Intelligent Compressed Air: Rotary Air Compressors

Air Compressor
Air Compressor and Storage Tanks

One thing that is found in virtually every industrial environment is an air compressor. Some uses for the compressed air generated are: powering pneumatic tools, packaging, automation equipment, conveyors, control systems, and various others. Pneumatic tools are favored because they tend to be smaller and more lightweight than electric tools, offer infinitely variable speed and torque, and can be safer than the hazards associated with electrical devices. In order to power these devices, compressed air must be generated.

There are two main categories of air compressors: positive-displacement and dynamic. In a positive-displacement type, a given quantity of air is trapped in a compression chamber. The volume of which it occupies is mechanically reduced (squished), causing a corresponding rise in pressure. In a dynamic compressor, velocity energy is imparted to continuously flowing air by a means of impellers rotating at a very high speed. The velocity energy is then converted into pressure energy. We’ve discussed the different styles of air compressors here on the EXAIR Blog in the past. Today I’d like to highlight the rotary compressors, one of the positive-displacement types of compressors.

Positive-displacement compressors are broken into two categories: reciprocating and rotary. The rotary compressors are available in lubricant-injected or lubricant-free varieties. Both styles utilize two inter-meshing rotors that have an inlet port at one end and a discharge port at the other. Air flows through the inlet port and is trapped between the lobes and the stator. As the rotation continues, the point inter-meshing begins to move along the length of the rotors. This reduces the space that is occupied by the air, resulting in an increase in pressure.

In the lubricant-injected varieties, the compression chamber is lubricated between the inter-meshing rotors and bearings. This lubricant protects the inter-meshing rotors and associated bearings. It eliminates most of the heat caused by compression and acts as a seal between the meshing rotors and between the rotor and stator. Some advantages of the lubricant-injected rotary compressor include a compact size, relatively low initial cost, vibration free operation, and simple routine maintenance (replacing lubricant and filter changes). Some drawbacks to this style of compressor include lower efficiency when compared with water-cooled reciprocating compressors, lubricant carry over must be removed from the air supply with a coalescing filter, and varying efficiency depending on the control mode used.

In the lubricant-free varieties, the inter-meshing rotors have very tight tolerances and are not allowed to touch. Since there is no fluid to remove the heat of compression, they typically have two stages of compression with an inter-cooler between and an after cooler after the second stage. Lubricant-free compressors are beneficial as they supply clean, oil-free compressed air. They are, however, more expensive and less efficient to operate than the lubricant-injected variety.

Each of these compressors can deliver air to your Intelligent Compressed Air Products. If you’re looking to reduce your compressed air consumption and increase the safety of your processes contact an EXAIR Application Engineer today. We’ll be happy to discuss the options with you and make sure you’re getting the most out of your compressed air usage.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Temperature Fluctuations Damage Control Panels. EXAIR’s Cabinet Coolers are Here to Save the Day!

It’s a longstanding joke for anyone that lives in the Cincinnati area that we can experience all (4) seasons in less than a week. This past weekend, we topped out at a high temperature of 83°F. This morning when I left the house it was a cool, crisp 37°F. With temperatures later on this week dropping below freezing, we’ve gone from the heat of summer to the cold of winter all in less than a week. These uncertain temperature fluctuations create all sorts of problems for farmers and home gardeners (like myself) as we struggle with determining the best time to plant (and rushing to cover up anything that’s already been planted!). Additionally, extreme temperature fluctuations can also cause significant issues for the electrical panels in your facility.

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Don’t open your panels to dirt and dust!

During times of high heat, the temperatures inside of these enclosures can reach dangerous levels. The use of fans, or worse opening the panel door, does help to keep the temperature down. But this can create even more issues. When using a fan or opening the panel door, you expose the sensitive internal electronics to any dirt, dust, debris, and even moisture from the ambient environment. Fortunately, maintaining a safe temperature and clean environment inside of your enclosure is simple.

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EXAIR’s Cabinet Cooler Systems were designed specifically to rectify these issues within your facility. Utilizing Vortex Tube technology, the Cabinet Cooler produces cold air from an ordinary supply of compressed air. This cold air keeps the enclosure free of debris and moisture and is easily installed in minutes through a standard electrical knockout. The Cabinet Cooler Systems are available in Aluminum, 303 Stainless Steel, and 316 Stainless Steel construction with Nema 4 (IP66) ratings. We also have Nema 12 (IP54) rated Cabinet Coolers that are available constructed of Stainless Steel. For systems that are not able to be mounted on top of the cabinet, we also have Side Mount Kits available in Aluminum, 303 Stainless, and 316 Stainless.

These systems are available with cooling capacities of anywhere from 275-5,600 Btu/hr. To make things much easier for you, we offer a Cabinet Cooler Sizing Guide that will allow us to recommend the most suitable model for your cabinet. With a few quick measurements, we’ll be able to determine the exact heat load that we’ll need to dissipate and offer you a quick and easy solution. If you’re experiencing heat related issues somewhere within your facility or remember the troubles that they caused you last year, contact an Application Engineer today and we’ll see to it that this summer your cabinets remain cool!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

EXAIR Products: The Importance of Oil Removal Filters

Oil Removal Filter
Oil Removal Filters

EXAIR’s Intelligent Compressed Air Products have no moving parts and require no maintenance. Most EXAIR products require no direct maintenance, and will continue to require no maintenance if the supplied air is clean. Keeping air clean, in EXAIR’s case, can be done with a simple water/dirt or oil filter separator close to the application of the product – usually within 10 feet. The reason for the filters is that many products have very tight orifices that could get clogged from contaminants such as particulate, condensate, and lubricant.

Oil is commonly present in a compressed air supply, whether that’s intentional or not. Many air compressors are lubricated by a constant supply of oil, inevitably some of this oil ends up in the air supply. As the compressor wears, more oil is permitted to pass and ends up in the distribution system. While this is kept to a minimum with proper maintenance, it is impossible to prevent unless using an oil-free compressor.

Sometimes oil is present in the air supply intentionally. Many pneumatic devices require a precise amount of oil to keep the internal moving parts lubricated. In the case of EXAIR Intelligent Compressed Air Products, we recommend particulate-free, moisture-free, and oil-free air.

EXAIR offers a line of Oil Removal Filters. These coalescing style filters are used to remove very fine water vapor as well as any residual oil. These filters are highly recommended to be installed just prior to dryers that contain a media that would be compromised by lubricant passing through it. Coalescing filters utilize an element typically made up of glass fibers that “coalesce”, or combine, the fine water vapor and oil aerosols until the droplet size becomes large enough that it drops off into the filter bowl. With a coalescing filter, the most common cause of pressure drop increase is due to particulate clogging the element. Because of this, a particulate filter should always be installed just prior to coalescing filters. Check out this video demonstrating an Auto-Drain Filter and Oil-Removal Filter in action:

Without filtration, oil in the air supply will pass through the point of use device and into your product or process. The elimination of this problem is such a simple solution. Don’t neglect your compressed air system and ensure you’re delivering clean, dry, oil-free air to all of your EXAIR Intelligent Compressed Air Products.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

It’s Shaping Up to Be a HOT Summer!

These last several weeks have been unprecedented for all of us. We’ve had a lot more time to spend isolated at home with our families and everyone’s begun to get a bit stir crazy. It’s a great opportunity to tackle some of those long overdue projects that have been stacking up. The lawns in the neighborhood have never been greener, there’s no excuses this year! This year’s summer garden is also shaping up to be a HOT one.

Starting my plants from seed this year has been a fulfilling journey (with plenty of learning curves!) but allowed me the opportunity to hand pick the varieties of peppers and tomatoes I’ll have later on in the year. For this year we’re really bringing the heat with a variety of superhot peppers: Peach Reapers, Purple Bhut Jolokia, Orange Long Tail Scorpion, and 7 Pot Lava Yellow along with a few “milder” peppers for when the heat gets a little too intense..

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It’s been a fun way to pass the time and look forward to this year’s growing season. But it won’t be just my mouth that’s hot this summer, the warmer temperatures associated with the summer months also cause numerous problems for the control panels in your facility.

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EXAIR’s Cabinet Cooler Systems were designed specifically to rectify these issues. Utilizing Vortex Tube technology, the Cabinet Cooler produces cold air from an ordinary supply of compressed air. This cold air keeps the enclosure free of debris and moisture and is easily installed in minutes through a standard electrical knockout. Here is a short video that shows just how simple it really is.

 

The Cabinet Cooler Systems are available with Nema 12 (IP54) ratings and are also available in Aluminum, 303 Stainless Steel, and 316 Stainless Steel construction for Nema 4/4X (IP66) rated enclosures. For systems that are not able to be mounted on top of the cabinet, we also have Side Mount Kits available in Aluminum, 303 Stainless, and 316 Stainless. EXAIR has also recently introduced a new line of Hazardous Location Cabinet Coolers for use in classified areas.

To determine which size Cabinet Cooler is right for you, simply complete the Cabinet Cooler Sizing Guide online. One of the EXAIR Application Engineers will then be able to determine the cooling capacity required based on the conditions of your cabinet. In less than 24 hours, you’ll have a response from us with the recommended model. With all Cabinet Cooler Systems available from stock, you can get one shipped out to you right away!

Don’t wait until it’s too late, EXAIR’s Cabinet Cooler is the simple solution for maintaining the temperature inside of your electronic enclosures.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Image courtesy of alvinmatt via Pixabay 

People of Interest: Giovanni Battista Venturi March 15, 1746 – April 24, 1822

Giovanni Battista Venturi was born in 1746 to an affluent family in Reggio, Italy. An aspiring student, Giovanni was ordained as a priest and a professor by the age of 23. An avid historian of science at the University of Modena, he was the first to emphasize Leonardo da Vinci as a scientist rather than just an artist as he’s more commonly known. Despite his love for history, it wasn’t long before the University of Modena became aware of his talents in mathematics where they appointed him as professor of geometry and philosophy in 1774. During his tenure at the University of Modena, Giovanni was promoted to the Professor of Experimental Physics, served as the Duke of Modena as the State engineer and auditor, later serving diplomatic roles in both France and Switzerland.

Giovanni is most well-known for his work in developing what is now known as the venturi effect. In 1797, he published a study on the flow of water through short cylindrical tubes. It wasn’t until 1888 that Venturi’s design was applied to something practical when a man named Clemens Herschel received a patent for the first commercial venturi tube. The original purpose of the venturi tube was to measure the amount of water used in individual water mills and is still used to this day as a means of measuring fluid flows.

Venturi tube.jpg
Venturi Tube

The venturi effect is a principle in fluid dynamics and 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 known as Bernoulli’s principle. Below is an illustration of how the venturi effect works inside of a constricted tube.

venturi

In everyday life, the venturi principle can be found inside of many small engines such as lawn mowers, gas powered scooters, motorcycles and older style automobiles. Inside the carburetor, there is a small tube through which filtered air flows from the intake. Inside of this tube is a short narrowing. When the air is forced to constrict, its velocity increases and creates a vacuum. This vacuum draws in fuel and mixes with the air stream causing it to atomize.  As the throttle valve is opened further, more fuel is forced into the engine. This increases the RPM and creates more power.

inlineworks
In-Line E-Vac

This principle is also applied to EXAIR’s line of E-Vac products to create vacuum. The .gif below illustrates how an In-Line E-vac works. (1) Compressed air flows through the inlet (2) and is directed through a nozzle, constricting the flow of air. (3) As the air stream exhausts, it expands causing a decrease in pressure and an increase in velocity prior to passing through the venturi. (4) A vacuum inlet tangential to the primary airflow is located at the suction point between the orifice and the venturi. (5) The airflow that is drawn through the vacuum inlet mixes with the primary airstream, then exhausts on the opposite end.

The venturi effect is used in a variety of other EXAIR products used for cooling, drying and cleaning, in addition to the vacuum generators. If you have a process in your facility that may benefit from an Intelligent Compressed Air solution, give us a call. We’d be happy to discuss your application and implement a solution to both reduce your compressed air costs and improve worker safety.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Photo: Venturi Tube with labels by ComputerGeezer an Geof.  GNU Free Documentation License

Centrifugal Air Compressors: What are they?

One thing that is found in virtually every industrial environment is an air compressor. Some uses for the compressed air generated are: powering pneumatic tools, packaging, automation equipment, conveyors, controls systems, and various others. Pneumatic tools are favored because they tend to be smaller and more lightweight than electric tools, offer infinitely variable speed and torque, and can be safer than the hazards associated with electrical devices. In order to power these devices, compressed air must be generated.

There are two main categories of air compressors: positive-displacement and dynamic. In a positive-displacement type, a given quantity of air is trapped in a compression chamber. The volume of which it occupies is mechanically reduced (squished), causing a corresponding rise in pressure. In a dynamic compressor, velocity energy is imparted to continuously flowing air by a means of impellers rotating at a very high speed. The velocity energy is then converted into pressure energy. For the purposes of this blog, I’m going to highlight the most common style of dynamic compressor: the centrifugal air compressor.

Dynamic compressors are composed of two main categories: axial and centrifugal. These types of compressors raise the pressure of air or gas by imparting velocity energy and converting it to pressure energy. In a centrifugal air compressor, air continuously flows and is accelerated by an impeller. This impeller can rotate at speeds that exceed 50,000 rpm. Centrifugal air compressors are generally much larger and can accommodate flow ranges of 500-100,000 CFM, although they’re more commonly used in the range of 1,000 CFM to 5,000 CFM.

Centrifugal Pic 1

In a centrifugal compressor, kinetic energy is transformed into pressure energy inside of the diffuser. The air passes through the inlet guide vanes and is drawn into the center of a rotating impeller. The impeller has radial blades that push outward from the center due to centrifugal force. This radial movement of air causes an increase in pressure and the generation of kinetic energy. This kinetic energy is then also converted into pressure as it passes through the diffuser.

According to the Compressed Air Challenge, some advantages of the centrifugal air compressor include:

  • Completely packaged for plant or instrument air up through 1,000 HP
  • Relative first cost improves as the size increases
  • Designed to deliver lubricant-free air
  • Do not require special foundations
  • Ability to deliver large volumes of air (up to 100,000 CFM)

Some disadvantages include:

  • Limited capacity control
  • Poor part-load efficiency
  • High rotational speeds require special bearings, sophisticated monitoring of vibrations and clearances resulting in specialized maintenance considerations
  • High initial purchase cost

A centrifugal air compressor is just one of the many different styles utilized in industry to supply a variety of point of use compressed air products. If you have an application in your facility that could benefit from an engineered solution, give us a call. An Application Engineer would be happy to discuss your options with you and see to it that you’re getting the most out of your compressed air!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Image courtesy of the Compressed Air Challenge

 

EXAIR’s Atomizing Nozzles for Decontamination Due to COVID-19

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At this time, countries across the world are all grappling with the constant change and disruption that is caused by COVID-19. As a worldwide supplier to manufacturers in a wide variety of industries, we’re seeing first-hand how important the manufacturing supply chain is. Many industries that we support including food, pharmaceutical, medical equipment, etc. are absolutely critical right now. EXAIR as a company is taking all necessary precautions to ensure that we can remain open to supply the manufacturers in these critical industries.

Manufacturers across the US and the rest of the world are re-purposing their facilities and production processes to manufacture medical supplies at a rapid pace. The situation evolves on a daily basis. The feeling is mutual among all of us, this entire situation is completely unprecedented and unlike anything we’ve experienced in our lifetime. I’ve recently spoken with numerous manufacturers and end users who are looking to utilize our products to help fight this pandemic.

One such product is EXAIR’s Atomizing Spray Nozzles. Designed to atomize fluids in a wide range of different spray patterns, they utilize a small amount of compressed air that mixes with the liquid supply to create a fine mist of atomized liquid. This makes them very effective in applications that utilize expensive paints, oils, or other liquids. Rather than wasting the expensive materials, the nozzle can be set to precisely dispense only what is necessary to achieve a successful application.

In the current situation, they’re being used for a range of applications for decontaminating rooms, personnel, and equipment. A customer utilizes the Model EF1010SS to perform a dry fogging process inside of residential and commercial rooms to eliminate mold, odors, and pathogens. For them this is a common process, but due to the concerns related to COVID-19 they’ve seen a dramatic increase in business related to pathogen removal. Using a two-step dry fogging process, the solution fills the entire volume of the space to remove any contaminants and prevent against microbial growth in the future. The nozzle provides a fine atomized mist that fills the entire space in a short amount of time. After a physical wipe down of all surfaces, a second solution is applied that prevents future microbial growth.

Atomizng Family

Another customer manufactures decontamination booths for personnel. They’re also noticing an increase in inquiries as companies look to decontaminate their employees upon entering the building. Utilizing (3) of EXAIR’s SF2020SS Atomizing Spray Nozzles, they’re able to spray a decontaminating solution to aid removal of pathogens from their clothing before it has an opportunity to spread around the office.

With the ability to produce a fine droplet size, the Atomizing Spray Nozzle is an ideal product to deliver the fine mist required for decontamination. If you have an application or process that could benefit from an EXAIR Intelligent Compressed Air Product please give us a call. We’re here, ready to help, as we all come together to fight this head on.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

COVID-19 image courtesy of enriquelopezgarre from Pixabay