Patent ID: 8147653

Claim:
An industrial woven fabric for filtration in formation of a fibrous cellulosic sheet, the fabric having a sheet side layer with a sheet side surface and a machine side layer with a machine side surface, the fabric being woven to an overall repeating weave pattern and comprising (i) sheet side layer weft yarns; (ii) machine side layer weft yarns; (iii) a first set of warp yarns comprising only intrinsic binder yarn pairs; and (iv) a second set of warp yarns comprising machine side layer warp yarns, contributing only to the machine side layer and interwoven only with the machine side weft yarns, wherein (a) for each intrinsic binder yarn pair, the first and second members follow complementary identical paths in which the two members alternate with each other to appear in turn in the sheet side layer and the machine side layer and cooperate to define a single combined path in each of the sheet side layer and the machine side layer; (b) in the machine side layer, each member of each intrinsic binder yarn pair follows a path in which either (A) for every pair, at each location at which a member of an intrinsic binder yarn pair interweaves with a machine side layer weft yarn to form a knuckle, at least one of the machine side layer warp yarns interweaves with the same machine side layer weft yarn in the same knuckle; or (B) for every pair, each member of the pair interweaves in sequence with two of the machine side layer weft yarns together with a first member of a pair of adjacent ones of the machine side layer warp yarns at a first interweaving point, and together with a second member of the pair of adjacent ones of the machine side layer warp yarns at a second interweaving point; and (c) a warp yarn path ratio of numbers of machine side layer warp yarns to single combined paths of the intrinsic binder yarn pairs is at least 1.5:1.