Patent GB-786808-A (GB)
Title: Improvements in and relating to apparatus for use in the production of viscose
Inventor: BARRATT HAROLD
IPC: C08B1/10
Filed: 1955-08-03
Abstract: <PICT:0786808/IV (a)/1> <PICT:0786808/IV (a)/2> <PICT:0786808/IV (a)/3> <PICT:0786808/IV (a)/4> Alkali cellulose is aged in a silomercerizer having a stationary ageing compartment through which the alkali cellulose crumbs pass downwards and pickers rotated by rams operated by fluid pressure to remove crumbs from the bottom of the compartment.  Fig. 1 is a section through a silomercerizer.  The alkali cellulose crumbs are fed to the top of the tank 1, which may be jacketed for temperature control, and distributed evenly over the area of the tank by any suitable means, e.g. a conveyer belt system. In passing vertically down the tank, the crumbs are aged and are removed by the picker rollers 3 and fall on to the belt 5 for conveyance to the next stage in the viscose process.  The cylindrical picker rollers 3, rotatable in alternate directions as shown by the arrows, each possess four blades 4 running the length of the roller and spaced 90 degrees apart around the circumference.  The rollers, which may be hollow with means for passing through a cooling fluid, are spaced so that blades on adjacent rollers have a small clearance and do not intermesh. Fig. 4 shows an hydraulic system for driving the pickers. Hydraulic fluid in tank 22 is pumped by pump 23 through relief valve 24 to a four-way valve 25 controlled by a pilot valve 33 actuated by projections 34, 35 on link rod 16.  The other parts of valve 25 feed to a return line 26, to a line 27 feeding the left-hand sides of hydraulic cylinders 19 and to a line 28 feeding the right-hand side of the end cylinder 19, which is double-acting.  The flow of liquid in 27 and 28, and hence the speed of rotation of the picker rollers, may be varied by control valves 30 and 29.  With the right-hand side of the end cylinder connected through valve 25 to return line 26, hydraulic pressure applied to the left-hand side of cylinders 19 moves pistons 21 and rods 18 to the right, rotating the inter-connected levers 13, 14, Fig. 2, in an anti-clockwise direction about an axis coinciding with the axis of shafts 6.  Fig. 2 is a plan view of a portion of the pickers and driving mechanism and Fig. 3 the view along line III-III of this Figure.  The levers 13, 14 are rotatably mounted on shafts 6, extensions of alternate rollers 3, and carry pawls 12 by means of pins 15.  The pawls engage toothed ratchet wheels 11, fixed to shafts 6, thereby rotating shafts 6 and rollers 3 in an anti-clockwise direction.  Shafts 7 carrying gears 40 engaging with gears 41 on shafts 6 are simultaneously rotated in a clockwise direction.  At the conclusion of the stroke, projection 34 acts on pilot valve 33 reversing the position of valve 25.  The left-hand sides of the cylinders 19 are then connected to return line 26 and hydraulic pressure is applied to the right-hand side of the end cylinder, forcing the piston to the left.  Since the groups of levers are connected by tie-bars 17, all the levers are returned to their original position, the pawls 12 riding over the ratchet wheels 11, which remain stationary.  When projection 35 acts on pilot valve 33, valve 25 is again reversed and the cycle repeated.  Specifications 672,302, 705,420 and 742,535 are referred to.