Headbox with conduits having multiply connected domains

摘要

A headbox comprising an inlet chamber communicating with a source of fiber suspension, an outlet chamber with a discharge opening for the fiber suspension and a diffuser to establish a fluid path between the inlet and the outlet chambers. The diffuser includes a cluster of tubes, each being divided in two successive portions of larger cross-sectional area separated by a step-like transition. Each tube comprises a stem mounted in the initial portion thereof to define a ring shaped fiber suspension passage.