The device has a ventilation pipe with shut-off valve, and cleaning elements for ambient air flowing into the pipe. The shut-off valve (9) and the cleaning elements are contained in a housing (8), which is located on the atmosphere-sided end of the pipe. The elements comprise of a diffusor (15) with a downward facing opening and a labyrinth (14) formed by baffle plates (18) and located behind the diffusor. There is also a suppressing chamber (12) and a dust filter (13). The filter is located between a chamber (11) containing the valve, and the settling chamber. The settling chamber has an aperture (17) at its lowest point, which is closed by an outward-opening lip valve (16).
