People of Interest: Robert Boyle – January 25, 1627 – December 31, 1691

Robert Boyle was born on January 25, 1627 in Lismore Castle, County of Waterford, Ireland.  He was an Anglo-Irish natural philosopher, chemist, physicist and dabbled in many other areas of study. He published the book The Sceptical Chymist in 1661, and many consider him and his work as the foundation of modern chemistry.  He was a very devout Anglican, and published numerous works in this area as well.

Robert Boyle

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. With Robert Hooke, a young university student as his laboratory assistant, Boyle began experimenting with air.  Together they made their first great discovery, now known as Boyle’s Law.

J-Tube 2
Boyle used a ‘J’ Tube – Sealed on the Short End, and Open at the Long End

The experiment was performed using a ‘J’ shaped glass tube sealed on the shorter leg, and open to atmosphere on the longer leg.  Quicksilver (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 on each tube leg were recorded.  The height difference of the mercury is effectively a measure of the pressure of the trapped air. Boyle, through the experiment and the data,  discovered a relationship between the volume and the pressure of air.  The data as published, is shown below.

Boyle's Data

Boyle noticed the pressure times the volume of air for the initial condition equaled the pressure times the volume at any other mercury height.

Known as Boyle’s Law – P ∝ 1/V,      pressure is proportional to the inverse of the volume

Alternately, PV = k,       pressure times volume is equal to a constant

For comparing the same substance under two different sets of conditions, the law can be expressed as P1V1 = P2V2

Of note is that Boyle’s Law, combined with Charles’s law and Gay-Lussac’s Law formed the combined gas law, and in combination with Avogadro’s law is the basis for the ideal gas law – PV=nRT, which include temperature, the amount of the substance, and the ideal gas constant to the mix.

It is noted that Boyle credited fellow scientist Richard Towneley for making the connection between the pressure of a gas and volume, but Boyle’s experiments and observations using the ‘J’ tube confirmed Towneley’s predictions, and the rest as they say is history.

If you would like to talk about compressed air or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Experiment Data from the book New Experiments Physico-Mechanicall, Touching the Spring of the Air, and Its Effects (1660)

 

About Sliding Vane Air Compressors

Over the last few months, my EXAIR colleagues have blogged about several different types of air compressor types including single and double acting reciprocating and rotary screw. (You can select the links above to check those out.) Today I will review the basics of the sliding vane type, specifically the oil/lubricant injected sliding vane compressor.

The lubricant injected sliding vane compressor falls under the positive displacement-type, the same as the other types previously discussed.  A positive displacement type operates under the premise that a given quantity of air is taken in, trapped in a compression chamber and the physical space of the chamber is mechanically reduced.  When a given amount of air occupies a smaller volume, the pressure of the air increases.

Each of the previous positive displacement type compressors use a different mechanism for the reduction in size of the compression chamber.  The single and double acting reciprocating use a piston that cycles up and down to reduce the compression chamber size. The rotary screw uses two inter-meshing rotors, where the compression chamber volume reduces as the air approaches the discharge end.  For the lubricant sliding vane type, the basic design is shown below.

Sliding Vane2
Air enters from the right, and as the compression chamber volume reduces due to counterclockwise rotation, the pressure increases until the air discharges to the left

The compressor consist of an external housing or stator, and the internal circular rotor, which is eccentrically offset.  The rotor has radially positioned (and occasionally offset) slots in which vanes reside.  As the rotor rotates, the centrifugal forces on the vanes cause them to move outwards and contact the inner surface of the stator bore.  This creates the compression areas, formed by the vanes, rotor surface and the stator bore.  Because the rotor is eccentrically offset, the volume of the compression area reduces as the distance between the rotor surface and the stator reduces.  As the rotor turns counterclockwise, the vanes are pushed back into the rotor slots, all the while in contact with the stator surface.  The shrinking of the compression area leads to the increase in air pressure.

Oil is injected into compression chamber to act as a lubricant, to assist is sealing, and to help to remove some of the heat of compression.

The advantages of the lubricant sliding vane compressor type is very similar to the lubricant injected rotary screw.  A few key advantages include:

  • Compact size
  • Relatively low initial cost
  • Vibration free operation- no special foundation needed
  • Routine maintenance includes basic lubricant and filter changes

A few of the disadvantages include:

  • Lubricant gets into the compressed air stream, requires an air/lubricant separation system
  • Requires periodic lubricant change and disposal
  • Less efficient than rotary screw type
  • Not as flexible as rotary screw in terms of capacity control in meeting changing demands

EXAIR recommends consulting with a reputable air compressor dealer in your area, to fully review all of the parameters associated with the selection and installation of a compressed air system.

If you would like to talk about compressed air or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Diagram:  used from Compressed Air Challenge Handbook

Coast to Coast and Beyond

Recently, I was working with  a customer looking for a Premium Reversible Drum Vac and wanted it shipped to the Northwest Territories of Canada –  which we could do!  It got me to thinking, what are the farthest US state and territory locations EXAIR has shipped to in the North, South, West and East directions.  I ‘scoured’ the records and came up with these.

Furthest North- We have shipped to Prudhoe Bay, Alaska.  Most recently, believe it or not, we shipped a NEMA 4X Cabinet Cooler to an Oil and Natural Gas Exploration Company.  Goes to show that even the coldest environments still have the need to provide cool, clean, dry air to cool and protect electronics in electrical enclosures.

Furthest South – We have shipped to the US Territory of Puerto Rico, city of Santa Isabel.  An Aerospace company needed a strong, laminar blast of air and utilized a 6″ Stainless Steel Air Knife.  An Air Knife offers a quiet, efficient way to clean, dry or cool parts, webs, or conveyors.

Furthest West- We have shipped to the US Territory of Guam.  The local University ordered a model 1111-4 Super Air Nozzle Cluster, for a good strong blast of air flow for a cleaning operation.  The model 1111-4 delivers 3.2 lbs of force, at just 82 dBA of sound. A safe and efficient nozzle for blowoff operations.

Furthest East- We have shipped to Eastport, Maine.  The customer in Eastport ordered a Line Vac and a section of Conveyance Hose.  The Line Vac is a great tool for conveying large volumes of material over long distances, through a standard hose or tube.  The compact design features large throat diameters for maximum throughput capability.

 

It was interesting to look back and see all the places that EXAIR has shipped.  We have customers from all over the globe. If you are outside the of 50 US States and Canada, we have a dedicated team of International Application Engineers that will work with you to select the best EXAIR product for your process and application, and direct you to your local International Distributor.

If you would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Super Air Knives – A Plethora of Materials and Sizes

EXAIR manufactures the line of air knives known as the Super Air Knife. We pride ourselves on the wide array of material types and lengths that we offer, all from stock.

The Super Air Knife is the latest generation of engineered air knife that dramatically reduces compressed air usage and noise when compared to other blowoffs.  It is a very efficient way to clean, dry, or cool parts, webs, or conveyors.  It delivers a sheet of laminar air flow across the entire length, with a smooth and consistent delivery of air.

gh_Super Air Knife 750x696

In order meet process environments that may be hot or corrosive in nature, EXAIR offers the Super Air Knife in four standard materials.  The materials for stock air knives are aluminum, Type 303 stainless steel, Type 316 stainless steel, and PVDF (Polyvinylidene Fluoride.) Aluminum is well suited for a wide variety of environments where corrosion or contamination is not a factor. Type 303 stainless steel is a very common grade of stainless steel, and is good for mildly corrosive environments up to 400 °F. Type 316 stainless steel offers excellent corrosion resistance, better strength properties, and resists pitting. It can handle temperatures up to 800°F.  Lastly, the PVDF air knives offer many benefits including resistance to UV light, inorganic chemicals, solvents, ozone, acids, weak bases and salts and can withstand temperatures up to 275°F.  If there is a certain material required, EXAIR can also do custom Super Air Knives and have done them in PVC and other plastics.  Check out this write up about a very unique custom material Super Air Knife that we made.

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Glass Filled PEEK Super Air Knife with Brass Hardware and PTFE Shim (Click Here or on Photo)

Not only is there a wide offering of materials of construction to meet the process needs, the Super Air Knives are available in many lengths to fit into the space available. From stock, we offer Super Air Knives in these lengths-

3″, 6″, 9″, 12″, 18″, 24″, 30″, 36″, 42″, 48″, 54″, 60″, 72″, 84″, 96″, and 108″

If a special length knife is needed, or one longer than the 108″, the Super Air Knives can be coupled utilizing the stocked Air Knife Coupling Kit to join multiple air knives as needed. If space is an issue, and certain length that is not stocked is needed, just give us a call –  we can manufacture them to your specifications, to the exact length that you need.  It takes just a few days and then the Super Air Knife of exactly the proper length will be on its way.

If you have questions about the Super Air Knives, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Video Blog: Material Selection Guide for EXAIR Air Wipes

The below video covers the Super Air Wipe and Standard Air Wipe and details the materials of construction of all options to help in the selection process.

 

EXAIR offers the Air Wipes in diameters from 3/8″ (10mm) to 11″ (279mm), all in stock!  (Note – 3/8″ (10mm) size available in aluminum only)

All Offerings and Sizes 2-1

 

As a final review, consult the table below for a comprehensive summary of the materials of construction for the EXAIR Stainless Steel and Aluminum Super Air Wipes and the Standard Air Wipe.

Summary Table3

If you have questions about the Air Wipes, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Two Types of Air Amplifiers – Volume and Pressure

When the topic of Air Amplifiers comes up, there are two avenues to consider –  is it the air pressure or the air volume that you wish to amplify?  There exists technologies to amplify either parameter, and we will examine them both.

There may be equipment or processes within a facility that operate best at air pressures higher than can be delivered, due to air compressor limitations or the supply system. An Air Pressure Amplifier can take the existing compressed air supply, and boost the pressure allowing for the higher needed air pressure without requiring a dedicated compressor capable of operating at the higher pressure.

An Air Pressure Amplifier is basically an air pump, driven by a portion of the compressed air supply.  The pump cycles and compresses the remaining amount of compressed air to a higher outlet pressure. This higher output pressure can be used to operate the equipment or process that required the pressure levels that the base system could not supply. The drawback is that the pump system consumes a good amount of the compressed air volume, to power the pump which reduces the amount of air available for other equipment or processes.  This drives up the compressed air consumption for the system, and requires the extra capacity to operate.

The other type of Air Amplifier is the kind that amplifies the air flow volume. EXAIR manufactures this type of amplifier.

AirAmplifiers

The air flow amplification works by taking compressed air (1) and directing into an annular chamber (2). It is then throttled through a small ring nozzle (3) at high velocity. This primary stream of air adheres to the Coanda profile (4) and is directed through the outlet. A low pressure area is created at the center, inducing a high volume flow (5) of surrounding air to be drawn in and added to the main air stream. The combined flow of primary and surrounding air exits as a high volume, high velocity flow.

salworksani

EXAIR manufactures (2) types of Air Amplifiers, the Super Air Amplifier and the Adjustable Air Amplifier.  In addition, a special model for High Temperature applications is available.  Sizes range from 3/4″ (19mm) to 8″ (203mm) to meet most air flow requirements.  Air amplification ratios start at 12:1 for the 3/4″ model and increase to 25:1 for the 4″ and 8″ models.

Charts and tables are available to help determine the right Air Amplifier for the job.

If you have questions about the Air Amplifiers, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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High Temperature Vortex Tube for Sensor Cooling

Last year I worked with a power company that was having issues with Position Feedback Sensors overheating causing erroneous readings and early failures.  The sensors were located above a steam turbine, and the ambient temperatures reached 128°F with spikes to 140-150°F.  The customer had called in looking for a way to keep the sensors cool, using minimal compressed air, and in a robust package.  After reviewing the details, we recommended the High Temperature Vortex Tube, model HT3210.  While using just 10 SCFM of 100 PSIG compressed air, the HT3210 provides 8 SCFM of cold air at a temperature drop of 54°F from the supply air temperature.  Bathing the sensor with this cool air keeps prevents it from heating up and has eliminated the bad readings and prevented the early failures.

The customer recently implemented the same fix for another set of sensors.

Plant Photo
Power Generation Process, with (3) Position Feedback Sensors
Sensor
Position Feedback Sensor

The High Temperature Vortex Tube is a special Vortex Tube offering from EXAIR that utilizes a brass generator and hi-temp seal for use in ambient temperatures up to 200°F.  Simply supply clean, dry compressed air, and get cold air starting at 50-54°F lower than the supply air temperature.  With sizes ranging from 2 to 150 SCFM, there is a Vortex Tube that will meet most applications.

Vortex tube
High Temperature Vortex Tube

If you have questions about the Vortex Tubes, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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