Abstract: The invention relates to a method for cleaning a filter element made of a porous material. The method comprises directing ultrasound to the filter element, and directing after a predefined time from starting of the ultrasound an impulse to a filtrate reservoir causing filtrate inside the filtrate reservoir to be forced inside the filter element in order to remove particles from the surface of the filter element. Pressure of the impulse is between 4 to 8 times higher than the forward pressure and also that the reverse flux, measured in volume per area time, caused by the impulse is at the minimum 2 to 8 times the feed flux. The invention also relates to a filtering device comprising a filter element made of a porous material.

Abstract: Apparatus (8) for filtering, clarifying or polishing, a liquid flow containing finely divided solids. In the apparatus (8), the liquid flow to be filtered is directed to the outer surface of a filter element (3) with high speed and in tangential direction, and thereby, influenced by the generated shearing force, part of the liquid penetrates the filter element (3) and is filtered. More precisely, the apparatus (8) includes a cross-flow tube (2) having a circular cylindrical shape and having apertures directed substantially in tangential direction towards the outer surface of the filter element (3). A method for removing finely divided solids from a liquid flow using such apparatus is also described.

Abstract: Apparatus (8) for filtering, clarifying or polishing, a liquid flow containing finely divided solids. In the apparatus (8), the liquid flow to be filtered is directed to the outer surface of a filter element (3) with high speed and in tangential direction, and thereby, influenced by the generated shearing force, part of the liquid penetrates the filter element (3) and is filtered. More precisely, the apparatus (8) includes a cross-flow tube (2) having a circular cylindrical shape and having apertures directed substantially in tangential direction towards the outer surface of the filter element (3). A method for removing finely divided solids from a liquid flow using such apparatus is also described.