Forming fabric for use in a paper machine, and method and apparatus for manufacturing such a forming fabric

Abstract

The present invention relates to a forming fabric ( 2 ), for use in the sheet-forming section of a paper machine, having or comprising a textile planar structure in which, in order to enhance inherent stability, crossing yarns ( 5, 6, 7 ) are engaged into one another at crossing points ( 14 ) and in which yarns ( 5, 7 ) additionally are fused to one another, which is characterized in that the planar structure comprises crossing first and second yarns ( 5, 7 ), the first yarns ( 7 ) having the property that they absorb laser energy and can be brought, by absorbed laser energy, to melting temperature at least at the surface; and that first and second yarns ( 5, 7 ) are fused to one another at at least some of their crossing points ( 14 ).

1 . A forming fabric ( 2 ), for use in the sheet-forming section of a paper machine, having or comprising a textile planar structure in which, in order to enhance inherent stability, crossing yarns ( 5 ,  6 ,  7 ) are engaged into one another at crossing points ( 14 ) and in which yarns ( 5 ,  7 ) additionally are fused to one another, 
 wherein the planar structure comprises crossing first and second yarns ( 5 ,  7 ), the first yarns ( 7 ) having the property that they absorb laser energy and can be brought, by absorbed laser energy, to melting temperature at least at the surface; and first and second yarns ( 5 ,  7 ) are fused to one another at at least some of their crossing points ( 14 ).    
     
     
         2 . The forming fabric according to  claim 1 , wherein the first and second yarns ( 5 ,  7 ) are fused to one another at all their crossing points.  
     
     
         3 . The forming fabric according to  claim 1 , wherein the second yarns ( 5 ,  6 ) absorb less laser energy than the first yarns ( 7 ) or none at all.  
     
     
         4 . The forming fabric according to  claim 1 , wherein the yarns ( 5 ,  6 ,  7 ) are otherwise not joined to one another.  
     
     
         5 . The forming fabric according to  claim 1 , wherein the first yarns ( 7 ) contain an additive that imparts the ability to absorb laser light.  
     
     
         6 . The forming fabric according to  claim 5 , wherein the additive is an NIR-active substance or an NIR-light-absorbing substance.  
     
     
         7 . The forming fabric according to  claim 5 , wherein the additive is incorporated into the first yarns ( 7 ) and/or applied onto the surface of the first yarns ( 7 ) and/or introduced at the crossing points between the first and second yarns ( 5 ,  7 ).  
     
     
         8 . The forming fabric according to  claim 5 , wherein the first yarns are bicomponent yarns, only one of the two components containing the additive.  
     
     
         9 . The forming fabric according to  claim 8 , wherein the bicomponent yarns comprise a core and a casing surrounding it, the additive being contained only in the casing.  
     
     
         10 . The forming fabric according to  claim 1 , wherein the planar structure comprises longitudinal and transverse yarns, and the first yarns extend in the longitudinal and/or the transverse direction.  
     
     
         11 . The forming fabric according to  claim 10 , wherein the only some of the longitudinal and/or transverse yarns are first yarns.  
     
     
         12 . The forming fabric according to  claim 1 , wherein the first yarns are part of the weave of the yarns in the planar structure.  
     
     
         13 . The forming fabric according to  claim 1 , wherein the first yarns are distributed in the planar structure in a consistently regular pattern.  
     
     
         14 . The forming fabric according to  claim 1 , wherein the first yarns are engaged in such a way that they do not reach as far as the paper side of the forming fabric.  
     
     
         15 . The forming fabric according to  claim 14 , wherein the planar structure is embodied with multiple plies; and the first yarns are engaged only in an internally located layer and/or a roller-side layer.  
     
     
         16 . The forming fabric according to  claim 1 , wherein the forming fabric ( 2 ) has a finite length with ends joinable via a seam, transverse yarns that are embodied as first yarns ( 7 ) being present in the region of both ends.  
     
     
         17 . The forming fabric according to  claim 16 , wherein the forming fabric ( 2 ) comprises longitudinal yarns ( 5 ) that extend into the region of the ends and that in the region of the ends are fused to first yarns ( 7 ) that extend in the transverse direction.  
     
     
         18 . A method for manufacturing a forming fabric ( 2 ) for use in the sheet-forming section of a paper machine, in which method a textile planar structure is manufactured from yarns ( 5 ,  6 ,  7 ) that intersect one another and are engaged into one another, and in which yarns ( 5 ,  7 ) are fused to one another at crossing points by heating to melting temperature, 
 wherein first and second yarns ( 5 ,  6 ,  7 ) are used in the manufacture of the planar structure, in which context the first yarns ( 7 ) can absorb laser energy; and first and second yarns ( 5 ,  7 ) are fused by means of laser energy at at least some of their crossing points ( 14 ).