Woven loop press base fabric having high density top layer

Abstract

A papermaker's fabric having a system of primary machine direction yarns which form seaming loops at each end of the fabric and a system of secondary machine direction yarns. A system of cross-machine direction yarns are interwoven with the primary and secondary systems of machine direction yarns in a weave pattern that provides adjacent balancing yarns that maintain the seam loops in substantially vertical alignment.

Description

BACKGROUND OF INVENTION1. Field of the InventionThe present invention generally relates to a woven fabric for use in a paper, cellulose or board manufacturing machine that is seamed by interlocking loops along each of two fabric edges to form an endless woven fabric.2. Description of the Prior ArtAs will be known to those skilled in the art, papermaking machines generally include three sections which are referred to as the forming, press and dryer sections. A felt is generally employed to transport the formed, wet sheet through the press and dryer sections of the papermaking equipment. The felt must be particularly adapted to specific conditions encountered in papermaking.Typically, such felts include a supporting base, such as a woven fabric, and a paper carrying or supporting layer fixed to the base. The paper carrying or supporting layer is generally softer and smoother than the base layer. The support layer is often a non-woven batt material which has been affixed to the base an...

AI Technical Summary

Problems solved by technology

Slight irregularities or imperfections in the support layer are undesirable in virtually all papermaking operations.

Inconsistencies in the felt thickness, gauge or weight can cause undesirable vibrations during operation of the equipment.

However, these base fabrics typically provide limited batt anchorage and sheet support due to low surface contact area.

This process can be costly and time consuming.

Another problem associated with endlessly woven seamed fabrics is seaming of the fabric.

A common problem associated with this type of loop formation is non-uniform loop alignment, both in the vertical and horizontal axis, when the forming wire is removed.

This misalignment creates a seam that is difficult to mesh.

However, the last warp yarn 2 does not have a balancing yarn on one of its sides and, therefore, an unbalanced crimp force is applied to the weft yarns in the loop area, as shown by the arrows in FIG. 2.

As a result, the two weft yarn passes which form each loop are not balanced by warps and the loops tend to be misaligned.

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