GB193965A - Improved manufacture of paper pulp and apparatus therefor - Google Patents

Abstract

193,965. Olier, A. Dec. 1, 1921. Pulp, preparation of. - Cellulose is obtained from ligneous materials in continuous manner, the cutting-up of the material, the separation of dust, the treatment with lye, bleaching, beating, and washing being effected successively in the same apparatus. In carrying out the process, the material is crushed by rollers 2, cut into short lengths at 4, pumped by a fan 9 to an agitator 10, wherein the dust is evacuated and from which the material falls into a macerating apparatus 12, and is there mixed with lye. The pulp and soda lye are fed through an outlet 13 to a press comprising two screws 14, 15, by which the pulp is squeezed through a conical chamber 16 into a lye vat 17 against the action of a valve 16<1>, the liquid squeezed out passing to a pulp collector. In the vat 17, lye from the vat 19 is sprinkled, and the material at the bottom is squeezed and fed by two screws 33, 34 to. the bottom of a washing-column 38, wherein two screws raise the material against the action of wash water to a beater 43. The beaten mass and water falls down a pipe 45 to a press 46, which eliminates the water and delivers the mass to two screws in a bleaching column 52, wherein it is raised against a stream of hypochlorite of soda admitted at branches 55. A press 58 squeezes out the bleaching liquor; the pulp is washed in a column 63, and delivered to a refiner 67, from which it passes to a pulp press or to a paper machine. The residual waters extracted are collected and the cellulose carried therewith is separated therefrom and returned to the circuit, and the liquid passed to a chloridizing vat wherein the combined organic substances are precipitated by hydrochloric acid or chlorine, and separated by decantation or filtration. The clear liquid containing sodium chloride is electrolyzed, and the soda, chlorine, and hypochlorite of soda produced are used in the present process. The material may be fed through the trunks by continuous chain conveyers, as shown in Fig. 4, the first and last trunks being higher than the intermediate trunks to ensure circulation of the liquid in opposition to that of the material. For the preparation of unbleached pulp suitable for cardboard or wrapping paper, bleaching and washing may be dispensed with, the maceration being effected by water at a suitable temperature. Where it is desired to carry out any operation under pressure, the material is fed into and out of a section of the apparatus through a vertical conduit closed by a distributor 94, Fig. 8, rotating. in a casing 97.