Provide filtration to protect against build-up or erosion caused by particulate matter in the large volumes of air that compressors handle. Moisture in compressed air can lead to scaling, rust, frozen lines, wear, and malfunctioning controls and air logic devices. The pressure dew point defines the amount of moisture removal necessary. When air is compressed, it is heated. When later cooled, condensate forms.
Lubricated compressors leave oil in the condensate.
An air receiver downstream of the compressor stabilizes system pressure, acts as a demand reservoir, and collects some moisture. Put an air dryer, selected to provide the proper pressure dew point, downstream of the receiver to trap remaining moisture. A coalescing filter after the dryer provides protection if upstream components fail. For instance, the coalescing filter captures a large portion of moisture traveling downstream of malfunctioning condensation traps. A modern, lubricated compressor and high-efficiency purification system produce instrument quality air with the minimum of stages of efficient compression.