How To Choose An Air Knife

The EXAIR Super Air Knife has a prominent place near the front of our catalog, and THIRTEEN pages of photos, application details, performance data & specifications. It’s the most efficient and quietest product of its kind on the market, and our most diverse product offering in terms of size range, operational adjustability, materials of construction, and accessories available. For almost any general industrial air blow off application, the EXAIR Super Air Knife is the superior choice in terms of air usage, sound level, and capability.

EXAIR Super Air Knives come in a wide range of lengths, for a wide range of possibilities.

EXAIR Super Air Knives come in a wide range of lengths, for a wide range of possibilities.

As tireless champions of the causes of reducing air consumption and noise, we’re always going to promote these benefits of the Super Air Knife. Still, a caller asked me the other day, “Well, why do you still make the others?”…meaning, of course, our Standard and Full Flow Air Knives. Why, indeed:

*Given the same air supply pressure, the Standard Air Knife generates the highest force of our three styles. The amount of force applied isn’t always a prime consideration…if you think about one of the more “textbook” applications for an Air Knife, it doesn’t take a great amount of force to blow off dust and light debris from a conveyor belt…certainly this is a case where efficiency factors in: the lower air consumption of a Super Air Knife can pay for the cost difference between it and a Standard Air Knife in as little as three months of operation.

The Standard Air Knife has the highest force, for when it's needed.

The Standard Air Knife has the highest force, for when it’s needed.

Of course, if you’re blowing stubborn debris out of tight spaces, like gummy, greasy dirt that’s accumulating in the recesses of a finned tube heat exchanger, that extra force can make all the difference. No; the Standard Air Knife isn’t as efficient or quiet as the Super Air Knife, but it’s still a far cry better than a drilled pipe.

*While the Super Air Knife is pretty compact – you only need a few square inches of profile area to successfully mount it – the Full Flow Air Knife is even smaller, requiring not much more than one square inch of profile for mounting. With ports on the rear face (instead of the ends & bottom for the Super Air Knife,) they can fit in very tight quarters.

Low profile and lightweight, the Full Flow Air Knives are a great fit for tight quarters.

Low profile and lightweight, the Full Flow Air Knives are a great fit for tight quarters.

The Full Flow Air Knife is also the lightest weight for a given length. A 36” Aluminum Super Air Knife, for instance, weighs about 8lbs. The 36” Aluminum Full Flow Air Knife weighs less than 4lbs. Most of the time, 8lbs is a very manageable amount of mass to support, but there are situations where every ounce matters, and if yours is one of them, you’re looking at the Full Flow Air Knife all the way.

*The biggest (in the most literal sense) factor in Air Knife selection is, well…size. We make the Standard Air Knives in lengths to 48”, and the Full Flow Air Knives come as long as 36”. The Super Air Knives, however, are stocked in lengths from 3” to 108”, and can be coupled together for as long of an uninterrupted, steady, laminar air flow as you need.

At the end of the day, a majority of blow off applications can be handled just fine with any of our Air Knives. If you’d like to discuss your application and see which one is best for you, give us a call.

Russ Bowman
Application Engineer
(513)671-3322 local
(800)923-9247 toll free
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Air Conveyor Improves Candy Bar Recovery

This week I worked with a candy company who was looking to improve their overflow product recovery. When their bulk bagging machine is inoperable, the wrapped candy bars are sent to an overflow container where they are manually scooped out by an operator. This process was causing damage to the bars and wrappers, as well as presenting an ergonomic hazard to the employee, so they called EXAIR for a solution.

I recommended using our Line Vac Air Operated Conveyor. The Line Vac  connects to hose or pipe to create an inline conveyor and is able to move large amounts of material over long distances, requires no electricity, has no moving parts, and provides maintenance free operation, making it the ideal choice for this application.

After discussing the details with the customer, they were concerned that the candy bars and wrappers, getting picked up by the airflow and transported through the hose, might continue to be damaged. I advised that by using a pressure regulator they could control the vacuum/conveying rate by increasing or decreasing the supply pressure, but their concern remained. I then offered to perform a conveyance test at our facility, if they were willing to send product. The customer agreed and was kind enough to send some of the candy, with some extra bags inside for the staff here at EXAIR. (Which is pretty awesome! I mean, FREE candy? Who doesn’t love that?!)

With a wide range of sizes and materials of construction, we've got your solution.  Call us.

Available in 11 sizes and different materials to meet many application requirements. Line Vacs have smooth ends for connecting hose with a clamp or threaded ends to connect with standard pipe sizes.

Our set up included our 3″ Line Vac with a 10′ section of 3” conveyance hose on the vacuum side and a horizontal conveyance run of approximately 35′, with a 13′ vertical run into a soft sided hopper. We were successful in conveying approximately 9.9 lbs. per minute, when operating at 80 PSIG, with no broken candy bars and no damage to the wrappers. We also determined that 40 PSIG inlet pressure was the lowest they could run the operation, if they were okay with a lower convey rate.

We provided the results to the customer and included a short video of our testing. Intrigued by the results, they are now looking in to other possible applications throughout their facility.

To discuss your Line Vac application, please do not hesitate to contact us for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Heavy Duty Line Vac for Blasting Media Recovery

hdlv

Many times we will get the call from customers who are in the media blasting industry. Media blasting is used in many cases to clean or strip debris, residue, paint or other contamination from the surface of a variety of parts. This cleaning process is generally used to prepare a surface to receive further preparations or perhaps even a coat of primer or paint.

The media blasting process works very well. The only downside is that once the media is spent through the nozzle, it bounces off the part and lands on the ground or any other horizontal surface in the blasting room. So, clean-up after a session of blasting can become a real headache for the operators. Generally, they will want to recover the media for re-use as it can be quite expensive to purchase.

That’s where EXAIR comes in with our Heavy Duty Line Vac product. The Heavy Duty Line Vac has exceptionally high suction capability to move even the densest of blasting media back up into the supply hopper so it can be run through the system over and over. The highly abrasion resistant material of the Heavy Duty Line Vac has been tested with aggressive media such as ground glass and ground garnet and has a proven record of tolerance for moving such material without excessive wear. Other materials of construction like aluminum, stainless steel or hard anodized coatings will wear and degrade – the hardened alloy of the Heavy Duty Line Vac is the best choice for abrasive materials. 

Normally, customers in this industry will opt for the 1-1/2” or 2” model of our Heavy Duty Line Vac for their post blasting clean-up processes. It really takes a task that is true drudgery and turns it into a simple task. It takes the pain away for sure.

If you are in the blasting industry and have similar issues, we invite you to contact us and ask about the Heavy Duty Line Vac range of products. You will be glad you did.

Neal Raker, Application Engineer
nealraker@exair.com

 

Which Vortex Tube Do I Need?

Last week, I wrote a brief introduction to vortex tubes, titled One Item Generates ¼ Ton of Refrigeration and Fits in the Palm of your Hand.” In it I introduced the Vortex Tube and the other products made from Vortex Tubes: Cabinet Coolers, Cold Guns, Adjustable Spot Cooler and Mini Coolers. I also introduced the idea of a cold fraction.  Today, I want to talk about specific Vortex Tube models.

The flow from the cold side of the Vortex Tubeis characterized in two different ways. First, we characterize the air by ΔT (temperature drop) from the starting compressed air temperature. With a supply pressure of 100 PSIG, the drop in temperature can range from 54° to 123° Fahrenheit. Second, we characterize the flow of air in Standard Cubic Feet per Minute. The different models of vortex tube are design to provide a range of flows and temperature.

Vortex Tube Specification

Vortex Tube Specification Chart

When facing this list you have numerous choices that can be daunting. My priorities for selecting a Vortex Tube for a customer are twofold. First, you need the Vortex Tube that will work in your application. Second, I want to choose the model with the least amount of compressed air in order to solve their problem with the least amount of air possible. The smallest Vortex Tube is a model 3202. It also utilizes the least amount of compressed air, 2 SCFM. At 100 PSIG and an 80 percent cold fraction, it will produce a cold flow of 1.6 SCFM at 54° F  below your compressed air temperature. If your compressed air temperature is starting at 70° F, your cold temperature will 16° F. All of the Vortex Tubes will be able produce this same temperature drop, but depending on which Vortex Tube you use will determine the volume of flow produced at that temperature.

1.6 SCFM of flow 54° F below compressed air temperature will take 135 BTU/HR away from a small 100°F box, which is enough energy to cool a needle, a small sensor, or a tiny camera, but what if you have a bigger area you need to cool. Then you need to use a Vortex Tube that will produce more flow. The 3202, 3204, and 3208 will all produce air at the same temperature, but the 3204 and 3208 will produce more volume of cold air.  With the same parameters as above (100 PSIG of inlet pressure and 80 percent cold fraction) the 3204 will produce 3.2 SCFM of cold air and cool 275 BTU/Hr. out of a 100° F environment. The 3208 will produce 6.4 SCFM of cold air and cool 550 BTU/Hr. These larger Vortex Tubes could be used to cool a closed circuit camera in a hot environment or a small drill bit where coolant is prohibited or undesired. From here our product continue to produce more volume of flow and we can go up to our largest Vortex Tube, 3299 which will use 150 SCFM of compressed and cool up to 10,200 BTU/HR.

What if you have an application where you don’t need more air but 16°F  isn’t cold enough? Then you can adjust your cold fraction. Adjusting the cold fraction will allow you to increase the temperature drop. Opening the brass hot valve, will lower the cold fraction. As more air is allowed to escape out of the hot end of the Vortex Tube, the temperature and the flow rate of the cold flow decrease.  If you need to cool below a 50% cold fraction we recommend the 3400 series Vortex Tubes. At 100 PSIG this would occur when you need more than 100° F temperature drop.

Vortex Tubes can be used in a variety of cooling application. If you have any question about the topic discussed above please contact me or another application engineer.

Dave Woerner
Application Engineer
DaveWoerner@EXAIR.com
@EXAIR_DW

Chain-Chain-Change, Change Out That Drilled Pipe…

Life is full of change.  It might sound trite, but truer words were never spoken.  I used to get up around 6:30 on work days.  Now, thanks to my son’s middle school schedule, I’m usually seeing him out the door at that time.  Getting up earlier was certainly a difficult change at first, but it’s had its benefits.  Not the least of which is spending a little extra time with the boy in the morning.

One of our favorite things to do while eating breakfast is to watch the ‘How things are made’ types of shows. Of course, watching these types of shows with an engineer has its downside.  While we can usually explain exactly what’s happening in the process of whatever is being made, the problem is that we often do.  Meaning we wind up talking over the program, which, ironically, is one of my greatest pet peeves.  Speaking of change, guess that’s something I need to work on…

20141002_062454

At any rate, this morning we saw a show on making saltines.  At the sight of the copper pipe positioned near where the cracker dough comes off the die-cut wheel, I knew exactly what was up. ‘They’re using drilled pipe! That’s not safe and a HUGE waste of compressed air!  That’s the perfect application for a Super Air Knife!”  Guess watching these programs with an EXAIR engineer has an additional risk: We can get a little over-excited when we see OSHA violations and wastes of compressed air! I think I about made my son jump out of his gym shorts, but he’s watched these sorts of shows with me before.  He knew the risks…

Life is full of change, and while perhaps I can get better at not talking while the TV show is on, I doubt I’ll ever stop cringing at safety violations and wasting compressed air.  Do you have drilled pipe in your plant?  If so, you could be in violation of multiple safety standards and are definitely wasting money on compressed air.  EXAIR can help you minimize harmful noise levels and keep you in compliance with OSHA’s dead-end pressure standard. Please give EXAIR a call to begin saving air and increasing safety!

Dan Preston
Engineer-at-large
DanPreston@exair.com
1-800-903-9247

 

 

Help with Choosing an E-Vac Vacuum Generator

This is a pretty common question when it comes to Vacuum Generator use in pick-and-place application, and although we can’t boil it down to a simple table & formula based on mass (like we can with the Vacuum Cups themselves,) we can usually hone right in on it, if we have enough details of the situation. And, if questions remain, we can always test one to find out…we’ve got an Efficiency Lab.

That’s what I did, first thing this morning. I had the pleasure of speaking with a robotics instructor at a vocational school yesterday…his class was building a robot to enter in a competition, and one of the operations it needs to accomplish is picking up a golf ball and carrying it a certain distance.  This sounded like a great application for a small E-Vac Vacuum Generator, and, considering the potential leakage at the Vacuum Cup face from the dimples on the golf ball, my first instinct was to consider our Model 810002M E-Vac Low Vacuum (Porous Duty) Generator w/Muffler, and a Model 900766 Bellow Style Vacuum Cup, with a 0.73″ diameter face…our smallest, and ideally sized for a golf ball.  They, however, have a VERY limited supply of compressed air, so the difference between the Model 810002M’s compressed air consumption (2.3 SCFM @80psig) and the Model 800001M E-Vac High Vacuum (Non-Porous Duty) Generator w/Muffler (1.5 SCFM @80psig) was worth considering.  Also, we figured that they might be able to use a Model 900804 Check Valve, so the only time they’d need to supply air was to pick it up, and, possibly intermittently to maintain the vacuum.  So, golf ball in hand, off to the Efficiency Lab I went.  I also took our trusty video camera:

As you can see, it locked on to the golf ball instantly, and the Check Valve allowed the Vacuum Cup to hold the ball for over 13 seconds with no air flow to the E-Vac, proving that there isn’t much leakage at all past those dimples.  I suspect we’ll be seeing this robotics class team in the winner’s circle at the competition.

In most cases, the difference between 1.5 SCFM and 2.3 SCFM consumption may go unnoticed when picking a short-duration pick-and place vacuum generator.  The higher usage product’s supply pressure can always be regulated down to reduce compressed air consumption and use only what’s necessary to do the task…we, in fact, recommend that on ANY compressed air application.  In this case, though, it was worth finding out.

If you have a pick-and-place application that you’d like help with in selecting the right system, give me a call.

Russ Bowman
Application Engineer
(513)671-3322 local
(800)923-9247 toll free
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Pressure Profile: Where to Measure Your Air Pressure

Generic Layout drawing of compressed air piping system.

In order to fully understand how efficient your compressed air system may be, you will need to generate a system pressure profile at some point.   This is a list or diagram of what pressures you have in your compressed air system at specific locations, as well as the pressure required by all the demand devices on your compressed air system.

One of the reasons for the pressure profile is that you may have an application that is far away from the compressor but also highly dependent on a specific operating pressure.   You may also find an application that, due to pressure losses within the system, causes an artificially high pressure demand.

The list below gives the critical points for measuring your compressed air system profile.

  1. At the air compressor discharge. (If using multiple compressors, measure at each.)
  2. If dryers of any type are being used after the compressor measure downstream from the dryer.
  3. Downstream of each filter. (If a particulate filter and oil removal filter are being used it is best to measure downstream of each individual device.   This is to tell when you have more than a 5 psig pressure drop or a clogged filter.)
  4. After each intermediate storage device, such as receiver tanks.
  5. At the point just before the main line from your compressor room branches off to distribution.
  6. The furthest point of each header line you have installed.
  7. On both sides of every filter/regulator units that are at high pressure point of use applications.

To give you an idea of why it is so important to measure these locations, take a look at the blogs we have posted on pressure drop. (Link Here)  As you can tell by the list of blogs that comes up, pressure drop through piping can really cause a lot of wasted energy in your compressed air system.   If you can get a good base line measurement by utilizing a pressure profile then you can start the process to optimizing your compressed air system.

6 steps

The EXAIR Six Steps To Optimizing Your Compressed Air System.

 

If you would like to discuss this or any of the other 6 steps to compressed air optimization, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

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