Decker Thickner operates decker or rotary filter machines to removewater
from pulp stock and reduce stock to specified consistency for bleaching
or beating: Turns valves to regulate flow of pulp stock into machine vat.
Starts machine and adjusts controls to regulate speed of cylindrical screen
in vat. Turns valve to adjust suction in cylinder to deposit pulp on screen
at specified rate and remove white water through meshes of screen.
Turns hand wheels or pulls lever to adjust press roll against screen to obtain
pulp of specified consistency. Pulls lever to adjust blade that scrapes pulp from
screen into storage chest. May tend flat or rotary screens to remove coarse fibers
Decker / Washer
The decker / washer has two functions. One function is the thickening of the pulp
slurry fed to it. Secondly is the washing action of draining away water that contains
residual minute ink particles and ash for brightness enhancement. Accepts from
the forward cleaners flow to one of two decker / washers. Consistency of the forward
cleaner accepts supplied to the decker / washer is 0.58 percent. Accepts from the
gravity decker / washer are diluted to 3.5 percent and sent to the second press.
Control for the decker / washer works off the tub level. As the level increases the
speed of the drum’s rotation increases to control level. Generally, every deinking
system has at least one stage of washing for the removal of fine ink and ash; this
system utilizes two washing cycles through this stage of the process.