The increasing need for compressed air and the filtration of this air from pollutants requires having deep experience and acquiring knowledge of technologies related to the functional field of filtration and the reliability of compressed air filtration to continuously fight the problems caused by the entry of pollutants to the compressed air system is very important.

The optimum solution for compressed air filtration is using a complete filtration network.

The compressed air that comes out of the compressor is the air that has entered the compressor from the surrounding environment, and depending on the environment in which the compressor is installed, the concentration of pollutants, pollution, suspended particles, humidity, and dust in the air coming out of the compressor is different.

All these masses become denser after entering the compressor and compressing the air. In addition to the particles in the air, the compressor also adds some oil to this air (except for oil-free compressors).

Dust, water, oil, and other solid particles and vapors enter the compressed air lines and consumers. Pneumatic valves of jacks, air motors, tools, and moving parts that work with compressed air are stopped or even damaged due to these impurities.

Clean air free of pollutants for machines is the same as clean breathing air for humans. There is a big difference between breathing in a place full of pollutants and dust and breathing in the middle of a forest full of trees. Increasing the quality of compressed air will dramatically reduce repair costs and stoppage.

In order not to stop the production lines and preserve capital and increase the lifespan of machines and piping and other parts and equipment that consume compressed air, we need to improve air quality.

The three main and important pollutants which its presence in compressed air lines is worrying and damaging are water, oil, and dust.

Of course, other pollutants such as microorganisms and harmful gases and odors can be mentioned, which are only harmful to some industries and production units and must be filtered from the air.

According to Roll Air Company's experience, some compressed air consumers considered the existence of oil in the lines even suitable for equipment lubrication and only limited themselves to humidity removal. This group of compressed air consumers used to suffer from stoppages and failure of pneumatic parts in their lines. After the examination of the company's experts, it was determined that due to the lack of use of a dust removal filter, as well as lack of sensitivity to the presence of oil in the lines, oil and dust were combined to form a viscous material, which was the cause of breakdowns and stoppage of pneumatic parts.

Therefore, the main purpose of compressed air filtration is to produce air that meets the consumer's needs.

As another example, for a food manufacturing company, the air directly related to product packaging must be free of all pollutants, microorganisms, and odors and requires high filtering.

This question is one of the basic questions of all compressed air consumers who know the importance of compressed air filtration. Many factors are involved in choosing the quality and quantity of compressed air filters, which should be carefully checked and put in the expert process.

To know what filters and compressed air filtration equipment are suitable for our compressed air line, first, we need to extract the list of all compressed air consumers. After that, let's determine the quality of air consumption needed by each consumer and classify it based on the existing standards. Finally, we select the filtration components and elements based on these data.

Identifying and classifying the air purity needed by each consumer is also important because, for example, in a production unit, maybe only a few devices need high-class filtering. Other equipment is protected with low-class quality, and there is no need for heavy investment to purchase high-class filtration for the entire compressed air.

In choosing filters for compressed air lines, attention should be paid to the volume and pressure of the air passing through the filter so as not to lead to premature clogging and pressure drop in the lines.

The use of low-quality filters, in addition to not delivering high-purity air, also leads to a large pressure drop in the line, resulting in more compressor operation, increased energy costs, device depreciation, and increased repair and maintenance costs.

Modern industrial technologies have reached very high levels of complexity. They require compressed air systems to be provided with higher purity levels. Inefficient filtration can cause a break in the lines and ultimately lead to high repair and maintenance costs and reduced productivity

Humans need to understand a common language to communicate with each other. For this reason, a language is introduced as an international language so that all humans on the planet can communicate with each other and exchange thoughts and experiences.

In the compressed air industry, the common language of ISO 8573 was designed and presented for the possibility of exchanging information and discussing the quality of compressed air all over the world, the latest version (3) of which was published in 2010.

With this common language, all reputable manufacturers of compressed air filtration equipment classify and present their products based on this standard, and buyers and consumers easily use the classification of their air to provide a combination of air filtration elements that complement each other to provide their optimal quality.

ISO 8573 is an international standard that defines the pollutants in compressed air and is known as an understanding of air purity levels in a compressed air system.

This standard consists of 9 parts, the first part, 85731, provides the classification of compressed air quality based on the description of its pollutants. The second part, the ninth part, provides test methods and analytical techniques for each type of pollutant.

ISO 85731 defines air quality classifications based on specific pollutant types to allow users to determine appropriate purity levels for any given application.

The three main pollutants in compressed air are solid particles, water, and oil.

The standard ISO 85731 is also classified based on these three pollutants.

The solid particles, water (liquid and vapor), and oil (oil particles and oil vapors).

Units of measurement in this standard

• Oil content is based on the mass per volume (mg/m3)
• Water content is based on dew point temperature in degrees Celsius
• Particle concentration is based on number per unit volume (number count per unit volume).

For example, consider that a device manufacturer has announced the specifications of the air consumed as follows, that the selection of air filtration equipment should be considered based on these three parameters:

1. Classification of particle purity
2. Classification of water purity
3. Classification of oil purity

Growth of microorganisms in a compressed air system

Microorganisms are very small and include bacteria, viruses, and bacteriophages. Typically, bacteria can range from 0.2 to 4 µ and viruses from 0.04 to 3.0 µ.

Pollution less than one µ in diameter, such as microorganisms, can easily pass through the compressor air inlet filter and enter all compressed air lines and machines.

These microorganisms are a serious problem in many industries because, as living organisms, they can reproduce freely under the right conditions for their growth.

According to research, humid air is one of these conditions suitable for the growth of microorganisms. Oil and other pollutants act as nutrients and allow microorganisms to grow.

Therefore, the growth potential of microorganisms in the compressed air system depends on the humidity level (dew point).

Compressed air plays a special role in product packaging for beverages, food, and pharmaceutical industries. It is very important to have a pollution-free compressed air line.

Therefore, it is necessary to use special filtration to remove microorganisms in addition to using equipment for filtering humidity and solid particles and oil.

Special filters for the removal of microorganisms are known as sterile filters. These filters are installed in a stainless steel chamber; depending on the compressed air quality, they must be washed with hot water vapor at specific and continuous times.

To maintain a good quality of compressed air, samples are taken from the exhaust air of these filters and based on planned and documented tests, filter sterilization time is extracted.

These filters' sterile and washing operation is called Clean-in-place (CIP

• Oil content is based on the mass per volume (mg/m3)
• Water content is based on dew point temperature in degrees Celsius
• Particle concentration is based on number per unit volume (number count per unit volume).