The Fourdrinier Papermachine

Further, fibre orientation in the plane of the web is influenced by the relative velocities of the mix flowing through the nozzle and the fast-moving wire. Generally the veloeity of the mix should eorrespond very closely to the velocity of the wire. 

The wire is a woven, multi-layered polymer fabric that forms an endless belt up to 10 metres wide and over 70 metres long. The openings in the wire are about 0.1 mm X 0.1 mm so the wire is not capable of trapping fines and fillers. Instead, free drainage through the wire is progressively impeded by the retention of fibres that in turn trap these materials within the developing web. 

Pressure pulse -Vacuum pulse -Movement of wire 

table rolls and suction boxes aid the natural drainage through the wire 

At the end of the Fourdrinier wire a couch roll removes more water from the web before it is transferred to the press section. At this point the moisture content of the web is about 80% water (20% consistency, 200g/L). The white water from the Fourdrinier is continuously recycled 1000 kg of stock at 0.5% consistency is reduced to a 25 kg mat (5 kg fibre, 20 kg water) by the time it leaves the wire and 975 kg of white water is recycled to the make-up chest and thence back to the headbox. A 500 tonne a day papermachine recycles some 100 000 m of water a day. 

---