The History of the Man Behind the Friendly Little Demon

James Clerk Maxwell was born in Edinburgh Scotland on June 13, 1831 and from the age of three years old he was described as have an innate sense of inquisitiveness. In 1839 at the young age of 8 years old James’ mother passed away from abdominal cancer which put the boy’s father and father’s sister-in-law in charge of his schooling. In February of 1842 James’ father took him to see Robert Davidson’s demonstration of electric propulsion and magnetic force; little did he know that this event would strongly impact on his future.

Fascinated with geometry from an early age James would go on to rediscover the regular polyhedron before he was instructed. At the age of 13 James’ would go on to win the schools mathematical medal and first prize in both English and Poetry.

Later in his life James would go on to calculate and discover the relationship between light, electricity, and magnetism. This discovery would lay the ground work for Albert Einstein’s Special Theory of Relativity. Einstein later credit Maxwell for laying the ground work and said his work was “the most profound and the most fruitful that physics has experienced since the time of Newton.”. James Maxwell’s work would literally lay the ground work for launching the world into the nuclear age.

Starting in the year 1859 Maxwell would begin developing the theory of the distribution of velocities in particles of gas, which was later generalized by Ludwig Boltzmann in the formula called the Maxwell-Boltzmann distribution. In his kinetic theory, it is stated that temperature and heat involve only molecular movement. Eventually his work in thermodynamics would lead him to a though experiment that would hypothetically violate the second law of thermodynamics, because the total entropy of the two gases would decrease without applying any work. His description of the experiment is as follows:

…if we conceive of a being whose faculties are so sharpened that he can follow every molecule in its course, such a being, whose attributes are as essentially finite as our own, would be able to do what is impossible to us. For we have seen that molecules in a vessel full of air at uniform temperature are moving with velocities by no means uniform, though the mean velocity of any great number of them, arbitrarily selected, is almost exactly uniform. Now let us suppose that such a vessel is divided into two portions, A and B, by a division in which there is a small hole, and that a being, who can see the individual molecules, opens and closes this hole, so as to allow only the swifter molecules to pass from A to B, and only the slower molecules to pass from B to A. He will thus, without expenditure of work, raise the temperature of B and lower that of A, in contradiction to the second law of thermodynamics.

Here at EXAIR we are very familiar with Maxwell’s “friendly little demon” that can separate gases into a cold and hot stream. His thought experiment, although unproven in his life time, did come to fruition with the introduction of the Vortex Tube.

Vortex Tube a.k.a Maxwell’s Demon

With his birthday being last weekend I propose that we raise a glass and tip our hats to a brilliant man and strive to remember the brilliant ideas that he gave us.

If you have any questions or want more information on EXAIR’s Cabinet Coolers or like 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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Choosing Max Refrigeration Or Max Cold Temp Vortex Tubes

Vortex Tubes have been studied for over 90 years. These “phenoms of physics” and the theory behind them have been discussed on this blog before. But, when it comes to the practical use of a Vortex Tube it is good to discuss how to correctly select the model that may be needed in your application. The reason being, there are different flow rates and an option for maximum refrigeration or maximum cold temperature.

The tendency is to say, well I need to cool this down as far as possible so I need the coldest air possible, give me the maximum cold temperature. More times than not, the maximum cold temperature model is not the best solution for your application because maximum cooling power and maximum cold temperature are not the same thing.  A maximum cold temperature Vortex Tube is best for spot cooling processes that require greater than 80F temperature drop covering a small area – spot cooling at its finest. Theis very cold air is delivered in a low volume. A maximum cooling power Vortex Tube is the best mix of cold temperature and volume of flow. This cold air (50F-80F temperature drop) is delivered at higher volumes which has the ability to remove more heat from certain processes. If you do not know which is bets for your application, follow these next steps. 

The first step, is to call, chat, or email an Application Engineer so that we can best outfit your application and describe the implementation of the Vortex Tube or spot cooling product for you. You may also want to try and take some initial readings of temperatures. In a perfect world you would be able to supply all of the following information to us, but recognizing how imperfect it all is…some of this information could go a long way toward a solution. The temperatures that would help to determine how much cooling is going to be needed are listed below:

Part temperature:
Part dimensions:
Part material:
Ambient environment temperature:
Compressed air temperature:
Compressed air line size:
Amount of time desired to cool the part:
Lastly desired temperature:

With these bits of information, we can use standard cooling equations to determine what temperature of cold air stream and volume of air is needed in order to produce the cooling and your desired outcome. To give an idea of some of the math we have used, check out this handy educational video of how Newton’s law of cooling was used to calculate the amount of time it takes to cool down a room temp beverage in an ice cold refrigerator. 

If you would like to discuss a cooling application, heating application, or any point of use compressed air application, contact an Application Engineer today.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – ThinkWellVids – Newton’s Law of Cooling – Feb. 27, 2014 – retrieved from https://www.youtube.com/watch?v=y8X7AoK0-PA

Pressure – Absolute, Gauge, and Units of Both

Compressed air is a common utility used throughout industrial facilities and it has to be measured like any other utility in order to know just how much a facility is using. When dealing with compressed air a common unit of measurement that readily comes up is psi, pound-force per square inch. This unit of measure is one of the most basic units used to measure pressure in the compressed air industry. There are other means to measure this though, so let’s discover the difference.

Again, the pressure is a force distributed over an area, the Earth’s atmosphere has pressure, if it didn’t we would all balloon up like the Violet from Willy Wonka, just without eating some prototype gum causing internal pressure. PSIA is a unit of measure that is relative to a full vacuum. It is pounds per square inch absolute (PSIA). The absolute pressure is calculated as the sum of the gauge pressure plus the atmospheric pressure. If you were to travel into space, the atmospheric pressure would be absolute zero which is actually a vacuum. There is nothing pushing from the outside in so the inside pushes out, hence the ballooning.

The atmospheric pressure on earth is based on sea level. This is 14.7 pounds per square inch absolute pressure. This pressure will change along with the weather and the altitude at which the measurement is taken.

So how do we get to the pressure that is displayed on a pressure gauge?  When shown open to room air, my pressure gauge reads zero psi. Well, that is zero psi gauge, this already has the atmosphere showing. It is not showing the Absolute pressure, it is showing the pressure relative to atmospheric conditions. This is going back to the fact that gauge pressure is the summation of absolute pressure and atmospheric conditions, for sea level on earth that is 14.7 psia. So how do we increase this and get the gauge to read higher levels?

We compress the air the gauge is measuring, whether it is using a screw compressor, dual-stage piston compressor, single-cylinder, or any other type of compressor, it is compressing the ambient, atmospheric air. Some materials do not like being compressed. Air, however, reacts well to being compressed and turns into a form of stored energy that gets used throughout industrial facilities.  By compressing the air, we effectively take the air from atmospheric conditions and squeeze it down into a storage tank or piping where it is stored until it is used. Because the air is being compressed you can fit larger volumes (cubic feet or cubic meters) into a smaller area. This is the stored energy, that air that is compressed always wants to expand back out to ambient conditions. Perhaps this video below will help, it shows the GREAT Julius Sumner Miller explaining atmospheric pressure, lack of it, and when you add to it.

Lastly, no matter where you are, there is a scientific unit that can express atmospheric pressure, compressed air pressure, or even lack of pressure which are vacuum levels. To convert between these scientific units, some math calculations are needed. While the video below is no Julius Sumner Miller, it does a great job walking through many of the units we deal with daily here at EXAIR.

 

If you want to discuss pressures, atmospheric pressure, how fast the air expands from your engineered nozzle to atmospheric, why all the moisture in the air compresses with it, and how to keep it out of your process, contact an application engineer and we will be glad to walk through the applications and explanations with you.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Willy Wonka & the Chocolate Factory – Violet Blows Up Like a Blueberry Scene (7/10) | Movieclips, Movieclips, retrieved from https://youtu.be/8Yqw_f26SvM

2 – Lesson 10 – Atmospheric Pressure – Properties of Gases – Demonstrations in Physics,  Julius Sumner Miller, Retrieved from https://www.youtube.com/watch?v=P3qcAZrNC18

3 – Pressure Units and Pressure Unit Conversion Explained, Chem Academy, retrieve from https://www.youtube.com/watch?v=2rNs0VMiHNw

 

The Scientific Legacy of James Clerk Maxwell

On June 13, 1831 at 14 India Street, in Edinburgh Scotland James Clerk Maxwell was born. From a young age his mother recognized the potential in James, so she took full responsibility of his early education. At the age of 8 is mother passed away from abdominal cancer, so his father enrolled him in the very prestigious Edinburgh Academy.

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James was fascinated by geometry at a early age, many times learning something before he was instructed. At the age of 13 he won the schools mathematical medal and first prize in both English and poetry. At the age of 16 he starting attending classes at the University of Edinburgh, and in 1850 he enrolled at the University of Cambridge.

 

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The largest impact he had on science were his discovery’s around the relationship between electricity, magnetism, and light. Even Albert Einstein credited him for laying the ground work for the Special Theory of Relativity. He said his work was “the most profound and the most fruitful that physics has experienced since the time of Newton.”

Maxwell also had a strong interest in color vision, he discovered how to take color photographs by experimenting with light filters.

But here at EXAIR we are very interested in his work on the theory that a “friendly little demon” could somehow separate gases into hot and cold flows, while unproven in his lifetime, did actually come to fruition by the development of the Vortex Tube.  Which does just that.

How A Vortex Tube Works

So here’s to you, James Clerk Maxwell…may we continue to recognize your brilliance, and be inspired by your drive to push forward in scientific developments.

Jordan Shouse
Application Engineer
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Photo credit to trailerfullofpix & dun_deagh