In Line Air Filters and Water Separators
In-line air filters for air compressors are essential in protecting the equipment your compressed air goes to. Even though your air compressor has an air filter on the intake (Generally 10 Micron) the compressor still ingests particulate, vapors, oily residue or anything else that is floating in the air that your compressor sucks in. Not to mention the water that results for the compression process and the oil carry over from the compressor itself. Different processes require different ISO classifications.
The most common levels of filtration in order from compressor are as follows:
Water Separator - The air compression process produces a lot of water! No matter what compressor you have. Compressed air filter water separators use a centrifugal action within the filter that spins the air and water against a screen mesh in most cases to knock out "bulk water". There will still be water mist and vapor in the air stream, but an air line water separator is a good first defense. Water separators should still be used even when an air dryer is in the system. Air dryers are not meant to handle bulk liquid and a water separator will knock the bulk liquid out of the air stream.
1 Micron - This air compressor line filter uses a coalescing action to trap particulate down to 1 micron within the filter bed. This filter will also trap some oil. This filter is often referred to as a " General Purpose" filter. Many non critical systems can get by with just a Water Separator and a 1 Micron "General Purpose Filter".
.01 Micron - This air line filter is also a coalescing filter designed to capture oil.
Carbon or Absorber - These compressed air line filters are not designed to see any moisture or bulk oil whatsoever. The primary reason for these filters is to remove any tastes or smell out of the air stream that may contaminate the end product. They are also used to eliminate almost all oil vapor out of the air stream.