FIBER WEB MACHINE AND METHOD OF FORMING A MULTI-PLY WEB

A method of forming a multi-ply web in a fiber web machine, comprises the steps:- feeding different pulp suspensions to diffusers of a multi-layer headbox,- guiding the different pulp suspensions through the diffusers of the multi-layer headbox to eject them onto a wire of a forming section, the wire forming a closed loop,- dewatering the liquid substances to form a filler ply in the form of an at least three-ply web,- merging the at least three-ply web with a second web formed at a second head box ejecting pulp suspension on a wire of a second forming section, andmerging the at least three-ply web with a third web formed at a third head box ejecting pulp suspension on a wire of a third forming section, wherein the third web is arranged on a side of the two-ply web opposite to that where the second web is arranged.