Adsorbers ensure that moisture and oil mist have no chance of entering the system.
Oil in hydraulic units, gearboxes and transformers expands during operation due to heat generation and contracts again when a system comes to a standstill due to cooling. Air is forced out of the system, or drawn in, to equalize the pressure. If this air is not filtered, humidity enters the system. It condenses inside and gets into the hydraulic or transmission oil in droplet form. Condensation water damage as well as contamination of the oil are the results. The same happens in tanks, barrels & IBCs when air flows in to equalize pressure during emptying.