kolvimyllyt

Kolvimyllyt, a Finnish term that translates to "folding mills," refers to a specific type of early paper-making machine. These machines were a precursor to the modern Fourdrinier machine and played a significant role in the industrialization of paper production. The fundamental principle of the kolvimylly was to form a continuous sheet of paper from a pulp slurry using a rotating cylinder.

The process involved a vat containing paper pulp suspended in water. A wire mesh cylinder, often covered in a fine mesh, was submerged in this pulp. As the cylinder rotated, water drained through the mesh, leaving a thin layer of pulp fibers behind. This layer would adhere to the cylinder's surface, forming a nascent sheet of paper. This wet sheet was then transferred from the cylinder to felt blankets, which would carry it through a series of pressing and drying stages.

Kolvimyllyt represented a significant advancement over earlier methods of papermaking, which were primarily manual and slow. By automating the sheet-forming process, these machines allowed for higher production volumes and a more consistent paper quality. While largely superseded by the more efficient Fourdrinier design, the kolvimylly was an important step in the evolution of papermaking technology, enabling wider availability of paper and contributing to the growth of literacy and communication.