Patent ID: 6425984
Filing Date: 2002-07-30
Classification: D21F

Abstract:
A paper forming machine headbox component for receiving a paper fiber stock and generating the paper fiber stock in a layered fiber structure for discharge upon a wire component moving in a machine direction (MD), the headbox component comprising:a distributor for distributing stock flowing into the headbox component in a cross-machine direction (CD), the distributor effective for supplying a flow of said stock across the width of the headbox in the machine direction; a nozzle chamber having an upper surface and a lower surface converging to form a rectangular outlet lip defining a slice opening for a jet flow of said stock for discharge upon the wire component; a diffuser block coupling said distributor to said nozzle chamber, said diffuser block comprising a plurality of tubular elements disposed between said distributor and said nozzle chamber, said tubular elements being oriented axially in the machine direction and arranged within the diffuser block as a matrix of rows and columns for generating multiple jets of said stock flowing into said nozzle chamber; wherein the plurality of tubular elements of said diffuser block have a longitudinal axis in the direction of the flow of stock, with at least one counter rotating vortex pair (CVP) being generated at one or more of said plurality of said tubular elements effective for swirling said stock in controlled pairs of axial vortices along the longitudinal axes of the tubular elements; said tubular elements generating the multiple jets with said stock flowing into said nozzle chamber; and a divider sheet disposed inside said nozzle chamber having an upstream lateral edge secured between at least one of the rows of the matrix of rows and columns of the tubular elements of the diffuser block, said divider sheet having an upper surface and a lower surface opposite the upper surface and the lower surfaces respectively of the nozzle chamber for imparting CD shear on the flow of said stock at said divider sheet to cause a directional change in the flow in said nozzle chamber.