Device for air circulation in a room is made of a casing with a concave wall having apertures and a flexible membrane which can seal the wall's apertures if there is a pressure difference between the two faces of the membrane

摘要

Device is made of a casing (4) with a concave wall (8) having apertures (9,9') and a flexible membrane (5) which can come in contact with the wall and seal its apertures (51,51') if there is a pressure difference between the two faces of the membrane.