SU1096128A1 - Method and apparatus for forming a wood-fibre mat - Google Patents

Abstract

1. A method of forming a wood fiber carpet, comprising injecting a stream of fibrous mass onto a forming mesh, dewatering the carpet, and mechanical spinning, so that, in order to improve the quality of the carpet, in the initial stage of the dewatering process, fractional separation of the fibers is performed by skipping the upper part flow through the grid classifier with the oscillation frequency of the latter 2-90 Hz with an angle of attack of 2-30 °. 2. A device for forming a wood-fiber carpet, including an inlet box, forming a grid, register, suction and pressing parts, characterized in that, in order to improve the quality of the carpet, the installation is equipped with a grid classifier, which from: is installed in the register part with a gap relative to forming mesh.

Description

The invention relates to the woodworking industry, in particular, to methods and devices for forming fiberboard carpet in the manufacture of fiberboard by the wet method.

Closest to the present invention is a method of forming a wood fiber carpet, including the inlet of a stream of fibrous mass on the forming network, dewatering. carpet and mechanical spin Ci.

The method is carried out by a device for forming a wood-fiber carpet, comprising an inlet box forming a grid, register, suction and press parts.

A disadvantage of the known method is the absence of a forced fractionation of wood fibers during the formation of a fibrous carpet, which ultimately degrades the quality of the fibrous plates.

The purpose of the invention is to improve the quality of the carpet.

This goal is achieved by the fact that according to the method of forming a wood-fiber carpet in the initial stage of the dewatering process, fractional separation of the fibers is carried out by passing the upper part of the stream through the net classifier at the oscillation frequency of the latter 2-90 Hz with an angle of attack of 2-30.

The installation for forming a wood-fiber carpet is equipped with a grid classifier, which is installed in the register part with a gap relative to the forming grid.

Fig. 1 shows an installation for carrying out the proposed method for forming a fibre mat J in Fig. 2 — the placement of the grid classifier in the register part of the installation.

The device includes a drain box 1, forming a grid 2, register 3, suction 4 and press 5 parts. The device is equipped with a grid classifier 6, which is installed in the register part 3 with a gap relative to the forming grid 2.

The grid classifier 6 is connected to the generator 7 of low-frequency oscillations by means of the pull 8 and is movably fixed to the body of the casting machine 9 by means of a shock-absorbing suspension 10 having at least two degrees of freedom. As a generator of low-frequency oscillations can be used vibrator casting machines.

The carpet forming method is carried out as follows.

The wood pulp mass expires from the hauling box 1 onto the supporting mesh 2 and flows around the net classifier 6. The classifier makes oscillatory movements at

frequency 2-90 Hz in the vertical

plane. Since the classifier is located in the upper part of the flow of wood fibrous mass, as the grid moves downward, small particles pass through its cells, turn out to be above the grid and are washed off of it by water flow, filtered through the classifier grid. Large fibers can not pass through the cells and move

along with the rest of the stream under the classifier. Then a stream of fine particles flows down from above onto the large fibers that have passed under the netting and forms the top layer of wood-fiber carpet.

Example 1. In the flow, the fibers of that mass in the register part of the tide mapin are set at an angle

attack 2 mesh classifier with cell size 4x4 mm. Oscillating motion with a frequency of 90 Hz and an amplitude of about 15 mm is attached to the classifier. In this case, with a degree

Grinding of a wood fiber mass, for example, 19.5 DS in the upper layers of a wood-fiber carpet, there is a mass with a grinding degree of about 23 DS. This redistribution

fibers increases the strength of the plates from 38.7 to 42.0 MPa and improves the quality of their surface.

Example 2. In the stream of fibrous mass in the register part of the casting machine, a grid classifier with a cell size of 4x4 mm is installed at the angle of attack IS. On the classifier impose a vibration field with a frequency of 10 Hz and an amplitude of about 15 mm. In this case, when the degree of grinding of the initial mass, for example, 21 DS in the upper layers, there is a mass with a grinding degree of 25-28 DS. Such a redistribution of fibers gives an increase in the strength of the plates from 40.1 to 52.0 MPa. Example 3. In a stream of wood, new-fibrous masses set the grid classifier at an angle of attack of 30 °. Oscillating motion with a frequency of 2 Hz and an amplitude of about 15 mm is attached to the classifier. With the degree of grinding of the initial wood 284 of a new fiber mass, for example, 18 DS, the mass with a power of times, mole 23.5 DS, is redistributed to the upper layers of the carpet, which increases the strength of the plates from 37.2 to 43.6 MPa. Surface quality is also improved. Fractional separation of the fibers at the initial stage of the dewatering process allows to increase the strength properties of the plates and improve their surface.

Claims (2)

1. A method of forming a wood fiber carpet, including the inlet of the flow of pulp onto the forming mesh, dehydration of the carpet, mechanical extraction, characterized in that, in order to improve the quality of the carpet, in the initial stage of the dehydration process, fractional separation of fibers is carried out by passing the upper part of the stream through a mesh classifier with a frequency of oscillations of the latter 2-90 Hz with an angle of attack of 2-30 °. 2. A device for forming a wood fiber carpet, including an inlet box forming a grid, register, suction and press parts, characterized in that, in order to improve the quality of the carpet, the installation is equipped with a grid classifier, which is installed in the register part with a gap relative to the forming grid.