Method for dry-forming a cellulose product and product forming unit for dry-forming a cellulose product

A method for dry-forming a cellulose product from cellulose fibers in a product forming unit comprising a forming mold wherein the forming mold comprises upper mold parts and lower mold parts forming a forming cavity

• wherein a flexible membrane connected to and arranged in fluid communication with a pressure lance is arranged in the forming cavity, wherein the method comprises the steps:
• opening the forming mold and arranging cellulose fibers into the open forming mold
• closing the forming mold around the cellulose fibers, wherein upon closing of the forming mold, the upper mold parts are moved towards each other in a lateral direction, and the lower mold parts are moved towards each other in the lateral direction and in a longitudinal direction towards the flexible membrane
• inflating the flexible membrane with a pressure medium entering from the pressure lance and applying a forming pressure onto the cellulose fibers by pressing the cellulose fibers against the upper mold parts and lower mold parts by means of the inflated flexible membrane, and applying a forming temperature onto the cellulose fibers, for dry-forming the cellulose product with a three-dimensional compressed fiber structure having a closed bottom portion and an upper portion,
• wherein the method further comprises the steps:
• partly inflating the flexible membrane with the pressure medium before movement or upon movement of the lower mold parts in the longitudinal direction towards the flexible membrane, wherein the partly inflated flexible membrane is pushing the cellulose fibers towards the lower mold parts and/or wherein the lower mold parts are pushing the cellulose fibers towards the partly inflated flexible membrane;
• and thereafter when the forming mold is closed around the cellulose fibers, fully inflating the flexible membrane with the pressure medium for applying the forming pressure onto the cellulose fibers.