APPARATUS FOR FORMING A FIBROUS MAT WITH IMPROVED EDGE STRENGTH

摘要

An apparatus and method for forming a thin fibrous mat, such as a tissue sheet, with improved edge strength is disclosed. The apparatus includes a headbox having a top, a bottom, a pair of lateral sides, a back with an inlet formed therein and a front with an outlet formed therein. The headbox is designed to receive a first aqueous slurry having a predetermined fiber consistency at the inlet. This first aqueous slurry is directed through the headbox to the outlet. A first conduit is connected to the inlet of the headbox and flow therethrough is regulated to convey the first aqueous slurry at a desired rate into the headbox. A second conduit is connected to one of the lateral sides of the headbox and flow therethrough is regulated to convey a second aqueous slurry at a much lower flow rate into the headbox than through the first conduit. The first and second aqueous slurries are blended to form a commingled aqueous slurry. The apparatus also includes a mechanism for draining water from the commingled aqueous slurry exiting the outlet to form a thin fibrous mat. The thin fibrous mat has increased strength adjacent to an edge located downstream from the second conduit. The method includes the steps of introducing the first aqueous slurry to the inlet of the headbox and introducing a second aqueous slurry to at least one side of the headbox to form a commingled aqueous slurry which can form a fibrous mat with improved edge strength and better basis weight uniformity. 25