The Importance Of Properly Sized Compressed Air Supply Lines

EXAIR Corporation manufactures a variety of engineered compressed air products that have been solving myriad applications in industry for almost 37 years now.  In order for them to function properly, though, they have to be supplied with enough compressed air flow, which means the compressed air supply lines have to be adequately sized.

A 20 foot length of 1/4″ pipe can handle a maximum flow capacity of 18 SCFM, so it’s good for a Model 1100 Super Air Nozzle (uses 14 SCFM @80psig) or a Model 110006 6″ Super Air Knife (uses 17.4 SCFM @80psig,) but it’s going to starve anything requiring much more air than those products.  Since compressed air consumption of devices like EXAIR Intelligent Compressed Air Products is directly proportional to inlet pressure, we can use the flow capacity of the pipe, the upstream air pressure, and the known consumption of the EXAIR product to calculate the inlet pressure of a starved product.  This will give us an idea of its performance as well.

Let’s use a 12″ Super Air Knife, with the 20 foot length of 1/4″ pipe as an example.  The ratio formula is:

(P2 ÷ P1) C1 = C2, where:

P2 – absolute pressure we’re solving for*

P1 – absolute pressure for our published compressed air consumption, or C1*

C1 – known value of compressed air consumption at supply pressure P1

C2 – compressed air consumption at supply pressure P2

*gauge pressure plus 14.7psi atmospheric pressure

This is the typical formula we use, since we’re normally solving for compressed air consumption at a certain supply pressure, but, rearranged to solve for inlet pressure assuming the consumption will be the capacity of the supply line in question:

(C2 P1) ÷ C1 = P2

[18 SCFM X (80psig + 14.7psia)] ÷ 34.8 SCFM = 49psia – 14.7psia = 34.3psig inlet pressure to the 12″ Super Air Knife.

From the Super Air Knife performance chart…

This table is found on page 22 of EXAIR Catalog #32.

…we can extrapolate that the performance of a 12″ Super Air Knife, supplied with a 20 foot length of 1/4″ pipe, will perform just under the parameters of one supplied at 40psig:

  • Air velocity less than 7,000 fpm, as compared to 11,800 fpm*
  • Force @6″ from target of 13.2oz total, instead of 30oz*
  • *Performance values for a 12″ length supplied with an adequately sized supply line, allowing for 80psig at the inlet to the Air Knife.

Qualitatively speaking, if you hold your hand in front of an adequately supplied Super Air Knife, it’ll feel an awful lot like sticking your hand out the window of a moving car at 50 miles an hour.  If it’s being supplied with the 20 foot length of 1/4″ pipe, though, it’s going to feel more like a desk fan on high speed.

The type of supply line is important too.  A 1/4″ pipe has an ID of about 3/8″ (0.363″, to be exact) but a 1/4″ hose has an ID of only…you guessed it…1/4″.  Let’s say you have 20 feet of 1/4″ hose instead, which will handle only 7 SCFM of compressed air flow capacity:

[7 SCFM X (80psig + 14.7psia)] ÷ 34.8 SCFM = 19psia – 14.7psia = 4.3psig inlet pressure to the 12″ Super Air Knife.

Our Super Air Knife performance chart doesn’t go that low, but, qualitatively, that’s going to generate a light breeze coming out of the Super Air Knife.  This is why, for good performance, it’s important to follow the recommendations in the Installation Guide:

This table comes directly from the Installation & Operation Instructions for the Super Air Knife.
All Installation Guides for EXAIR Intelligent Compressed Air Products contain recommended air supply line sizes for this very reason.  If you have any questions, though, about proper compressed air supply, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Reduce Sound Levels In Less Than A Minute

Okay, I will admit, the title may be a tad bit leading.  The fact is, it can be done.  I speak to customers almost daily who are struggling with the noise levels produced from open pipe blowoffs.  With Noise Induced Hearing Loss (NIHL) a significant problem among manufacturing workers, reducing the noise form compressed air can be a simple solution and contribute toward reducing overall noise exposure levels. Many of these calls and emails revolve around reducing these exact noise levels, sometimes the open pipes have existing threads on them to install the solution immediately.

To reduce these noise levels, we need to simply reduce the amount of energy that is being expelled through the pipe. How do we do this you might ask?  The use of an air nozzle will reduce the energy being dispersed from an open pipe.  This will result in lower air consumption as well as lower sound levels while actually increasing velocity as the pipe will maintain higher operating pressures. Be cautious about the air nozzle you choose, however, they are not all created equal. EXAIR’s engineered air nozzles are among the quietest and most efficient air nozzles available.

Family of Nozzles

What size pipes can we fit nozzles to?  That’s a great question.  We have nozzles that range from a 4mm straight thread all the way up to 1-1/4″ NPT thread.  This also includes nearly any size in between especially the standard compressed air piping sizes.  For instance, a 1/4″ Sched. 40 pipe that has 1/4″ MNPT threads on it can easily produce over a 100 dBA noise level from 3 feet away.  This can easily be reduced to below 80 dBA from 3′ away by utilizing one of our model 1100 Super Air Nozzles.  All it takes is a deep well socket and ratchet with some thread sealant.

This doesn’t just lower the sound level though, it reduces the amount of compressed air expelled through that open pipe by creating a restriction on the exit point.  This permits the compressed air to reach a higher line pressure causing a higher exit velocity and due to the engineering within the nozzle, this will also eliminate dangerous dead-end pressure and complies with OSHA standard 29 CFR 1910.242(b).

Easy Install

All in all, a 30-second install can make an operator’s work station considerably quieter and potentially remove the need for hearing protection.  If you would like to discuss how to lower noise levels in your facility, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Which Air Nozzle Is Right For Me?

Well, the obvious answer is, of course, an engineered air nozzle…you’re likely aware of this, or you wouldn’t be reading posts on the EXAIR Corporation blog.  We have no issue with narrowing that down a bit, and saying that the answer is an EXAIR air nozzle.  I bet you knew that was coming as well.  So let’s assume that, because of the cost of compressed air, the potential hazards of its unregulated discharge, and the flat-out racket it can make (unless you do something about it,) you’re looking for something efficient, safe, and quiet.

Now that we’re on the same page, let’s unpack that question.  The nature of the application will let us know the airflow pattern & characteristics (mainly flow & force) that we need.

For example, if you need just a pinpoint of airflow, our Atto Super Air Nozzle blows a 1/2″ diameter pattern at a distance of 3″.  Get a little closer than that, and it’s as tight as you want it to be.  Now, it’s only generating a force of 2oz (at 12″ away) but keep in mind that’s all concentrated in a small fraction of an inch diameter.  Which is plenty for most applications that need that precise of an airflow.

Atto Super Air Nozzle

If you DO need a little more flow & force, our Pico and Nano Super Air Nozzles offer incremental increases in performance.  The pattern starts to widen out, but that’s a function of the increased flow expanding in to atmospheric pressure…it has to go somewhere, you know.  But, again, the closer you get, the more focused the flow is to the centerline of the nozzle.

On the other end of the spectrum are EXAIR’s High Force Air Nozzles.  These are particularly useful for stubborn blowoff applications – a foundry blowing slag off hot strip as it cools, for example.  Our largest of these, a 1-1/4 NPT model, generates 23 lbs of force…that’s over 25 times the power of our standard Super Air Nozzle.

 

With 23 lbs of hard hitting force, this 1-1/4 NPT Super Air Nozzle is perfect for the most extreme blow off and cleaning jobs.

Speaking of the standard Super Air Nozzle, it’s the most popular answer to the Big Question.  It’s suitable for a wide range of blowoff, drying, and cooling applications, like the kinds of jobs an awful lot of folks use open end blowoff devices on.  Open ended tubes blow out a great amount of air, but they’re wasteful and noisy, and OSHA says you can’t use them unless you regulate the pressure to 30psig…where they’re not even going to be all that effective.

Choose from (top left to bottom right) 316SS, Zinc Aluminum, or PEEK Thermoplastic…whatever you need to stand up to the rigors of your environment.

If you’ve got a 1/4″ copper tube, for example, it’ll use 33 SCFM when supplied with compressed air at 80psig.  It’ll for sure get the job done (albeit expensively, when you think of all that compressed air consumption,) but it’ll be loud (likely well over 100 dBA) and again, OSHA says you can’t use it at that pressure.  So, you can dial it down to 30psig, where it’ll be marginally effective, but it’s still going to use more air than the Model 1100 1/4 NPT Super Air Nozzle does at 80psig supply pressure.  The hard hitting force of the Model 1100, under those conditions, will make all the difference in the world.  As will its sound level of only 74 dBA.  Not to mention, it’s fully compliant with OSHA 1910.242(b).  Oh…and you can even install it directly on the end of your existing tube with a simple compression fitting.

One of our customers installed Model 1100 Super Air Nozzles on all their lathe blowoff copper tubes, and saved almost $900 a year in compressed air costs.

We’ve also got engineered Air Nozzles smaller than the 1100 (all the way down to the aforementioned Atto Super Air Nozzle) and a good selection of larger ones, including Cluster Air Nozzles that hold tighter airflow patterns than similar performing single Super Air Nozzles.  They’re available in materials ranging from Zinc-Aluminum alloy, bare aluminum, brass, 303SS, 316SS, or PEEK thermoplastic polymer to meet the requirements of most any area of installation, no matter how typical or aggressive.

If you have an loud, wasteful, and likely unsafe blowoff, you owe it to yourself and everyone else who has to put up with it to consider a better solution.  Call me; let’s talk.

Russ Bowman
Application Engineer
EXAIR Corporation
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Free Money! Flat Super Air Nozzles Qualify for Energy Incentive

The patented design of EXAIR’s 1” and 2” Flat Super Air Nozzles makes them a highly efficient option when seeking a powerful, flat airflow. A precise air gap across the width of the nozzle provides a forceful stream of high velocity, laminar airflow without consuming high amounts of compressed air and also resulting in a greatly reduced sound level compared to some of the alternative flat nozzles available in the market.

Flat SAN not dumb picture
EXAIR’s Flat Super Air Nozzles have been blowing away the competition since 2003.

Did you know that upgrading to an efficient engineered air nozzle, such as the 1” or 2” Flat Super Air Nozzle, can make you eligible for an incentive from your energy provider? Similar to other energy-saving programs for upgrading to LED light bulbs or high-efficiency HVAC systems, these are made available to you as an incentive to start using more energy efficient products.

The energy costs associated with the generation of compressed air, often referred to in industry as a 4th utility, can make it expensive. These programs are offered to encourage you to use engineered products that are more energy efficient due to the reduction in compressed air consumption. Essentially, they’re offering you free money to implement a solution that will also save you money. It almost sounds too good to be true!! But these products, after implementation and receiving the incentive, will continue to save you money year after year.

The US Department of Energy, in conjunction with the NC Clean Energy Technology Center, provides a website that allows you to search the various programs available to you in your state. The DSIRE® website allows you to select your state, then select your energy provider to determine what programs are offered.

In Southwest Ohio, Duke Energy provides an incentive that offers $40 USD each per engineered air nozzle that is installed. When replacing open pipe or tube, these nozzles generally pay for themselves relatively quickly. But, when combined with a $40 USD rebate, that return on investment happens even quicker!!!

Don’t leave free money on the table. If you’re using open pipe or tube, or inefficient plastic flat nozzles, replace them with an engineered air nozzle from EXAIR. If you need help determining what rebate programs are available to you in your area, we’re also here to help. Contact an EXAIR Application Engineer today!

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