You probably already know your compressed air supply is vital to the production process, if it comes into direct contact with your product or automates a process, a reliable supply is essential.
But here's the deal: Did you know that your compressed air supply could be polluted by up to ten contaminates that could have a detrimental effect on your facility, employees and your customers?
Identifying the risks
By understanding the source of contamination a solution to reduce them can be quickly identified. Normally, the cause of any contamination can be narrowed down to four sources: The ambient air the compressor draws in, the compressor, the systems air receiver and finally the distribution piping.
Now that you are aware of where the contamination could be entering your supply, it is important to understand how these contaminants could infect a compressed air supply.
The compressor draws in and releases both solid and fluid mass. Typically the term fluid is often misused, as if it means liquid only, but it actually refers to anything that has a molecular structure that can move freely, allowing it to conform to the space that it occupies, fluid actually means a liquid or a gas.
In the first part of this two part blog series we will focus on contamination in a fluid state.
Contaminate 1,2 and 3
- Water vapour, water aerosol and condensed water - The ability of air to hold water vapour is dependent upon its pressure and temperature. The higher the temperature, the more water vapour that can be held by the air. The higher the pressure, a greater amount of water vapour is squeezed out.
- As large volumes of air are drawn into the compressor and compressed, the temperature of the air increases significantly. This allows the heated air to easily retain the water vapour in the atmospheric air. Prior to exiting the compressor, compressed air is normally cooled to a usable temperature. This reduces the air’s ability to retain water vapour, resulting in a proportion of the water vapour condensing into liquid water.
- In a typical compressed air system, up to 99.9% of the total liquid contamination is water.
- Oil Vapour - Atmospheric air also contains oil in the form of unburned hydrocarbons which are drawn into the compressor intake. Typical concentrations can vary between 0.05 and 0.5mg per cubic metre of ambient air. Once inside the compressed air system, in a similar fashion to water, oil vapour will cool and condense. Vaporised oil from the compression stage of a lubricated compressor will also condense within the system and add to the overall level of oil contamination.
Contaminate 5 and 6
- Liquid Oil and Oil Aerosol - Most air compressors use oil in the compression stage for sealing, lubrication and cooling. During operation, lubricating oil can be carried over into the compressed air system as liquid oil and aerosols.
How these contaminants can cause issues
When the above contaminants combine the result is a highly acidic condensate that has the potential to cause damage to the compressed air systems storage and distribution, as well as equipment and products that use the air.
In the second post in this series we will look at the remaining four contaminants of a compressed air system, how the failure to prevent them can cause further issues and how international standards can help guide you on what level of contamination must be reduced to within your industry.
This post was contributed by Dave Sykes, Marketing Communications Team Leader, Parker domnick hunter Filtration and Separation Division EMEA