Traditional forming fabric structures involve a series of design compromises in which fabric life, fabric stability; sheet formation, fiber retention, and fabric drive-load are traded off, one for another, in order to achieve a specific end result. This paper describes a new approach to fabric design in which all the aforementioned properties can be maximized without coincidental negative trade-offs. Beginning with the paper making surface, all yarns should be identical in size for the most uniform paper surface possible, but this is usually not the case. Cristini's Essential ESB is the result of a technology that begins with this as a premise. These same-sized yarns are then spaced in such a manner that the drainage holes are square in shape, accommodating fibers in all possible orientations, to maximize retention, thereby allowing for reduced headbox consistency, a squarer sheet, and consequent better formation. In the past, structures like these were thought not possible, because of fabric manufacturing considerations and the need for various mechanical properties in the fabric. Historically, this type of embodiment would automatically result in loss of overall fabric life, but, in the case of this new family of designs, a binding yarn is incorporated which is simultaneously out of the plane of the papermaking surface, and conversely out of the wear plane on the machine side of the fabric. As will be shown in the paper, this then allows for a larger diameter wear surface yarn opposite the papermaking side. These larger yarns are made from a super-tough material that maximizes abrasive wear while sliding easily over stationary elements. A little addressed cause of total energy usage is the extra drag load created as large diameter wear yarns pass over stationary and vacuum elements, ie, the yams used to increase life simultaneously increase the drag load and thereby require a larger horsepower demand. This obstacle has been largely surmounted by the usage of yarn materials which have inherently lower coefficients of friction and a low contact area to further reduce drag load and, therefore, drive amperage. Because of this feature, this new family of structures is generically called ESB (Enclosed Strand Binder) designs, to differentiate them from the current SSB (Surface Strand Binder) top of the line structures. The term ESB is used generically in this paper to describe these internally bound fabrics.
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