Compressed air leaves the compressor hot and saturated with water vapour. As it cools in the pipe network, that vapour condenses into liquid water that corrodes pipes, contaminates tools and ruins sensitive processes. An air dryer removes this moisture before it causes damage.
Dryer types compared
- Refrigerated dryers — cool air to about 3°C pressure dew point; the economical choice for general industry
- Adsorption (desiccant) dryers — reach dew points of -20°C to -70°C for outdoor lines, food, electronics and pharmaceutical use
- Membrane dryers — compact, low-flow units for point-of-use drying
Choosing by dew point
Match the dryer to the required ISO 8573-1 water class. If pipes run indoors in a warm climate, a refrigerated dryer is usually enough. If lines pass through freezing areas or the process demands very dry air, choose an adsorption dryer sized for the compressor output.
Integration tips
Install the dryer downstream of an aftercooler and water separator, and upstream of filtration. Size the dryer at the worst-case inlet temperature, and add a coalescing pre-filter to protect desiccant beds from oil. A poorly placed or under-sized dryer cancels the benefit of the whole treatment train.