People of Interest: Robert Boyle – 1627 to 1691

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
Twitter: @EXAIR_jb

Robert Boyle image courtesy of Skara KommunCreative Commons License

About OSHA 29 CFR 1910.242(b) for Compressed Air Safety

In February of 1972 OSHA released a standard to improve worker safety when operating handheld compressed air devices being used for cleaning purposes. This directive focuses around human skins permeability. That is, if you were to take an open ended pipe that had compressed air being discharged over 30 psig it can actually push through the skin and create an air embolism.

OSHA’s Directive 29 CFR 1910.242(b)

Air Embolisms are extremely painful, and in extreme cases, can be deadly. The risk associated with an air embolism can be mitigated by following the OSHA directive and reducing the downstream pressure of an air nozzle or nozzle pressure below 30 psi for all static conditions. Dead ending is when the passageway for the air becomes blocked and turns a dynamic flow of air into a static flow. This is in the event the pipe, nozzle, lance, etc. becomes blocked by a human’s body. This is a directive that all Intelligent Compressed Air® products from EXAIR focus on meeting or exceeding.

Our Air Nozzles and Jets video shows a great depiction of how this can be achieved with our engineered design of nozzles. The recessed holes and the fact that there are multiple passages for the air to exit are easy to see on the nozzle. Products like the Super Air Knife may not be so easy to see but the way the air knife cap overlaps prevents the Super Air Knife from being dead ended in the event an operator comes into contact with the discharge air.

Even though this directive was created in 1972 it continues to be at the forefront of industrial environments. I have even been to a custom artwork facility that was effected by this standard because they would use a handheld blowgun to remove dust and debris before matting and framing artwork with glass. They also removed dirt and dust from the frames before paint. This wasn’t your typical manufacturing environment yet they were still held to the same standards and were made safe by implementing engineered solutions such as our Super Air Nozzle.

If you would like to discuss how we can help increase your operator safety and ensure you meet or exceed OSHA 29 CFR 1910.242(b), please contact an Application Engineer today.

Brian Farno
Application Engineer

1 – OSHA Instruction STD 01-13-001 – Retrieved from:

Robert Boyle the Father of Chemistry and Boyles Law

Robert Boyle, one of the founding fathers of modern chemistry and a man who changed the very way we look at scientific research. From the Scientific Method to the very laws that govern gasses, 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.

Robert Boyle

Starting in mid-1644 Robert would make his residence in Dorset England were 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.

Though he was primarily interested in chemistry, one of Boyle’s most famous discovery 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.

Boyle’s Law

In 1669 his health, although which was never very good, began to fail seriously and he withdrew from the public. In his later days he would propose some important chemical investigations which he wanted to leave as a sort of legacy for those who would were also “Disciples of the Art”, essentially future chemists. On the winters day on December 31, 1691 Robert Boyle took his final breath. In his will Robert Boyle left a series of lectures known as the Boyle Lectures the talked about the relationship between Christianity and today’s science.  

Here at EXAIR we use Boyle’s Law everyday as nitrogen, oxygen, and hydrogen (the three main elements that make up air) are all considered ideal gas. This means that all of our products are governed by the relationship between pressure and volume.

If you have questions about any of our quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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Robert Boyle image courtesy of Skara KommunCreative Commons License

Carburetors and Venturi Tubes: Thank You Giovanni Battista Venturi

I know it has been a little while since I blogged about something with a motor so it should be no surprise that this one ties to something with a combustion chamber. This all starts with an Italian physicist, Giovanni Battista Venturi. His career was as a historian of science and a professor at the University of Modena. He gave Leonardo da Vinci’s creations a different perspective by crediting da Vinci to be a scientist with many of his creations rather than just an amazing artist. He then began to study fluid flow through tubes. This study became known as the Venturi Tube. The first patents in 1888 came to fruition long after Giovanni passed away. So what was this Venturi effect and how does it tie in to carburetors let alone compressed air?

The illustration below showcases the Venturi effect of a fluid within a pipe that has a constriction. The principle states that a fluid’s velocity must increase as it passes through a constricted pipe. As this occurs, the velocity increases while the static pressure decreases. The pressure drop that accompanies the increase in velocity is fundamental to the laws of physics. This is another principle we like to discuss known as Bernoulli’s principle.

1 – Venturi

Some of the first patents using Venturi’s began to appear in 1888. One of the key inventors for this was Karl Benz who founded Mercedes. This is how the Venturi principle ties into combustion engines for those that do not know the history. This patent is one of many that came out referencing the Venturi principle and carburetors. The carburetors can vary considerably in the complexity of their design. Many of the units all have a pipe that narrows in the center and expands back out, thus causing the pressure to fall and the velocity to increase. Yes, I just described a Venturi, this effect is what causes the fuel to be drawn into the carburetor. The higher velocity on the input (due to this narrowing restriction) results in higher volumes of fuel which results in higher engine rpms. The image below showcases Benz’s first patent using the Venturi.

2 – Venturi Patent

While carburetors slowly disappear and now can mainly be found in small engines such as weed eaters, lawn mowers, and leaf blowers, the Venturi principle continues to be found in industry and other items. Needless to say, I think Giovanni Battista Venturi would be proud of his findings and understanding how monumental they have been for technological advancements. For this, we will recognize the upcoming day of his passing 199 years ago on April 24, 1822.

Brian Farno
Application Engineer

1 – Thierry Dugnolle, CC0, Venturi.gif, retrieved via Wikimedia Commons

2 – United States Patent and Trademark Office – Benz, Karl, Carburetor – Retrieved from,585.PN.%2526OS%3DPN%2F0382,585%2526RS%3DPN%2F0382,585&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page