SU720088A1 - Net assembly of paper-making machine - Google Patents

Description

(54) NETWORK PART OF A PAPER MACHINE

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The invention relates to papermaking equipment and can be used in pulp and paper industry.

There are various designs of grid parts of papermaking machines with double-mesh ({cheating, on which the molding of elementary layers of a multi-layered fabric takes place on two grids, into the gap between which paper pulp is fed, which provides an attachment (connection) of elementary layers l. On these grid parts trad mass-wise paper is produced by the industrial wet method.

The constructions of the grid parts of papermaking machines with air-forming molding allow to increase the machine speed, the weight of the produced web and to obtain multi-layer products (as compared with the design of the mesh screen and paper machines with one flat mesh).

The main disadvantages of such structures of the grid parts are the significant consumption of fresh water for the production of multi-layer fabric, as well as the need for fiber regeneration and the provision of appropriate wastewater treatment.

The known structure of the net part for the production of multi-layered paper webs by dry molding, containing two inclined grids ({elementary layers by the dry method and a device for bonding (e.g., glue) into the wedge between the conforming I2 elementary layers | |.

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When forming a multi-layer web on this grid part, it is used, which eliminates the costs of wastewater treatment. Using fibers that are different in chemical and morphological composition, a web with special properties can be obtained on this grid part (in the case of paper web forming, fiber is used).

a certain composition that provides only mass types of paper

A significant disadvantage of this grid part is that paper is less uniform in its structural parameters than paper obtained by the traditional wet method, which limits its field of application.

Also known is the net part of a papermaking machine, which contains net conveyors, a double headbox, parallelly installed two suction cylinders for forming the web and dewatering elements, as well as a collection of circulating water GZ.

When the grid part is operated, the liquid is: and the pulp under pressure is fed into the pressure box. Two elementary layers are formed on the endless grid conveyors covering the suction cylinders. When two grids are similar, the elementary layers are joined into a uniform web. Dehydration of a single web is performed on a flat vertical 1: the nominal portion of the movement of the nets by air blowing. Next, the web is transferred to the press section.

Such a net part allows to obtain a uniform web of mass types of paper,

A serious disadvantage of this grid part is the impossible. It is impossible to produce special types of paper.

Special papers can be obtained by further processing (impregnation, coating, gluing) mass types of paper or using various synthetic fibers.

On this grid part, a fabric of synthetic fibers cannot be formed because the pulp of synthetic fibers requires more than usual, wandering (requires even lower concentration) and the formation of elementary layers from it on such a grid part is impossible,

In addition, this mesh part has disadvantages inherent in all mesh parts operating in the wetting method — using large quantities of fresh water to mold, since the molding process requires a low concentration of fibers in an aqueous medium and forms fiber-fiber bonds. Consequently, significant costs for cleaning industrial waste.

The purpose of the invention is to get paper from and with backward properties.

This goal is achieved by the fact that the grid part is equipped with dry molded devices, each of which has a forming cylinder with a diffuser and is installed above the suction cylinder of the corresponding grid conveyor.

The drawing shows the schematic diagram of the proposed grid part,

The grid part includes pressure boxes 1, installed over the network of transporters 2, grid straightening rollers 3, parallel suction cylinders 4 with vacuum chambers 5, Infinite wire conveyors, envelopes of suction rings. have on the vertical section dewatering elements 6. Above the suction cylinder of each grid conveyor there is a device for dry forming of paper consisting of a forming cylinder 7 with a vacuum chamber 8 and a pressure chamber 9 and a diffuser 10

The grid part works as follows.

Paper pulp is supplied from the headboxes 1 to the endless grids 2, Pootame water suction;; the chamber 5 on the grids enveloping the suction cylinder 4 envelops two elementary layers of paper and their partial decompression: live, Into the diffusers 1O the pressure: / Aerospace CG consisting of dry fibers and air is supplied. Nepag fiber from the expanses of the lumen of the center of the fuser fiber, with the help of the vacuum created in chamber 8, settles kaggo. the surface of the forming cylinder 7, forming the elementary layer of dry fiber. When the forming cylinder rotates, the elementary layer of dry fiber that forms on it is connected with an elementary layer formed from the paper pulp on the net 2, and the excess Veda in the elementary layer formed from the paper pulp provides the connection and fixation of the dry cotton windows.

Further, both layers; River Shies: -; On the net conveyors 2j, one web is joined, consisting of four elementary layers (layers of dry fibers are between the wet layers).

On the vertical sections of the net conveyors under the action of dehydration

Claims (1)

Claim The mesh part of the paper machine containing mesh conveyors, pressure boxes, suction cylinders and dewatering elements, characterized in that, in order to obtain paper with desired properties, the mesh part is equipped with dry forming devices, each of which has a forming cylinder with a diffuser and is installed above the suction cylinder of the corresponding mesh conveyor.