MULTI-STAGE FORMING DRUM COMMUTATOR

摘要

A method and apparatus (20) for forming a fibrous web (50) includes a movable, foraminous forming surface (22) and a substantially stationary, vacuum-commutator duct system (24) which is located substantially subjacent the forming surface (22). The vacuum-commutator duct system (24) has an entrance opening (26) that changes in configuration along a longitudinal dimension (30) of the entrance opening (26).