Using compressed air in industry is not something new. Although there are references to its use in the Old Testament, it was only recorded in 1776 in an English factory the use of a compressor to generate the surprising pressure of 1 bar!

After the Industrial Revolution, it began to be used in scale production and, currently, plays an

essential role in almost every industry. In addition to being a clean and renewable energy option, companies benefit from its use as an alternative to reduce costs, since it can complement and, in some processes, even replace the use of electricity.

This odorless, non-toxic and non-flammable gas accumulates energy through compression and storage in an appropriate cylinder. That is, the air undergoes a mechanical process that changes its volume and pressure.

This procedure causes the air pressure inside the cylinder to be higher than the atmospheric pressure and... voilà! We have pneumatic energy available for the most diverse uses, such as tooling, transport of materials, cleaning and maintenance of machinery, drying of articles and a multitude of possibilities.

The reason for compressed air to be an accessible energy is mainly due to the fact that the raw material for its creation is always the local atmosphere or, in other words, the air that we have available. On the other hand, production is subject to all atmospheric and climatic variations of the environment where it originates. Thus, the composition of the compressed air will change according to the place and the compression method used. The problems related to compressed air quality are closely related to these variations, since the cleaner and drier it is, the better it will be considered.

Some applications of the food industry, medical and dental area require that, in addition to clean and dry, the air is free of odors. Controlling the contamination of compressed air is not so easy, once the generation system itself produces particles originated in its set of  components and materials, such as droplets of lubricant and small fragments from the sealing elements and oxidation of part of the structure.

The use in the industry further aggravates this scenario, since the heavy manufacturing environment can contain 200 times more airborne particles in the air than in an urban center. To diminish these effects it is possible to use artifices that reduce the presence of such undesired elements.

Particle filters block solid contaminants, which could cause damage to the piping or in the circuits of the machines which use compressed air. The adsorbent filters purify the air by capturing the odor molecules of the fluid that adhere to the surface of activated carbon. In applications where the minimum presence of oil is critical, the solution may be to use an oil-free compressor.

This equipment has been structured to work with the air having no contact with the lubricant, canceling the possibility of contamination. However, there is another factor that can be even more treacherous in the quality of compressed air, as it is something inherent in its composition: condensed water. Let me explain: air is a compound of gases and water vapor. Water vapor is always present in atmospheric air, in greater or lesser amounts. It stays suspended in the air and we can express its abundance through the measurement of relative humidity. Simplifying, the relative humidity expresses how much water the air is holding in relation to the maximum that can be admitted. When the relative humidity reaches its maximum point, that is to say, 100%, the water begins to condense, passing from the state of vapor to its liquid state. This phenomenon is directly related to the temperature, which we call the dew point. That is, the dew point is the temperature at which the water vapor transforms into small drops (the dew!). The compression of the air inevitably changes the pressure and temperature of the water vapor and, therefore, the dew point as well. And this is the problem... Water can condense inside the compressed air pipe, causing air contamination, damage to machinery, blockage in the pipeline and even variation in the final product, such as irregularities in the texture of the painted products, for example.

To promote air drying, some models of dryers basically works cooling the air to the dew point so that the water condenses, is collected and eliminated. However, the first step to achieve the best result in this process is to have good control of the system. There are devices that allow to measure and control the variations of temperature, relative humidity and dew point. They notify if any of the parameters go beyond the specified limits, which allows the reparative action in real time and, subsequently, the action in the prevention of future problems, by analyzing the data records that were sent through the available communication network. By controlling, associated with an efficient drying method and adjusted to the specific characteristics of the industrial process, it is possible to have results that meet the demanding production requirements. In the end, compressed air, as well as other techniques used many years ago, can survive and be of great value to heal basic needs of the industry even today.