| 摘要 |
A method and apparatus for forming a web of material, by laying particles distributed in a gaseous medium onto a particle-laying surface (20), in which method the stream of material (4), comprising the gaseous medium and the particles, is conducted along a cylindrical wall. The invention is characterised by first imparting to the stream of material (4) a given velocity in the inlet (14) of a vessel (1), and, by maintaining a flow of gas in the axial direction of the vessel (1), guiding the stream of material in a helical path to the region of an outlet (17) from the vessel, the helical path followed by the stream of material having a pitch which is selected in dependence upon the velocity in the inlet and the velocity of the axial gas flow. |
