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The Basics of Compressed Air Made Easy

compressed air

When we think about compressed air, it can seem like a simple concept, as it is just air that has been put under large amounts of pressure and crammed into a small space. While it may sound simple, air treatment and air systems have many complex layers to go through to completely understand how they work. We are going to be covering just some of the basics of air compression and how that is applied in industrial and individual settings.

What Is Compressed Air?

When it comes to compressed air, the baseline is not exactly clear on what is classified as such. Simply put, compressed air is kept under a pressure that exceeds our atmospheric pressure, and this stored pressure is used as a medium to transfer energy and power tools. The air is compressed and put under pressure by an air compressor, which can use different methods of compression with the most common being rotary screw compressors and reciprocating (piston) compressors. However, the manner of compression usually revolves around environment and application rather than the effectiveness of air output.

As the air is compressed and pressure is added, the space between particles is reduced and thus energy is created and held by the air under pressure. When the pressure is released, so is the energy and the air rushes out. This pressurized air is a mix of nitrogen and oxygen that help make up the ambient air around us. The energy that is created through the process of compression is directly related to the temperature of the air. The more movement of the particles the more energy that is created and the movement can be manipulated by putting the air under pressure.

Some of the most common daily applications of compressed air are in balloons and sports balls. The air is blown or pumped into the container area and as that air is held in there it exists at the pressure and energy levels needed to inflate the object. When more air is added the pressure and energy increase and that is what will allow the ball to bounce higher and the balloon to expand, but if air keeps getting added the pressure will eventually exceed the vessel and it will burst or deform the container.

How Does Compressed Air Work?

Using the prior information to form an understanding of the nature of compressed air may lead you to wonder how compressed air has an industrial application, especially considering the most common applications you might see are used by children. The reality of compressed air is it is often unseen in its application, especially when it is used as a power source for tools and other equipment in industrial applications. The air is moved along air systems through either positive displacement or dynamic displacement.

Positive Displacement: Air is forced into a confined space through the use of a mechanical device and as the machine moves the space decreases and compresses the air more.

Dynamic Displacement: Rather than changing the space that the air is forced into, dynamic displacement speeds up the air itself to a high velocity to create air pressure that way.

Not only do multiple forms exist to add pressure to the air, but the medium of compression can be different as well. Positive Displacement usually falls into two categories: rotary and reciprocating, and this explains why those two machines are the most common. These categories each have subtypes of compressors as well

Rotary Compressors:

  • Screw

    • This compressor uses two rotors that are meshed together to the point of almost touching, so as the air gets moved along the rotating vanes of the rotor, it becomes compressed down and put under pressure continuously until it reaches the desired point of pressure as it exits the compression chamber.
  • Scroll

    • In a similar concept to the rotary screw, the scroll has two scrolls with one stagnant or fixed scroll and then another scroll that rotates around in a circular motion to compress the air as it moves along and the pocket of space shrinks forcing the air into a continuously smaller space until it is released at the desired pressure.
  • Vane

    • Rotary vane compressors use a similar idea to the scroll compressors but rather than using two different scrolls, it uses one rotor with vane blades inserted into slots along the rotor. The rotor is placed off center so that when it rotates the vanes change the size of the space the air is trapped in and the blades slowly slide back in the vane as the space is reduced to add pressure.

Reciprocating Compressors:

  • Piston

    • Piston Compressors are the main type of reciprocating compressor to the point where piston and reciprocating can be used interchangeably. These compressors operate in a manner identical to internal combustion engines- you know the ones that power most of our cars- except instead of the energy from combustion being pushed through, compressed air is the byproduct.
    • The crankshafts control the rods and pistons that are responsible for compression, and as it rotates the piston moves through the cylinder to compress the air, and then when it pulls back to go again the first pocket of compressed air is moving towards the next step. The output or pressure can be varied by the number and size of pistons on the crankshaft.

Air quality is another factor that is extremely important when it comes to air compressors and the air byproduct. Many instances where compressed air is used as a source of energy are riddled with safety standards and specific quality standards that need to be reached. In instances like that are perfect for an oil-less air compressor. Compressors of this nature use a different material for

Standard Applications of Compressed Air

Now you might be wondering where compressors are used or what a good application for compressed air would be. Compressed air is used as a medium for transporting energy to be able to power equipment like pneumatic tools like drills, hammers, wrenches, and more. These tools are often used during the construction of products or places as the air does not increase the likelihood of a fire occurring like electric or gasoline-powered equipment. This also allows for the use of equipment in less than ideal places or in places where electricity might not be available thanks to tow-behind compressors that can be moved around to where it is needed.

The application of compressed air is extremely versatile but it typically is used in specific industries due to its effectiveness. The most common applications are instances where cleanliness and precision are high priorities. These industries include but are not limited to:

Food & Beverages

  • The use of compressed air in food and beverage is simple yet necessary due to the ability of air systems to remove particulates and ensure the cleanliness of the product. Compressed air can be used for a variety of reasons from the process of capping bottles and cans and the fermentation of food and liquids. This process is used in brewing beer and by major beverage consumers as well. Air can be used to move products along the production line, the final packaging, and movement of product components as well.

Pharmaceuticals

  •  Compressed air plays a major role in pharmaceutical production from cleaning and aeration to product movement. The air is monitored very strictly in this application due to the products needing to be safe, clean, and consistent. Compressors in this industry are often oil-free with an emphasis on filtration as well to reach the sterile environment that is expected in this industry. It is due to compressed air that products like lactose enzymes are able to be reliably isolated and produced for those who are lactose-intolerant as well as the coating on tablets to prevent the bitter medicinal taste from coating your mouth.

Chemicals

  •  When manufacturers are producing chemicals they want to rest assured of the quality of their products. Clean compressed air can be used to assist in the handling of materials, creating air curtains for isolation purposes, and drying out different products. Oil-free air is a necessity in this industry due to strict safety standards and the potentially negative downsides that can come out of the potential mixing of chemicals with oil.

Automotive

  •  The automotive industry is one of the major users of compressed air due to the precision required for success. Whether it is the outer coat of paint or the fastening of internal components, precision and accuracy are of high importance. Not only are air tools prominent in production but also in maintenance and simple tasks like putting air in the tire are dependent on a properly sized air system. The quality of the products is dependent upon the quality of the air.

Industrial

  •  The use of compressed air is quite prominent in industrial applications. Compressed air is used in places like construction sites, mechanic shops, road maintenance, factories, and other similar places. The main benefit of air is the price it costs to power all of the tools as well as the widespread application of pneumatic tools.

Electronics

  •  Electronics is another industry where it might not be obvious why compressed air is used. In the instance of electronics, it is used for the production and assembly of intricate pieces like circuit boards, wafers, memory chips, and other internal computer components. The use of air does not stop there as it is also used to polish and clean the finished products to ensure the quality and removal of chemicals on their products.

Although the application of compressed air may not seem prominent, it is indeed a heavily relied upon utility, to the point where it is often referred to as the fourth utility. Compressed air is an important resource when it comes to productivity and it is also one of the most environmentally sound options available. The industries that were previously mentioned are only some of the industries and environments in which this energy source can be used. The widespread quantity of air makes it an extremely valuable source of energy as it can be used in so many different applications.

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  1. Compressor Basics
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