Air Compressor Filters

The most common problem with air tools and pneumatic equipments is the air contaminants from the air supply collected by the air compressors. It may not affect them at first but in the long run as these dusts accumulate it can cause poor performance and increase wear and tear thus reducing its service. These includes small dust particles and moisture content, they are very small that we couldn’t see them with our naked eyes. Other particles such as water that evaporated in the air are invisible and can only be seen if they are condensed in the reservoir of the air compressor. Sometimes we keep wondering why there’s water accumulated at the bottom of the tank of the air compressor? Because once these water vapor gas cools down in the air tank it condenses and go back to its liquid state which is water. Because water is incompressible once it enters our equipment it can cause the pneumatic actuators and valves to malfunction and stop working. This is very bad especially if these equipments like packaging machines are being used in a business, downtime equals money loss. To avoid these, some air compressors like the Ingersol-Rand air compressors incorporates a filter at the air pump intake, just like the one used in automotive intake filters. These filters need to be cleaned or replaced regularly to avoid it from restricting the air which can reduce the compressors efficiency. It can only filter dust particles and not the water vapor in the form of gas but some of it can be separated in the air tank and can be drained using the built-in valve located at the bottom of the tank.

In large companies which use pneumatic machines and equipments that are very sensitive and operating 24 hrs a day, a much more complicated air filter system is used. Beside from the built-in filter from the compressor a series of other filters are used not to mention the individual air filter installed in each machines. Some machines like in food and semi-conductor companies that have a clean room environment uses a micron filter in series with the main line filter, air-dryer and after cooler. These micron filters can remove ultra-small particles including odors and gas water vapors.

To remove the water completely you need to condense from its gas state to liquid form before purging it out of the system. This is done by installing a refrigerated air-dryer after the compressor and the main line filter, provided that the temperature of the air leaving the compressor is normal, meaning not very hot. If it’s very hot then you need to add additional after-cooler after the air compressor before it enters the air dryer to maximize the air-dryer’s efficiency and prevent it from overheating. The principle behind refrigerated air-dryer is very similar to the refrigerator and air-conditioning system used in homes. It cools down the air temperature and condenses the water vapor before it automatically ejected through an automatic drain valve. The measurement of dryness is denoted by the outlet temperature of the air dryer, the lower the temperature less moisture in the air is present. As long as the air piping doesn’t go to a room lower that the outlet temperature of the air-dryer no more condensation will take place and we can consider it as dry air.

The compressor filters (not the intake filter) are a bit hard to find because only few companies actually make them. You can normally buy them at pneumatic companies like “SMC Pneumatics Ltd.”, CKD, Festo, and Bosh. These companies sell pneumatic valves, actuators, air-filters and more.