GB2141150A

GB2141150A - System for forming a weblike stuff track from loose fibres or particles

Info

Publication number: GB2141150A
Application number: GB08414252A
Authority: GB
Inventors: Arto Bothas
Original assignee: Yhtyneet Paperitehtaat Oy
Current assignee: Yhtyneet Paperitehtaat Oy
Priority date: 1983-06-09
Filing date: 1984-06-05
Publication date: 1984-12-12
Also published as: FI832075L; DE3420891A1; FI832075A7; SE8403097D0; SE8403097L; NO842311L; GB8414252D0; AU2931684A; FI832075A0

Abstract

A system for forming a weblike stuff track from loose fibres or particles, in which invention the particles and air mixture fed to the equipment is distributed as evenly as possible in the direction transverse to the material truck to be formed on a wire 9, and in which the material is mixed and dispersed with the aid of rotating brush rollers (5). In the invention the material is constrained to pass through a screen element (6) to a chamber element (7), in which the material is allowed to fall onto the the track forming wire (9). The invention is characterised by the element 6 being supported by rotating rolls 10 or by a sliding bar 11 in a direction transverse to the forming track. The equipment is divided in said transverse direction by partition walls 3, 4, 3 into several regions. <IMAGE>

Description

SPECIFICATION System for forming a weblike stuff track from loose fibres and particles The subject of this invention is a system for forming a weblike stuff track of loose fibres or particles, in which system the material flow is led to a wire, and in which invention the mixture of particles and air fed into the equipment is separated as evenly as possible in the direction transverse to the stuff track to be formed, and in which the stuff is mixed and dispersed with the aid of brush rollers, and in which the material so treated is allowed to fall to a screen element.

In order to form the stuff track, that is the web, from the particles dispersed to air, it is recognised to use rotating brushes or blades to constrain the dispersed material through perforated drums or perforated sheets to a chamber, in which the stuff is allowed to fall onto the track and thus form the stuff track.

In certain known equipment the material dispersed into the air is fed into a drum rotating about its axle shaft, inside which a brush is rotated in the opposite direction to the drum itself. With the aid of the rotating movement of the brush rollers and drum the particles are constrained to move outwards through the holes in the drum casing. In order to achieve an even material distribution the drum can only be supported at its ends, so that particularly when forming a wide track the drawback is that it is difficult to make a drum that is sufficiently stiff in its axial direction. the equipment in question is also limited in that both the brush rollers and the devices to divide the material, with which it is endeavoured to distribute the material evenly over the whole width of the web to be formed, must be sited inside the drum.This imposes many limitations on the size and construction of both brush roller and material separator. In addition the equipment in question has the disadvantage that the fibre bunches collecting into the construction at the upper part of the track forming equipment outside the drum and which consist of fibres adhering to one another, can fall without impediment onto the stuff track and thus affect the nature of the web by weakening it.

The intention of this invention is to eradicate the aforementioned disadvantages, amongst others. For this reason the system in accordance with the invention is fundamentally characterised in that the screen element is supported by a rotating roll or slide bar, in the direction transverse to the stuff track. As the benefit of this support the contact between brush roller and screening element is even over the whole length so that particles pass through the screening element evenly, over the whole width of the stuff track to be formed. On the merits of this construction even, relatively wide stuff tracks can be formed without transverse deflection of the screening elements occuring to lead the uneven thickness in the stuff track to be formed.

At the same time the devices supporting the screen elements seal the chamber relative to the screen element.

It is characteristic to the system according to the same invention that the particles or fibres are allowed to fall after screening through an essentially closed chamber to the track forming wire. Now all particles from which the stuff track is formed are made to pass through the screen element. The nature and height of the space between the screen element and the track forming wire are decisive factors from the point of view of quality and evennesss of the stuff track. In accordance with the invention the material passed through the screen element is allowed to settle and spread evenly in the chamber before it is let out onto the material forming wire.

It is characteristic to several advantageous modes of application of the system according to the invention that the forming device is divided up in the web transverse direction by several partition walls into a number of separate parts. The screen element can then be combined with all or separate sections of the track forming equipment. This construction is advantageous for example in the formation of layered material tracks, when the various parts of the forming equipment can feed different types of fibre cr particle.

It is characteristic to several advaantageous modes of application of the system according to the invention that the screening element is an endless wire which runs around the brush rollers and material separation equipment.

The invention is explained more exactly in the following example, assisted by reference to the accompanying drawings in which Figure 1 illustrates a mode of application of equipment in accordance with the the invention, shown in half-section and from the side, Figure 2 depicts the equipment in accordance with Fig. 1, in cross-section along the line I-I of Fig. 1, Figure 3 illustrates the equipment in accordance with Fig. 1, in plan view along the horizontal line ll-ll of Fig. 1.

In Figs. 1-3 the material dispersed to air is blown through the separating device 1 into the equipment. It is endeavoured, with the aid of separating equipment 1, to distribute particles as evenly as possible over the whole width of the web to be formed. In addition to the air and particle mixture air can be let into the equipment through the grill 2 situated in its upper part. In addition to its surrounding outer wall 3, the equipment can be furnished with partition walls 4 which divide up the equipment into separate vertical compartments over the whole width of the track to be formed. Inside the equipment one or more brush rollers 5 rotate in clockwise or counterclockwise direction as sifting elements operating against the wire 6 to constrain particles through the mesh of wire 6 to the chamber 7, which is situated beneath the wire in question.The wire 6 is supported by roll 10 or alternatively by the sliding bar 11, at a suitable point.

The passage of particles through wire 6 is assisted by suction provided by suction box 8.

With the aid of brush rollers 5 the mixture of air and materials is stirred up inside the equipment keeping the particles moving and separated from one another. In penetrating through wire 6 into chamber 7 the particle movement evens out and they finally drop under the acceleration provided by suction boxes 8 onto the track forming wire 9 which is above the boxes, the particles of the mixture remaining in layers on top of the track forming wire, the air of the mixture being drawn into suction boxes 8. A continuous web is formed as the track forming wire travels forward, the particles simultaneously landing upon the wire in question. The chamber space 7 can be sealed against the stuff track being formed with the aid of the sealing roll 1 2.

The chamber space above wire 6 is furnished with a separate end chamber 1 3. By extracting part of the air and particle mixture that is fed into the unit out of exit channels 14 the mixture inside the unit can be set in motion in a direction transverse to the web.

The fibre bunches and other unseparated material parts which cannot pass through the holes in wire 6 can return through the exit channels 14 to be separated into fibres again.

To persons expert in this field it is clear that the various modes of application of the invention are not limited only to the example presented above but can be changed within the bounds of the patent claims hereinafter presented.

Claims

1. A system for the formation of a weblike stuff track composed of loose fibres or particles in which system the stuff track is led to the wire (9) and in which invention the mixture of particles and air fed to the equipment is distributed as evenly as possible in the direction transverse to the stuff track to be formed, and in which material is mixed and dispersed with the aid of rotating brush rollers and in which the material so treated is allowed to fall to a screening element, characterised in that the screening element is supported by a rotating roll or sliding bar in the direction transverse to the stuff track to be formed.

2. A system in accordance with Patent Claim 1 characterised in that the fibres or particles are allowed to fall after screening through an essentially closed chamber to the track forming wire.

3. A system in accordance with Patent Claims 1 or 2 characterised in that the forming equipment is divided in the direction transverse to the web by partition walls into several separate parts.

4. A system in accordance with Patent Claims 1, 2 or 3 characterised in that the screen element is an endless wire which runs around the brush rollers and material separating equipment.

5. A system for the formation of a weblike stuff track composed of loose fibres or particles substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.