Proper Supply Lines are Key to Air Knife Performance

A few weeks back I chatted with a customer on an Air Knife application where they were using our 48″ aluminum Super Air Knife to remove leftover dough from a baking pan. The knife was working somewhat, but they were seeing some residual dough being left in certain areas on the pans due to what they perceived as “weak” airflow. After reading through our catalog and installation guide, they noticed that there were available shim sets that would allow them to increase the gap setting to get more force and flow out of the knife.

Available in lengths from 3″ to 108″ in aluminum, 303ss or 316ss construction

Our aluminum Super Air Knives are shipped from stock with a .002″ shim installed. The optional shim set includes a .001″, .003″ and .004″ shim that would allow you to decrease or increase the performance. By operating the Super Air Knife with the .003″ shim installed, this would increase the force and flow by 1.5 times and using the .004″ shim would double the performance. Sometimes achieving greater force and flow may be required but with the customer saying they were seeing weak airflow, it seemed there may be a restriction on the supply side.

Super Air Knife with Shim Set

I asked the customer how the knife was plumbed and what size supply lines he was using. He advised that they were plumbing air to all 3 inlets on the bottom of the knife but they were using 3/4″ hose with a run of about 30′. I advised the customer that plumbing air to all 3 inlets is required for a 48″ Super Air Knife but we actually recommend 3/4″ Schedule 40 Pipe up to 10′ or 1″ pipe up to 50′. If using hose, he would need to go up a size to maintain a large enough ID to carry the volume required for the unit. In his case, since the length of the supply is close to 30′, he would need to use 1-1/4″ ID hose.

Improper plumbing line size is a common issue we deal with here at EXAIR. Using undersized supply lines can cause excessive pressure drops because they aren’t able to carry the volume of air necessary to properly supply the compressed air device. In this particular application, if the customer were to install either the .003″ or .004″ shim, while keeping his current plumbing size, the performance would actually be worse as now the lines are even more undersized due to the increased air volume requirement from the larger Super Air Knife gap.

If you are looking to change the performance with one of our Air Knives or if you would like to discuss a particular application or product, please contact one of our application engineers for assistance at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

What’s So “Super” About The Super Air Amplifier?

EXAIR Intelligent Compressed Air Products such as (left to right) the Air Wipe, Super Air Knife, Super Air Nozzle, and Air Amplifier are engineered to entrain enormous amounts of free air from the surrounding environment.

“Free air” from the surrounding environment?  You might think it’s too good to be true, and if you think you’re getting something for nothing, you’re right.  If you consider, though, that it’s oftentimes preferable to work smarter, not harder, then the use of engineered compressed air products is too good NOT to be true.  Case in point: the Super Air Amplifier.

The Coanda Effect is the “work smarter, not harder” part of the Super Air Amplifier

Simple and low cost, (hey, “engineered” doesn’t necessarily mean “complex and expensive”) the EXAIR Super Air Amplifier uses a small amount of compressed air to generate a tremendous amount of air flow through entrainment.  How much do they pull in?  Depending on the model, they entrain air at rates of 12:1 (for the 3/4″ Model 120020) to 25:1 (4″ & 8″ Models 120024 & 120028, respectively.)  The larger diameters mean there’s more cross sectional area to entrain air, so there is indeed efficiency to scale, size-wise.  There are a couple of great visuals in this video, if you want to see the entrainment in action (1:50) or the difference that the entrainment makes (1:30):

 

Where can you use a Super Air Amplifier?  The easy answer is, anyplace you want a consistent, reliable air flow.  The pressure supply can be regulated from a “blast to a breeze,” depending on the needs of your application.  The patented shim can be replaced for even higher performance, while maintaining the efficiency that makes it so valuable.  The balanced flow makes for incredibly quiet operation…no more noisy fans, blowers, or open-end compressed air pipes.  The body (3/4″ to 4″ sizes) is cast with a 2-hole flange for ease of installation.

When can you use a Super Air Amplifier?  Another easy answer: anytime you want.  If you need a continuous air flow, there are no moving parts to wear or electrical components to burn out.  Supply them clean, dry air, and they’ll run darn near indefinitely, maintenance free.

Alternately, if you need intermittent air flow, starting & stopping operation is as simple as opening & closing a valve in the compressed air supply line.  They produce rated flow immediately, and cut it off just as fast.

Some of the more popular applications are ventilation/exhaust, cooling, drying, cleaning, and dust collection.  There are five distinct models to choose from, and they’re all in stock.  We’re also happy to discuss special requirements that might lead to a custom product too.  Our Application Engineers work with Design & Production all the time to meet specific needs of particular situations.

If you’d like to find out more about letting the Super Air Amplifier, or any of EXAIR’s Intelligent Compressed Air Products work smarter for you, give me a call.

Russ Bowman
Application Engineer
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Proper Supply Line Size And Fittings Provide Peak Performance

Many times when we provide the air consumption of an EXAIR product, we get a response like…. “I’ve got plenty of pressure, we run at around 100 PSIG”. While having the correct pressure available is important, it doesn’t make up for the volume requirement or SCFM (Standard Cubic Feet per Minute) needed to maintain that pressure. We commonly reference trying to supply water to a fire hose with a garden hose, it is the same principle, in regards to compressed air.

When looking to maintain an efficient compressed air system, it’s important that you use properly sized supply lines and fittings to  support the air demand (SCFM) of the point-of-use device. The smaller the ID and the longer the length of run, it becomes more difficult for the air to travel through the system. Undersized supply lines or piping can sometimes be the biggest culprit in a compressed air system as they can lead to severe pressure drops or the loss of pressure from the compressor to the end use product.

Take for example our 18″ Super Air Knife. A 18″ Super Air Knife will consume 52.2 SCFM at 80 PSIG. We recommend using 1/2″ Schedule 40 pipe up to 10′ or 3/4″ pipe up to 50′. The reason you need to increase the pipe size after 10′ of run is that 1/2″ pipe can flow close to 100 SCFM up to 10′ but for a 50′ length it can only flow 42 SCFM. On the other hand, 3/4″ pipe is able to flow 100 SCFM up to 50′ so this will allow you to carry the volume needed to the inlet of the knife, without losing pressure through the line.

Pipe size chart for the Super Air Knife

We also explain how performance can be negatively affected by improper plumbing in the following short video:

 

Another problem area is using restrictive fittings, like quick disconnects. While this may be useful with common everyday pneumatic tools, like an impact wrench or nail gun, they can severely limit the volumetric flow to a device requiring more air , like a longer length air knife.

1/4″ Quick Connect

For example, looking at the above 1/4″ quick disconnect, the ID of the fitting is much smaller than the NPT connection size. In this case, it is measuring close to .192″. If you were using a device like our Super Air Knife that features 1/4″ FNPT inlets, even though you are providing the correct thread size, the small inside diameter of the quick disconnect causes too much of a restriction for the volume (SCFM) required to properly support the knife, resulting in a pressure drop through the line, reducing the overall performance.

If you have any questions about compressed air applications or supply lines, please contact one of our application engineers for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Crescent Hammers, Phillips Head Punches, and Other Cautionary Tales

I don’t want to sound “preachy,” but I’m a stickler for using the right tool for the job. Case in point: just the other day, I noticed (OK; my wife told me about) a loose drawer handle. I went to my toolbox in the garage to get a flat-head screwdriver, even though the drawer in question had a selection of butter knives, any one of which could have been used to tighten that screw.

I can trace this, without doubt or hesitation, to my service in the US Navy, under the direction of Senior Chief Cooper.  Proper tool selection & use was VERY important to him.  He stressed the issues of safety, quality, and performance, but if that didn’t work, he’d make his point with an offer to demonstrate the use of a specific tool (a ball peen hammer) on a sensitive part of your anatomy (it’s exactly the part you’re thinking of.)  At that point, it would have been unwise (and unsafe) to question whether that was a proper use of the tool or not.

Only one of these is a hammer………………..….only one of these is a punch………………..…..only one of these is a chisel.
Choose wisely.

Likewise, there are safety, quality, and performance issues associated with compressed air blow offs.  At EXAIR, we’re ALL sticklers about this, and we get calls all the time to discuss ways to get more out of compressed air systems by using the right products.  Here’s a “textbook” example:

A hose manufacturer contacted me to find out more about our Air Wipes, and how they might be a better fit for their various cleaning & drying applications (spoiler alert: they are.)  The blow offs they were using were made of modular hose, designed (and very successfully used) for coolant spraying in machine tools.

Only one of these is a compressed air blow off. Again…choose wisely.

The selection process was two-fold: they purchased one Model 2401 1″ Super Air Wipe to verify performance, and they sent in some of their modular hose assemblies for Efficiency Lab testing.  The first part was just as important as the second because, no matter how much air they were going to save (another spoiler alert: it was significant,) it wouldn’t matter if it didn’t get the job done.  At the station shown above, the Super Air Wipe resulted in superior performance, and a compressed air cost savings of over $400.00 annually.  For that one station.  Based on that, they outfitted TWENTY FIVE stations with engineered product sized for their different hoses, using our Model 2400 (1/2″), 2401 (1″), 2402 (2″) and 2403 (3″) Super Air Wipes.

If you’d like to find out how using the right product for the job can help your operation, give me a call.

Russ Bowman
Application Engineer
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EXAIR Super Air Knives Helps Keep Labels on the Bottles.

Super Air Knife Blower Air Knife

Sometimes you need more power.  I received a phone call from a bottling facility that was currently using a blower style type of air knives.  They increased their production rate from 220 bottles/min to 300 bottles/minute, and they started to see issues in the labeling process.  Their operation consisted of a wash cycle, rinse cycle, drying cycle, then labeling.  They determined that the bottles were not getting dry enough during the drying cycle before the labels were applied.  They had a VFD (Variable Frequency Drive) for the blower system, and they reached the maximum rate.  Still the bottles were not getting dry enough to allow the label to stick to the surface properly.  This meant that they would have to increase the size of their blower system.  With the capital cost of a blower system, they decided to call EXAIR to see if we could help them with the drying application.

Compressed air is the best way for establishing a strong blowing force.  Instead of air pressures in the range of inches of water, the compressed air system can generate over 40 times the amount of pressure than a typical blower system.  EXAIR products uses this power of the compressed air to give you a wide range of blowing forces for drying, cooling, or moving products.  For the above application, I recommended two model 110212 Super Air Knife kits.  The kit includes the Super Air Knife, a filter, a regulator, and a shim set.  They mounted one knife on each side of the bottles to blow off and remove the liquid after the rinse cycle.  Even at the increased bottle speeds, the EXAIR Super Air Knives had no issues in keeping the bottles dry.  With the regulator and the shim, it was easy for them to dial in the correct amount of force without using excess compressed air.  The labels remained glued and the bottling process ran smoothly.  Because the company was impressed by the Super Air Knives, they wanted to comment on the comparisons between the blower knife and the Super Air Knife.

  1. Cost:
    1. Blower System – The reason for contacting EXAIR. Blower-type air knives are an expensive set up.  They require a blower, ducting, and a knife.  To have any flexibility, a control panel with a VFD will be needed.
    2. Super Air Knife – It is a fraction of the cost. With their system, we were roughly 1/10 the cost; even with the kit.  No capital expense report would be needed for the two air knives.
  2. Installation:
    1. Blower System – They stated that it took them a week to install the entire system before they were able to operate. They had to run electrical wires, controls, ducting, and they even had to change the conveying system slightly to accommodate the blower size.
    2. Super Air Knife – They mounted the filter and the regulator on the conveyor, and ran tubing to the Super Air Knives. Even with a fabricator making a bracket to fit into their system, they had the system up and running is less than two hours.
  3. Size:
    1. Blower System – The foot print of the blower is large and it takes up floor space. The 3” ducting had to be ran to an oversized air knife.  With the congestion of the bottle system, it made it difficult to optimize the position and the blowing angle to adequately dry the bottles.
    2. Super Air Knife – With the compact design, the Super Air Knife packs a large force in a small package. It has a footprint of 1 ¾” X 1 ½” X 12” long.  The air knife only required a ¼” NPT compressed air line to supply the compressed air.  It opened up the floor space as well as the bottling area.
  4. Maintenance:
    1. Blower System – The blower filter had to be changed regularly, and system had to be checked. Being that the blower motor is a mechanical device, the bearings will wear and the motor will fail over time.  These items should be checked quarterly as a PM which increase the cost to run the system.
    2. Super Air Knife – No moving parts to wear out. The only maintenance would be to change the filter once a year.
  5. Versatility:
    1. Blower System – They did have a VFD to control the blowing force. But it was still very limited.  With a 36% increase in the bottle speed, they went beyond the maximum capacity of the blower.
    2. Super Air Knife – With a regulator and the shim set, the blowing force can be controlled easily from a breeze to a blast. With their application, the customer only required 40 psig with a standard 0.002” shim to clean and dry the bottles.  They had the option to adjust the regulator or change the shim to get the appropriate amount of blowing force.  So, with any changes in the bottling operations, the Super Air Knife could easily be adjusted.  Also, with the blowing force being optimal from a distance of 3” to 12” from the target, they had more flexibility in angle and distance to hit the moving target.
  6. Quiet:
    1. Blower System – With the blower and turbulent air flow, the units are very loud. It had a sound level near 93 dBA, and with the operators working around the system, they needed PPE to protect them from the high potential of noise induced hearing loss.
    2. Super Air Knife – These units are very quiet. At 40 PSIG, the sound level is only at 61 dBA.  (Even operating at a pressure of 100 PSIG, the sound level is only 72 dBA).  This was very nice for the operators to work around as it wasn’t a constant noise nuisance.

In using the compressed air, the Super Air Knives are engineered to be very efficient.  The design creates a 40:1 amplification ratio which means that for every 1 part of compressed air, 40 parts of the ambient air is entrained.  But, even with the use of compressed air, the customer still wanted to share the ease of installing, the effectiveness of blowing, and the improvements to their process.  With the 6 points noted above, the customer wished that they would have contacted EXAIR at the beginning.

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

Two Birds With One Stone (and A Shim)

Blowing off bottles is such a popular application for the EXAIR Super Air Knife, it’s been featured on the cover of our Catalog…several times…and is the “banner” pictures on the Super Air Knives page on our website:

This always makes me thirsty for orange soda.

I had the pleasure of helping a caller from a bottling plant recently with just such an application.  Thing is, they run a couple of different size bottles, and it’s not a very big facility…they didn’t want to, or have room to, install different lengths of Air Knives, and also didn’t want to waste air flow when they were running the shorter bottles.

9″ Air Knives were required for the taller bottles, but their shorter bottles were a little under 6″ tall.  They had considered buying both 6″ and 9″ Air Knives, but called me to see if there was a less expensive, and possibly, easier way.  (There is!)

EXAIR makes, and stocks, every product in our 208 page catalog right here in this building in Cincinnati, Ohio.  We also make custom parts when the need arises…and custom Air Knife shims were the solution to this customer’s application.

By installing two Model 110009 9″ Aluminum Super Air Knives, one on either side of the conveyor (just like the photo above,) they’re able to blow off the taller bottles.  When they run the shorter bottles, they change out the shims for ones that limit the flow to a 6″ curtain.

So…for a little under $50.00 (2017 cost for those custom shims,) they’re going to save almost $550.00 per year in compressed air costs – AND make sure that their compressed air system is optimized & available for other loads throughout the plant.

EXAIR offers the Super Air Knife in lengths from 3″ to 108″, with a 0.002″ shim installed.  They’re ideal for most industrial and commercial blow off applications, right out of the package.  If your application calls for something a little “outside the box,” you may only be a shim away from success.  If you have such an application, give me a call.

Russ Bowman
Application Engineer
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EXAIR Standard Air Knife: Overview

Standard Air Knife

EXAIR manufactures three different styles of Air Knives; Super, Standard, and the Full Flow.  In this excerpt, I am going to discuss the Standard Air Knives.

The Standard Air Knife uses a Coanda profile for blowing.  The Coanda effect was named after a Romanian aerodynamic pioneer, Henri Coanda where he found a fluid phenomenon.  He stated that “a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region of lower pressure develops” (1).  Being that air is a fluid, it will react in the same manner.

How the Standard Air Knife Works

The EXAIR Standard Air Knife creates a high velocity air stream along an engineered profile.  So, as the air “hugs” the profile, a low pressure is created which will draw in ambient air.  What does this mean for you?  It will use less compressed air to save you money.  For the Standard Air Knife, it has an amplification ratio of 30:1.  (For every 1 part of compressed air, 30 parts of ambient air is drawn into the stream).  This design makes the product very efficient.  We can use less compressed air and bring in more of the free ambient air to create a strong blowing force.

We make the Standard Air Knife in various lengths from 3” to 48” (76mm to 1219mm).  We make the air knives in two different materials, aluminum and stainless steel.  The unique design is very compact; so, it can fit into tight places for blowing and cooling.  The aluminum version uses plastic shims to set the gap.  They come standard with a 0.002” shim installed.  We have additional shims to make the Standard Air Knife more versatile.  The shim set includes a 0.001”, 0.003”, and a 0.004” thickness shim for applications that may require a small breeze up to a strong blast of air.  The shims are color coded for easy verification.  The stainless steel Standard Air Knife comes with a stainless steel shim for higher temperatures or chemical resistance.

Standard Air Knife Kit

We do offer the Standard Air Knives in kits for a more complete package.  It comes with a filter, regulator and the above mentioned shim kit.  The filter removes the debris and water from the compressed air line to optimize the performance of the air knife as well as keeping your product clean.  The regulator is used to make “fine” adjustments to the blowing force.  The shim set is used as a “coarse” adjustment to the blowing force.  Together, you can “dial” in the right amount of air required to do the job without wasting compressed air.

Universal Mounting System

For easy mounting, we do offer a Universal Air Knife Mounting System.  This kit is used to position your air knife securely and precisely.  It comes with a bracket and an articulated arm that can reach up to 30” (762mm).  You can orient the Standard Air Knife in any position to maximize the effectiveness.

With the today’s cost to make compressed air, it is important to do it as efficiently as possible.  The Standard Air Knife has the ability to give you the effective blowing for removing debris, drying parts, or cooling objects without using a large amount of compressed air.  As an additional feature, the Standard Air Knife only has a sound level of 83 dBA at 80 psig (5.5 bar).  So, in using this EXAIR product, you are not creating a noise nuisance in the work environment.  If you have any questions about the Standard Air Knife or if you would like to discuss an application, you can contact an Application Engineer at EXAIR.

 

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

 

(1) from Wikipedia

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