Force And Flow…Which One Is The Right Tool For The Job?

If you’re even a casual, occasional reader of the EXAIR Blog, you know we write an awful lot about efficiency…namely, the ability of engineered products to conserve compressed air, while optimizing its effectiveness. Oftentimes, these blogs are inspired by a conversation we’ve had with a user of simple and inexpensive (but wasteful and unsafe) blow off devices, such as open-end tubing, or drilled pipes. The first thing the caller wants to talk about is the force produced by one of our products…will it be the same as what’s being currently used?

The quick answer is no. In fact, if you’re looking for maximum force, there’s no better way to get it than simply blowing compressed air out the end of an open pipe. This has to do with nothing more complicated that grade school science – converting the potential energy (due to the compression of the air) to kinetic energy (what happens when it’s put into motion.) See, with an open-end blow off, almost all of the potential energy is converted to force. Plain old brute force. And it works GREAT for blowing stuff around…the larger the opening, and the higher the supply pressure; the more air will flow, and faster. Thing is, to produce a good blow off, you don’t need maximum force.

EXAIR’s Intelligent Compressed Air Products are engineered to use some of that potential energy of the compressed air to entrain large amounts of “free” air from the surrounding environment. That’s the purpose of the jets recessed between the fins of our Super Air Nozzles, and the Coanda profile of our Air Knives, Air Wipes, & Air Amplifiers.

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 air from the surrounding environment.

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 air from the surrounding environment.

These designs reduce the amount of compressed air that is used, which reduces the load on your air compressor, which makes everyone happy (OK, maybe not that happy, but pretty happy still.) They also mean that your blow offs will be quieter, and safer.

Perhaps your application calls for higher force. If that’s the case, EXAIR’s Air Knives, Air Amplifiers, and Air Wipes can be fitted with thicker shims for additional flow and force. So can our Flat Super Air Nozzles. And our largest High Force Super Air Nozzles are capable of generating up to 23lbs (10.4KG) of force.

Perhaps, though, your application calls for the highest force that can only be achieved with an open-end blow off. If that’s the case, you can still meet OSHA compliance through the use of extra protective equipment, pressure relief valves, guarding devices, etc. But the costs of those measures can make the cost of engineered products pale in comparison, so I highly recommend you make sure of what you need.

If we can be of any assistance with that, give us a call.  We can discuss your application, and get you the right tool for the job.

Russ Bowman
Application Engineer
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There Must Be A Better Way To Save…

 

I’m writing this blog at almost the top-dead-center midpoint of Spring Break week. My teenage sons have been “enjoying” their time off thus far with the housekeeping duties their mother has been assigning them, and the labor they’ve been providing their uncle, as he installs a new garage door for us…the one my mother-in-law paid for. I definitely married out of my league.

The last half of Spring Break, though, we’re taking a little vacation. We looked at the activities and attractions at our destination, came up with a plan on what to do and when (including an analysis of the 10 day weather forecast…which prompted me to find our rain ponchos) and have even purchased some tickets in advance, because advertising “5% SAVINGS!” on stuff really works on me, even when it’s on a $20 ticket. Before you grab your calculator, yeah…that’s a dollar. But since there are four of us, I’ve multiplied our savings by 400%! Yes; I know…four bucks.  Still, I’ll take it.

We talk to folks almost every day who want, like I do, to save money on goods and services they’re going to purchase anyway. Some have performed comprehensive energy audits, and identified opportunities to lower their compressed air generation and/or consumption rates. Others have just been looking at the bent copper tubes that are blowing off their parts and thinking there has to be a better way.

(Full disclosure: I’ve had these two exact conversations so far this week.)

Today, I want to tell you about the latter: It’s an aluminum casting plant with about a dozen lines where a robot grabs a fresh casting from the machine, dips it in a quench tank, and holds it in front of an array of copper tube blow offs for a few seconds before placing it in a bin, bound for the machine shop. Not only were they blowing at it from both sides with the copper tubes, but they were also blowing continuously…including the majority of the cycle time that did NOT include holding the part in the air flow.  Dear reader, if you’re familiar AT ALL with the EXAIR blog, you’ll know that we simply cannot abide that. Continuous flow when flow is only needed a fraction of the time is wasteful and expensive. Not to mention blowing air out of open tubes is dangerous, loud and requires and unneccessary volume of compressed air.

It's like they WANT to upset us.  What's up with that?

It’s like they WANT to upset us. What’s up with that?

They installed (2) Model 110018 18” Aluminum Super Air Knives, in place of the copper tubing, which cut down on their air consumption…and noise levels…considerably. I gave them some further recommendations on reprogramming the robot to turn the part in front of one Air Knife, and using an EFC Electronic Flow Control to turn the air off when a part was not present.

EXAIR's EFC automatically turns the air off when a part is not present.

EXAIR’s EFC automatically turns the air off when a part is not present.

Is there a better way to use the compressed air in your facility? Whether you’ve got comprehensive data from a detailed audit, or if that open pipe is just too darn loud, all the time – give me a call…we’ll find out.

Russ Bowman
Application Engineer
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Air Knives – What Are They Good For?

It is rare that a week goes by without a unique application of an EXAIR product…

This week I was speaking with a DJ who wished to use an air knife to create a blast of air that would add emphasis to the musical experience had by his fans. He wanted a small burst of air that would last less than a second, but would add an additional element to an already very complicated setup. My initial reaction was that no DJ I have ever seen would possibly be able to supply an air compressor big enough to feed the air knives, but over the course of our conversation, I found out that the DJ travels with 2 semi trucks of equipment, so he had some space.

SAK

An Aluminum EXAIR Super Air Knife

Another topic that came up in our conversation was how air knives were generally used. I have been asked this in a number of ways: What are they designed to do? Where do they work best? or What are they for?

I never have a succinct answer… The air knives create a flat laminar sheet of air in various sizes from 3″ up to 108″. This laminar sheet of air can be used to move, open, float, or separate. It can be used to clean, dry, or cool. I try to categorize these applications as best I can when speaking to customers, but then you talk to a DJ, and he wants an air knife to make a crowd cheer. I never thought that would be an application for an air knife. Knowing this, how do you convey all the air knife can do in a succinct answer?

Well, I can’t, so please be patient when you ask me the same question and I run through applications from cleaning surfaces to entertaining DJ crowds.

Here is a rundown of air knife applications. In case you don’t believe me.

Move: Air Knives are used around to world to move product from a conveyor to another location.

Open: Air Knives uniform air flow is perfect for opening bags or other packaging on a packaging machine.

Float: If you need to bridge a gap between two conveyors, the air knife has done this for products from pizza dough to sheets of veneer.

Clean: Blowing products off after removing them from a CNC machine is an easy air knife application.

Dry: One of my tastiest applications was to use an air knife to blow water from a potato chip after washing, but before frying.

Cool: Extrusion, molds, and baked goods have all been cooled with an air knife.

Just because it isn’t on this list though, doesn’t mean it is not possible.  This is why we will stand behind our stock product with our 30 day guarantee.   So if you want to try an EXAIR Air Knife in your application, give us a call.

30 Day Guarantee

30 Day Guarantee

Dave Woerner
Application Engineer
@EXAIR_DW
DaveWoerner@EXAIR.com

Product of the Year Award Winner- Long Super Air Knives

20150327_134253

Plant Engineering’s 2014 Product of the Year Award!

 

Last week, Plant Engineering presented EXAIR’s Long Super Air Knives the Bronze award for Product of the Year in the compressed air category.  In 2014, EXAIR introduced one piece, seamless Long Super Air Knives up to 108″ in length. No other company in the world can provide a one piece compressed air operated air knife over 54″ long. This one piece design allows for minimal footprint for long units, and an unparalleled uniform sheet of laminar air flow.  These long Super Air Knives conserve compressed air over drilled pipes or a manifold of air nozzles. Their compact design excels at large web drying and cleaning operations i.e. paper, rolled steel, aluminum foils, or plastic sheets. Air knives also excel at cooling extrusions, molds, heated rollers, or components. The air knives entrain ambient air at 40:1 ratio (40 parts ambient to 1 part compressed air) which means it moves a tremendous volume of air and delivers it to your target. The Super Air Knives provide all of these benefits quietly and efficiently. The air knife creates only 69 dBA of noise at 80 PSIG of pressure and it would be a great addition in areas where anyone is trying to limit harmful noise exposure to personnel.

 

LSAKpr_110072PKI_300x300

72″ Long Super Air Knife – One Piece Air Knives available in lengths up to 108″

These air knives continue EXAIR’s history of pushing the envelope in air knife technology. In 2010, EXAIR introduced the first polyvinylidene fluoride (PVDF) air knife to the market. The PVDF Super Air Knives provide resistance to UV light, inorganic chemicals, solvents, ozone, weather, fungi, chlorinated hydrocarbons, highly corrosive acids, weak bases and salts while maintaining a quiet operation (69 dBA).  This material change opened EXAIR to a variety of environments that cannot be served by blowers, aluminum, or stainless steel air knives.

For any questions about EXAIR’s Air Knives please contact an Application Engineer at 1-800-903-9247.

Dave Woerner
Application Engineer
@EXAIR_DW
DaveWoerner@EXAIR.com

 

Tag Teams

Some of the perks with my job are the ways we create solutions.  And with this solution, we had to create a “Tag Team” to meet the criteria.  We have a customer that has a long conveyor line that travels outdoors from a quarry to the facility.  The issue was with snow.  With the amount of snow that we have been getting this winter in the northern regions, they had to try and keep their product free from snow and ice.  Most of the time, the snow could be easily displaced with our Super Air Knives.  But, when the temperature increased; the snow became wet and heavy.  This would cause the wet snow to stick and roll up into small snow balls.  With the speed that the conveyor was traveling, the Super Air Knives needed help.

 

Knife and Nozzle (Tag Team)

Knife and Nozzle (Tag Team)

In analyzing a solution, we could increase the shim thickness to increase the force.  But when the temperature decreased and the snow was light and fluffy, the excess compressed air would be wasted.   We decided to add High Power 2” Flat nozzles with the Flexible Stay Set Hoses.  They were positioned at different angles to break the wet snow into smaller forms.  Then the Super Air Knives would clear the finer snow off the product.  If the temperature decreased and the wet snow was not an issue, the High Power 2” Flat Nozzles could be shut off.  This kept the conveyor running as well as saving compressed air during the cold season.  In some applications, we may have to combine EXAIR products to solve a problem.  If you ever feel that your compressed air application seems difficult, just tag one of our Application Engineers to team up and find a solution.

John Ball
Application Engineer
johnball@exair.com
twitter.com/exair_jb

 

EXAIR Distributor Solves Problem For End User

Our Thai distributor, OilPure Management Systems, recently worked through an application with an end user in need of both debris and heat removal at a gas cylinder recycling facility.

Dirty cylinder

Dirty cylinder which needs to be cleaned and cooled

In this application, the end user needed to remove heat and debris from the gas cylinders shown above.  These cylinders are recycled and as part of the recycling process, the previous exterior coating and labeling must be removed.  To remove the coating and labels, the cylinders are subjected to a rigorous cleaning and heating process that leaves them with debris around the O.D. of the cylinder at a temperature around 300°C.

Cylinders travelling through chamber

Cylinders exiting the last stage of cleaning and heating

Given the need to simultaneously remove debris and cool the cylinders, our distributor recommended a series of Super Air Knives mounted around the exterior in a hex pattern.

Cylinders with SAKs

Proposed solution to removed debris (and heat) from the exterior of the cylinders

After travelling through the air curtain made by the series of Super Air Knives, the cylinders will have been treated for both debris and heat, preparing them for a final coating to look like the finished product shown below.

Final coated cylinders

Final product, re-coated

If you have a need for EXAIR products, contact an Application Engineer or consult one of our worldwide distributors.  (For an interactive map of EXAIR distributors around the world, click here.)

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

What Size Pipe Should I Use?

Yesterday, I had a customer with a tough application for a Standard Air Knife. The customer was quenching individual 11″ x 11″ steel plates in oil after they had been heated to over 1,200° Celsius. Following quenching, the plate is pulled out of the oil with a fair amount of excess oil still attached. This excess oil is relatively hot and could be dangerous, if it drips from the plates as they are conveyed to the next process. The oil removed from the tank is also lost, so the tank needed to be refilled regularly. This oil added up to quite a large expense every year for this company. The customer installed (2) 12″ Standard Air Knives above the oil quenching tank to blow the oil off of the plate back into the oil quenching tank as the plate is raised out of the tank and in between the two air knives.

How the Standard Air Knife Works

How the Standard Air Knife Works

The customer called to express some disappointment about the air knife performance, I asked him a few questions about his application.

Q:What pressure is supplied to the air knife?
A: 100 PSI
Q: Where are you measuring this pressure?
A: That is our shop pressure and the pressure I’m measuring at the regulator.
Q: How are you connecting the regulator to the air knife?
A: We are using 10 feet of 3/8″ ID tubing.

At this point I suspected that the problem was in the compressed air supply line. To confirm this, I asked the customer to install a pressure gauge in the unused air inlet of the air knife. This pressure gauge read only 52 PSIG. The customer had a pressure drop of 48 PSI through the 10 foot of 3/8″ tubing, fittings, and valves that connected the regulator to the air knife.  The 12 inch Standard Air Knife utilizes 41 SCFM of compressed air when fed with 80 PSIG. In order to determine what to expect for a reasonable pressure drop, you could use EXAIR’s Air Data charts. According to EXAIR’s air data chart, for 1/8″ schedule 40 iron pipe, which has around 1/4″ ID (Which is very similar to the Inside Diameter of the 3/8″ tube) at 8 SCFM of flow the line will create a 18.6 PSIG pressure drop. When you try and shove more than 8 SCFM through the 3/8″ OD (1/4″ ID) tubing, you create a higher pressure drop. In this customer’s case it created a 48 PSI drop across the air line. This 48 PSI pressure drop was caused by the supply line as well as the fittings or valves used to connect valve to the regulator. This pressure drop limited the air knife to only 52% of its performance. In an application with a viscous fluid like oil , this drop in pressure led to lower force upon the steel plate and disappointing performance.

After getting the proper plumbing in place, the pressure drop was eliminated and the the Air Knives were operating at peak performance to remove the oil from the plates.

During the course of our troubleshooting, the customer also discovered Russ Bowman’s excellent video Proper Supply Plumbing for Compressed Air Products. In the video, our customer discovered the impact both the cross sectional area and overall length of compressed air piping can have on the performance of an air operated device.

The customer wanted to use a 12″ Air Knife to blow off the oil from the plates, which is a great application for the air knife. By properly plumbing the supply of an Air Knife, the customer contained hot oil, reclaimed quenching oil for future use, and maintained a clean shop floor. This installation was well worth the time and effort of installing the air knife properly. If the customer would like, we also have a Super Air Knife which will only use 35 SCFM and could help to save more compressed air. This savings of 7 SCFM may not seem like much, but it will have a significant impact on the energy cost of running his air compressor.

Dave Woerner
Application Engineer
@EXAIR_DW
DaveWoerner@EXAIR.com

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