DD277041A1 - METHOD FOR PRODUCING SINGLE-LAYER, MINERALLY-JOINED SPAN AND FIBER COMPONENTS - Google Patents

Abstract

The invention relates to the production of single-layer, mineral bonded chip and fiber components, in particular thin-walled panels for the entire interior design of buildings and for use in the furniture industry. A homogenous mixture of water-poured chips and / or fibers and a mineral binder, produced by a continuous mixer, passes through a distributor on a flat vibrating device corresponding to the width of the nonwoven, forms a nonwoven here with the aid of rotating brushes, which in free fall reaches a height of 30 cm passed endless forming belt or formed on the continuous band stray sheets and further stacked with the scattering sheets and pressed. On the oscillating device, the continuously discontinued mixture in the axial direction with simultaneous horizontal compensation is promoted. The forming nonwoven has a matted chip and / or fiber matrix. The single-layer components produced in this way achieve such a smooth surface as has hitherto been achieved only with multilayer components.

Description

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field of use

The invention relates to the production of monolayer, mineral bonded chip and fiber components, in particular thin-walled panels, which can be used throughout the interior design of buildings, but also in the furniture industry.

Characteristic of the state of the art

There are known methods for producing single-layer particleboard and fiberboard, with which in all directions of the plate plane the same properties are to arise. The embedding of the chip and fiber materials serves primarily to increase the strength of the component, but also causes a reduction in the overall bulk density.

One method of production relies on gypsum mixed with fibers, predominantly of wood, in a high-speed continuous mixer to form a homogeneous batch and conveyed to a bunker of a spreader. In the bunker there is a uniform distribution of the spreading material over the entire width of the spreading machine.

With the help of the spreading machine, the mixture is spread onto a scattering belt as an endless mixture fleece with simultaneous spraying with water.The device can be leveled, side bolstered and fed to a belt press with further devices (Siempelkamp / Feld method).

It is apparent from the literature that throwing the batch produces a separating effect of the fibers which causes stratification within the mat, thereby causing uneven flexural strengths within the board. Another disadvantage oesteht is that cellulose fibers are used as reinforcing components, d. H. The wood fibers must first be plasticized in cookers, digested in refiners and then dried. The cost of such a fiberboard is considerably increased with the elaborate Tasertechnologie.

The flexural strengths are determined by the fiber content. The proportion of fibers is about 10% of the gypsum, whereby the strength values are approximately comparable to those of the plasterboard.

In DE-OS 3608581 components, especially plates made of gypsum with the addition of a wood chips mixture are proposed in which the wood chips are subjected to only one crushing process. The wood chips, on the one hand stripe-shaped shavings, on the other platelet-shaped particles with a maximum of 10-40mni length, 1-5mm width and 0.2-fl, 5mm thickness are further processed by mere mixing with gypsum brittle to a homogeneous mixture. The prescribed Spangeometrie generated when spreading to a fleece a very rough surface. With the technology of manufacturing the plasterboard this rough plaster surface is laminated. Instead of the carton, a jacket with glass fiber fleece is also possible.

Using moist particles, predominantly Holztoilchen, other production methods of gypsum or gypsum chipboard are known (semi-dry method). The aggregates serve once as a water depot (DE-AS 2919311), on the other hand as fillers (DD-WP 250630, DE-OS 3336243) and / or for reinforcement (DE-OS 3431593).

When Toilchon come, for example, in the endless process according to bison predominantly chips of the sieve fraction <2 mm χ 2mm are used. In a metering hopper, gypsum is added to the agitated particles immediately before mixing via a feed roller. Subsequently, the submixing is done by means of a head litter box. According to the air classification principle, a fleece is formed on a base, which may be a conveyor belt or a form. According to DE-OS 3247009, gypsum and moist particles are homogeneously mixed during the fall on the substrate by means of mixing rolls. The mixture falls substantially vertically by pouring onto the conveyor belt.

The chip geometry for a reinforcement function in the building entails the risk of springback of the chips in itself. It requires a high compression. Another disadvantage is the very rough surface that causes additional grinding work. By producing multi-layer elements with gypsum topcoats, which are either fiber-free or contain fiber fractions, this disadvantage is avoided. This requires an additional technological effort. The production of thin chipboard according to the Texpan system or according to the calendering process is based on a uniform wood chip (organic binder) gluing, but under no circumstances can with the aim of producing smooth non-porous plates, which require no grinding dispense complicated and expensive litter and / or wind sprinkling (DE-OS 2402410).

The web formation in the sense of a discontinuous filling of the molds for the production of moldings is carried out according to DE-OS 2609248, for example by means of contour-matched Schüttsieben, this Schüttsiobe can simultaneously perform oscillatory movements, but this with the main Zip! the pre-compression (DE-OS 2709467). DE-OS 3259606 proposes for web formation a chute with so-called rocker plate. A flat plate is hinged on one side below a chute, obliquely downwards, in this way releasing an opening for the transport of bulk material suspended. The freely movable side of the plate is moved by a mechanical eccentric pendulum. The transport over the Schwingtischpiatte is possible only by a considerable downward inclination. As a result, the horizontal distribution of the bulk material is limited, wns the use of a second oscillatory plate, below the first, arranged in series, necessary mucht.

Object of the invention

With the invention, the goal is pursued. Chip and fiber components, especially thin-walled mineral bonded plates, with improved properties based on the semi-dry process easier and cheaper using known starting materials, such as wood chips as water-storing aggregates to produce.

Essence of the invention

The invention is based on the object homogeneously scattered single-layer, mineral bonded chip and fiber components with aggregate particles, which have the ability of water storage and exercise in the finished component, inter alia, the function of the reinforcement matrix to produce as far as possible with a smooth surface.

With chips and / or fibers whose moisture is predetermined and pass through dosing in continuous mixer, soaked with procedurally necessary amount of water and then mixed with added from dosing bunkers mineral binders to a homogeneous mixture, the object is achieved in that the homogeneous mixture of one or more continuous mixers via distributor of a flat, the fleece width corresponding vibrating device, here with the help of arranged at a certain distance above the conveyor bottom, against the conveying direction rotating brushes formed into a web, in free fall at a height = 30cm an endless form band or on passed to the continuous band formed scatter plates, known leveling preconsolidated and pressed.

The water-storing particles may be organic and / or inorganic in nature.

The mixture can also fall out of the continuous mixer or on a rotating conveyor belt, leveled and then fed via part, steering and Rutscherichtungen the vibrating device. This achieves better pre-distribution.

On the vibrating device, the continuously discontinued mixture is conveyed in the axial direction with simultaneous horizontal compensation. This process is supported by the rotating brushes projecting into the oscillating device.

The fleece forming here achieves a felt through the geometry of the chips and / or fibers, which however still allow relative movements to one another. As a result of this entanglement, the components produced in this way acquire virtually direction-independent physical properties. This is particularly advantageous when grooving and milling and by a high nail and Schraubenausziehwiderstand parallel to the plate surface, regardless of whether transversely or longitudinally to the scattering direction. Perpendicular to the surface, multiple pull-out resistances are achieved in comparison to conventional products.

Furthermore, the isotropic plate structure causes a comparatively very good dimensional stability with one-sided Feushtigkeitsbeanspruchung. According to the invention single-layer fiber / chip components are produced with such a smooth surface, which was previously achieved only in multi-layer components. By eich reduce three to four streams in the multi-layer plate on a single stream in the single-layer plate, the technologically necessary effort for the process steps conveying, interim storage, crushing, classifying, dosing, weighing and the cost of measurement and control technology decreases many times over.

Complicated and space-intensive throwing and / or spreading machines are replaced by a simple oscillating device. The process according to the invention can be used for chipboard and fiber-based building materials depending on the recipe and specific Proßdruck with different physical properties.

Embodiment 1

Figure 1 shows the technological scheme for producing a gypsum-bonded single-layer board. Wet or dry wood chips of the sieve fraction <2mm with a length of 5mm are first wetted in the continuous compulsory mixer (1) with the necessary water lungs, and then mixed with gypsum. The water can be added depending on the Bodarf means for selectively influencing the setting time.

Due to the turbulent motion in the compulsory mixer (1), a homogeneous, earth-moist mixture is obtained. This is quartered by means of sub-device (2) and falls on a 1.25 m wide electromagnetic vibrating device (3) with a flat oscillating floor. It forms a fleece with felt matrix whose Fördergoschwindigkeit is set on the vibration amplitude. An adjustable scraper (4), which projects from the outside into the oscillating device (3), supports horizontal leveling by means of horizontal reciprocating movements, which take place transversely to the conveying direction. A similar effect is achieved with counter to the direction of rotation rotating brush rollers.

From the vibrating device (3), the fleece is poured onto an endless dispensing tape. Any remaining unevenness on the shaken fleece are equalized by a rotating brush roller (5). By subsequent pre-compaction by means of roller (6) whose peripheral speed corresponds to the belt speed, the felt matrix of the wood particles is finally fixed, so that transport and compression are carried out with virtually no wastage.

The pressing is carried out, for example, using the retarder Protol for 45 minutes in the stack or in the clamping package.

The wetting of the plate in the first press phase * is achieved at 3-5 N / mm ² . In the second pressing phase with low pressure, the setting of the plate takes place. After relaxing and unstacking, a smooth plate is obtained, which is dried to a residual moisture content of 2%.

To improve the web formation, a circulating belt (7) is arranged between the mixer discharge and the distributor, which allows a precalibration of the poured mixed material by means of rotating brushes.

Example meadow were with the recipe

330kg / m ³ sawdust 360kg / m ³ water 820kg / m ³ gypsum

following plate properties produced:

7 N / mm ² bending strength 1200 kg / m ³ gross density 2500N / mm ² modulus of elasticity.

Embodiment 2

The inventive method allows the processing of different formulations, so be with

220kg / m ³ wood chips 360kg / m ³ water 1060 kg / m ³ gypsum

the properties

10N / mm ² bending strength 1450kg / m ³ gross density 3500N / mm ² modulus of elasticity

orreicht.

The following table shows the comparison of different gypsum-bonded plate products.

N / mm ² Plasterboard plate Gypsum fiber plate gypsum-bonded chipboard in accordance with the invention, a gypsum-bound single-layer plaster. flexural strength kg / dm ³ 4-8 6-8 7-10 5-12 Plate dough, dry N / mm ² 1 1.2 1.2 1.0-1.6 Compressive strength kN / mm ² 13 20 40 20-40 Modulus N / mm ² 4 3-3,5 3,5-4 2-4 Transversely to (ifestigkeit N / mm ² 0.38 0.55 0.6 0.5-1.6 Sohraubenausziohwidorstand N / mm ² 20 40 80 80-160 Nagalausziohwidorstand - 35 70 70-120

Claims (2)

1. A method for producing single-layer, mineral bonded chip and fiber components with chips and / or fibers, which have the ability of water storage, with predetermined moisture via dosing pass in continuous mixer, there impregnated with procedurally necessary amount of water and then with added from dosing bins mineral binders mixed into a homogeneous mixture, characterized in that the homogeneous mixture of one or more continuous mixers (1) supplied via distributor (2) a flat, the web width corresponding vibrating means (3), with the aid of arranged at a certain distance above the conveyor bottom, molded in the direction of the conveying direction rotating brush roller to a nonwoven, in free fall at a height <30cm an endless forming belt or on the continuous band formed scattering üoergeben and leveled known, pre-compressed and pressed wi following approx. 2. The method according to claim 1, characterized in that the homogeneous mixture of the one or more continuous mixers (1) on a rotating conveyor belt (7) falls, leveled and part, steering and sliding devices (2) of the Schwinyeinrichtung (3) is supplied.