Multi-ply papermaking fabric with binder warps

A forming fabric for use at the wet end of a paper making machine for receiving wet pulp, said fabric comprising a multi-ply fabric having a width corresponding to the width of the paper-making machine and a length in the form of a continuous loop corresponding to the length of the path of travel of the fabric through the paper machine, and having a top pulp face and a bottom machine face, said top pulp face forming the pulp into a consolidated web by affording discharge of the free water content of the wet pulp from the bottom machine face, said fabric comprising:

• a top ply having a self-sustaining weave construction comprising top warp yarns interwoven with top shute yarns in a weave pattern on the top face selected to produce a desired surface texture in the paper produced from the web formed on said top pulp face, said top warp yarns having substantially uniform spacing across the width of the fabric and having a warp density to provide channels between the yarns affording said discharge of free water;
• a bottom side consisting essentially of a series of bottom shute yarns;
• and
• binder warp yarns interweaving the top ply and the bottom shute yarns to form a self-sustaining fabric construction which is characterized by a high degree of porosity, said binder warps being arranged in pairs between adjacent top warp yarns and having a warp density not greater than the warp density of the top ply, and so arranged that the binder warps cannot block all of the channels provided in the top ply,
• said top warp yarns and said binder warp yarns constituting the only two warp systems in the fabric, said binder warp yarns providing the only components interweaving the bottom shute yarns with one another and with the yarns in the upper ply.