A filter for cylindrical of flat filter equipment for the mechanical purification of liquids as described which is assembled of several filter elements (4) arranged one above the other which disclose always gap-shaped filter openings between them and which are fastened by rods led through them and locking flanges. The passage openings for the rods are formed as sleeves (7) to which distance holders (8) belong. The filter elements have trapezoidal cross-section, the outer longer base side (16a) of which, together with the height of a filter opening, make out the height of the sleeve (7).