Device for air generate purified

The device for generating purified air to a sheltered area (12) from air contaminated with a reference pressure (PR) includes a housing (20), a fan (32) and a filter (90). The fan (32) and the air filter (90) are surrounded by the housing (20) there is provided a first partial chamber (30) in the housing (20), depression (P1) and a second chamber part (60) at an internal pressure (P2), the housing (20) has an outlet (114) from which purified air exits in a sheltered zone pressure (P3). The filter (90) is arranged between the output (114) and the second partial chamber (60) and is provided between the second partial chamber (60) and the sheltered area (12) a safety chamber (S) in which there is a safety pressure (PS) which is less than the sheltered zone pressure (P3).