Twin-wire paper machine

Abstract

In a twin wire former, white-water withdrawal means ( 20 ) for withdrawing white water ( 15 ) dewatered to the opposite side of a roll is arranged to the upstream side of a pressure element ( 30 ) to suppress the interference of the dewatered white water ( 15 ) with the pressure element ( 30 ). This renders it possible to prevent damage to the pressure element ( 30 ) that is caused by a collision with white water ( 15 ) during dewatering and to manufacture defect-free paper that has even dispersion of fibers.

1 . A twin wire former for supplying a suspension of fibers between first and second looped wires arranged opposite each other, and dewatering said suspension of fibers held between said first and second wires, running a looped interior surface of said first wire and a looped exterior surface of said second wire around a roll, said former comprising: 
 a pressure element, arranged on the looped interior surface side of said second wire and opposite said roll, applying dewatering pressure on the looped interior surface of said second wire; and    a deflector, arranged to the upstream side of said pressure element, withdrawing white water dewatered to the looped interior surface side of said second wire.    
     
     
         2 . The twin wire former as set forth in  claim 1 , wherein: 
 at least two said pressure element arranged along a direction in which said second wire travels; and further comprising    a deflector blade at a forefront of said pressure elements.    
     
     
         3 . The twin wire former as in  claim 1 , wherein said deflector being deflector blade arranged on the looped interior surface side of said second wire and opposite arranged said roll.  
     
     
         4 . The twin wire former as in  claim 3 , wherein said deflector blade has a tip end curved toward an upstream side.  
     
     
         5 . The twin wire former as in  claim 3 , further comprising suction means for suctioning white water from said deflector blade.  
     
     
         6 . The twin wire former as in  claim 3 , further comprising a first position adjuster adjusting the position of said deflector blade in the direction of said roll.  
     
     
         7 . The twin wire former as in  claim 6 , further comprising a first pressure detector detecting pressure that acts on said deflector blade.  
     
     
         8 . The twin wire former as in  claim 6 , further comprising a second position adjuster adjusting the position of said pressure element in said roll direction.  
     
     
         9 . The twin wire former as in  claim 8 , further comprising a second pressure detector detecting pressure that acts on said pressure element.  
     
     
         10 . The twin wire former as in  claim 1 , wherein said roll comprises a suction forming roll.  
     
     
         11 . A method of manufacturing paper by employing a twin wire former for supplying a suspension of fibers between first and second looped wires arranged opposite each other, and dewatering said suspension of fibers held between said first and second wires running a looped interior surface of said first wire and a looped exterior surface of said second wire around a roll, said former comprising: 
 a pressure element, arranged on the looped interior surface side of said second wire and opposite said roll applying dewatering pressure on the looped interior surface of said second wire; and    a deflector, arranged to the upstream side of said pressure element, withdrawing white water dewatered to the looped interior surface side of said second wire, comprising the steps of:    detecting pressure that acts on said deflector blade by a first pressure detector; and    adjusting the position of said deflector blade in said roll direction by a first position adjustor for controlling the detected pressure is within a proper range.    
     
     
         12 . A method of manufacturing paper as in  claim 11 , comprising the steps of: 
 detecting pressure that acts on said deflector blade by said first pressure detector and also detecting pressure that acts on said pressure element by a second pressure detector; and    adjusting the position of said deflector blade in said roll direction by said first position adjustor for controlling the detected pressure is within a first proper range, and also adjusting the position of said pressure element in said roll direction by a second position adjustment means so that adjustor for controlling the detected pressure within a second proper range.