Compressed Air Knives vs. Blower Air Knives, an Application Comparison

A company was needing to dry vegetables after a washing system.  They currently had three blower air knives (as shown in the photo above) to remove the water before packaging.  The issues that they presented to me were in two parts.  They were not able to generate enough force to remove enough water from larger products like cauliflower and broccoli.  And, the heat from the blower system was affecting the appearance of the thinner vegetables like snow peas.  They purchased the blower-style air knives under the belief that they would save money by not using compressed air.  They found out quickly that it was not a true statement especially when it comes to the total cost of ownership.

Super Air Knife drying fruits and vegetables

When comparing the EXAIR Super Air Knife to a blower-type air knife, there are many features that should be reviewed.  For the customer above, they used an 18” (457mm) wide conveying system to wash more than twenty different fruits and vegetables.  So, they needed versatility to dry the different types of products.  With the Super Air Knife, we have a simple way to adjust the force by changing the inlet air pressure.  So, we can blow air at a light breeze for the snow peas to a very strong force to dry the cauliflower and broccoli.  With the engineered design of the Super Air Knife, we can achieve a 40:1 amplification ratio.  That means for every 1 part of compressed air, we are able to entrain 40 parts of ambient air.  This unique feature allows for the Super Air Knife to be very efficient with your compressed air as well as keeping the blowing air at ambient temperatures.  The design of a blower system allows the air to become hot, turbulent, and limited in force.  As noted in the photo above, they had to use three blower knives to try to remove the liquid water.  With the Super Air Knife, I recommended just one air knife to do the job.  They decided to try an EXAIR model 110218SS 18″ Stainless Steel Super Air Knife Kit to see if their concept of “saving money” with the blower-type air knife was valid.

To better explain the concept, I divided the comparisons into different categories.  You can decide if the Super Air Knife would be a better product than the blower-type air knife.  It sure was for the customer above.

  1. Initial Cost:
    1. Blower System – They are an expensive product when you have to include a blower, ducting, and a knife. To have any flexibility, a control panel with a VFD will be needed.  A capital expenditure is typical for a complete system.
    2. Super Air Knife – It is a fraction of the cost. With their system above, we were roughly 1/10 the cost.  A capital expense would not be required for ordering a Super Air Knife to remove the water.
  2. Maintenance:
    1. Blower System – The intake filter has to be changed periodically as well as the motor and belt has to be checked as a preventive maintenance. Being that the blower motor is a mechanical device, the bearings and belts will wear and have to be replaced.  Without proper maintenance, things can break prematurely.  Loss of production will cost you much money.
    2. Super Air Knife – They do not have any moving parts to wear out. Only compressed air is needed to operate.  The maintenance requirement is to change the compressed air filter once a year.
  3. Compressed air usage:
    1. Blower System – This device does not need any compressed air to work, but it does use an electric motor. For this customer, they had a 7.5KW blower motor.  With the inherent design of blower-type air knives, they have a reduced blowing force and turbulent air flow.  This combination required the maximum power output on the 7.5KW blower motor.
    2. Super Air Knife –With their unique design, it has one of the highest efficiencies in the market place. It can entrain 40 parts of ambient “free” air with every 1 part of compressed air.  With laminar flow and the power of compressed air, the Super Air Knives can be used at a much lower air pressure.  To compare with the electric blower motor above, the Super Air Knives would use 10KW of compressor power to operate at the highest force rating.  So, at lower air pressures, the blower motor and compressor requirement will be very similar.
  4. Noise:
    1. Blower System – With the turbulent air flow, the blower units are very loud. If operators are working near the system, they would need PPE for hearing protection, or elect to purchase (for even more money) a sound enclosure which some of the blower manufacturers offer.
    2. Super Air Knife – These units are very quiet. Even at a higher pressure, the sound level is only 72 dBA at 100 PSIG (6.9 Bar).  This level is well below the maximum noise exposure for hearing safety as marked in OSHA 29CFR 1910.95(a).
  5. Installation:
    1. Blower System –Just to begin, the installers will have to run electrical wires, controls, and ducting. The foot print is large and will need space to install.  They will have to drill holes in the floor to hold the blower in place, and perhaps build an attenuation chamber.  This can take days with no production to start operating.  And time is money.
    2. Super Air Knife –They are compact and do not take up much space. They mount easily into a system.  You can run a plastic tube or rubber hose to the Super Air Knife from a compressed air source.  If you use the Universal Mounting Kit, they will only need a 1/2″ hole for attaching.  Even if a fabricator has to make a bracket to fit into their system, the timing is in hours not days.
  6. Heat:
    1. Blower System – Besides being quite loud, blower systems get very hot as a function of the operation. While this may be sold as a benefit for some applications, it is considered a significant drawback for drying fruits and vegetables. The air can reach a target temperature of 180°F (82°C).
    2. Super Air Knife – The advantage for the Super Air Knife is the amplification ratio. The total volume of air that comes from it is 40 parts ambient and 1 part compressed air. So, the temperature of the airflow is going to be the same as the ambient environment surrounding the Super Air Knife.

The total cost of ownership is quite clear when you look at loss of output, loss of product, and breakdown of equipment.  After reviewing the information above, it was easy for them to try the model 110218SS Stainless Steel Super Air Knife Kit.  When they replaced the blower-type air knives, the customer did share some information with me.

First, they were amazed at the ease of installation and the compact design.  The customer also mentioned the amount of force that could be created by the Super Air Knife.  They were able to increase and decrease the required force to remove the liquid water from all the different fruits and vegetables.  This gave them the flexibility that they were looking for in their process.  And of course, the maintenance time and cost were eliminated.

Compressed air can be expensive, but if you use EXAIR products, you can use the compressed air very efficiently.  You do not have to sacrifice other areas within the total cost of ownership.  If you have a similar application, you can contact an Application Engineer at EXAIR.  We will be happy to discuss the benefits of using the EXAIR Super Air Knives over a blower-type air knife.

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

Opportunities To Save On Compressed Air

If you’re a regular reader of the EXAIR blog, you’re likely familiar with our:

EXAIR Six Steps To Optimizing Your Compressed Air System

This guideline is as comprehensive as you want it to be.  It’s been applied, in small & large facilities, as the framework for a formal set of procedures, followed in order, with the goal of large scale reductions in the costs associated with the operation of compressed air systems…and it works like a charm.  Others have “stepped” in and out, knowing already where some of their larger problems were – if you can actually hear or see evidence of leaks, your first step doesn’t necessarily have to be the installation of a Digital Flowmeter.

Here are some ways you may be able to “step” in and out to realize opportunities for savings on your use of compressed air:

  • Power:  I’m not saying you need to run out & buy a new compressor, but if yours is
    Recent advances have made significant improvements in efficiency.

    aging, requires more frequent maintenance, doesn’t have any particular energy efficiency ratings, etc…you might need to run out & buy a new compressor.  Or at least consult with a reputable air compressor dealer about power consumption.  You might not need to replace the whole compressor system if it can be retrofitted with more efficient controls.

  • Pressure: Not every use of your compressed air requires full header pressure.  In fact, sometimes it’s downright detrimental for the pressure to be too high.  Depending on the layout of your compressed air supply lines, your header pressure may be set a little higher than the load with the highest required pressure, and that’s OK.  If it’s significantly higher, intermediate storage (like EXAIR’s Model 9500-60 Receiver Tank, shown on the right) may be worth looking into.  Keep in mind, every 2psi increase in your header pressure means a 1% increase (approximately) in electric cost for your compressor operation.  Higher than needed pressures also increase wear and tear on pneumatic tools, and increase the chances of leaks developing.
  • Consumption:  Much like newer technologies in compressor design contribute to higher efficiency & lower electric power consumption, engineered compressed air products will use much less air than other methods.  A 1/4″ copper tube is more than capable of blowing chips & debris away from a machine tool chuck, but it’s going to use as much as 33 SCFM.  A Model 1100 Super Air Nozzle (shown on the right) can do the same job and use only 14 SCFM.  This one was installed directly on to the end of the copper tube, quickly and easily, with a compression fitting.
  • Leaks: These are part of your consumption, whether you like it or not.  And you shouldn’t like it, because they’re not doing anything for you, AND they’re costing you money.  Fix all the leaks you can…and you can fix them all.  Our Model 9061 Ultrasonic Leak Detector (right) can be critical to your efforts in finding these leaks, wherever they may be.
  • Pressure, part 2: Not every use of your compressed air requires full header pressure (seems I’ve heard that before?)  Controlling the pressure required for individual applications, at the point of use, keeps your header pressure where it needs to be.  All EXAIR Intelligent Compressed Air Product Kits come with a Pressure Regulator (like the one shown on the right) for this exact purpose.
  • All of our engineered Compressed Air Product Kits include a Filter Separator, like this one, for point-of-use removal of solid debris & moisture.

    Air Quality: Dirty air isn’t good for anything.  It’ll clog (and eventually foul) the inner workings of pneumatic valves, motors, and cylinders.  It’s particularly detrimental to the operation of engineered compressed air products…it can obstruct the flow of Air Knives & Air Nozzles, hamper the cooling capacity of Vortex Tubes & Spot Cooling Products, and limit the vacuum (& vacuum flow) capacity of Vacuum Generators, Line Vacs, and Air Amplifiers.

Everyone here at EXAIR Corporation wants you to get the most out of your compressed air use.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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EXAIR Manufactures Custom Solutions with Precision and Speed

Customs
An Air Amplifier with a PTFE plug (left,) a curved Super Air Knife (center,) and a flanged Line Vac are just a few ways EXAIR has provided custom solutions.

Because EXAIR designs and manufactures our own products here in Cincinnati, we can take advantage of the speed, control, and flexibility that comes with full service manufacturing. If you need a customization of a current production product or if you would like to start a compressed air application from scratch, we can probably help. This is true throughout our entire product line, the following custom examples are of our Super Air Knife products.

Do you have an application that may not be best served by one of our stock Super Air Knife products? While we have quite a variety of both materials, sizes, and connection types sometimes a special application requires a special solution. For this reason,  EXAIR manufactures special Super Air Knives suited EXACTLY for the type of application or environment that it’ll be operating in.

Unique applications are fairly common, and the Super Air Knife provides a great solution to many of them.  Consider these situations:

  • A machine builder had to fit an air knife in a 43″ channel.  We had it covered: we made them a custom (non-stock) 43″ 303SS Super Air Knife and shipped it in three days.
  • A user needed 15″ (and only 15″) of air flow.  A Model 110018 18″ Aluminum Super Air Knife, off the shelf, would provide an “overflow” which would disturb product in the vicinity of the blow off.  We had it covered…a custom shim can be made to provide 15″ (and only 15″) of air flow out of an 18″ Super Air Knife.  It only takes a couple of days to get the special shim. We can make shims to center the airflow, keep it all on one side of the knife, have it come out two separate areas etc.
  • Our customer needed the lightweight of the aluminum air knife, but the ambient air temp was causing the stock plastic shim to melt and cause leaks. So we made a custom 4″ Super Air Knife and installed a Stainless Steel Shim.
custom air knives
If your application is more challenging than a custom shim, we’ve also made Air Knives with (left to right) curved radius, special material (glass filled PEEK shown here,) flat, double-sided, and even one with end-mount threaded holes.

We’ve also made a variety of special Air Knives, when more than just length is a consideration.  So, even if your application is “Unique” it’s very likely that we still have you Covered. Give us a call and we can prove it to you!

Jordan Shouse
Application Engineer
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EXAIR Super Air Knives Improve Labeling Process on Bottling Line

I recently worked with our Argentinian Distributor on an application for a local beverage manufacturer. The customer has a wide range of different beverages that they produce in various sizes and bottles and was having issues with a labeling operation.

plastic water bottles

After the bottles are filled and sealed, they go through a washing operation to remove any contaminants from the outside of the bottle. Afterwards, they make their way along a conveyor where a label is applied around the outside of the bottle. The bottles aren’t always completely dry by the time they get to the labeling step. Any residual moisture on the outside of the bottle can present a problem where the label doesn’t fully adhere to the bottle.

After complaints from their customer about product being received with labels that were peeling off, they implemented a quality check to ensure that the bottles that weren’t properly labeled were fixed before they were shipped out. While this resolved the problem for their customer, it required an extra step.

After searching and discovering EXAIR’s Super Air Knife they reached out for assistance. Due to the variability of the bottle sizes, they needed a solution that was easily adjusted based on what product was being run that day. Fortunately, EXAIR offers a Universal Mounting System for our Super Air Knives that’ll allow them to easily position their blowoff as they need.

The video below shows just how versatile the system is, once locked into position it will stay put until you reposition it! This way, they can set up prior to each shift according to the bottle they’ll be running through.

The solution was to install (2) 110036 36” Super Air Knives with (2) Universal Mounting Systems for each. Any knife 24”-54” will necessitate (2) Universal Mounting Systems, 55”-71” will require (3), 72”-95”, and 96” and over will require (5) to sufficiently support the weight of the knife.

The knives provided a strong blast of air that was able to remove any residual moisture from the exterior of the bottles. This eliminated the need to have a post labeling inspection and the bottles were labeled properly on the first go! Adjustments in between different bottle sizes were made simple with the help of the Universal Mounting System.

SAK pre label blowoff
(2) 110036 Super Air Knives positioned with Universal Mounting System

At EXAIR, we’re all about providing safe, efficient, and reliable solutions to a host of industry related problems. With same day shipment for stock items with an order received by 3:00 ET and a team of highly trained Application Engineers, we’re ready to take your call and get a solution out to you today. Don’t just take my word for it, find out for yourself!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Plastic bottle photo courtesy of Klearchos Kapoutsis via Creative Commons License

Reduce Sound Level in your Factory, Improve Worker Safety and Comfort

Checking the sound level in your processes is an important aspect of ensuring a safe working environment for your employees. Loud noises and the exposure time can lead to significant health concerns. Permanent hearing loss, increased stress levels due to the uncomfortable work environment, and potential injury due to lack of concentration or inability to hear the surroundings are all examples of some risks associated with a noisy environment.

The Occupational Safety and Health Administration, known by most simply as OSHA, introduced Standard 29 CFR 1910.95(a) as a means of protecting operators from injury associated with high noise levels. The chart below indicates maximum allowable exposure time based on different noise levels. At just 90 dBA, an operator can operate safely for 8 hours. Open end pipe blowoffs and some air guns fitted with cross drilled relief holes will often result in noise levels in excess of 100 dBA. At 110 dBA, permanent hearing loss can be experienced in just 30 minutes!

OSHA Chart

The first step to lowering your sound level is to take a baseline reading of your various processes and devices that are causing the noise. EXAIR’s Sound Level Meter, Model 9104, is an easy to use instrument that provides a digital readout of the sound level. They come with an NIST traceable calibration certificate and will allow you to determine what processes and areas are causing the most trouble.

SoundMeter_new_nist225

From there, EXAIR has a wide range of Intelligent Compressed Air Products® that are designed to reduce compressed air consumption as well as sound levels. For noisy blowoffs where you’re currently using an open-ended pipe or a loud cross-drilled nozzle, EXAIR’s Super Air Nozzles are the ideal solution. Not only will they pay for themselves over time due to compressed air savings, but your operators will thank you when they’re able to hear later on in life!!

Drilled pipe is another common culprit of high noise levels. Rather than purchasing an engineered solution, the idea is that a simple drilled pipe is just as effective right? Not at all!! Not only does a drilled pipe produce exceptionally high sound levels, but the amount of compressed air used is also very inefficient. EXAIR’s Super Air Knife is available in lengths ranging from 3”-108” and has a sound level of just 69 dBA at 80 PSIG. At this sound level, operators won’t even require hearing protection at all!

SAK vs drilled pipe
EXAIR’s Super Air Knife is the ideal solution for replacing noisy, inefficient drilled pipe

With all of these products available in stock, EXAIR has the tools you need to reduce sound level in your processes. If you’d like to talk to an Application Engineer about any applications that you feel could benefit from a sound reduction, give us a call.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Candy Producer Saves $4600 in Compressed Air with EXAIR’s EFC

A few months ago, I took a phone call from a manufacturing engineer who worked at a large candy production facility here in the United States. Extra chocolate was dripping out of the candy molds onto the conveyor belt below.  Within a few hours the belt was dirty enough they would have to stop the line and clean the residual chocolate off the belt. 

The best solution I found was a 72” 316 Stainless Steel Super Air Knife. It worked great when powered at 60 psig inlet pressure. The laminar flow of the Super Air Knife was perfectly suited for this application.  The knife was mounted between the mold and the belt to help solidify and blowoff the excess drips of chocolate. There was one drawback, the Super Air Knife was not needed to blow the belt continuously and the continuous demand was not desirable during peak production.

The simple solution for this was the EXAIR Electronic Flow Control, the EFC minimizes compressed air use by turning off the air when a sensor is triggered. Since there was a 4.5-minute time gap between each mold set this was a great solution. When the photoelectric eye saw a mold, it then told the solenoid valve to open and supply the knife with compressed air for 30 seconds while the mold was open and the excess chocolate would be dripping. See the Savings calculations below;

efcapp

Without using the EFC

(* Using $ 0.25 per 1000 SCFM used)

  • 72” Super Ion Air Knife = 165.6 SCFM @ 60 PSIG
  • 165.6 SCFM x 60 minutes x $ 0.25 / 1000 SCFM = $ 2.48 per hour
  • $ 2.48 per hour x 8 hours = $ 19.84 per 8-hour day
  • $ 19.84 x 5 days = $ 99.20 per work week
  • $ 99.20 per week x 52 weeks =$5,158.40 per work year without the EFC control

 

With the EFC installed (turning the compressed air off for 4 minutes 30 seconds with a 30 second on time = 6 minutes/hour compressed air usage)

  • 165.6 SCFM x 6 minute x $ 0.25 / 1000 SCFM = $ 0.25 per hour
  • $ 0.25 per hour x 8 hours = $ 2.00 per 8-hour day
  • $ 2.00 x 5 days = $ 10.00 per work week
  • $ 10.00 per week x 52 weeks = $520.00 per work year with the EFC control 

$ 5,158.40 per year (w/o EFC) – $ 520.00 per year (w/ EFC) = $4,638.40 projected savings per year by incorporating the EFC.

EFC287x250

This example illustrates, clearly, why choosing the EFC is a good idea. It has the ability to keep compressed air costs to a minimum and saves compressed air for use within other processes around the plant. With this type of compressed air savings, the unit would pay for itself in less than 3 months.

If you would like to see how we might be able to improve your process or provide a solution for valuable savings, please contact one of our Application Engineers.

Jordan Shouse
Application Engineer
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Proper Compressed Air Supply Plumbing Equals Success

EXAIR manufactures and stocks Super Air Knives in lengths ranging from 3”-108”. They’re designed to dramatically reduce compressed air usage when compared to similar blowoffs while still maximizing both force and flow. With an air entrainment ratio of 40:1, it’s the ideal solution for a variety of applications that necessitate a wide, laminar sheet of high velocity airflow.

I recently worked with a customer who makes wooden pallets. They were using a Model 110048 48” Super Air Knife to remove sawdust from the pallets prior to stacking them. When the grooves are cut into the pallet to accommodate the forks from a forklift or pallet-jack, there’s a good amount of sawdust that remains on the pallet. They would prefer to not have sawdust all over the finished pallets that they send to customers, so they looked towards a Super Air Knife to provide a curtain of air capable of removing that sawdust just prior to stacking them.

They purchased the Model 110048, but after installing it they didn’t get the level of force they had been hoping for. After some initial discussions, we identified that the issue lied with the plumbing of the air supplied to the knife. A 48” Super Air Knife will need to be fed with compressed air to (3) of the ¼ NPT air inlets. This ensures that an adequate volume of air is fed to the full length of the knife, keeping a consistent airflow.

Not only had they been plumbing compressed air to just (1) air inlet, but they were also using a restrictive quick-disconnect fitting. The I.D. of a quick connect fitting restricts the overall volume of air that can be passed through it. Length of the pipe or hose is also critical as the diameter of the pipe will need to be larger for longer runs or greater volumes. Accompanying any Super Air Knife is our Installation & Maintenance Guide which outlines the necessary requirements for each available length that we have available as well as how many air inlets need to be supplied with compressed air.

SAK pipe sizing

To confirm that air supply was the issue, they installed a pressure gauge directly at the air inlet to the knife. Line pressure was around 90 PSIG, but when they opened the valve and supplied air to the knife the pressure gauge dropped all the way to 35 PSIG. We’ve talked about pressure drop before here on the EXAIR Blog, the only way to confirm this is to take a pressure reading directly at the air inlet.

They removed the quick disconnect fitting, increased to a 1/2″ supply hose in place of 1/4″, and plumbed compressed air to each end and the center air inlet. On all Super Air Knives, compressed air inlets are available on either end as well as on the bottom. After fixing their plumbing, they noticed a dramatic increase in both force and flow and the pressure directly at the air inlet increased to 85 PSIG. The sawdust was easily blown off of the pallets and the customer was pleased that their pallets were free of sawdust.

sak pallet

At EXAIR, we stand by our products with the Unconditional 30 Day Guarantee. If you’ve just purchased a new product and aren’t seeing the results that you were hoping for give us a call. Our highly-trained team of Application Engineers is ready and standing by to investigate the application and provide support to help make sure you’re getting the most out of our products. Most of the times the solution is simple, but we won’t be satisfied until we find a resolution!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD