GB708061A - Improvements in and relating to apparatus for ageing alkali cellulose - Google Patents

Abstract

Apparatus for use in the ageing of alkali cellulose for viscose production comprises a series of containers mounted in a horizontal ring in a framework which is rotatably mounted about a central vertical axis, each container having a capacity of one xanthate charge and being provided at the top with a charging opening and at the bottom with a discharge opening, a stationary shoot for charging one container at a time with alkali cellulose, a second stationary shoot into which one container is discharged at a time, and a mechanism for intermittently rotating the ring so as to allow each container in turn to remain stationary when opposite the charging and discharging shoots for a sufficient length of time to allow the charging and discharging to be effected, the length of the circular path of travel of a given container from the charging shoot to the discharging shoot and the speed of rotation of the ring being such that the time required for the container to travel from the charging shoot to the discharging shoot is equal to the ageing time for the alkali cellulose. As shown in Fig. 2, at a charging station A the charges of alkali cellulose crumbs are introduced by way of a shoot 14 into the containers 9 (which are formed by segmenting a vertical cylindrical tank carried by a vertical cylindrical framework 1 mounted upon a vertical rotatable <PICT:0708061/IV(a)/1> <PICT:0708061/IV(a)/2> shaft 2), and each charge is carried round in the apparatus in the direction shown by the arrow towards a discharging station B, adjacent to the charging station A. The aged alkali cellulose is discharged by means of a shoot 17 into a funnel 18 and thence to a xanthation churn. The containers 9 are brought in sequence to the charging and discharging stations by the action of a ram 15 on a ratchet 16 mounted on the shaft 2, in keeping with the demands of the xanthation churn. The time cycle is predetermined so that the period taken for a container to pass in steps from the charging station A to the discharging station B is that required for the ageing of the alkali cellulose. As shown in Fig. 3, the whole of the bottom of each container 9 consists of a door 19 pivoted by a hinge 20 on the interior wall 21 of the container 9 and is locked by a bolt 22 to a fastening 23 on the exterior wall 24 of the container 9. A fin-shaped plate 25 is fixed to the underside of each door 19. When a charged container 9 is brought to the discharge station B above the funnel 18, the bolt 22 is withdrawn and the door 19 swings open, allowing the contents of the container 9 to discharge into the funnel 18. The door 19 is then mechanically closed by a wheeled trolley 26 having a freely mounted roller 27 which is pushed against the open door 19 by a hydraulic ram 28. The roller 27 moves against the plate 25 and, owing to the cam shape of the plate 25, the door 19 is forced to its closed position and the bolt 22 is then manually replaced. The trolley 26 is then retracted for the operation to be repeated when the next container 9 is discharged. Specifications 488,793, 497,977, 526,061 and 5349/39 (as laid open to inspection under Sect. 91) are referred to.