Method and headbox for inducing shear and turbulence in a fibrous suspension

摘要

A papermaking assembly has a head-box (1) surrendering a fiber suspension (3) through (S) a feed passage (4) vortex generator (5) to jets (6, 6.1, 6.2). The jets esp. generate a sheer flow (R1, R2) pattern through angles alpha (() and beta ((). Also claimed is a commensurate head-box assembly for the manufacture of paper or carton in which the jets are directed at different angles to each other. Further claimed is that the process operates efficiently at a fiber density of 1-3%, combining low costs with good paper machine runnability. The suspension moves at a speed of ( 1 m/s in the vicinity of the first jets, ( 3 m/s in the vicinity of the second jets, and ( 1-20 m/s in the vicinity of the third jets.