this varies by size, call for details, or see on the link), and your cost of compressed air. We have $0.25 in this blank as a general standard, but if you know your actual, you will get a more concise answer. Your cost could be much higher, I’d be surprised if it is lower. The Example to the left shows the effects of a $1200 EFC that runs a product at 80 SCFM, and needs to be on 45% of the day. The EFC turns off the air the other 55% of the day when there is no reason to run the air. This pays for itself in 76 days, and adds $3960 to the bottom line each and every year.

The 3rd and final calculator that EXAIR offers online is the most used. It is our Cabinet Cooler System Calculator. Electrical cabinets get hot, and will overheat your electronics. Our Cabinet Coolers are the most efficient method to cool these cabinets, and eliminate electronic damage from overheating. There are no moving parts in these Cabinet Coolers, and the Vortex based system cools these with little to no maintenance. You simply need to supply these with clean, dry, compressed air. As you can imagine, these cabinets come in all sizes, and there are all sorts of various electronics that can be inside of these. We need the measurements and temperatures so that we can calculate the correct size Cabinet Cooler system for you. Our Cabinet Coolers have large size differences, from as little as 4 SCFM and 275 Btu/hr, up to 80 SCFM and 5600 Btu/hr, and we can go larger than this if necessary. The good thing about this calculator is that all of the information you need to enter is readily available to you as long as you have a a tape measure and a thermometer.

We do encourage everyone to take advantage of these on-line tools, however always remember that experienced application engineers like me, are here M-F 7AM-4PM EST to help you in any way possible.

Thank you for stopping by,

Brian Wages

Application Engineer

EXAIR Corporation
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Cover photo by Peggy_Marco licensed by Pixabay

Know How Much Money You Can Save with EXAIR’s Efficiency Lab

Free testing. Verifiable data. EXAIR Efficiency Lab.

When it comes to buying new gear for any kind of outdoor hobby the research almost becomes a full-time job to decided what to get. When I’m hanging 200 ft. in the air off of a single rope, I want to make sure that my harness, rope, and all my other gear is top notch and not going to fail me as my literal life is hanging on the line. Sometimes it would be nice to have a professional climber standing there telling you all of the pros and cons, what they like and dislike about it, and weather it’s worth the buy. Outdoor gear is expensive and climbing equipment is no exception, in an ever-changing world of innovation new things are coming out every week and is just to hard for one person to keep up with.

Similarly, EXAIR has multiple product lines, many new products, and countless applications for our products. That is where our Application Engineers come in; as experts on our products and their applications we can provide in-depth knowledge on the various uses and expected outcomes. 

EXAIR’s Products in action

EXAIR has been making compressed air products since 1983, and have since created a culture of making high quality, safe, and efficient compressed air products. With this in mind we started the Efficiency Lab program for people to take advantage to test your current pneumatic blow-off device and compare it to an EXAIR Intelligent Compressed Air product. We will generate a detailed report on our findings and send it to you for your review. This free service provided to U.S. and Canadian companies allows people to test and look into possible upgrades and cost savings.

During my time as a project and process engineer at Valeo and Tyson I wish I had known about this service.  The Efficiency Lab allows you to look at what your current process is, whether it is an open-ended pipe or some other nozzle and have EXAIR compare it to an EXAIR product for free. Its like getting a free inspection of all your gear and having an expert help you find the best replacement if needed.

You may be wondering why we offer this service; it’s simple, compressed air can be expensive and we want to save you money. Not only are open ended pipes unsafe and can violate OSHA Standards on both dead-end pressure and noise level, but they also use a lot of compressed air. To operate an 1/8” open pipe you are looking at over $2000 a year for just one pipe; there isn’t a single plant that is just going to use one pipe. That is a lot of money that can add up over time, which could easily be saved by changing out what you are using.

The Efficiency Lab is quite simple to use. The simplest way is to contact us (my info below) and we can exchange the information needed to get your product into EXAIR. Once received, we will proceed. We will then calibrate the equipment and standardized procedures to test for noise level, air consumption, and force generated. Based off of this information we will recommend a similar product. Don’t be afraid, let us take care of the hard part of choosing which product is best for your application. If you cannot send any product in, use our  Product Efficiency Survey to provide as many details as possible. 

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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Controlling Compressed Air can be Easy, and Save Thousands of Dollars

The history of automated controls can be traced back to inventors in ancient Greece & Egypt, who sought ways to keep more accurate track of time than afforded by sundials and hourglasses.  Their efforts, dating as far back as 300BC, produced devices actuated by water flow, which is actually quite reliable and repeatable: a set amount of water will flow via gravity through a fixed conduit in the exact same amount of time, every time.  These were in fairly common use until the invention of the mechanical clock in the 14th century.

The Industrial Revolution grew the need for automated processes exponentially…the need to control objects or tooling in motion, fluid flow, temperature, and pressure, just to name a few.  As time passed, the sky was literally the limit: modern aircraft & spacecraft rely on a staggering amount of automated processes from production to operation.

All throughout history, though, the benefits of automation remain the same: making processes more efficient.  That’s where the EXAIR EFC Electronic Flow Control comes in, for automating processes involving compressed air use, by turning air flow off when it’s not needed.  In fact, not only do they provide simple on/off control to blow only when a part is “seen” by the photoelectric sensor, there are eight distinct modes to incorporate delay on or off, flicker on or off, signal on/off delay, interval, or “One-Shot,” where the sensor detects the part, delays opening the valve per the timer setting, and blows for one second.

EFC Electronic Flow Control Systems are already assembled & wired for quick & easy installation.

The EXAIR EFC Electronic Flow Control is a true “plug and play” solution for automating a compressed air application.  Mount the sensor, plumb the valve, plug it in, and you’re ready to go.  There’s no complicated PLC wiring or programming, although the aforementioned mode selections do offer a great deal of flexibility other than “on when the sensor sees it; off when it doesn’t” operation, if desired.  Here are some prime examples of that flexibility, and the monetary benefits due to the compressed air consumption savings:

(Left) On/Off Delay setting used in tank refurbishment application to operate a “halo” of Super Air Knives for blow off as tanks exit oven where old paint is burnt off – $3,393 annual air savings. (Center) Interval setting actuates a Super Ion Air Knife for flat panel display dust blow off/static elimination – $2,045 annual air savings. (Right) Interval setting actuates a “halo” of Super Ion Air Knives to clean & remove static charge from plastic automotive bumper covers prior to painting – $5012 annual savings.

If you’d like to find out more about the EFC Electronic Flow Control can save you time, air, and money, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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