Backwashable filter having elements with elastically deflectable lips

A backwashable filter, comprising:

• a layer of superimposed elements made from an elastically deformable material, where each two adjacent of said elements form a gap through which a flow takes place, said elements having a connecting body, an inflow side located on one side of the elements and forming an accumulation point for contaminations by particles such as sand grains, and an outflow side formed on the other side of the elements;
• spacing members located on said elements adapted to space apart said elements from one another;
• a lip on the inflow side of each said element, for each element said lip having a wide front face, an upper edge defining a first opening edge and a lower edge defining a second opening edge, said lower edge being connected to the connecting body and said lip extending upwardly therefrom such that a cavity is formed between the lip and the connecting body, wherein the first opening edge forms a flap opening with the second opening edge of an adjacent element, and wherein said cavity allows the lip to be elastically deflectable in the flow direction;
• and
• wherein least one support, for each element, adjacent said lip, said at least one support having a facing side spaced from said lip such that said facing side allows a small movement in the flow direction of said lip until said lip strikes against said facing side of said at least one support;
• wherein the gap opening formed between the first opening edge of the lip and the facing, fixed second opening edge of the adjacent element being reduced by the elastic deflection of the lip, starting from a position without loading by flow forces and decreasing in the flow direction until striking the facing side of the at least one support arranged alongside the lip, so that a particle jamming in the gap opening with the flow exerts a driving force on the opening edge of the lip which narrows the gap opening.

A filter having improved backwashing capabilities comprising:

• a plurality of filter elements arranged one on top of the other to form a filter candle evidencing a longitudinal axis, said stacked elements being separated by at least one support substantially disposing said elements at a predetermined spacing;
• said elements defining a gap between a lower most portion and an upper most portion of adjacent elements;
• said elements each having a body terminating at a distal inflow end in a lip, said lip extending upwardly from a cavity formed in said body;
• wherein, for each element, said at least one support is attached to said element proximate said cavity and has portion thereof extending upwardly;
• and
• wherein, for each element, said lip is radially deformable about said filter candle axis in spaced relation from a respective upward extension of said at least one support to a position proximate said upward extension of said respective support to narrow said gap between adjacent elements.