Paper-making stock inlet - has parallel channels to generate micro-turbulence with hollow zones of different cross=sections in variable geometry

摘要

To generate micro turbulence within the stock inlet of a papermaking machine, a number of channels run parallel to each other to the jet end, each with at least two hollow zones sliding partially within each other to vary the inner cross-section. The hollow zones slide against each other along the channel axis to vary the effective path length through a channel or the path lengths ratio through hollow zones of different cross-section. An elastic membrane pref. connects the channel hollow zones to give a variable cross-section through them. At least one pressure zone is at the outer side of the membrane, partially defined by the membrane, filled with a pressure medium at an adjustable pressure for each channel or in gps. The cross-section can also be varied by a solid body pressing against the membrane from the outside, e.g., a pressure ring. At least one part of the channel is of an elastic material, so that a significant length of the channel can be distorted by external pressure to alter its cross- section. ADVANTAGE - The turbulence system gives a variable geometry for different machine speeds and various compositions of fibre suspension.