Papermachine fabric

Abstract

A papermachine fabric for dewatering a fibrous web in a machine producing a fibrous web. The fabric including a laid scrim having at least one layer of longitudinal threads and at least one layer of transverse threads crossing the layer of longitudinal threads. At least a selection of the longitudinal threads being laid at different distances both symmetrically and asymmetrically in relation to one another, the distance between two adjacent threads changing in the course of a laying pattern.

1 . A papermachine fabric for dewatering a fibrous web in a machine producing a fibrous web, the fabric comprising: 
 a laid scrim including: 
 at least one layer of longitudinal threads; and  
 at least one layer of transverse threads crossing said layer of longitudinal threads, at least a selection of said longitudinal threads being laid at different distances both symmetrically and asymmetrically in relation to one another, the distance between two adjacent threads changing in the course of a laying pattern.  
   
   
   
       2 . The papermachine fabric of  claim 1 , wherein a selection of threads of said layer of longitudinal threads and said layer of transverse threads are laid at different distances both symmetrically and asymmetrically in relation to one another.  
   
   
       3 . The papermachine fabric of  claim 1 , wherein said longitudinal threads are laid symmetrically or asymmetrically in relation to one another in a plurality of groups.  
   
   
       4 . The papermachine fabric of  claim 3 , wherein said groups of said longitudinal threads are laid symmetrically or asymmetrically in relation to one another.  
   
   
       5 . The papermachine fabric of  claim 4 , wherein said different distances are selected in accordance with at least one of a pattern, randomly and a combination thereof.  
   
   
       6 . The papermachine fabric of  claim 1 , wherein at least two adjacent layers of said at least one layer of longitudinal threads and said at least one layer of transverse threads having approximately the same alignment, in at least some regions have a complementary positioning of threads in relation to one another.  
   
   
       7 . The papermachine fabric of  claim 6 , wherein interspaces are provided between threads of said at least two adjacent layers in at least some regions, said interspaces being filled with a permeable material.  
   
   
       8 . The papermachine fabric of  claim 7 , wherein said permeable material includes at least one polyurethane foam.  
   
   
       9 . The papermachine fabric of  claim 6 , wherein a layer that is permeable is introduced between said at least two adjacent layers of threads at least in some regions.  
   
   
       10 . The papermachine fabric of  claim 9 , wherein threads arranged above one another of said two adjacent layers have at least one different property in at least some regions.  
   
   
       11 . The papermachine fabric of  claim 10 , wherein threads of one of said two adjacent layers have the at least one different property alternately and offset with respect to the threads of another of said two adjacent layers.  
   
   
       12 . The papermachine fabric of  claim 10 , wherein said different property is at least one of thread thickness, thread hardness, thread structure and thread material.  
   
   
       13 . The papermachine fabric of  claim 10 , wherein said at least two adjacent layers of threads run at an angle α in at least some regions, said angle α assuming a value in the range of 0°≦α≦90°.  
   
   
       14 . The papermachine fabric of  claim 1 , further comprising a plurality of layers of laid scrims.  
   
   
       15 . The papermachine fabric of  claim 14 , wherein at least two of said plurality of layers of laid scrims are separated from one another by a separating layer.  
   
   
       16 . A press felt for dewatering a fibrous web in a machine producing a fibrous web, the fabric comprising: 
 at least one fine fiber batt on the side of the fabric facing the fibrous web;    at least one coarse fiber batt on the side of the fabric facing away from the fibrous web; and    a central layer having a laid scrim between said fine fiber batt and said coarse fiber batt, said laid scrim including: 
 at least one layer of longitudinal threads; and  
 at least one layer of transverse threads crossing said layer of longitudinal threads.  
   
   
   
       17 . The fabric of  claim 16 , wherein said longitudinal threads and said transverse threads of said central layer are filled with a permeable material.  
   
   
       18 . The fabric of  claim 17 , wherein said permeable material is polyurethane foam in two lateral regions of the fabric.