Proper Air Supply Is Key To Optimal Performance

I recently worked with a customer who was using our 36″ aluminum Super Air Knife to remove dust and light debris from a conveyor but wasn’t seeing good performance. They initially called because they read in their catalog that increasing the shim gap would increase their force and flow and wanted to know what kind of increase in performance they would see.

The Super Air Knives are shipped from EXAIR with a .002″ shim installed and the performance data shown in the catalog reflects this gap setting. The shim sets, for aluminum knives, include a .001″, .003″ and .004″ shim and by changing to the .003″ shim, the force and flow would be 1.5 times as great and using the .004″ shim would double these amounts. While some applications do require the additional force and flow, trying to blow off dust or light materials typically wouldn’t fall into this category.

sak-shims

Replaceable shims provide varying levels of force and flow.

Switching our focus to the supply side of things, it turns out they were using 1/4″ hose and only plumbing one end of the unit. This poses 2 concerns that relate directly to the mentioned poor performance. The first would be the 1/4″ hose is severely undersized for a 36″ Super Air Knife. We recommend 3/4″ Schedule 40 pipe if the length of supply from a main header is 10′ or less and a 1″ pipe up to 50′ of supply run. It is possible to use hose but that hose needs to be at least 1″ ID to be able to carry enough volume to support a 36″ unit. Secondly, for knives that are 24″ in length or longer, you need to plumb air to both ends to maintain an even, laminar flow across the length of the knife.

With the proper supply, the Super Air Knife is going to produce an exhaust air velocity of 11,800 feet per minute when operated at 80 PSIG, which is more than enough to eject lightweight material from a flat surface (in fact you could most likely clean dust and light debris at a lower pressure). If the customer did increase the shim gap dimension, the increase in  air demand would only worsen the problem of undersized supply lines.

Pipe sizes

Recommended supply line sizes per the IOM – Installation and Operation Manual.

This is just one example of how proper supply line size and installation is key to achieving optimal performance. If you are experiencing similar issues or need any assistance with a product or application, give me a call, I am glad to help.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

How Do You Make Cement? Start with Clinkers

Last week I wrote about the use of the Atomizing Nozzles to create a fog for wet room curing of concrete samples poured during road construction.  This week, I had the opportunity to work with another customer about concrete, but this time it was regarding the the manufacturing process.  Invariably, I always learn something new , and for this interaction, it was the term ‘clinkers.’

Concrete is a composite material composed of coarse aggregate bonded together with a fluid cement that hardens over time.  The customer I was working with was a cement manufacturer.  Cement production is basically a 2 step process – 1) clinker is produced from raw materials and 2) cement is produced from cement clinker.

clinkers

Typical Cement Clinkers

To make the clinker (step one), several powder raw materials are fed into a rotary kiln.  The kiln is heated to very high temperatures, and when the materials are mixed and heated, new compounds are formed and hydraulic hardening occurs resulting in the formation of the clinker.

My customer needed a way to clean off the residual dust left on the transport belts, after the clinkers were transported to storage silos.  Due to the high temperatures in the area, we focused in on the EXAIR Type 303 Stainless Steel model of the Super Air Knife, as it can withstand temperatures up to 800°F.  The customer went with (3) of the Super Air Knife Kits, which include the Shim Set, Auto Drain Filter Separator, and Pressure Regulator w/ Gauge, for easiest installation with maximum functionality.

The Super Air Knife is a tried and true product for cleaning, drying, cooling and general blowoff for conveyors.  And with widths up to 108″ available, any size conveyor can be handled.

To make cement (step two), the clinker is ground into fine powder with other ingredients including gypsum (calcium sulphates) and possibly additional cementitious (such as blastfurnace slag, coal fly ash, natural pozzolanas, etc.) or inert materials (limestone). It is then stored or packaged and ready to be made into concrete.

To discuss your application and how an EXAIR Super Air Knife can benefit your process, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Finding The Right Solution Through Dedicated Engineering Support

crate

Plastic crate in need of blow off after washing

An OEM of crate washing equipment in Lebanon recently contacted me about an application on one of their conveyors.  The conveyor carries a plastic crate out of a washer and excess water on the crate was presenting a problem in the application.  In order for the crate to move on to the next step in the machine, a blow off solution was needed, but the exit rate from the washer was inconsistent.  In a given minute there could be 5 crates exit the washer, or there could be 20.  So, the ideal solution needed to have intermittent control options with instantaneous on/off functionality.

We immediately began discussing Super Air Knives, not only because we show plastic crate blow off in one of our many videos, but also because these units are instant on/off with full compatibility with a flow control device.  Utilizing a flow controller, such as the EXAIR Electronic Flow Controller or PLC device, will allow for precise control of the blow off solution, limiting compressed air use to a minimum.

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The first blow off system design

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This layout utilizes Air Knives on each side of the blow off as well as the top

After discussing application details we came to the design shown above, using one 24” Air Knife on the top of the crate and two 9” Air Knives on the sides.  However, this OEM had purchased numerous 2” Flat Stainless Steel Super Air Nozzles in the past (model 1122SS) and had a number available on site.  Modifying the system to utilize the nozzles already on-site, we came to this design:

system-layout

The finalized layout for this blow off system. Click for a larger view.

This layout utilizes (1) 24” Stainless Steel Super Air Knife on the top of the crate and (2) sets of (3) 2” Flat Stainless Steel Super Air Nozzles on the sides, held in place with EXAIR Stay Set HosesNotice the independent pressure regulators for the nozzles and the knife.  This is to allow the customer to balance the air flows, because the 2” flat nozzles will create a higher force than the Air Knife when operating at the same pressure.

In this application we were able to help a returning OEM solve their problem with the right mix of needed products.  Exploring the problem and discussing numerous viable solutions led to the best fit for the application and customer.  That’s precisely why EXAIR Application Engineers are available for any application call or question.  If you’d like to explore an EXAIR solution we’ll be happy to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

 

Cookie Blowoff Using The Full-Flow Air Knife

A machine manufacturer was working with a food company who was looking to design a blowoff station for their cookie making process. During the production cycle, the cookie dough is put into a former that pushes the dough through round dyes that forms several rows of cookies across a conveyor. As the cookies travel down the conveyor, they are topped with ground peanut bits and sent through a flash freezing process. It was after this process, the company was looking to install the blowoff station to remove any excess peanut bits but were concerned if the air velocity was too high, they may remove too much of the ground peanuts or possibly blow the cookies themselves off of the conveyor. Another area of concern was the amount of space available to install the station was limited, so they were needing something “compact” so they could design the machine to take the least amount of real estate as possible.

The machine designer was somewhat familiar with our Air Knives, but was unsure which design would best fit the customer’s needs so they decided to reach out for assistance. After discussing the particulars, I recommended our 36″ Stainless Steel Full-Flow Air Knife Kit. Of the 3 designs of Air Knife we offer, the Super, Standard and Full-Flow, the Full-Flow Air Knife produces the lowest outlet velocities, it is also our smallest profile offering at only 1.25″ x 1″  for stainless steel construction. The Full-Flow Air Knife provides a laminar flow of air the entire length of the knife and uses a 30:1 amplification rate (entrained air to compressed air) for efficient compressed air usage. By incorporating the pressure regulator included in the kit, they would be able to easily control the exiting air velocity to effectively remove the excess peanut bits without ejecting the cookies from the line.

Full-Flow

The Full-Flow Air Knife is the ideal choice where mounting space is limited. Lengths available up to 36″ in aluminum or stainless steel construction.

For assistance in selecting the best Air Knife to fit your needs or for additional support with another application or EXAIR product, give me a call at 800-903-9247, I’d be happy to help.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Cooling Punch Points with a Super Air Knife

A stamping facility had a high speed perforating operation. The idea was to punch holes into a matrix at a fast feed rate.  In their operation, they started to see issues with the punched holes, and they also noticed that the punch points were prematurely failing.  With a tight punch-to-matrix clearance, heat was building up from the friction.  This effect was galling the material and affecting the hole appearance and dimensions.  They also noticed heat damage to the punch points.  They either had to slow their process down, or find a way to cool the punch points.  They contacted EXAIR to see if we could help.

To remove heat, you need to have a fluid moving across the material to carry the heat away. For this customer, the fluid would be air.  Just like a hot cup of coffee, you can cool it by blowing across the top of it.  In this instance, EXAIR can blow a lot of air with using very little amount of compressed air.  Because of the gap opening of the tool die was narrow, I suggested the Super Air Knife.  It has a compact design and can blow nicely between the upper and lower die.  With slight modifications, they were able to mount the Super Air Knives right into the base set.  Because the tool die was a “bowl” type design, I suggested that they should use two pieces of the model 110206 Super Air Knife.  They could mount one to each side to make sure to hit all the punch points.  (Reference the picture below).

Punch Press with a Super Air Knife

Punch Press with a Super Air Knife installed

EXAIR Super Air Knives are the most efficient compressed air knives in the market. It is designed to have a 40:1 amplification ratio.  That means for every one part of compressed air, it will entrain 40 parts of the free ambient air.  As with the coffee reference above, the more air that you can blow, the better the cooling effect.  With the Super Air Knife, we can reach a velocity of 11,800 feet per minute at 80 PSI.  After the customer installed the Super Air Knives, they were able to increase production by 10%.  Also, they found that the punch points were lasting twice as long.  They were so impressed with the effectiveness of the Super Air Knives, they mounted them to all their punch press machines.

Super Air Knife

Super Air Knife

If you find that heat is affecting your process, EXAIR could have a product to help you. We have a variety of efficient air movers to cool your parts.  As for this customer above, we were able to increase production and extend the life of their tools.

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

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.

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

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Seven days of accumulation without the Super Air Knife installed

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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

Explanation of OSHA Standard 1910.242(b)

Open air lines and homemade blow offs violate OSHA standard 1910.242(b) because of harmful dead end pressures. In 1972, OSHA established Standard 29 CFR 1910.242(b) requiring that the outlet pressure of an open pipe, nozzle, air gun, etc., when used for cleaning purposes, must remain below 30 PSI with the intent to protect workers from serious injury. They determined that when dead-ended against the skin, if the outlet pressure reached 30 PSI 0r higher,  it posed a risk of entering the bloodstream through the skin. This is commonly referred to as an air embolism – a serious condition which can be life threatening. Once air has entered the bloodstream, it can restrict the free movement of blood throughout the body, disrupting normal heart function, leading to abnormal heart rhythm, possible lung or brain damage, cardiac arrest, stroke or possible death.

OSHA explains that you can use compressed air for cleaning purposes, as long as the outlet or source is fitted with some type of relief device that drops the outlet pressure to below 30 PSI if dead ended. There are basically two ways to go about gaining compliance. The first is to regulate the operating supply pressure to less than 30 PSI, assuring that the outlet pressure doesn’t exceed the threshold. While this does comply with the Standard, it can negatively affect the performance by reducing the strength of the outlet flow, limiting the usefulness of the blowoff device.

The other method is to use some type of nozzle which includes a pressure reducer or a relief device which will reduce the air pressure to less than 30 PSI if the nozzle is dead ended.

For example, EXAIR engineered air nozzles are designed so the outlet holes cannot be blocked directly. Any potential obstruction of the outlet air holes results in the air having an alternative exit path to avoid injury to operators and personnel.

sag-osha-compliant

With our Super Air Nozzles, the air exits through a series of jets, recessed behind an array fins so the exhausting airflow can never be blocked.

With the design of our Super Air Knife, the cap overlaps the body, leaving a gap on both sides of the knife, allowing the exhausting air to safely vent.

osha-sak

Picture of the Super Air Knife, showing how the cap overlaps the body and cannot be blocked, providing a safe exit path.

ALL of EXAIR‘s engineered products incorporate these principles, providing some type of relief, allowing for the air to safely vent well below the 30 PSI requirement, meeting and in many cases, exceeding the OSHA Standard.

To discuss how EXAIR can help you gain OSHA compliance to improve operator safety, avoid costly fines and improve overall efficiency, contact an application engineer for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

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