Web forming apparatus and method

An apparatus for forming a fibrous web from a gaseous suspension of fibers, said apparatus including a fiberizing roll for separating fibers from a fibrous feed mat and entraining said fibers in a gaseous medium, a foraminous forming surface through which the gas of said suspension passes and upon which said fibers are condensed to form said fibrous web, a formation duct having an upstream end adjacent the fiberizing roll and and a downstream end adjacent the forming surface for providing a flow path for the gaseous suspension of fibers from said fiberizing roll to said forming surface;

• the improvement including a pair of passageways adjacent the upstream end of the formation duct, each passageway extending through a formation duct wall and said passageways being located only adjacent opposite side margins of the formation duct, and vacuum means communicating with said passageways for creating a lower pressure outside said duct than inside said duct for removing air from within upstream side margins of said formation duct to eliminate the adverse effect of vortices which are created adjacent said side margins by rotation of the fiberizing roll.