Machine for producing a fibrous web, comprising an inclined wire former and a dewatering device

Abstract

The invention relates to a fibrous web formation device comprising an inclined wire former, an inclined wire headbox and a drainage device. The inclined wire headbox has at least one conveyor wire which transports the fibrous web in the direction of travel thereof and which has a portion that runs at an angle from the horizontal, in which portion the inclined wire headbox is arranged. The inclined wire headbox allows a fibrous suspension to be applied to the conveyor wire. In a drainage device that has a roll, a drainage wire lying against said roll, and a pressing wire pressing against said roll, the fibrous web being arranged between the drainage wire and the pressing wire in the region of the drainage device, drainage can be performed gently so that the fibrous web at least partially maintains voluminous structures.

What is claimed is: 
     
         1 . A fibrous web forming device for forming a fibrous web, comprising:
 an inclined wire headbox;   an inclined wire former including at least one transport belt which transports the fibrous web in a direction of travel thereof and which has a section that progresses at an angle to a horizontal in which the inclined wire headbox is arranged and a fibrous suspension can be applied onto the at least one transport belt; and   a dewatering device including a roll, a dewatering belt which fits closely against the roll, and a press belt, wherein the fibrous web is arranged in a region of the dewatering device between the dewatering belt and the press belt.   
     
     
         2 . The fibrous web forming device according to  claim 1 , wherein the transport belt is arranged in the region of the dewatering device between the dewatering belt and the press belt. 
     
     
         3 . The fibrous web forming device according to  claim 1 , wherein the dewatering device includes at least one of the following characteristics:
 a blower hood surrounding the roll partially in circumferential direction for a supply of a liquid of at least one blow zone of the roll surrounded by a blower hood, wherein a blow zone angle which is determined in a circumferential direction of the roll has a value of between 10° to 270°; and   an additional press device arranged in a direction of travel after the roll.   
     
     
         4 . The fibrous web forming device according to  claim 1 , wherein the dewatering device includes at least one of the following characteristics:
 the dewatering device is positioned in the direction of travel after the inclined wire headbox; wherein the at least one dewatering element is arranged between the inclined wire headbox and the dewatering device;   the dewatering device is positioned in the direction of travel after a turn roller which limits a partial section progressing at an angle to the horizontal in the direction of travel, wherein the fibrous web is arranged in the direction of travel after the turn roller such that the direction of travel and a gravitational direction form a pointed angle (α), wherein between the turn roller and the dewatering device at least one dewatering element can be arranged;   the dewatering device is positioned in the direction of travel immediately before a transfer point of the fibrous web into a drying device which is positioned after the fibrous web forming device, viewed in the direction of travel;   the dewatering device is positioned so that the turn roller is the roll of the dewatering device; and   the dewatering device is positioned so that the fibrous web fits closely against the dewatering belt and the transport belt fits closely against the press belt.   
     
     
         5 . The fibrous web forming device according to  claim 1 , wherein the transport belt includes at least one of the following characteristics:
 a structured surface which is oriented toward the fibrous web;   a structured surface having a protected region of greater than between 60% to 100% of an imaginary planar surface, arranged vis-à-vis a planar reference surface;   a structured surface having a press region of between less than 40% to 100% of the imaginary planar reference surface, arranged vis-à-vis the structured surface;   a partial section progressing at an angle relative to horizontal in such a way that a partial section progresses at a pointed angle (β) of greater than between 0° to 45° relative to the horizontal.   
     
     
         6 . The fibrous web forming device according to  claim 1 , wherein the roll is designed as a suction roll having a suction zone extending partially in a circumferential direction, wherein a suction zone angle determined in the circumferential direction has a value of between 10° to 270°. 
     
     
         7 . The fibrous web forming device according to  claim 1 , wherein the dewatering belt includes at least one of the following characteristics:
 designed as a felt; and   a dewatering zone which is defined by wrapping around the roll, having a dewatering zone angle of between 10° to 270° which is determined in a circumferential direction of the roll.   
     
     
         8 . The fibrous web forming device according to  claim 1 , wherein the press belt includes at least one of the following characteristics:
 a belt tension of between 10 to 80 kN/m;   a contact pressure onto the roll of greater than 20 kPa;   an open surface of between at least 25% to 100% of an imaginary planar reference surface, arranged vis-à-vis the press belt;   a pressing surface of between at least 10% to 100% of an imaginary planar reference surface, arranged vis-à-vis the press belt;   a press zone which is defined by wrapping around the roll, having a press zone angle of between 10° to 270° which is determined in a circumferential direction of the roll; and   designed as a cover of a shoe press.   
     
     
         9 . The fibrous web forming device according to  claim 1 , wherein the dry content of the fibrous web is increased by the dewatering device to a value of between 14 to 60%. 
     
     
         10 . The fibrous web forming device according to  claim 1 , further including at least one of:
 a dryer device arranged downstream from the fibrous web forming device, viewed in the direction of travel, a press roll allocated to the fibrous web forming device, with which the fibrous web is transferred at a transfer point to the dryer device, wherein a press roll makes contact with a line force of between 60 to 120 kN/m, a Yankee-cylinder allocated to the dryer device, and a blower hood which partially surrounds the Yankee-cylinder in a circumferential direction of the Yankee cylinder;   a TAD system;   a dryer cylinder arrangement assigned to the dryer device, including at last one dryer cylinder; and   a pick-up roll allocated to dryer device, including a suction roll and with which the fibrous web is taken at a transfer point into the dryer device.