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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Process Improvement, ROI and Safety from One Air Nozzle

Process improvement projects can be detailed, complex, expensive, and take a long time to prove their worth.  Today, I want to tell you about one that WAS NOT ANYTHING like that.

A metal stamping company used compressed air to blow their products from their dies.  They did what many do – they ran some copper tubing, and aimed it at the platen so it would properly eject the parts as they were stamped.  They KNEW it was loud, and they suspected it was inefficient as well.

After discussing the setup and seeing a picture of it (the one on the left, below,) I recommended installing a few engineered Super Air Nozzles to lower the noise levels considerably.  Boy, was I wrong.  About “a few” nozzles, that is…turns out, they only needed one Model 1122-9212 2″ Flat Super Air Nozzle with 12″ Stay Set Hose.  The copper tubes come from a manifold that already had 1/4 NPT ports – installation took a matter of minutes.  Nothing detailed, complex, or expensive about it:

This loud & inefficient copper tubing blowoff was just a compression fitting (and a Model 1122 2″ Flat Super Air Nozzle) away from being quiet and efficient.

It didn’t take much longer than that to prove its worth either: as soon as they noticed how much the noise level went down on THIS press, they ordered them for the other eighteen presses in their facility as well.

The 1/4″ copper tubes blew continuously from a pressure regulator set @60psig…the three of them theoretically consumed a total of ~80 SCFM.  The Model 1122, at 60psig supply, consumes only 17.2 SCFM.  Simple return on investment was as follows:

  • 80 SCFM was costing them $48.00 a week
    • 80 SCFM X 60 min/hr X 8 hr/day X 5 days/week X $0.25/1,000 CFM = $48.00
  • 17.2 SCFM, using the same formula, only costs $10.32 a week (I’ll let you do the math; it’s good practice.)
  • They saved $37.68 a week.  The Model 1122-9212 costs $116.00 (2020 pricing) – that means that each of them paid for themselves in just a hair over three weeks.
  • $37.68 x 50 work weeks per year = $1884.00 saved annually per nozzle
  • $1884 x 18 (the number of presses) = $33,912 saved annually 

Considering they also didn’t have to listen to those very loud open ended copper tube blowoffs, I think you’ll have to agree it made for a very good investment.  They did. The new nozzle runs at 77 decibels, a comfortable level and well below the OSHA standard [29 CFR – 1910.95(a)] for allowable noise exposure.

If you’d like to find out how EXAIR Intelligent Compressed Air Products can save you money on compressed air – and save everyone’s hearing – give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Compressor Maintenance: Steps to Minimize Wear

While I was still in college, I worked in a meat processing plant as a Project Engineer in the maintenance department. During my time in the maintenance department I learned the importance of proper maintenance on machines. A meat processing plant is one of the most taxing environments on machines as they will have to survive in extreme cold temperatures to extreme hot temperatures; they are also put through deep sanitation wash downs multiple times a day sometimes for periods of over an hour. The plant really put into perspective the importance of preventative maintenance of machines. This includes utilities such as a boiler and of course your air compressor.

Industrial Air Compressors
Neglected air compressors can cause a lot of issues ranging from expensive repairs to a decrease in efficiency. Wear and tear placed on the motor of an air compressor can cause the compressor to produce less compressed air (SCFM) at the same power consumption. This means you are paying the same amount of money for less compressed air.

A primary focus to prevent an increased amount of wear on your compressor motor is to seal up compressed air leaks. Leaks can cause the compressor to cycle more often and/or refill receiver tanks on a more frequent basis, causing the motor to run more often. With the motor having to run more often to keep the air present, it will wear down faster. Using EXAIR’s Ultra Sonic Leak detector, leaks can be found in the pipes so that they can be sealed up.

EXAIR Ultrasonic Leak Detector
Another important maintenance is to make sure that the compressor gets cleaned. As the motor runs excess heat is generated; the heat generated then needs to be dissipated which is done by exhausting air through vents. If these vents become dirty or blocked and the air cannot escape then the temperature of the motor and winding resistance will increase; this in turn will shorten the life of the motor and increase the energy consumption. Using one of EXAIR’s Super Air Nozzles is a sure way to keep your compressor vents clean and dust free in a quiet and efficient manner.
EXAIR Nozzles
There are many other items that require maintenance over time such as keeping belts in good condition and the drain traps clean. Good maintenance on any item whether it’s a production machine or  air compressor keeps it running a peak performance helping you save money and headaches in the long run. 

If you have any questions about compressed air systems or want more information on any EXAIR’s of our products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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Air Savings Calculator

I received an email from an engineer that was looking at our Super Air Nozzles.  They currently were using four blow-off lines that were made from 6mm ID copper tubes. The system was designed to blow out holes after machining.  The engineer was in charge of the task of optimizing 25 machining stations similar to this one.  He was familiar with EXAIR products from his previous employment, and he recognized the waste of compressed air by using open pipe.  He purchased four Nano Super Air Nozzle, model 1110SS, for a trial.  He was impressed with the performance, the low sound level, and the engineered design in safety.  But, for upper management in his company, he had to show a cost savings in order to change all the stations in the facility.  He asked me to help him in calculating the compressed air savings.

nano nozzle

He gave me some additional details about their application.  He was using the compressed air about 30% of the time throughout an 8 hour day at a pressure of 80 PISG.  He wanted to present the savings per day, week, and year as well as the payback period in his evaluation.  I have performed many of these calculations for other customers and was happy to help.  It is sometimes easier to speak in terms of savings, as everyone can relate to money, especially management.

Knowns:

Flow: 1110SS Nano Super Air Nozzle – 8.3 SCFM at 80 PSIG

Flow:  6mm ID copper tube – 42 SCFM at 80 PSIG

This is where the COST SAVINGS CALCULATOR on our website shines!

The Calculator tells us you will see a ROI (Return on investment) is less than 5 days! And will save you $3,033.00 over a full year on compressed air generation cost alone!

Don’t be fooled by the initial cost of a tube, pipe, drilled holes, or a substandard nozzle.  You can see by the facts above, if you use any additional compressed air in your blow-off application, it will cost you a lot of money in the long run.  If you need any help in calculating how much money EXAIR products can save you, you can use our Air Savings Calculator from our website, or you contact an Application Engineer at EXAIR.  We will be happy to help you.

Jordan Shouse
Application Engineer

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