Improvements in and relating to the production of viscose

Apparatus for ageing alkali cellulose comprises a silo mercerizer having a stationary ageing compartment, through which the alkali cellulose crumbs pass vertically downwards, and mechanical pickers to remove crumbs continuously or intermittently from the bottom of the compartment, the pickers comprising rotatable members with non-circular transverse cross-sections of the same size and shape extending across the full width of the silo and having a substantially uniform clearance, there being substantially no permanent straight vertical path between adjacent pickers during their rotation. The pickers may be hollow and provided with means for passing a cooling fluid through them. They may be prismatic in form with a transverse cross-section having the shape of an equilateral triangle with straight or slightly curved convex sides and rounded apices. As shown, alkali cellulose is supplied continuously to the ageing compartment 11 of a silo mercerizer 10 through the supply hopper 14 and is distributed uniformly over the compartment by the cone 15. The alkali cellulose passes slowly down the compartment 11 and is maintained at a constant temperature by a fluid circulated through the jacket 17. It ages during its passage through the compartment and is discharged without compression by the rotating mechanical picker members 20 into the hopper 21, from which it passes through the outlet 22 to a xanthating churn or cooling drum. The pickers 20 are hollow and are all rotated at the same speed in the directions shown by the arrows by means such as is described in Specifications 672,302 and 705,420. The apparatus eliminates or minimises compression of the alkali cellulose crumbs when they are picked from the bottom of the ageing compartment.