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公开(公告)号：EP2673416A1
公开(公告)日：2013-12-18
申请号：EP11779403.2
申请日：2011-11-07
申请人： Voith Patent GmbH
摘要： The invention relates to a sheet-forming device (1) for producing a two-layer or multilayer fiber web (2) from at least two fiber suspensions (3), at least comprising a first screen (4) onto which a first, preferably single-layer headbox (5) applies a first layer (6) of fiber suspension (3) and which is guided together with the applied layer (6) of fiber suspension (3) via a stationary screen table (7) and multiple dewatering elements (8); a second headbox (9) that applies a second layer (10) of fiber suspension (3) onto the first fiber suspension (3) layer (6) that rests on the first screen (4); and a second screen (11) which forms a double screen zone (12) with the first screen (4) at least along some sections, said zone having a wedge-shaped inlet gap (13). The sheet-forming device (1) according to the invention comprises a dewatering element (17) on the lower face of the first screen (4) in the application region (B), preferably upstream of where the second layer (10) of fiber suspension (3) is applied onto the first layer (6) of fiber suspension (3), when seen in the running direction (S) of the screen, said dewatering element guiding the first screen (4) and having a guiding surface (17.A) that bends downwards at a bend angle (17.W) = 1°, preferably = 2°, in particular = 3°. The sheet-forming device further comprises at least one inlet strip (21) which is arranged in the region of the wedge-shaped inlet gap (13) and/or downstream of the region of the wedge-shaped inlet gap (13), when seen in the running direction (S) of the screen, said strip being supported by means of at least one flexible element (22) and being pressable with a selectable force (22.F) against the first screen (4) and/or against the screen sandwich formed by the two screens (4, 11) and the layers (6, 10) that lie between said screens.
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公开(公告)号：EP2449174A1
公开(公告)日：2012-05-09
申请号：EP10720288.9
申请日：2010-05-05
申请人： Voith Patent GmbH
摘要： The invention relates to a forming unit (1), in particular a sheet forming unit for use in a machine for producing a material web from a fibrous or nonwoven suspension (FS), comprising at least two endlessly circulating wire belts (2, 3) which are guided over at least a subregion of the circulation path thereof, forming a twin-wire zone (4), a dewatering apparatus (11) which is arranged within the twin-wire zone (4) in the second of the two wire belts (3) and which forms a supporting surface (9) for this second wire belt (3), is rigid in the functional position and has openings (10) to which a vacuum can be applied, and at least one further dewatering apparatus (12) which is arranged before the entry line (E), running in the cross machine direction (CD) of the second wire belt (3), on the supporting surface (9) and acts on the first wire belt (2), forming a first dewatering section (I), comprising at least one dewatering element (13.1-13.n) that can be supported flexibly and positioned against the first wire belt (2). The forming unit (1) according to the invention is characterized in that at least one subregion (9.1), arranged directly after the entry line (E) in the wire running direction, of the supporting surface (9), describing a second dewatering section (II), is of curved design.
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4.发明公开
公开(公告)号：EP2464783A1
公开(公告)日：2012-06-20
申请号：EP10718981.3
申请日：2010-05-10
申请人： Voith Patent GmbH
摘要： The invention relates to a method for operating a sheet-forming unit (3) for a machine for producing fibrous material webs from at least one fibrous material suspension (FS), comprising a headbox (1) and a forming unit (2) arranged downstream of the headbox (1). In this method, the at least one fibrous material suspension (FS) is fed to the headbox (1) over the machine width, is conducted in a plurality of turbulence-generating channels (8; 8.1-8.n; 8.11-8.nn) to form sub-flows, and fed to a nozzle (9). From said nozzle, the at least one fibrous material suspension (FS) is applied or introduced in the form of a free jet (F) into the forming unit (2) to define a contact line (21), wherein within an individual turbulence-generating channel (8; 8.1-8.n; 8.11-8.nn) a pressure loss (∆p) is set in the fibrous material suspension. The method according to the invention is characterised in that in a final fluidisation region (15) of an individual turbulence-generating channel (8; 8.1-8.n; 8.11-8.nn) a pressure loss (∆p) of ≥ 50 mbar is generated within the fibrous material suspension (FS) before inlet (14) thereof into the nozzle (9), and the fibrous material suspension (FS) is guided from said final fluidisation region (15) as far as the contact line (21) in such a way that the dwell time (TV) of the suspension in the region defined by said final fluidisation region (15) as far as the contact line (21) ranges from > 30 ms to ≤ 300 ms.
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