Abstract: An edge tracking apparatus for maintaining a continuous circulating papermaking fabric in an aligned position as it moves through a papermaking machine. The edge tracking apparatus includes a pivotally mounted guide roll and a laser scanner. The laser scanner, which produces a laser screen, is positioned relative to an edge of the papermaking fabric so that the edge bisects the laser screen. A controller is connected with the laser scanner. The controller acts to receive signals from the laser scanner in response to transverse movement of the edge of the papermaking fabric and to convert those signals into control signals which activate a drive in the steering apparatus. The drive shifts the longitudinal position of the guide roll causing it to steer the papermaking fabric back into its aligned position. A recording unit is also connected with the controller and is controlled to plot the position of the edge during operation of the papermaking machine.
Abstract: A woven fabric for use in papermaking machines and particularly with through air drying machines. The fabric comprises a paper support surface having spaced diagonal rows pockets which are effective to create diagonal rows of uncompressed paper forming fibers over the surface of paper formed on the papermaking machine. The rows of pockets are separated by diagonal strips of support surface arranged along substantially a single plane. The diagonal strips provide support areas over the width of the paper forming fibers which firmly secure the fiber sheet with the papermaking fabric during paper forming. The strips also produce diagonal rows of compressed paper forming fibers which provide for a more stable paper product.
Abstract: A woven fabric for use on papermaking machines having first and second sets of filaments interwoven with each other to provide a first grouping of coplanar top surface crossovers and a second grouping of recessed sub top surface crossovers. The first grouping of top surface crossovers are in spaced relation to define a plurality of at least first and second cavities. The first ones of the cavities are arranged along substantially parallel lines in the cross machine direction and the machine direction. The second ones of the cavities are spaced from the first ones of the cavities and are arranged along substantially parallel lines which extend in both the cross machine direction and the machine direction. Individual ones of the first cavities are arranged adjacent of and are interconnected with individual ones of the second cavities. The interconnected first and second cavities form cavity pairs.
Abstract: A woven paper making fabric (A) is disclosed having a profiled permeability characteristic which varies across the width of the fabric yet the tensions are relatively uniform across the width of the fabric. The fabric includes a plurality of warp yarns (20, 22, 24, 26) extending in a machine direction and a plurality of weft yarns (28, 30, 32) extending in a cross-machine direction in the fabric woven with the warp yarns. The weft yarns and warp yarns are woven to provide at least two layers (60, 62, 64) in the fabric. A number of unwoven fabric closure elements (B) are bound between the weft yarns of two of the fabric layers (60, 62) extending in the machine direction adjacent the lateral edges (42, 44) of the fabric (A). The closure elements (B) extend through the fabric parallel to the edges in a generally straight configuration between the two fabric layers (60, 62) in a generally tensionless state so as not to effect the tension of the weave of the fabric.