Overflow sieve

An overflow sieve, comprising:

• a support structure extending over an arc and having a concave side and a convex side, said support structure comprising an array of transversely spaced arcuate longitudinal bars extending between opposite rails, each of said bars being individually of triangular cross section, and transverse bars perpendicular to said longitudinal bars and forming a grid with the longitudinal bars;
• a sieve bottom fitted onto said support structure along said concave side and constituted of a perforate sheet formed with noncircular openings in an array distributed over said sheet, said sieve bottom having a concave surface and a convex surface, said convex surface being in linear contact with apexes of said individual longitudinal bars, said transverse bars being spaced from said convex surface, said openings being selected from:
• slots having a width <1.0 mm and a length of 0.5 to 4 mm of a slotted hole sheet, and
• noncircular perforations with a greatest width of <2 mm;
• means for releasably attaching said sieve bottom to said support structures at said rails so as to enable replacement of said sheet;
• and
• means for applying a mixture of solids and liquid to said concave surface.