Contact Time: How to get the most from your EXAIR products

Poor Position vs Good Position

You may have heard us speak about contact time.  I would like to cover what that means in this blog.  Contact time refers to the amount of time that a target part is in the high-velocity airstream produced by an EXAIR blowing product.  The longer the contact time, the more effective the blow-off or cooling effect. Optimizing the mounting position of the EXAIR solution relative to the target makes a huge difference in effectiveness.  When our customers typically purchase EXAIR products, they have a tendency to improperly install them, reducing their performance capabilities.  Let’s look at a Super Air Knife.  In the photo above, you can see the relationship between a perpendicular and a recommended setup angle.  I have some recommendations that can help to increase the contact time and improve the performance. 

Super Air Knife Chamfer
  1. Angle – EXAIR machines a chamfer on the cap of the Super Air Knife as a starting point.  You want to have the chamfer parallel with the target line of movement.  This will create an air flow angle of about 45 degrees relative to the target.  This angle will increase the contact area and contact time, which is very beneficial for removing debris and/or heat.  Depending on the speed and height of the target, this can be altered for further refinement.
  2. Distance – For optimum performance, the Air Knife should be between 3″ (76 mm) to 12″ (305 mm) from the target.  If you are too close, the amplification ratio is sacrificed, and the force is reduced.  If you are too far, the air pattern will start to change, causing the velocity and force to decrease. 
  3. Counter-Flow – The direction of the air flow should be blowing in the direction opposite the target movement.  As an example, if the parts are moving from left to right, you want the Air Knife to blow from right to left.  This will allow the contamination to be blown back away from the cleaned surfaces, and it will increase the impact force to remove contamination, i.e. a head-on collision vs. a rear-end collision.

With these few simple steps, you will begin to maximize the performance and effectiveness of your EXAIR blowing solution.  Some accessories can help with the setup, like Swivel Fittings and Stay Set Hoses for the nozzles and the Universal Mounting Kit for the Air Knives.  You can modify the impact angle to best suit complex parts and systems.  If you need any help to get the most out of our products, you can contact an Application Engineer at EXAIR.  We will be happy to hear from you.     

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

EXAIR Efficiency Lab at Your Service

I couldn’t count the number of times we have written a blog about the EXAIR Efficiency Lab because its that cool, unlike the number of wins the Cincinnati Reds have right now. I can count that on two hand 10………10-26 as of writing this blog and I could go on and on about the pain but I will spare you the tears and write about how amazing the Efficiency lab is for any company that utilizes compressed air!

Is the Mascot signing something? Or hanging his head? We will never Know!

First – what is the EXAIR Efficiency Lab? Well several years ago EXAIR created a free program called the Efficiency Lab.  This program is to compare your current pneumatic blow-off device with an EXAIR engineered product.  The values we compare are air consumption, noise level and force. We generate a detailed report to send to you for review.  It is a free service that EXAIR provides for U.S. and Canadian companies to know more details about solutions you are currently using in your processes.

The EXAIR Efficiency Lab

Why do we offer this?  Air Compressors demand significant electrical power and compressed air is considered to be a fourth utility within plants and industries.  Many people do not realize the cost and safety concerns when using improper blow-off devices.  As an example, if you look at a single 1/8” open pipe for blowing compressed air, it can cost you over $2,000 a year to operate.  This will add to your overhead and cut profits.  Another reason to consider your blow-off device is that compressed air can be dangerous.  With that same 1/8” open pipe, it can violate OSHA standards for noise exposure and dead-end pressure.  In deciding your “vehicle” for blowing compressed air, cheap is not typically best option.  To put it in other terms, a cheap nozzle is like a cheap old car, it’s cheap because it gets 3 MPG with faulty brakes.

With our Efficiency Lab, a comparison it is quite simple to do.  An easy way is to call us and explain the details. These details can be data such as the inside diameter and length of a an open tube you are using, or the actual performance data of a cheap air nozzle you have chosen to use. Perhaps the easiest way to make the comparison is to let EXAIR do it – send in your blowoff product or a sample of the tube, nozzle, modified fitting, etc. We will then put them through our testing process. You can also fill out our Product Efficiency Survey on our website to give the conditions for testing. 

We will run the tests at the specified conditions or in a range of settings.  We will then return your pneumatic device back to you at our cost with a detailed report of the comparison.  Your information will be confidential, and we will not share it without your permission.  We will also provide a simple ROI – many customers like to use this report to show managers, executives, HSE, etc. on the improvements that EXAIR can provide including cost savings and safety.

How do we do the Efficiency Lab?  We use calibrated equipment and standardized procedures to test for noise levels, flow usage, and force measurements.  We will recommend an EXAIR engineered solution as a replacement to your current device to do the comparison.  With the analytical information, we can also figure the total amount of air savings, return on investment, payback period and safety improvements.

Don’t Swing and miss…. (Like the Reds)  You do not want to sacrifice safety, time, and money with a sub-standard product.  Let EXAIR solve this dilemma with our free service; the Efficiency Lab.  Take advantage of our expertise by using the Efficiency Lab service, we will provide you a detailed report with a comparison analysis to make a great choice. 

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

Reds Image Provided by IndyDina with Mr. Wonderful via Creative Commons Attribution 2.0 Generic (CC BY 2.0)

EXAIR’s Efficiency Lab Shows How Much Compressed Air You Can Save

The EXAIR Efficiency Lab

EXAIR has been manufacturing compressed air products since 1983, and we created a culture of making high quality products that are safe, effective, and very efficient.  Since we stand by our products, we created a program called the Efficiency Lab.  This program is to compare your current pneumatic blow-off device with an EXAIR engineered product.  The values we compare are air consumption, noise level and force. We generate a detailed report to send to you for review.  It is a free service that EXAIR provides for U.S. and Canadian companies to know more details about solutions you are currently using in your processes.

Why do we offer this?  Air Compressors demand significant electrical power and compressed air is considered to be a fourth utility within plants and industries.  Many people do not realize the cost and safety concerns when using improper blow-off devices.  As an example, if you look at a single 1/8” open pipe for blowing compressed air, it can cost you over $2,000 a year to operate.  This will add to your overhead and cut profits.  Another reason to consider your blow-off device is that compressed air can be dangerous.  With that same 1/8” open pipe, it can violate OSHA standards for noise exposure and dead-end pressure.  In deciding your “vehicle” for blowing compressed air, cheap is not typically best option.  To put it in other terms, a cheap nozzle is like a cheap old car, it’s cheap because it gets 3 MPG with faulty brakes.

With our Efficiency Lab, a comparison it is quite simple to do.  For starters, you can go to our Product Efficiency Survey on our website to give the conditions for testing.  If you wish for a side by side analysis, you can place your pneumatic device (nozzle, open tube, modified fitting, etc.) in a box and send it to EXAIR.  We will run the tests at the specified conditions or in a range of settings.  We will then return your pneumatic device back to you at our cost with a detailed report of the comparison.  Your information will be confidential, and we will not share it without your permission.  We will also provide a simple ROI – many customers like to use this report to show managers, executives, HSE, etc. on the improvements that EXAIR can provide in cost savings and safety.

How do we do the Efficiency Lab?  We use calibrated equipment and standardized procedures to test for noise levels, flow usage, and force measurements.  We will recommend an EXAIR engineered solution as a replacement to your current device to do the comparison.  With the analytical information, we can also figure the total amount of air savings, return on investment, payback period and safety improvements.

Don’t be fooled; not all blow off devices are the same.  You do not want to sacrifice safety, time, and money with a sub-standard product.  Let EXAIR solve this dilemma with our free service; the Efficiency Lab.  Take advantage of our expertise by using the Efficiency Lab service, we will provide you a detailed report with a comparison analysis to make a great choice. 

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

What is Laminar Flow and Turbulent Flow?

Super Air Knife

Fluid mechanics is the field that studies the properties of fluids in various states.  There are two areas, fluid statics and fluid dynamics.  Fluid dynamics studies the forces on a fluid, either as a liquid or a gas, during motion.  Osborne Reynolds, an Irish innovator, popularized this dynamic with a dimensionless number, Re. This number determines the state in which the fluid is moving; either laminar flow or turbulent flow.  Equation 1 shows the relationship between the inertial forces of the fluid as compared to the viscous forces.

Equation 1:  Re = V * Dh/u

Re – Reynolds Number (no dimensions)

V – Velocity (feet/sec or meters/sec)

Dh – hydraulic diameter (feet or meters)

u – Kinematic Viscosity (feet^2/sec or meter^2/sec)

The value of Re will mark the region in which the fluid (liquid or gas) is moving.  If the Reynolds number, Re, is below 2300, then it is considered to be laminar (streamline and predictable).  If Re is greater than 4000, then it is considered to be turbulent (chaotic and violent).  The area between these two numbers is the transitional area where you can have eddy currents and some non-linear velocities.  To better show the differences between each state, I have a picture below that shows water flowing from a drain pipe into a channel.  The water is loud and disorderly; traveling in different directions, even upstream.  With the high velocity of water coming out of the drain pipe, the inertial forces are greater than the viscosity of the water.  This indicates turbulent flow with a Reynolds number larger than 4000.  As the water flows into the mouth of the river after the channel, the waves transform from a disorderly mess into a more uniform stream.  This is the transitional region.  A bit further downstream, the stream becomes calm and quiet, flowing in the same direction.  This is laminar flow.  Air is also a fluid, and it will behave in a similar way depending on the Reynolds number.

Turbulent to Laminar Water

Why is this important to know?  In certain applications, one state may be better suited than the other.  For mixing, suspension and heat transfer; turbulent flows are better.  But, when it comes to effective blowing, lower pressure drops and reduced noise levels; laminar flows are better.  In many compressed air applications, the laminar region is the best method to generate a strong force efficiently and quietly.  EXAIR offers a large line of products, including the Super Air Knives and Super Air Nozzles that utilizes that laminar flow for compressed air applications.  If you would like to discuss further how laminar flows could benefit your process, an EXAIR Application Engineer will be happy to help you.

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