SU795509A3 - Method of paper web forming - Google Patents

Description

(54) METHOD OF FORMING PAPER CLOTH

one

The invention relates to a method of forming a paper web and can be used in the pulp and paper industry.

A known method of forming a paper web by dewatering a fibrous suspension when it is fed between forming grids with converging paths and removing water flows through each of the forming grids into the system of successive sealing ducts lJ from the Fibrous suspension.

A disadvantage of the known method lies in the low homogeneity of the formed web, in particular when operating at high speeds.

The purpose of the invention is to increase the uniformity of the paper web.

This is achieved by the fact that when diverting streams of water from the fiber suspension, their speeds in the respective sealing boxes are controlled separately, and the water level in the boxes is maintained above the level of water coming from the corresponding parts of the forming grids.

The fiber suspension is fed to the dehydration evenly and at a constant rate, with the water level

in boxes, the fiber content of the dehydratable suspension is maintained at least 12%.

FIG. i schematically depicted

paper machine; Fig. 2 is a schematic of the installation showing the paths of movement of the sweat; in fig. 3 - section A-A of FIG. 2; in fig. 4 - section bb FIG. 3

Suspended fibrous fiber - paper pulp is prepared in the usual way in the tank 1, then pumped through the pipeline 2 with a blade.

pump 3 and enters the distribution system 4.

The distribution system 4 provides a uniform supply of paper pulp to the inlet 5 of the inlet section 6.

From the inlet section 6, the pressurized mass created by pump 3 enters the forming section 7, where water is removed from the suspension flowing through the forming grids 8

and 9, and willow sealing boxes 10 and 11, which are sealed against the atmosphere (see Fig. 2-4). Each box 10 and 11 is connected to a properly closed exhaust pipe.

water 12 coming from the corresponding

the box to collector 13 to which it is connected to a lower normal water level. In each of the exhaust pipes 12 there are a flow meter 14 and a control valve 15. In addition, if necessary, pressure sensors may be installed at various points along the mass path.

The machine operates in a flooded condition, i.e. sealing boxes 10 and 11 are maintained in a water filled condition. This ensures that the entrances to the appropriate box 10 and 11 are filled with water. Since the slurry stream cannot pass from the pump 3 to the forming section 7, air does not enter the system until it is fully received and it does not exit the forming section 7 through its outlet. Boxes 10 and 11 are located with a slope upward from their inlets in the resultant air, which accidentally enters the system, for example, at the beginning of work or with the mass, coming in. pump. 3, will rise above the inlets of the boxes 10 and 11. The discharge pipes 12 may extend from the respective boxes 10 and 11 at their highest points to ensure that the water-filled boxes are received.

The dewatering process in accordance with the invention proceeds less violently than in conventional long-wire papermaking machines using register rollers, foils and suction boxes in the forming section. When water is removed from the mass without sudden shock waves, which occurs in conventional machines, the molding process is better controlled, and the fine fibers are kept in the Cloth and are not washed into the collector.

The web formed by the proposed method is protected against the impact of shock waves, but its

the concentration is at least 12%. This allows cheaper paper to be obtained without loss of quality. In addition, it significantly reduces the amount of fine fibers in the recycled water and, therefore, eliminates the problem associated with waste disposal.

Claims (3)

1. A method of forming a paper web by dewatering a fibrous suspension when it is fed between forming grids with converging removal trajectories from a fibrous suspension of water flows through each of the forming grids into a system of successive sealing boxes, improve the homogeneity of the paper web; when diverting streams of water from the fiber suspension, they separately regulate their velocities in the respective sealing boxes, and the water level in the boxes is maintained at a higher ur level ext water coming from their respective areas formuk Tsikh nets. 2. Method POP1, characterized in that the fibrous suspension is fed to the dewatering evenly and at a constant rate. 3. Method POP1, characterized in that each forming 5, the grid is kept covered with water on both sides until a fiber content of both suspension is at least 12%. 0 Sources of information taken into account in the examination 1. The patent of France 2.117.102, cl. D 21 F.9 / 00, publ. 07.21.72 (prototype). FIG. 2 $ i / f.3