How to choose the right compressed air system
03 April 2018
Air Main Charging Valve
The question often asked is ‘why do we need compressed air treatment?’
Air compressors use the ambient air for compression, this air contains contaminants which are compressed and intensified, without treatment these pollutants can find their way into the compressed air system.
These contaminants are in three different forms:
- Solids: dirt, dust, pipe scale, wear particles
- Liquids/aerosols: oil and water
- Gases/Vapours: water, oil (hydro carbons) Co2, chemical pollutants
Compressed air applications can range from shop air to food production, to pharmaceuticals and medical equipment production, with a wide range of applications in between, so the first step in meeting your air treatment needs is to look closely at your application and the air quality it requires.
ISO 8573.1 is the standard for measuring air quality classes for specific applications, this helps engineers to specify the desired compressed air quality by providing ‘Quality Classes’ for solid particles, humidity and oil.
A typical application in a pharmaceutical plant would have a ISO Quality Class 1.2.1, this would be equivalent to 0.1 micron particulate filtration, -40 Deg C dew point and 0.01 mg/m3 oil filtration.
How do we achieve the correct air quality?
Based on the application, we can match the different levels of quality required to the air treatment equipment needed to achieve a classification in accordance with the ISO 8573-1, typically this would include the following options
Dew point: The removal of water in the system is vital not only to the air quality but also to correct operation and reliability of equipment in the plant that uses the air.
This is achieved through drying and the most common applications use Refrigerant Dryers which will give a dew point of +3 deg C, which is Class 4.
For more stringent requirements an Adsorption Dyer is used which will achieve dew points of -20, -40 or -70 deg C, which equates to Class 0,1,2 and 3.
Minus dew points give a higher class in moisture removal, however, this is at a cost in terms of energy and so on, and therefore it is important to see what level is really needed by your application.
All compressed air systems need filtration to remove:
- Oil Droplets
- Vapours and Odours
This is true for a standard shop air system to ensure the reliability of the machine or tools at point of use and different filtration is needed in the manufacture of food, pharmaceuticals and applications where high quality air is needed.
No matter what the air compressor type is, whether it is oil lubricated or oil free, downstream filtration is needed to achieve the air quality to the required class.
Air main charging valve
Compressed air treatment is designed at a specific pressure of 7 bar, pressures above or below this will change the operating parameters of the air treatment equipment, for example, if a system is started from zero bar, then the initial charging to working pressure will see a large increase in the volume flow through the filters and dryers, this can overload the treatment and cause particles and liquids to travel into the network.
The solution is an air main charging system that enables the build-up of pressure in a controlled way and ensures the integrity of the air quality systems.
Compressed air treatment is a key component in all applications, and at KAESER we can advise on all aspects of air quality needed to ensure compliance with the ISO 8573-1 standard.
We have a chart which gives guidance on the different components required for specific applications, if you would like a copy please email us at firstname.lastname@example.org. In the subject line please quote ‘Air Quality’.
Our applications engineers are available to give you exact guidance on air quality in your industry, both in terms of ISO 8573-1 and of the lifecycle costs of the systems needed.
In 2019 KAESER will celebrate 100 years of designing and supplying systems for all aspects of industry, so let our experience help you in this very important aspect of compressed air production.
KAESER Compressors Ltd
Units 43/44 Western Parkway Business Park
Phone +353 1 4565433