Reference Manual

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Chapter 17
Paper Machine
Wet End
The paper machine is essentially a series of
processes all tied together (figure 17-1). These
processes are designed to take fibers in a dilute
slurry of water and produce a dried web of paper.
The paper machine is described in two parts: the
wet end, which is the forming section, and the dry
end, which includes the pressing and drying
operations.
Fourdrinier Single-Ply Process
The following are the steps taken to form the
fibers onto the wet end of the paper machine in
new and more modern pulp and paper mills:
Tapered Manifold
The stock heading toward the headbox is coming
from the headbox pressure screen (figure 17-2).
This stock is to be spread uniformly over the entire
width of the paper machine where some machines
are up to 400 inches wide. This is accomplished
by using a tapered manifold (figure 17-3).
The tapered manifold starts large at the inlet end
and tapers down over the length of the device.
This allows the pressure to remain the same even
though stock is being diverted through numerous
tubes to the headbox. At the end of the manifold is
a recirculation line that allows one to balance the
manifold for different flow rates.
Figure 17-1. Fourdrinier Paper Machine
Drawing is from TAPPI’s Making Pulp and
Paper Series and is used with permission.