Abstract: To move debris (6), the porosity of which presents certain properties, from a space subjected to the pressure of a compressible substance, such as air, where the pressure is high (pressure chamber, (1)) to a space (3) where the pressure is lower, the invention provides for an extraction chamber (2) to be positioned between the pressure chamber (1) and the space (3), which extraction chamber can be closed in relation to both spaces by means of slides (4 and 5). When the slide (4) is opened and the slide (5) is closed the extraction chamber (2) is filed with debris using the positive pressure in the chamber (1). After the slide (4) is closed and the slide (5) is opened the debris (7) contained in the extraction chamber (2) is evacuated from the chamber (2) into the space (3) by the pore pressure present in the debris.