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Raw material feed<br />
TwinDrum pulping system<br />
High density cleaning<br />
Rejects thickening Sludge thickening Water cleaning<br />
Dump chest<br />
operating or planned to be installed in<br />
Germany. With a capacity of 1,300 t/24 h<br />
of finished stock, Schwarza will operate<br />
the TwinDrum pulper with the highest<br />
pulping capacity up to now.<br />
The drum pulper’s principle has been<br />
described in detail in twogether 9.<br />
Based on the positive experience with the<br />
TwinDrum pulping system at the Burg<br />
mill, two-stage hole screening with an<br />
MSS screen (1.6 mm holes) in the first<br />
stage and a Combisorter in the second<br />
stage will be used. This concept ensures<br />
efficient, cost-effective and space-saving<br />
coarse screening.<br />
After pre-screening, an MSF fractionator<br />
separates the stock into short and long<br />
Hole screening<br />
<strong>Paper</strong> Machines<br />
Fractionation<br />
LF heavyweight cleaning<br />
LF slot screening<br />
fiber fractions. While the short fiber fraction<br />
will be clean enough to be just<br />
passed through cleaners before being<br />
thickened, the long fiber fraction is first<br />
fed to EcoMizer cleaners and then to a<br />
three-stage LC screening system with<br />
0.20 mm slots.<br />
Jass has thus adopted a simple, yet clear<br />
stock preparation concept with the aim of<br />
removing disturbing components from<br />
the stock as early as possible. Consequently,<br />
screening in the approach flow<br />
system is merely a policing function.<br />
By installing <strong>Voith</strong> Bagless disc filtering<br />
for thickening the short and long fibers,<br />
Jass has selected the most advanced disc<br />
filter technology available, as presented<br />
in detail in twogether 16.<br />
SF heavyweight cleaning<br />
37<br />
The stock preparation philosophy used in<br />
the Schwarza mill will ensure the required<br />
end product quality is achieved<br />
without the need for dispersion.<br />
The rejects handling machines, such as<br />
magnetic separators, shredder and compactors,<br />
will be supplied by <strong>Voith</strong> <strong>Paper</strong>’s<br />
joint venture partner meri. For water<br />
treatment the well-known DeltaPurge and<br />
Elephant units have been selected. For<br />
sludge thickening, a gravity table and a<br />
Thune screw press will be installed.<br />
<strong>Paper</strong> Machine<br />
Thickening<br />
Storage<br />
Fig. 1: Simplified flow sheet of the stock<br />
preparation system at the Schwarza mill.<br />
The forming section of the <strong>Voith</strong> paper<br />
machine is equipped with a DuoFormer<br />
Base including a two-layer MasterJet<br />
<strong>17</strong>/04<br />
LF refining
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