Air dryers are applied in pneumatic installations because moisture flowing in the air due to pressure and temperature changes condenses on inner walls and intensifies corrosion process to metal conductors, valves and servo-motor elements. It also purifies the air from solid contaminants. Another dangerous element is water freezing during winter which may cause immobilizing of crucial mechanisms. During the air flow through the dryer an absorption takes place, which is a chemical bonding of moisture by special granulate with highly hygroscopic properties. A special filtering medium is commonly used in dryers it is a combination of filtration fabric, stopping efficiently solid contaminants of size 0,5 µm with special polymer fibres stopping and chemically bonding moisture from the air. Application of these dryers significantly extends the life of pneumatic installations even up to four times, eliminating practically the corrosion effect in the system.