Papermaking fabric

Abstract

The invention relates to a papermaking fabric which is designed as a multi-layer woven fabric having an upper fabric layer and a lower fabric layer. The upper fabric layer has a plurality of upper longitudinal threads which run solely in the upper fabric layer and a plurality of upper transverse threads which are interwoven with the upper longitudinal threads and each run at least primarily in the upper fabric layer. The lower fabric layer has a plurality of lower longitudinal threads which run solely in the lower fabric layer and a plurality of lower transverse threads which are interwoven with the lower longitudinal threads and run solely in the lower fabric layer. The upper fabric layer has a repeating upper weave pattern on the upper side thereof which is formed from nine upper longitudinal threads and three upper transverse threads. The three upper transverse threads of the upper weave pattern each have the following course in the upper weave pattern: under a upper longitudinal thread, over the next upper longitudinal thread, under the next upper longitudinal thread, over the next upper longitudinal thread, under the four next successive upper longitudinal threads and over the following upper longitudinal thread, wherein, in the upper weave pattern, the course of the respective upper transverse thread is arranged offset to the course of the adjacent upper transverse thread in the transverse direction by three upper longitudinal threads. At least some of the upper transverse threads in the woven fabric are designed as binding transverse threads which, in order to bind the upper fabric layer to the lower fabric layer, temporarily switch into the lower fabric layer during the course thereof under the four successive to longitudinal threads and there run under at least one lower longitudinal thread.

1 . Paper machine screen,
 formed as a multi-layer fabric,   having an upper fabric layer and a lower fabric layer,   wherein the upper fabric layer comprises a plurality of upper longitudinal threads which extend solely in the upper fabric layer, and a plurality of upper transverse threads which are interwoven with the upper longitudinal threads and each extend at least predominantly in the upper fabric layer,   wherein the lower fabric layer comprises a plurality of lower longitudinal threads which extend solely in the lower fabric layer, and a plurality of lower transverse threads which are interwoven with the lower longitudinal threads and extend solely in the lower fabric layer,   wherein the upper fabric layer has a recurring upper pattern repeat on its upper side, which is formed by nine upper longitudinal threads and three upper transverse threads,   wherein the three upper transverse threads of the upper pattern repeat each comprise the following course in the upper pattern repeat: under an upper longitudinal thread, over the next upper longitudinal thread, under the next upper longitudinal thread, over the next upper longitudinal thread, under the four next successive upper longitudinal threads and over the following upper longitudinal thread,   wherein in the upper pattern repeat the course of the respective upper transverse thread is arranged to be offset with respect to the course of the neighboring upper transverse thread by three upper longitudinal threads in a transverse direction, and   wherein in the fabric at least some of the upper transverse threads are formed as connecting transverse threads which temporarily change into the lower fabric layer during their course under the four successive upper longitudinal threads for connecting the upper fabric layer with the lower fabric layer, and there extend under at least one lower longitudinal thread.   
     
     
         2 . Paper machine screen according to  claim 1 ,
 wherein the lower longitudinal threads are greater in diameter than the upper longitudinal threads, and/or   wherein the lower transverse threads are greater in diameter than the upper transverse threads.   
     
     
         3 . Paper machine screen according to  claim 1 ,
 wherein the ratio of upper longitudinal threads to lower longitudinal threads in the entire fabric is 3:2 or 1:1, and/or   wherein the fabric comprises or consists of a recurring total repeat in which the ratio of upper longitudinal threads to lower longitudinal threads is 9:6 or 9:9.   
     
     
         4 . Paper machine screen according to  claim 1 ,
 wherein the ratio of upper transverse threads to lower transverse threads in the entire fabric is 2:1 and/or   wherein the fabric comprises or consists of a recurring total repeat in which the ratio of upper transverse threads to lower transverse threads is 6:3 or 12:6.   
     
     
         5 . Paper machine screen according to  claim 1 , wherein at least one of the three upper transverse threads of each upper pattern repeat is formed as a connecting transverse thread which temporarily changes into the lower fabric layer during its course under the four successive upper longitudinal threads and there extends at least under one lower longitudinal thread, in order to connect the upper fabric layer to the lower fabric layer. 
     
     
         6 . Paper machine screen according to  claim 5 , wherein at least two of the three upper transverse threads of each upper pattern repeat are formed as a connecting transverse thread. 
     
     
         7 . Paper machine screen according to  claim 1 , wherein the respective connecting upper transverse thread extends under exactly one lower longitudinal thread or exactly two successive lower longitudinal threads during its course under the four successive upper longitudinal threads for connecting the upper fabric layer with the lower fabric layer. 
     
     
         8 . Paper machine screen according to  claim 1 , wherein the connection of the upper fabric layer and the lower fabric layer occurs exclusively by means of the upper connecting transverse threads. 
     
     
         9 . Paper machine screen according to  claim 1 ,
 wherein the upper fabric layer exclusively consists of a plurality of abutting upper pattern repeats and/or   wherein the respective upper pattern repeat exclusively consists of the nine upper longitudinal threads and the three upper transverse threads.   
     
     
         10 . Paper machine screen according to  claim 1 , wherein the lower transverse threads are interwoven with the lower longitudinal threads in such a manner that they form a three-shaft or six-shaft weave in the lower fabric layer, in which the course of the respective lower transverse thread recurs after three and six longitudinal threads, respectively. 
     
     
         11 . Paper machine screen according to  claim 1 , wherein the longitudinal threads are formed as warp threads and the transverse threads are formed as weft threads. 
     
     
         12 . Paper machine screen according to  claim 2 ,
 wherein the ratio of upper longitudinal threads to lower longitudinal threads in the entire fabric is 3:2 or 1:1, and/or   wherein the fabric comprises or consists of a recurring total repeat in which the ratio of upper longitudinal threads to lower longitudinal threads is 9:6 or 9:9.   
     
     
         13 . Paper machine screen according to  claim 2 ,
 wherein the ratio of upper transverse threads to lower transverse threads in the entire fabric is 2:1 and/or   wherein the fabric comprises or consists of a recurring total repeat in which the ratio of upper transverse threads to lower transverse threads is 6:3 or 12:6.   
     
     
         14 . Paper machine screen according to  claim 2 , wherein at least one of the three upper transverse threads of each upper pattern repeat is formed as a connecting transverse thread which temporarily changes into the lower fabric layer during its course under the four successive upper longitudinal threads and there extends at least under one lower longitudinal thread, in order to connect the upper fabric layer to the lower fabric layer. 
     
     
         15 . Paper machine screen according to  claim 2 , wherein the respective connecting upper transverse thread extends under exactly one lower longitudinal thread or exactly two successive lower longitudinal threads during its course under the four successive upper longitudinal threads for connecting the upper fabric layer with the lower fabric layer. 
     
     
         16 . Paper machine screen according to  claim 2 , wherein the connection of the upper fabric layer and the lower fabric layer occurs exclusively by means of the upper connecting transverse threads. 
     
     
         17 . Paper machine screen according to  claim 2 ,
 wherein the upper fabric layer exclusively consists of a plurality of abutting upper pattern repeats and/or   wherein the respective upper pattern repeat exclusively consists of the nine upper longitudinal threads and the three upper transverse threads.   
     
     
         18 . Paper machine screen according to  claim 2 , wherein the lower transverse threads are interwoven with the lower longitudinal threads in such a manner that they form a three-shaft or six-shaft weave in the lower fabric layer, in which the course of the respective lower transverse thread recurs after three and six longitudinal threads, respectively. 
     
     
         19 . Paper machine screen according to  claim 2 , wherein the longitudinal threads are formed as warp threads and the transverse threads are formed as weft threads.