Another Unique Solution in an Aluminum Processing Plant

Fine dust particles needed to be removed from this belt on the underside of a conveyor

A few months back I wrote about the impact of installing Super Air Knives in an aluminum processing plant.  Those Super Air Knives solved a recurring problem with cleaning alumina dust around conveyors and reduced costs for the end user by over $80k.

That same customer has also found a method to remove fine dust from the underside of the conveyor belt in an application area not suitable for an Air Knife.  In this application there was no dust collection system in place to carry away the fines as they are blown off of the belt, so a different type of solution was needed.

Model 150200 Heavy Duty Line Vac provides the vacuum needed to remove the dust fines.

That solution was to install a Heavy Duty Line Vac affixed to a vacuum hood to remove fines from the belt and convey them back to the head chute.  The only problem with this setup was that the 2” Heavy Duty Line Vac produced a bit too much vacuum flow than what was really needed in the application.  So, a pressure regulator was installed to allow for adjustment and fine tuning of the vacuum solution.  The customer was able to adjust the operating conditions for the Line Vac and minimize compressed air use while maximizing the vacuuming effect on the fines stuck to the conveyor.

The Line Vac used in this application quickly and easily solved a chronic problem plaguing this manufacturer.  By installing this vacuum solution they were able to prevent build-up of dust and debris underneath the conveyor which originally required shutting down the line to clean.  This improved process uptime, reduced cleaning costs, and increased throughput in the application.

If you have an application in need of a vacuum solution, consider an EXAIR Line Vac.  And, if you have any questions, contact an EXAIR Application Engineer.  We’ll be happy to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

EXAIR Super Air Knives Improve Process in an Aluminum Rodding Shop

pile-of-product

Piles of material underneath conveyor in aluminum making process

Recently, one of the world’s largest producers of aluminum initiated a study to determine the costs associated with material spillage in their facilities.  The purpose of their internal investigation was to quantify the time, money, and production losses derived from material spillage and accumulation in their rodding shop (the portion of the aluminum making process in which the anode rods are recycled).  Their findings were astounding.

sak-before

Material buildup underneath conveyor in rodding shop

Underneath the conveyors in the rodding shop were mountains of spilled material.  This material would accumulate to dangerous levels, causing safety hazards for workers to potentially slip or trip, interference with conveyor belt operation, an inability to service the conveyors, and a constant cleaning requirement.  Essentially, the accumulation of material would reduce the lifespan of conveyor components while simultaneously preventing maintenance personnel from being able to service the failed components.

failed-roller-1

Failed rollers, pulled from conveyors in the rodding shop

So, the spilled material would be vacuumed from the affected area, conveyor maintenance would be performed, and then the (vicious) cycle would repeat.

Overall, these spills cost over $85,000 per year in cleaning costs (vacuuming spilled material weekly at a cost of $1,650.00), 7100 minutes of unscheduled downtime loss (the process must be stopped during vacuuming and repair to the conveyors), an increased safety risk due to slips and trips on the spilled material, and reduced life of their conveyor belting, rollers, and pulleys due to operating in bath of rubble and dust.

Finding a solution for this problem was no small matter.  This customer needed a permanent and reliable solution to eliminate the mountains of material underneath their conveyors.  And that solution was to install EXAIR Super Air Knives on the underside of the belts, aimed opposite the direction of belt travel, and aimed toward the dust collection system, as shown below.  Before and after photos of the installation are shown below as well.

sak-installed-underneath-belt

An aluminum Super Air Knife (with plumbing kit from EXAIR) installed on the underside of a conveyor.

sak-before

Seven days of accumulation without the Super Air Knife installed

sak-after-pile-was-there-before

Seven days of accumulation with the Super Air Knife installed. Note: the pile in the background was there from the previous week.

The images above show how the Super Air Knives perfectly solve this problem.  They prevent the accumulation of material underneath the conveyors, eliminating $85,000/year in cleaning costs and 7100 minutes of unscheduled downtime, removing the safety and maintenance concern, and adding longevity to the conveyor components.

Cleaning intervals were revised from daily requirements to an interval up to 12 weeks in some locations.  (The shortest interval was revised from daily to every 3 weeks.)

return-roller

No more of these. This is a failed end roller, replaced after only two weeks in service. Lifespan for conveyor components was greatly improved after the installation of Super Air Knives.

So, the burning question is “How much did this solution cost the end user?”

Total costs to implement this solution were $16,000.00.  Based on the cleaning costs alone, the return on investment for this project was under three months.  When the downtime and additional conveyor maintenance is factored in, ROI is realized even faster, perhaps in under two months.

For EXAIR Application Engineers, thoroughly identifying customer problems and integrating an optimal solution is one of our specialties.  In this case we were able to see the benefits our products can have on a single process, saving the customer tens of thousands of dollars per year.

If you have a problem plaguing your facility and would like to discuss potential solutions using EXAIR products, contact one of our Application Engineers.  We’ll be happy to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

Line Vac Troubleshooting / Alumina Ball Conveying

Recently, I had a good interaction with a customer on a Line Vac Application. You can read through the e-mail below to get a better understanding of the issues at work in a typical conveying application.

INQUIRY:
Dear Sir,

We have Line Vac model 6084 operating at between 80 & 90 psig. We are trying to convey alumina balls to a height of about 12 ft. The balls are spherical with diam. between 4 & 7mm (about 1/4 inch). Packed density =50lbs/ ft3 actual density must be in region of 60lbs/ft3. We are only able to convey a very small amount of alumina. Feeding more than a nominal amount blocks the feed tube. Can you please help?

Regards,
Robert

RESPONSE:
Hello Robert,

Yes, I think we have a few ideas you can consider to make the application work a little better.

First thing you must do is to verify with zero doubt about the actual, net operating pressure at the Line Vac inlet. The way you do this is to install a pressure gauge onto a pipe tee and install the pipe tee into the inlet of the Line Vac. Then re-connect your compressed air supply to the 3rd leg of the pipe tee. Operate the Line Vac and note your working pressure on the gauge. If it is less than 80 PSIG, you could do better on the pressure by up-sizing your feed lines and all fittings that are included within. Re-test the Line vac as outlined above and note any improvement in net working pressure.

OK, let us assume you were able to fix the supply problems that contributed to the excessive pressure drop. You can then make a modification to the Line Vac itself by taking it apart and removing the internal part called a generator. This is the part with the air jet holes drilled into it. You can proceed by enlarging these holes to a larger diameter. This will give you higher vacuum performance similar to our Heavy Duty Line Vac series of Line Vac. Do note that if you do not check your plumbing supply lines as indicated in the first paragraph, making this modification could make things worse. So, you do need to be confident that your compressed air system is up to the task.

Another direction you can take will be to go to a smaller size Line Vac to improve your performance. This may seem counter-intuitive at first, but have an open mind.  Going smaller size on Line Vac reduces your air consumption requirement which makes the demand on your compressed air system less which reduces the chances of you have an extreme pressure drop at the Line Vac. The other idea at work here is that you are essentially trying to pull a vacuum over a smaller cross-section area with a smaller Line Vac which enables higher air velocity within the conveying tube with less effort. That higher conveying air velocity is what you need to pull these relatively dense alumina balls without having them stall inside the conveying hose.

If I were to suggest a size to move down to, I’d go with a 1-1/4″ unit from the 2″ model you have now. That would take your air requirement at 80 PSIG down from 45 SCFM to 26 SCFM. In other words, cutting the air required by almost half.  Hopefully, now you are beginning to have the understanding. And then, you can make the same hole enlarging modification to the 1-1/4″ unit that I described above if you wanted to in order to improve through put by about 20 – 30%.  Do note that you have to be able to maintain input pressure right at the Line Vac in all cases.

Best regards,
Neal Raker, Application Engineer
nealraker@exair.com

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