Paper-making fourdrinier

摘要

At the fourdrinier section, of a papermaking or cardboard prodn. machine, the underpressure unit (22) for water extraction is shrouded by a continuous impermeable belt (26) on the side of the fourdriniers (16, 18) away from it. It prevents air from the water extraction unit (22) being sucked through the fibre suspension (14). Also claimed is an operation where the fibre suspension (14) is delivered from the stock inlet, to the upper surface of a fourdrinier (16, 18) which is air permeable and water absorbent or permeable to water, to be carried through water extraction stage of the fourdrinier section (10). Water is extracted from the suspension (14) by an underpressure extraction unit (22) at the side of the fourdriniers (16, 18) away from the pulp (14). An impermeable belt (26) is on the opposite side of the fourdriniers (16, 18), to prevent air from the extraction unit (22) being sucked through the fibre pulp (14).