Abstract: A suction dredge for the planned taking up of suction material, particularly for excavating soil from underground pipes, has a pneumatic suction hose for taking up the suction material and at whose lower end is provided a suction stub. At its opposite, upper end the suction hose issues into a collecting tank. To simplify the handling of the suction stub, it is provided with a guide body fitted to the suction hose and a suction nozzle axially movable relative thereto and which by means of a drive mechanism can be retracted into and extended from the guide body. As a result the stroke frequency of the suction nozzle and/or its stroke length and/or the impact energy on the soil can be adjusted.

Abstract: The invention relates to an excavator for suction material, particularly for removing soil from underground pipes. The excavator has a pneumatic elephant trunk for removing the suctioned material and which issues into a storage tank for the suctioned material and to which is connected an exhaust fan. In the storage tank the suctioned material is separated from the suction air flow and is subsequently passed through a filter positioned between an elephant trunk opening and the exhaust fan. In order to ensure a good separation on the part of the filter for a long period of time, the filter is formed by a coarse filter and a fine filter connected to the latter. The coarse filter is formed by a labyrinth or cascade-like flow channel, which is bounded by reciprocally displaced partitions and whose flow cross-section increases in the flow direction.