Tank breathers type DTR and AFI have been developed specifically for the ventilation of storage tanks and transport vessels. The breathers are filled with desiccant, which prevents the entering of moist air into the tanks or vessels via the vent during breathing or discharging, thus protecting the contents and avoiding a corrosion of the tanks.
The desiccant is provided with an indicator, displaying an orange colour in its active state; a colour change from orange to translucent indicates that the desiccant is saturated with moisture and has to be regenerated.

The selection of the breathers depends on following criteria:
required service time
discharge capacity/day
allowable pressure drop