Papirmaskine

Papirmaskine, or paper machine, is a large continuous machine used in pulp and paper mills to manufacture paper by forming a continuous sheet from a pulp suspension. It supports the conversion of wood fibers or recycled fiber into a uniform sheet and is central to modern high-volume paper production.

The machine typically consists of the forming section (headbox and forming fabric), a press section, a dryer section, and optional sizing and calendering units. The most common form is the Fourdrinier machine, which uses a moving forming wire to support the forming sheet and remove water during formation.

In operation, a slurry of fibers and water, called furnish, is delivered to a headbox, which distributes it onto the forming fabric. Water drains through the wire and gravity or vacuum aids drainage, forming a wet sheet. The sheet then passes through press rolls to remove more water, then through drying cylinders warmed by steam or other heat sources, to reduce moisture to the desired level. Additional sizing or coating stages may be added before drying or after to suit product requirements.

After drying, the sheet may be passed through size presses or coating stations, and finally through calenders to adjust thickness and surface finish before winding onto reels. Different machines exist for different products: Fourdrinier machines for machine-made papers, cylinder machines for specialty grades, and tissue machines for thin tissue papers.

Modern papirmaskiner emphasize energy and water efficiency, with closed-loop water systems and energy recovery. Maintenance includes keeping the forming wire clean, monitoring fiber consistency, temperatures, tensions, and speeds. The papirmaskine remains a central component of the papermaking process and essential for high-volume production.