Stock inlet for papermaking has structured turbulence generators with different distributions to maintain a homogenous high speed suspension flow and prevent the formation of stripes in the paper

摘要

In the production of paper, a suspension (3) of fibers with water is delivered from a stock inlet at an equal pressure over a working width (6) and arrival height to be pressed in a working direction (5). Through turbulence, the suspension retains a homogenous character and is delivered in a flat stream (11) with acceleration in the working direction (5) to reduce the arrival height. Through turbulence, the suspension retains a homogenous character and is delivered in a flat stream (11) with acceleration in the working direction (5) to reduce the arrival height. In the flow direction (5), a second turbulence generator acts on the suspension (3) downstream of the first turbulence generator, with different distributions. The two turbulence generators can be followed downstream by a third and fourth turbulence generator, with different distributions from the others. At least one turbulence generator has a distribution with a time difference in the suspension flow (3). The fiber suspension flow (3) is allowed to mix over the working width (6) and laying height between the turbulence generators. The turbulence in the suspension (3) is generated so that the eddies lie generally at right angles to the laid suspension height. The fiber suspension is distributed over the working width by the turbulence generators, with different height distributions at each generator. An Independent claim is included for an assembly of a stock inlet where, in the ante-chamber (7), a turbulence generator and a further turbulence generator is downstream of the first in the flow direction (5) across the working width (6) and the laying height and with a different distribution from the first. Preferred Features: The turbulence generators are formed by rods (8), arranged in rows (9) across the working width (6). At least one drive gives a turbulence generator an action with a different timing. The turbulence generators can be blades in the walls which determine the suspension flow, across the working width.