Air – What Is It?

Air… We all breathe it, we live in it, we even compress it to use it as a utility.  What is it though?  Well, read through the next to learn some valuable points that aren’t easy to see with your eyes, just like air molecules.

Air – It surrounds us – (Yosuke,1)
  1. Air is mostly a gas.
    • Comprised of roughly 78% Nitrogen and 21% Oxygen.  Air also contains a lot of other gases in minute amounts.  Those gases include carbon dioxide, neon, and hydrogen.
  2. Air is more than just gas.
    • While the vast majority is gas, air also holds lots of microscopic particulate.
    • These range from pollen, soot, dust, salt, and debris.
    • All of these items that are not Nitrogen or Oxygen contribute to pollution.
  3. Not all the Carbon Dioxide in the air is bad.
    • Carbon Dioxide as mentioned above is what humans and most animals exhale when they breathe.  This gas is taken in by plants and vegetation to convert their off gas which is oxygen.
    • Think back to elementary school now.   Remember photosynthesis?
      • If you don’t remember that, maybe you remember Billy Madison, “Chlorophyll, more like Bore-a-fil.”
    • Carbon dioxide is however one of the leading causes of global warming.

      Moisture In The Air – (Grant)2
  4. Air holds water.
    • That’s right, high quality H2O gets suspended within the air molecules causing humidity.  This humidity ultimately reaches a point where the air can simply not hold anymore and it starts to rain.  The lack of humidity in the air leads to static, while lots of moisture in the air when it gets compressed causes moisture in compressed air systems.
  5. Air changes relative to altitude.
    • Air all pushes down on the Earth’s surface.  This is known as atmospheric pressure.
    • The closer you are to sea level the higher the level of pressure because the air molecules are more densely placed.
    • The higher you are from sea level the lower the density of air molecules.  This causes the pressure to be less.  This is also why people say the air is getting a little thin.

Hopefully this helps to better explain what air is and give some insight into the gas that is being compressed by an air compressor and then turned into a working utility within a production environment.  If you would like to discuss how any of these items effects the compressed air quality within a facility please reach out to any Application Engineer at EXAIR.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Air – Creative Commons – Tsurutea Yosuke – https://www.flickr.com/photos/tsurutayosuke/47732716442/in/photolist-2fHYDBG-dd5e5z-5snidD-oaU8fm-68kqiz-8sMG3P-fnqYx7-9bkTrx-5P2BDv-6R75dG-9vi5xL-5yADR-8EAFci-9NQvER-8sMGoR-4Uybwo-9bNqfB-6N9qf8-6LZyG-7MF4aZ-dehz3-5h1wXk-6uJWNq-7eQCUU-6qoUm6-8sQHxo-uqDdE-6NDHW3-8sQMDQ-7wyCsV-dd5io5-5yAwX-ZmCdh2-BMZCW-agSno-bQ8UFK-6d8Pkz-ars544-novykD-3PF1FT-W13jE9-3GSRLj-7r9Msu-6yn1Ne-32iJKf-7CPqWv-8qhcn-4Eicvh-LLgb4-54ixko

2 – DSC_0750 – Creative Commons – David Grant – https://www.flickr.com/photos/zub/24340293/in/photolist-39Kwe-2cZxjuw-6ywctR-26b7Z2F-84vqJN-bpjRN3-6aDzQR-i84BUr-xbu1Us-fxyvn-5UPDBh-VDz7nD-8Be4fP-a6MVGC-nP4end-PA5nb9-3ddwtq-nRF2yr-j4XPzo-cd5CvJ-eoGFTQ-rYNapy-pKAJpQ-pVrbq6-21hFhHB-n8hpva-7uMwPs-4EZ9ok-jGahK-foR798-JP9rcG-cMRjhu-i74Qo-2d1nE-7nXj3e-9tMib1-6JrXP-9tMdnd-4o5ZCx-6uk2LG-9Gt8K4-5xksdV-9tJgMa-9tMh8b-kkZNy5-c8oM8C-8reqky-4KXe87-aFt7kn-MNNDwU

Video Blog: How To Calculate Air Consumption At A Pressure Other Than Published Values

The below video shows how to calculate the air consumption when operating at any pressure.

If you want to discuss efficient compressed air use or any of EXAIR’s engineered compressed air products, give us a call or email.  We would enjoy hearing from you!

Steve Harrison
Application Engineer
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How to Calculate SCFM (Volume) When Operating at Any Pressure

If you need to operate at a different pressure because you require less or more force or simply operate at a different line pressure, this formula will allow you to determine the volume of air being consumed by any device.

Volume Formula

Using the EXAIR 1100 Super Air Nozzle as our example:

1100

Lets first consider the volume of the 1100 Super Air Nozzle at a higher than published pressure.  As shown in the formula and calculations it is simply the ratio of gauge pressure + atmospheric divided by the published pressure + atmospheric and then multiply the dividend by the published volume.  So as we do the math we solve for 17.69 SCFM @ 105 PSIG from a device that was  shown consume 14 SCFM @ 80 PSIG.

higher

Now lets consider the volume at a lower than published pressure.  As shown it is simply the ratio of gauge pressure + atmospheric divided by the published pressure + atmospheric and then multiply the dividend by the published volume.  So as we do the math we solve for 11.04 SCFM @ 60 PSIG from a device that was shown to consume 14 SCFM @ 80 PSIG.

lower

When you are looking for expert advice on safe, quiet and efficient point of use compressed air products give us a call.  Experience the EXAIR difference first hand and receive the great customer service, products and attention you deserve!  We would enjoy hearing from you.

Steve Harrison
Application Engineer
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Find us on the Web 
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Estimating the Cost of Compressed Air Systems Leaks

Leaks in a compressed air system can waste thousands of dollars of electricity per year. In fact, in many plants, the leakage can account for up to 30% of the total operational cost of the compressor. Some of the most common areas where you might find a leak would be at connection joints like valves, unions, couplings, fittings, etc. This not only wastes energy but it can also cause the compressed air system to lose pressure which reduces the end use product’s performance, like an air operated actuator being unable to close a valve, for instance.

One way to estimate how much leakage a system has is to turn off all of the point-of-use devices / pneumatic tools, then start the compressor and record the average time it takes for the compressor to cycle on and off. The total percentage of leakage can be calculated as follows:

Percentage = [(T x 100) / (T + t)]

T = on time in minutes
t = off time in minutes

The percentage of compressor capacity that is lost should be under 10% for a system that is properly maintained.

Another method to calculate the amount of leakage in a system is by using a downstream pressure gauge from a receiver tank. You would need to know the total volume in the system at this point though to accurately estimate the leakage. As the compressor starts to cycle on,  you want to allow the system to reach the nominal operating pressure for the process and record the length of time it takes for the pressure to drop to a lower level. As stated above, any leakage more than 10% shows that improvements could be made in the system.

Formula:

(V x (P1 – P2) / T x 14.7) x 1.25

V= Volumetric Flow (CFM)
P1 = Operating Pressure (PSIG)
P2 =  Lower Pressure (PSIG)
T = Time (minutes)
14.7 = Atmospheric Pressure
1.25 = correction factor to figure the amount of leakage as the pressure drops in the system

Now that we’ve covered how to estimate the amount of leakage there might be in a system, we can now look at the cost of a leak. For this example, we will consider a leak point to be the equivalent to a 1/16″ diameter hole.

A 1/16″ diameter hole is going to flow close to 3.8 SCFM @ 80 PSIG supply pressure. An industrial sized air compressor uses about 1 horsepower of energy to make roughly 4 SCFM of compressed air. Many plants know their actual energy costs but if not, a reasonable average to use is $0.25/1,000 SCF generated.

Calculation :

3.8 SCFM (consumed) x 60 minutes x $ 0.25 divided by 1,000 SCF

= $ 0.06 per hour
= $ 0.48 per 8 hour work shift
= $ 2.40 per 5-day work week
= $ 124.80 per year (based on 52 weeks)

As you can see, that’s a lot of money and energy being lost to just one small leak. More than likely, this wouldn’t be the only leak in the system so it wouldn’t take long for the cost to quickly add up for several leaks of this size.

If you’d like to discuss how EXAIR products can help identify and locate costly leaks in your compressed air system, please contact one of our application engineers at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

 

 

 

Dirty Compressed Air Consequences Are Avoidable

I would like to discuss the importance of clean and dry filtered air.  This all comes from some discussions I have had with customers over my time here at EXAIR, as well as from my time in the machine tool industry. It is notable to state that we simply ask for clean/dry air to run through our products, not “instrument” or “process” air which is typically held at a different pressure, temperature, or volume and can be more expensive to generate. All of EXAIR’s products use general plant air and can be cleaned up with simple point of use filters.

Clean and dry compressed air is essential for ensuring a long and easy life of almost any compressed air product.   One product in particular that I have some data on is the EXAIR Line Vac.  The pictures below show the inside wall of a Stainless Steel Line Vac.  This unit was used in a harsh outdoor environment.   The compressor was not maintained and did not have any form of filtration on the lines feeding the Line Vac unit. The first picture shows where all the dirt and particulate were impacting the internal generator wall as it entered the air chamber.

Damaged Generator

The two dark grey marks are actually the impact points on the unit.   There is only one air inlet on the Line Vac, this means that the unit was taken apart during the two months and actually inspected then put back together and the generator was rotated slightly during this process.  These spots are similar to what sandblasting does to metal, just to illustrate how much particulate was in the air stream. Since the air has not yet reached its full velocity within the Line Vac, it has left only those visible surface blemishes.

As the air begins to exit the array of small generator holes it begins to rapidly increase in velocity while it is trying to expand to atmospheric conditions.  Because of this increased velocity, the wear the generator holes experience is greater and as seen below it is causing some extreme wear.

Worn Generator Holes

To give you an idea of what a new generator should look like is below. Here you can see uniform holes that go precisely through the generator.

IMG_4283

To prevent a disaster like this from happening to your end-use compressed air products, all you need are some simple, low maintenance filters.   EXAIR offers dirt / water filter separators that will filter your compressed down to 5 micron particulate size.   The will catch the good majority of rust, water, and dirt within your compressed air system.   Then you can also install an oil removal filter which will filter all oils and particulate out of your compressed air system down to 0.03 micron particulate level.

Each of these units are great point of use filtration to keep any of your processes from experiencing what this Line Vac experienced.   If you have any questions about the quality of your compressed air or why you are seeing failures in product on your compressed air system, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF