Pulpers: Efficient Waste Paper Processing in the Paper Industry

What are Pulpers and How Do They Work?

A pulper is similar in its functioning to an oversized mixer. It consists of a large vat with a capacity between 12 and 100 cubic meters. At the bottom, there is a sieve plate over which the dissolved fiber suspension is pumped out.

The dissolution of the waste paper or pulp is carried out by a rotating shaft, which is installed vertically or, in some cases, horizontally. The pulper is first filled with water, then the material to be processed is added. Through rotation, it is broken down into its fibers and dissolved.

There are two types of processes:

• In the discontinuous process, the pulper is filled, the material is dissolved, and then completely pumped out before the process starts anew.
• In the continuous process, filling with water and raw material as well as pumping out the suspension takes place in a continuous process.

Advantages of Pulpers in Paper Production

Pulpers offer several crucial advantages in waste paper processing:

• High efficiency: Through intensive mixing, even large quantities of waste paper and pulp can be quickly and thoroughly dissolved.
• Flexibility: Pulpers are suitable for processing various raw materials such as waste paper, cardboard, or pulp.
• Space-saving: Compared to other processing methods, pulpers require relatively little space.
• Energy-efficient: Modern high-consistency pulpers work with a higher stock density of 12-18%. This allows for energy savings.

However, when using waste paper, impurities such as plastic parts, wires, or non-dissolvable paper components must be removed from the pulper. This is done either manually or with the help of special cleaning devices such as the "tail", which continuously filters out the impurities.

Areas of Application for Pulpers

Pulpers are used whenever waste paper or pulp is to serve as a raw material for paper production. They are suitable for the production of most types of paper such as:

• Newsprint paper
• Tissue papers
• Packaging papers and cardboard
• Recycled papers

Only for the production of high-white graphic papers or specialty papers are pulpers of limited suitability, as the pure pulp fibers required for this can be more gently opened up in the so-called pulp dissolver.

Pulpers are thus an efficient and flexibly applicable solution for waste paper processing in the paper and cardboard industry. They thereby make an important contribution to recycling and the conservation of natural resources in paper production.