Fabric with stair-case weft arrangement to generate topography

Abstract

A forming fabric for a papermaking machine woven according to a repeating pattern. The fabric includes a PS layer having a PS surface, with the PS layer including PS warps and first PS wefts, second PS wefts, and binder PS weft pairs interwoven in a first repeating pattern, and a MS layer having a MS surface, with the MS layer including interwoven MS warps and MS wefts. The binder PS weft pairs are interwoven with the PS warps and the MS warps to bind the PS and MS layers together. The first PS wefts have a larger diameter than the second PS wefts, the second PS wefts have a larger diameter than the binder PS weft pair, and in each repeat, the first PS wefts, the second PS wefts, and the binder PS wefts are inserted sequentially, preferably from large to small, forming a stair step topography.

1 . A forming fabric for a papermaking machine woven with a fabric weave pattern, the forming fabric comprising:
 a PS layer having a PS surface, with the PS layer including PS warps and first PS wefts, second PS wefts, and binder PS weft pairs interwoven in a repeating pattern;   a MS layer having a MS surface, with the MS layer including interwoven MS warps and MS wefts;   the binder PS weft pairs are interwoven with the PS warps and the MS warps to bind the PS and MS layers together in the forming fabric, and each binder yarn of the binder PS weft pairs interchanges between the layers;   the first PS wefts have a larger diameter than the second PS wefts, the second PS wefts have a larger diameter than the binder PS weft pair; and   the first PS wefts, the second PS wefts, and the binder PS wefts are inserted sequentially in each repeat of the repeating pattern to form a stair step topography.   
     
     
         2 . The fabric according to  claim 1 , wherein the first PS wefts, the second PS wefts, and the binder PS wefts are inserted sequentially from large to small in the repeating pattern. 
     
     
         3 . The fabric according to  claim 1 , wherein the PS warps, the PS wefts, the binder PS weft pairs, the MS warps, and the MS wefts are polymeric yarns made from at least one material selected from PET, PA, PBT, PEN, PPS or PEEK. 
     
     
         4 . The fabric according to  claim 1 , wherein the first PS weft yarns have a diameter of about 0.15 to about 0.30 mm. 
     
     
         5 . The fabric according to  claim 4 , wherein the second PS weft yarns have a diameter of about 0.12 to about 0.25 mm. 
     
     
         6 . The fabric according to  claim 5 , wherein the PS binder weft yarns  118  have a diameter of about 0.08 to about 0.20 mm. 
     
     
         7 . The fabric according to  claim 6 , wherein the PS warps have a diameter of about 0.08-about 0.25 mm. 
     
     
         8 . The fabric according to  claim 7 , wherein MS warps and the MS wefts have a diameter of about 0.10 to about 0.40 mm.