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AssigneeValmet Technologies Oy
InventorsJuan Cecchini, Juha Kivimaa, Kari Lamminmäki, Antti Poikolainen
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The invention relates to a method for forming a three-layer board web, preferably a folding box board (FBB) or a solid bleached (sulfate) board (SBS), in a forming section (300) comprising a multilayer headbox (100) and a forming unit (200). In the method the layers of the three-layer board web are first formed of pulp suspension in the multilayer headbox (100) and fed to only one forming unit (200), a gap former where the pulp suspension from the multilayer headbox is fed to a gap between lower and upper wires for water removal and for joining the layers of the three-layer board web and where water is first removed by a non-pulsating forming shoe (37, 39).
A method for forming a three-layer board web, in a forming section comprising a multilayer headbox and a forming unit, the method including the steps of first forming the layers of the three-layer board web of pulp suspension in the multilayer headbox and then feeding the output from the multilayer headbox to only one forming unit, the forming unit being a gap former where the pulp suspension from the multilayer headbox is fed directly into a gap between lower and upper wires for joining the layers of the three-layer board web and for first water removal by a curved non-pulsating forming shoe adjacent the gap where dewatering happens on the curved non-pulsating forming shoe in both directions, wherein, after the curved non-pulsating forming shoe, pulp suspension between the lower wire and the upper wire is guided below a suction unit located inside a loop of the upper wire.
Dependencies are inferred from the claim text.