Tag: air volume

Robert Boyle – Real Men of Genius!

Published on by Jordan T ShouseLeave a comment

EXAIR presents, Real Men of Genius. Today we salute you Mr. Robert Boyle, highly regarded as one of the founders of modern chemistry! Your law perfectly describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system. (Make sure you go back and read that in the old Budweiser song tune!!)

But back on a serious note, Robert Boyle is a man who changed the way we look at scientific research. From the Scientific Method to the laws that govern gases, Robert Boyle was able to change the very way we look at life and solve our problems. One could say that Robert Boyle didn’t really have what you would call a humble beginning; he was born in January 1627 to the 1st Earl of Cork, Richard Boyle and his wife Catherine Fenton at Lismore Castle in Ireland. When he was only 8 years of age, he was sent off to Eton College in order to study under a private tutor. In 1641, Robert would spend the winter in Florence, Italy studying the “paradoxes of the great star-gazer” Galileo Galilei.

Starting in mid-1644, Robert would build his residence in Dorset, England, where he conducted many experiments and from then devote his life to research. In 1654, Boyle would move to Oxford from Ireland in order to further pursue his studies in chemistry. It was here in 1657 that he would read about Otto von Guericke’s air pump, and would set out to improve the system along with Robert Hooke. In 1659, the “Pneumatic Engine” would be completed, and he began a series of experiments on the properties of air. He would further go on to coin the term factitious airs, which is a term used to describe synthetic gases after isolating what is now understood to be hydrogen.

Boyle’s Law

Though he was primarily interested in chemistry, one of Boyle’s most famous discoveries was what is now known as the first of the gas laws, rightfully named Boyles’s Law.  Boyle’s Law defines the relationship between pressure and volume in a closed area given the mass of an ideal gas. Boyle and his assistant Robert Hooke used a closed J-Shaped tube and poured mercury in from the open side, forcing the air on the other side to contract under the pressure. After repeating this using several different amounts of mercury, Boyle deducted that the pressure of a gas is inversely proportional to the volume occupied by it.

Boyles law apparatus
Boyles law apparatus is used to visualize the relationship between the absolute pressure and volume of a gas.

Robert Boyle passed away on December 31st, 1691, and from his work, EXAIR uses the pressure and volume of compressed air for our Intelligent Compressed Air® Products to make them efficient, safe, and effective.  If you would like to speak more about how EXAIR can benefit your pneumatic system, one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
Email: jordanshouse@exair.com
Twitter: @EXAIR_JS

Robert Boyle image courtesy of Skara Kommun, Creative Commons License

Boyles law apparatus image courtesy of Siyavula Education, Creative Commons License

People of Interest: Robert Boyle – 1627 to 1691

Published on by John BallLeave a comment

Being in the compressed air industry for over 35 years, you come across many interesting people from the past that have created laws that we are still using today.   Robert Boyle is one of those people.  He was born on January 25, 1627 in Lismore Castle in Ireland.  He published the book “The Sceptical Chymist” in 1661, and many considered his work to be the foundation of modern chemistry.  He dabbled in many areas of study, but with a young university student, Robert Hooke, they found Boyle’s Law.

 The experiment was performed using a ‘J’ shaped glass tube sealed on the shorter leg, and open to atmosphere on the longer leg.  Mercury was poured into the tube, such that the level was equal on each side. The volume of the trapped air was noted. Additional mercury was poured into the tube, and it was observed that the mercury did not stay level, and measurements of the heights of each tube leg were recorded.  The height difference of the mercury is effectively a measure of the pressure of the trapped air.  Through the experiment and the data, Boyle discovered a relationship between the volume and the pressure of air.  The data as published, is shown below.

Boyle noticed the pressure times the volume of air for the initial condition equaled the pressure times the volume at any other mercury height.  So, the pressure is proportional to the inverse of the volume, Equation 1.

Equation 1: P ∝ 1/V

Or P * V = k (a constant)

For comparing the same substance under two different sets of conditions, Boyle’s law can be expressed as Equation 2.

Equation 2:  P1 * V1 = P2 * V2

Equation 2 looks very familiar.  One of Boyle’s most famous discoveries was to become the first of the gas laws, relating the pressure of a gas to its volume. Combining Boyle’s Law with Charles’s Law, Gay-Lussac’s Law, and Avogadro’s Law; you will have the basis and creation of the ideal gas law;

Equation 3:   P * V = n * R * T

which includes the major factors that affect a gas; temperature, pressure, volume, the amount of the gas, and the ideal gas constant.

Robert Boyle passed away on December 31st, 1691, and from his work, EXAIR uses the pressure and volume of compressed air for our Intelligent Compressed Air® Products to make them efficient, safe, and effective.  If you would like to speak more about how EXAIR can benefit your pneumatic system, one of our Application Engineers can help you determine the best solution.

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

Robert Boyle image courtesy of Skara Kommun, Creative Commons License

ICFM, SCFM, ACFM, CFM What does it all mean!

Published on by Jordan T ShouseLeave a comment

A common question we get asked is “What does SCFM mean?” Most people are aware of CFM but the “S” in front seems to be less known about! Well strap on your seat belt, we are about to go into a compressed air worm hole all about volumetric flow rates!

Here at EXAIR we rate all of our products air consumption in SCFM at a given supply pressure. CFM stands for Cubic Feet per Minute, but one definition will not satisfy the conditions that will be experienced in many applications by a number of variables  (altitude, temperature, pressure, etc.). Air by nature is a compressible fluid. The properties of this fluid are constantly changing due to the ambient conditions of the surrounding environment.

This makes it difficult to describe the volumetric flow rate of the compressed air. Imagine you have a cubic foot of air, at standard conditions (14.696 psia, 60°F, 0% Relative Humidity), right in front of you. Then, you take that same cubic foot, pressurize it to 100 psig and place it inside of a pipe. You still have one cubic foot, but it is taking up significantly less volume. You have probably heard the terms SCFM, ACFM, and ICFM when used to define the total capacity of a compressor system. Understanding these terms, and using them correctly, will allow you to properly size your system and understand your total compressed air consumption.

SCFM is used as a reference to the standard conditions for flow rate. This term is used to create an “apples to apples” comparison when discussing compressed air volume as the conditions will change. EXAIR publishes the consumption of all products in SCFM for this reason. You will always notice that an inlet pressure is specified as well. This allows us to say that, at standard conditions and at a given inlet pressure, the product will consume a given amount of compressed air. It would be nearly impossible, not to mention impractical, to publish the ACFM of any product due to the wide range of environmental conditions possible.

ACFM stands for Actual Cubic Feet per Minute. If the conditions in the environment are “standard”, then the ACFM and SCFM will be the same. In most cases, however, that is not the case. The formula for converting SCFM to ACFM is as follows:

ACFM = SCFM [Pstd / (Pact – Psat Φ)](Tact / Tstd)

Where:

ACFM = Actual Cubic Feet per Minute
SCFM = Standard Cubic Feet per Minute
Pstd = standard absolute air pressure (psia)
Pact = absolute pressure at the actual level (psia)
Psat = saturation pressure at the actual temperature (psi)
Φ = Actual relative humidity
Tact = Actual ambient air temperature (oR)
Tstd = Standard temperature (oR)

The last term that you’ll see floating around to describe compressed air flow is ICFM (Inlet Cubic Feet per Minute). This term describes the conditions at the inlet of the compressor, in front of the filter, dryer, blower, etc. Because several definitions for Standard Air exist, some compressor manufacturers have adopted this simpler unit of measure when sizing a compressor system. This volume is used to determine the impeller design, nozzle diameter, and casing size for the most efficient compressor system to be used. Because the ICFM is measured before the air has passed through the filter and other components, you must account for a pressure drop.

The inlet pressure is determined by taking the barometric pressure and subtracting a reasonable loss for the inlet air filter and piping. According to the Compressed Air Handbook by the Compressed Air and Gas Institute, a typical value for filter and piping loss is 0.3 psig. The need to determine inlet pressure becomes especially critical when considering applications in high-altitudes. A change in altitude of more than a few hundred feet can greatly reduce the overall capacity of the compressor. Because of this pressure loss, it is important to assess the consumption of your compressor system in ACFM. To convert ICFM to ACFM use the following formula:

ICFM = ACFM (Pact / Pf) (Tf / Tact)

Where:

ICFM = Inlet Cubic Feet Per Minute

Pf  = Pressure after filter or inlet equipment (psia)

Tf = Temperature after filter or inlet equipment (°R)

If you’re looking into a new project utilizing EXAIR equipment and need help determining how much compressed air you’ll need, give us a call. An Application Engineer will be able to assess the application, determine the overall consumption, and help recommend a suitably sized air compressor.

Jordan Shouse
Application Engineer

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How Can You Benefit from EXAIR’s Efficiency Lab?

Published on by EricKuhnash@EXAIR.comLeave a comment

How many times have you purchased a new product and worried if it was the right choice? Well EXAIR can provide that confidence using our calibrated testing equipment to compare your current product to an EXAIR product, in our Efficiency Lab. Whenever I needed a new process or product I would spend countless hours researching how will this benefit me, my employer or my customer? Research is not only time consuming but also very costly.

EXAIR believes in their product so much that we offer an Efficiency Lab where we will test your production product and help show that our products will not only work for you, but also show that they can save money, as well as make your work environment a safer place.

EXAIR has provided performance values (force, noise, air consumption, ROI) for many of our products. We make purchasing from EXAIR fun because you know in advance that our products will meet or exceed your expectations. Further backing up our commitment with the Efficiency Lab we offer an 30 Day Unconditional Guarantee. EXAIR believes in our products and want to make your purchase a risk free process.

We can test the performance of your current product to EXAIRs Intelligent Compressed Air products for air consumption, force, noise levels… and provide a comprehensive report of our analysis, including simple ROI.  

What does our Efficiency Lab cost? EXAIR believes in our products so much, that this is a free service to our customers. Simply call and talk to one of our Application Engineers at 800.903.9247 or you can send an email to lab@exair.com or visit www.exair.com and talk on our live help. If you feel we can help with a comparison them simply send your product(s) freight prepaid to EXAIR Corporation attention to our Efficiency Lab. All trials will be on a confidential basis unless you provide permission to share.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK