Abstract: In a method for preparing glyoxylated polyacrylamide, in which an aqueous solution of polyacrylamide is supplemented with ethanedial (glyoxal) under stirring by means of a circulation pump, the reaction is started by the addition of a base, at a basic pH value above 8, and is allowed to react under stirring and/or circulating, whereupon the reaction is stopped by the addition of an acid under stirring and/or circulating after completion of a predetermined reaction time, wherein the method is per as a discontinuous method in which the quantitative reaction of ethanedial with an excess amount of polyacrylamide in an aqueous basic medium is controlled and/or regulated by at least one, of the following factors: a) turbidity measurement b) adaptation as a function of the temperature c) pH adaptation as a function of the reaction time d) drop of pH the value, or e) current consumption of the circulation pump.

Abstract: In a method for preparing glyoxylated polyacrylamide, in which an aqueous solution of polyacrylamide is supplemented with ethanediol (glyoxal) under stirring by means of a circulation pump, the reaction is started by the addition of a base, at a basic pH value above 8, and is allowed to react under stirring and/or circulating, whereupon the reaction is stopped by the addition of an acid under stirring and/or circulating after completion of a predetermined reaction time, wherein the method is performed as a discontinuous method in which the quantitative reaction of ethanediol with an excess amount of polyacrylamide in an aqueous basic medium is controlled and/or regulated by at least one, of the following factors: a) turbidity measurement b) pH adaptation as a function of the temperature c) pH adaptation as a function of the reaction time d) drop of pH the value, or e) current consumption of the circulation pump.

Abstract: In a screw extruder comprising a screw shaft on which at least one screw blade is disposed, a filter screen surrounding the screw shaft and including filter openings is arranged within oppositely located frames and a funnel-shaped filtrate trough is disposed below and on the outer side of the filter screen, the screw shaft is cylindrical in the region of an inlet port, widens conically in its central region, and is cylindrical in the region of the discharge port, and the filtrate trough comprises at least two chambers, which chambers are each provided with a drain for filtrate, and the first chamber in the region of the inlet port has a longitudinal extension corresponding to at least the length of the cylindrical portion of the screw shaft in the same region.

Abstract: In a method for manufacturing paper or the like, in which cationic polymer microparticles comprised of polyacrylamide and a fine-particle inorganic component are added to the paper pulp following the final shearing step and prior to the headbox, whereupon the paper pulp is subjected to dehydration while forming sheets, followed by sheet drying, a polymer mixture comprising a linear cationic polymer and a linear anionic copolymer, whose overall ionicity is anionic, is additionally added immediately prior to the headbox.