US Patent 8147653 High fiber support intrinsic warp-tied composite forming fabric

A woven filtration fabric for cellulosic sheet formation. The warp yarns comprise intrinsic binder yarn pairs, and a set of dedicated machine side layer warp yarns. The members of each intrinsic binder yarn pair alternate with each other to define a single combined path in each layer. Whenever a member interweaves with a machine side layer weft yarn, at least one machine side layer warp yarn interweaves with the same weft yarn in the same knuckle. In some embodiments, the members form double knuckles in the machine side layer, firstly together with a first machine side layer warp yarn and then together with a second machine side layer warp yarn. The warp yarn path ratio of machine side layer warp yarns to single combined paths of the intrinsic binder yarn pairs is at least 1.5:1. The fabrics provide increased center plane resistance, resulting in improved drainage and sheet uniformity.