Method and apparatus for dry manufacturing rigid cellulose products

An apparatus for dry manufacturing rigid cellulose products having essentially non-flat general shape, the apparatus comprising:

• a disintegrating unit configured to provide a quantity of separated cellulose fibres from a cellulose raw material;
• and
• a cellulose blank forming unit comprising:
• a dispenser configured to guide a cellulose-fibre-carrying air flow from the disintegrating unit,
• a cellulose blank forming drum having an outer surface comprising perforations, the outer surface:
• configured to receive cellulose fibres and to form a continuous or discontinuous cellulose blank from the quantity of separated cellulose fibres transported by the air flow via the dispenser;
• and
• comprising a first area having a first perforation density and a second area having a second perforation density that is less than the first perforation density for forming the cellulose blank with higher grammage at first locations originating from the first area than at second locations originating from the second area;
• an air removing device arranged inside the forming drum, and
• a support structure for receiving the cellulose blank formed on the forming drum;
• and.
• a product forming unit configured to produce the rigid cellulose product from the cellulose blank by pressing.

A method for dry manufacturing rigid cellulose products having essentially non-flat general shape, the method comprising the steps of:

• providing a quantity of separated cellulose fibres by disintegrating a cellulose raw material,
• transporting the separated cellulose fibres by an air flow to an outer surface of a forming drum, wherein the outer surface of the forming drum comprises perforations,
• forming a continuous or discontinuous cellulose blank at the outer surface of the forming drum by removing air from inside the forming drum in order to temporarily retain the cellulose fibres at the outer surface of the forming drum,
• transferring the continuous or discontinuous cellulose blank from the forming drum to a support structure, and
• producing rigid cellulose products having essentially non-flat general shape by pressing the continuous or discontinuous cellulose blank in a product forming unit, wherein the continuous or discontinuous cellulose blank comprises first locations and second locations, the first locations having higher grammage than the second locations, and the first locations originating from a first area of the outer surface of the forming drum having a first perforation density and the second locations originating from a second area of the outer surface of the forming drum having a second perforation density that is less than said first perforation density.