Multilayer forming fabric

DETAILED DESCRIPTION OF THE INVENTION The present invention is a triple layer forming fabric having a top fabric layer with a superior papermaking surface and a bottom fabric layer with superior wear and abrasion resistance characteristics.
The papermaking fabric of the present invention forms a more uniform paper sheet because the selection of yarn diameters, weave patterns, and number of yarns is based on the interrelationship of the following Fiber length to supporting spans between yarns.
Selection of weave pattern for optimum fiber support.
Selection of mesh together with yarn diameters to maximize support for fibers of known length.
Selection of yarn diameters together with mesh and weave pattern to give a controlled drainage rate in order to minimize sheet density differences.
Selection of yarn diameters to minimize the degree of penetration into the sheet which in turn will minimize density differences.
A sheet of paper is formed when a solution of water which contains suspended fibers is passed through a woven structure.
The fibers are retained on the yarns of the woven structure while the water passes through the holes in the structure.
The number of fibers retained will be influenced by not only their length but also the distance between the yarns (support spans) of the woven structure.
The rate of passage of the water through the woven structure will be influenced by the size of holes (orifices) which are formed by the yarns of the woven structure.
With reference to FIG.
1, it is clear that due to fiber build-up over a span between yarns, ink penetration will be light.
The fiber build up over a yarn will be less, and thus ink penetration at that point will be higher.
As explained above, the difference in the depth of ink penetration into the sheet is referred to as density difference in the sheet and caused by the topography of the fabric on which the sheet is formed.
Both the amount of fiber retained and the speed of drainage are very important in the process of papermaking