Backflush filter and filter insert for the latter

A backflush filter for liquid media, the backflush filter having a filter housing that has a filter inlet, a filter outlet and a flushing connection, the backflush filter having a filter insert, being fixedly arranged in the filter housing, flowable through by an associated medium to be filtered from the inside to the outside and formed by at least one supporting cage, which has at least two groups of slot-type apertures, and at least one filtering means supported on the supporting cage, the apertures within each group of the at least two groups extend in parallel alignment with one another and are separated from one another by mutually parallel ribs of the at least one supporting cage, and the backflush filter having a backflushing device, which is arranged in the interior of the filter insert, is rotatable in the filter insert about an axis by an actuating drive, has at least one slit and extends over the height of the filter insert, the backflushing device serving for zone-wise flushing of the filtering means via the slit and apertures and for carrying filter residues to the flushing connection during a backflush cycle, the slot-type apertures of one of the at least two groups are arranged offset relative to those of the other of the at least two groups, and the apertures of the one group lie in a common plane with the ribs of the other groups, the backflushing device further including at least two mutually separate flushing chambers, arranged vertically offset relative to one another and having associated slits, and a hollow shaft, which is capable of limited rotary motion relative to the flushing chambers and the hollow shaft has a first radial outlet in a region of the first flushing chamber and a second radial outlet in a region of the second flushing chamber, which second radial outlet is arranged on the hollow shaft in a manner vertically offset and circumferentially offset relative to the first radial outlet, the direction of movement of the backflushing device can be reversed by the actuating drive during the backflush cycle, and driving means for simultaneous movement of the flushing chambers and the hollow shaft in the respective direction of motion after a reversal of direction and for rotation of the hollow shaft and the flushing chambers relative to one another are provided for both directions of motion, the filtering means comprising a pleated filter fabric or filter cloth with pleating folds, and the ribs fit with a rib front into respective pleating folds.