Headbox for papermaking machine with more uniform flow

摘要

A headbox for a papermaking machine with an outlet slot that distributes pulp suspension over the, working width of the papermaking machine. For controlling operating parameters of throughput, pulp density and fiber quality of the suspension over the width of the machine, the headbox has a plurality of individual sections across the width of the machine. Each section has respective channels therethrough for passing pulp suspension. At least one connection at each section is to a controllable supply of pulp suspension where the operating parameters of that supply are controllable. Only separate operating parameter controlled streams pass through the sections of the headbox. Operating parameter control devices may deliver adjusted streams to a mixer upstream of the headbox channels. The mixer may also have individual sections across the width of the machine. The headbox has a common outlet nozzle downstream of the individual channels and the individual sections, where the pulp suspension stream from channels with controlled suspension parameters and from any channels without controlled suspension parameters are reconstituted to have the desired suspension operating parameters.