Video Blog: Which EXAIR Air Knife Is Right For You?

The following short video explains the differences between the 3 styles of Air Knives offered by EXAIR – The Super, Standard and Full-Flow. All of these Models are IN STOCK, ready to ship, with orders received by 3:00 PM Eastern.

If you need additional assistance choosing your EXAIR Air Knife, please contact an application engineer at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

EXAIR Blogs This Week Are Almost As Cool As Shark Week

Yes, ALMOST. This week, the EXAIR Blog has featured some excellent explanations of the science behind the operation of compressed air products. On Tuesday, John Ball posted the best explanation of SCFM vs ACFM that I’ve come across, and I’ve been explaining this to callers for almost four years now. I’m using his blog to perfect my “elevator pitch” on this topic. It will still likely require a building with more than ten floors, but I think that’s OK.

Also on “Two Blog Tuesday,” (this week only; I’m not trying to start anything) Dave Woerner’s gem of a blog detailed the terminology associated with pressure measurement, and why we use “psig” (g = gauged) – in a nutshell, the compressed air inside the pipe doesn’t care what the pressure outside the pipe is. And, since he mentioned it, I might add that most of agree that we care even less about how a certain NFL team’s footballs were (or were not) properly inflated.

Brian Farno’s “One Blog Wednesday” entry was a quite useful (if not alphabetical…OK; now I AM trying to start something) list of some common terms and expressions we use on a regular basis while discussing the operation and performance of EXAIR compressed air products. If you liked his photo demonstration of the Coanda effect with the foam ball & Super Air Amplifier, I encourage you to experience the Coanda effect for yourself, if you have access to a leaf blower and a volleyball:

I mention these earlier blogs to get to the point of MY blog today…a bit of theory-to-practice, if you will. Once you’ve gotten a decent understanding of these principles (or have the above links bookmarked for quick reference,) we can apply it to what’s needed for the proper operation of a compressed air product itself.

With a working knowledge of air flow (SCFM) and compressed air supply pressure (psig,) we can more easily understand why certain pipe sizes are specified for use with particular products. For instance, the longer the Super Air Knife and/or the longer the run of piping to it, the larger the pipe that’s needed to supply it:

This table comes directly from the Installation & Operation Instructions for the Super Air Knife.

This table comes directly from the Installation & Operation Instructions for the Super Air Knife.

The reasons for this are two-fold: First, the pipe…longer runs of pipe will experience more line loss (a continuous reduction in pressure, due to friction with the pipe wall…and itself) – so, larger diameter pipe is needed for longer lengths. For another practical demonstration, consider how much faster you can drink a beverage through a normal drinking straw than you can through a coffee stirrer. Not as dramatic as the leaf blower & volleyball (you really want to try it now, don’t you?) but you get my point.

Second, the Air Knife…the longer the Air Knife, the more air it’s going to use. And, if it’s longer than 18”, you’ll want to feed it with air at both ends…line loss will occur in the plenum as well.

In closing, I want to leave with another video, shot right here at EXAIR, showing the actual reductions in pressure due to line loss through different lengths, and diameters, of compressed air supply line to a Super Air Knife.

If you ever have any questions about compressed air use, or how EXAIR products can help you use your compressed air more efficiently, safely, and quietly, please give us a call.

Russ Bowman
Application Engineer
Find us on the Web
Follow me on Twitter
Like us on Facebook

A (Sample) Lexicon For Compressed Air

Every industry and different technical subject matter comes with it’s own lexicon of terms or vocabulary words.  More often than not, when speaking to an Application Engineer here at EXAIR you are going to hear words within our lexicon. The list I have compiled below is merely a sampling to help translate some terms that we forget not everyone knows.  Some of these are merely acronyms that get thrown around a good amount.

SCFM – Standard Cubic Feet per Minute – This is the unit we use to represent the volumetric flow rate of compressed gas that has already been corrected to standardized conditions of pressure and temperature.

PSIG – Pounds per square inch gauge – This is the unit which we use to represent the operating inlet pressure of the device.  When requesting this, we generally are looking for a pressure gauge to be installed directly on the inlet to the device with no other form of restrictions between the two.  For the most part, catalog consumption values are given in SCFM at 80 psig.  The main exception to that rule are the Vortex Tube based products.

Compressed Air – This is a utility that most industrial manufacturing facilities have available to them.   It is regular, atmospheric air which has been compressed by an air compressor to a higher pressure than atmospheric.  Generally speaking, compressed air systems will be at a range of 85-120 psig.

OSHA – Occupational Safety and Health Administration – This is the main federal agency that enforces two of the major conformance standards that EXAIR products meet or exceed.

29 CFR- 1910.95 (a) – Maximum allowable noise level exposure.  The great majority of EXAIR products meet or exceed this safety standard, our largest Super Air Nozzles
1910.242 (b) – This is the standard which states compressed air blow off devices cannot exceed 30 psig of dead end pressure.  This means, if the exit point of the air can be blocked the operating pressure must be below 30 psig.  The reason for this standard is to prevent air embolism which can be fatal.  All EXAIR products meet or exceed this standard by having multiple orifice discharge.

Coanda Effect – This is the effect that numerous EXAIR products utilize to amplify and entrain ambient air.   The Coanda effect is when a fluid jet (stream of compressed air) tends to be attracted to a nearby surface.  This principle was found by a Romanian aerodynamics pioneer, Henri Coandᾰ.  The picture below shows a Super Air Amplifier blowing a foam ball into the air and suspending it due to the Coanda effect on the surface of the ball.

A Super Air Amplifier's air stream causes a foam ball to be suspended in mid air thanks to the Coandᾰ effect.

A Super Air Amplifier’s air stream causes a foam ball to be suspended in mid air thanks to the Coandᾰ effect.

Rigid Pipe or Hard Pipe – This is the term we will often use when discussing the compressed air line that can be used to support and supply certain EXAIR products.  Generally we are referring to a Schedule 40 steel pipe, Type L copper line, stainless steel tube, or any form of pressure rated hard pipe that can be used for supplying compressed air.

Plenum – the state or a space in which a gas, usually air, is contained at pressure greater than atmospheric pressure. Many of our products feature a plenum chamber. 

Again, this list is only a sample of the terminology you will hear us use when discussing compressed air applications.  If there are any other air/compressed air/fluid dynamic terms you may be unsure of, please contact us.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

%d bloggers like this: