Patent ID: 8640883

Claim:
A filtration barrier comprising: a plurality of combs; each comb comprising a plurality of flexible elements securely attached at a common support strip to form the comb; a plurality of filter apertures defined between the flexible elements of a comb that permit a fluid to flow through, but restrict the passage of particles of sizes greater than an aperture width; wherein each flexible element of a comb has a free portion and an anchor portion; wherein the anchor portions are attached at the corresponding support strip; wherein the flexible elements of each comb branch from the corresponding support strip and lie parallel to each other in a laterally extending common plane in their relaxed state; wherein the free portions of the flexible elements are abuttingly supported against downstream deflection for forward fluid flow through the filtration barrier; wherein the free portions of the flexible elements are unsupported against downstream deflection for reverse fluid flow through the filtration barrier so that the free portions are yieldably displaceable under pressure from the reverse fluid flow such that the corresponding apertures are enlarged relative to their size during forward fluid flow; wherein the laterally extending common plane is transverse to a direction of forward fluid flow; wherein the flexible elements of a comb are arranged in groups; wherein each group comprises two or more elements including a first element and a second element adjacent the first element; wherein the first and second elements of a group are disposed in a sequence of decreasing flexibility within that group such that, when fluid flows in a reverse direction, differing size backwash openings are associated with each flexible element of the group; wherein the sequence extends laterally such that the sequence indexes in a direction transverse to the direction of forward fluid flow; wherein, in response to reverse fluid flow through the filtration barrier, the backwash opening associated with the second element is smaller than the backwash opening aperture associated with the first element of that group; wherein, in response to forward fluid flow through the filtration barrier, the flexible elements are disposed in a regular pattern such that the filter apertures between the flexible elements are substantially similar in size to each other.