REVERSIBLE-FLOW FILTER WITH SCAVENGING DEVICE

A reversible-flow filter with a filter insert in a filter housing, the inner space of which being connected to a fluid inlet, an outlet and a backwash device being rotatable and having a backwash body with a washing gap, reaching near the surface of the filter wall, for cleaning off the filter wall in backwash operation. The backwash device is coupled at one axial end to a rotary drive and at its other end to a sludge discharge. The backwash body having a suckaway slot openable into the inner space, separate from the washing gap and having a larger opening cross-section than the washing gap, wherein the backwash device has a hollow shaft partially movable in relation to the backwash body and rotatable for connecting the washing gap or suckaway slot to the sludge discharge as a function of the relative position between the backwash body and the hollow shaft.