Compressing unit

About the sound

The compressor is a pair of large cylinders, through which the web is driven. Pulp slurry goes through compressing unit where cylinders press water from it with the rolling felt sheets. When entering the compressing unit the dry content of the web is 17-20 %. Coming out of wire, the dry content has increased around 35 to 50 %. In the compressing unit all the different layers (the cover layer, inside layers and background layer) are pressed together. Then the web can be transferred to the dryer unit.
Manufacturer Ahlström Karhula Plant in 1981.

Metsä Board Tako is the last large industrial establishment still working beside the Tammerkoski rapids in the center of Tampere. Metsä Board Tako is part of Metsä Group, one of the largest forest industry groups in the world.
The mill produces high-quality paperboard to be used for all kind of consumer products like chocolate boxes and hard packs for cigarettes. The raw material is in form of CMTP –bales, which are delivered to the factory by trucks. The process of board machines is highly automatized, 200 employees working in shifts can produce 205,000 tons of cardboard annually. The process includes grinding of raw material, the cardboard machine with “wet end”, compressing and drying units and finishing jobs like polishing, coating and cutting units. There are three board lines (cardboard machines) in the factory with two still in operation. The factory has also some supporting units like its own hydroelectric power plant. The factory was established in 1865 and the current mill was built in 1930s.
max. dB. 85.0

Sound recordist: Maasa Järvinen
Photographer: : Leena Ahonen
Video recordist: Kimmo Kestinen