Pulper

Under a pulper is meant a big beating vat, which is used in paper, cardboard or paperboard industry to dissolve waste paper or pulp.

It works like an oversized blender, which under the driver has a mesh screen over which the material is pumped out. The volume of the pulper is 12-100 m³. The pulper is first filled with water, then the waste paper or pulp is added and dissolved therein. Thereafter, the pulp suspension is pumped out and further processed. The consistency pulpers normal is about 3 to 6%. However, one can also dissolve cellulose with Hochkonsistenzpulpern. The achievable consistency in this case is 12 to 18%. Advantages are that the mixture dissolves better and thus you can save energy and space. This is because that the shear force between the fibers is much higher due to the absence of water. To pump the mixture must also be diluted to about 5%.

Construction and types of procedures

There are two different types, one with a vertical rotor shaft ( most common), and having a rotor shaft which is mounted horizontally.

In the process we distinguish between two types of processes:

• In the batch process the pulper is filled and drained after the dissolution time.
• In the continuous process of the pulper is continuously filled with waste paper or pulp and water and pumped out.

Cleaning of contaminants

In the processing of waste paper also impurities are introduced into the pulper regularly. Wires and plastic parts tangled up gradually with each other and must be removed after a few hours with the crane. This scrub is named Bear. In order to prevent this is also the so-called braid are used. You can have a bearing roller which is provided with a counterweight, a long rope down into the mixture so that it caught on wires and plastic parts. The braid is then every few minutes pulled a piece while it tracks at the bottom again and again. If it breaks, it must, like the bear, be removed by crane. Items that are not caught by means other sorting systems the screened lead the sorted material back into the pulper. Contaminants that are going through the screen plate away in finer sorts.