Composite forming fabric
A composite forming fabric for a papermaking machine woven according to a repeating fabric weave pattern is provided. The fabric includes a paper side (PS) layer having a PS surface, with the PS layer including PS warps and PS wefts interwoven in a first repeating pattern, and a machine side (MS) layer having a MS surface, with the MS layer including interwoven MS warps and MS wefts. A plurality of pairs of binder weft yarns each including first and second binder weft yarns that are interwoven with the PS warps and the MS warps to bind the PS and MS layers together in the composite forming fabric. In each pattern repeat of the fabric weave pattern at least three of the MS warps pass under each MS weft, where said at least three of the MS warps are co-located adjacent to one another with a further one of the MS warps separating a first of the at least three warps from the others of said at least three warps, and each of the MS warps interlaces with at least two non-adjacent ones of the MS wefts.
1. A composite forming fabric for a papermaking machine woven according to a repeating fabric weave pattern, comprising a paper side (PS) layer having a PS surface, the PS layer including PS warps and PS wefts interwoven in a first repeating pattern, a machine side (MS) layer having a MS surface, the MS layer including interwoven MS warps and MS wefts, and a plurality of pairs of binder weft yarns, each of the pairs of binder weft yarns comprising first and second binder weft yarns interwoven according to a binder weft pattern with the PS warps and the MS warps to bind the PS and MS layers together in the composite forming fabric, and each interchanges between the layers at exchange points, wherein in each pattern repeat of the fabric weave pattern:
at each said MS weft, at least three of the MS warps pass under said MS weft, where said at least three of the MS warps along with a further single one of the MS warps that passes over said MS weft are co-located one adjacent to another, and the further single one of the MS warps that passes over said MS weft separates a first of the at least three MS warps from the others of said at least three MS warps, and
each of the MS warps interlaces with at least two non-adjacent ones of the MS wefts.
2. The fabric according to claim 1 , wherein in each said pattern repeat of the fabric weave pattern no two of the MS warps interlace with a same two of the MS wefts.
3. The fabric according to claim 1 , wherein each of the binder weft yarns in the pairs of binder weft yarns interlace with only one MS warp yarn in each said pattern repeat of the fabric.
4. The fabric according to claim 1 , wherein each of the binder weft yarns in the pairs of binder weft yarns interlace with up to three MS warp yarn in each said pattern repeat of the fabric.
5. The fabric according to claim 1 , wherein an interweaving pattern of each of the binder weft yarn pairs in the PS layer forms a part of the first repeating pattern.
6. The fabric according to claim 1 , wherein the number of MS warp yarns in one said pattern repeat of the fabric weave pattern is the same as a number of PS warp yarns in the same pattern repeat.
7. The fabric according to claim 1 , wherein a ratio of a number of PS weft yarns, including allowing for pairs of the binder weft yarns, to a number of MS weft yarns is in a range from 1:1 to 5:2 in one said pattern repeat of the fabric weave pattern.
8. The fabric according to claim 1 , wherein a cross-sectional shape of at least some of the warps, the wefts, or the binder yarns is selected from one of: generally circular, ovate, elliptical, square or rectangular.
9. The fabric according to claim 1 , wherein at least one of the warps, the wefts, or the binder yarns are polymeric yarns made from at least one material selected from PET, PA, PBT, PEN, PPS or PEEK.
10. The fabric according to claim 1 , wherein in each pattern repeat of the fabric weave pattern said at least three of the MS warps that are co-located along with the further single one of the MS warps that passes over said MS weft include exactly three of the MS warps.