Patent GB-310495-A (GB)
Title: Apparatus for the rapid and homogeneous transformation of alkali cellulose into viscose
IPC: D01F2/08
Filed: 1928-10-12
Abstract: 310,495. Jardin, L. C. P. April 28, 1928, [Convention date]. Rotary mixers. - Apparatus for rapidly and uniformly transforming alkali cellulose into viscose comprises a polygonal drum A, provided with double walls 1 and 2 mounted to rotate on trunnions 3 carried in the bearings of supports 4 and containing heavy spheres 8. The defibred and ripened alkali cellulose is introduced through the manhole 9 provided with a closing plug 10 and the drum is then rotated by a shaft 5 driven by a suitable motor carrying a helical toothed pinion or worm 6 engaging with a toothed wheel 7, which is rigid with one of the trunnions. The spheres 8 made of lead or other suitable material crush and roll the, material during rotation. Carbon disulphide is passed slowly into the drum through the duct 15 fitted with a cock 16 and spreads slowly into the drum through the screen 17. During this treatment, the temperature in the drum is regulated by circulating brine through the double casing 1, 2, by way of the duct 18, provided with a cock 19, pipes 20 and 21 and duct 22, provided with a cock 23. If the surrounding temperature is cold, the temperature of the barrel is regulated by cold or heated water circulated through the double casing by way of the duct 24, provided with a cock 25, and pipes 20, 21 and 26 after the cock 27 has been opened. An inspection window and thermometers are provided in the drum. As a result of the intense trituration of the material by the lead spheres, the reaction is effected in a homogeneous manner and consequently it is possible to work at higher temperatures and thus accelerate the formation of xanthate When the conversion to xanthate is completed, caustic soda is passed slowly into the drum through the pipe 28, provided with a cock 29, and the screen 17. The additional water required to dilute the solution to the necessary degree is added gradually, a fraction being admitted into the drum through the duct 30, provided with a cock 31, whilst the remainder is reserved for rinsing the drum, after the contents have been emptied into a mixer in which the dissolving is completed, and is then added to the contents of the mixer. The contents of the drum are transferred to the mixer when they have assumed a homogeneous appearance, but, before this, it is necessary to remove the excess of carbon disulphide by suction through screen 32, pipe 33 and duct 34, provided with a cock 35. In order to transfer the contents of the drum, the manhole 9 is brought into the position shown in Fig. 2 and the closing plug 10 is replaced by a grating with spaces smaller than the diameter of the spheres. Then the drum is turned so that the contents drop into the hopper 36, which conveys them to the mixer in which the final dissolving is completed. When almost the whole amount has been transferred, the plug 10 is replaced, more water is added through a pipe 30, provided with cock 31, and the drum is rotated. The rinsing liquor is then transferred to the mixer through the orifice 11, which can be closed by the regulator 12, operated by the ring 13 and situated beneath the grating 14, which retains the lead spheres. Alternatively the rinsing liquor can be transferred through the manhole 9 in the same manner as the first batch of the contents of the drum. Specification 20593/09 is referred to. The Specification as open to inspection under Sect. 91 (3) (a), comprises also a reference to the employment of a cylindrical drum. This subjectmatter does not appear in the Specification as accepted.