FI53725B

1391112 Centrifugers VYSKUMNY USTAV PAPIERU A CELULOZY 10 March 1972 [11 March 1971] 36711/74 Divided out of 1391111 Heading B2H [Also in Division D2] Apparatus for separating paper from a mixture thereof with an ink-carrying carrier comprises a series of conical vortex separators 10, 13, 16 of which units downstream of each other are of progressively smaller maximum diameter and progressively shorter, the separators being so connected that the overflow from separator 10 is fed to separator 13, and the underflows from separators 10, 13 are fed to separator 16. In use, a mixture comprising waste paper pulp and ink-carrying particles formed in pulper 1 is fed via storage tank 3 and pump 4 to a separator 5 for separation of heavy contaminants, and to a strainer 6 where any residue which has not been repulped is separated out. The stock is then diluted in tank 8 and fed by pump 9 to separator 10 which separates out the coarsest portion of ink-carrying particles, the latter being passed to tank 14. The overflow of purified stock is fed via tank 11 and pump 12 to separator 13 for separation of the remaining ink-carrying particles, the latter also being passed to tank 14. The material collected in tank 14 is then fed to separator 16, the resulting overflow being returned to dilution tank 8 and the underflow being collected in tank 17. The overflow from separator 13 is passed to a separator 21 for removal of the finest contaminants from the stock. Separator 21 comprises a cylindrical vessel 23 provided with tangentially arranged inlet 22 and outlet 24 for vortex flow, axially disposed outlet 25 for withdrawing the finest contaminants, and an inlet 26 through which a gaseous medium or a water/gas dispersion may be introduced into the separator. A perforated screen 27 may be located above inlet 26 to distribute the medium or dispersion uniformly. (For Figure see next page)