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EP-3854554-B1 - A DEVICE FOR THE UNIFORM DISTRIBUTION OF SLURRIES

EP3854554B1EP 3854554 B1EP3854554 B1EP 3854554B1EP-3854554-B1

Inventors

  • KARAKOUSSIS, Stergios
  • KOCH, THOMAS
  • Krämer, Thomas
  • HARTMANN, ALEXANDER
  • PARASKOV, Georgi
  • Schneiderbanger, Reiner
  • KNAUF, Carlo

Dates

Publication Date
20260513
Application Date
20151217

Claims (6)

  1. A conveyor line (1) for producing gypsum plasterboards, comprising a conveying device, at least one mixing device (18) for mixing at least one slurry and at least one slurry distributing device (22), wherein the at least one slurry distributing device (22) is disposed between one or more delivery hoses (19) for supplying the at least one slurry from the at least one mixing device (18) to the slurry distributing device (22), and the conveying device, where the at least one slurry is delivered to the conveying device, and wherein the at least one slurry distributing device (22) is equipped to be supplied with the at least one slurry from the at least one mixing device (18), to adapt a conveying speed of the at least one slurry to a conveying device speed and to distribute the at least one slurry uniformly over a desired width and then to deliver the distributed at least one slurry essentially uniformly onto a lower layer, wherein the lower layer is the conveying device itself or a casing material lying on the conveying device, and preferably is fed continuously, and wherein a discharge height of the slurry from the at least one slurry distributing device (22) onto the surface of the lower layer is less than 5 cm, wherein the at least one slurry distributing device (22) comprises a process belt (230) to actively transport the at least one slurry in a delivery direction of the at least one slurry and to adapt the conveying speed of the at least one slurry to the conveying device speed, such that a relative speed of the at least one slurry in the delivery direction in relation to a speed at which the lower layer is moving is approximately equal to zero, wherein the one or more delivery hoses (19) lie on the process belt (230) to deliver the at least one slurry onto the process belt (230).
  2. The conveyor line (1) according to claim 1, wherein the discharge height of the slurry is less than 4 cm, preferably less than 3 cm.
  3. The conveyor line (1) according to any one of claims 1 or 2, wherein a plurality of slurry distributing devices (22) are disposed one after the other, by means of which identically or differently constituted slurries are delivered onto the lower layer.
  4. The conveyor line (1) according to any one of claims 1 to 3, wherein the at least one slurry distributing device further comprises a vibrator to assist to distribute the slurry.
  5. The conveyor line (1) according to any one of claims 1 to 4, wherein the process belt (230) is a knife-edge belt.
  6. Use of a conveyor line (1) according to any one of claims 1 to 5 for producing gypsum plasterboards in a continuous process.

Description

The invention relates to a conveyor line for producing gypsum plasterboards. Drywall boards, for example based on gypsum, are typically produced by continuous production processes. A slurry comprising the solid and the liquid components, essentially calcined gypsum, water and additives, is first produced in a mixer. The slurry is optionally foamed mechanically or chemically. The slurry is then deposited on the casing material or directly on a belt. Cardboard or nonwoven fabric are typically used as casing materials. If a multilayer drywall board is to be produced, a plurality of layers of identical or different slurries are deposited upon one another. Located in the middle of the board is the so-called core layer, which typically makes up 50 to 90 wt.-% of the total mass of the plasterboard. When a plurality of mixers is used, the core layer is fed from the main mixer. During the setting of the material, a forming station is usually passed through, said forming station ensuring that a clean edge formation takes place. The endless strip thus produced is then cut into pieces. The excess (hyperstoichiometric) water, which has not reacted with the calcined gypsum, is expelled in a drying station. If the drywall board has a multilayer structure, a plurality of layers of slurry have to be deposited upon one another in production. For this purpose, the slurry is often deposited on a lower layer by means of one or more hoses. When the slurry strikes the lower layer, it has a speed dependent on the cross-section of the delivery hose and on the delivery pressure. In order to achieve a good bond between the individual plies or layers, the next layer is deposited before the preceding layer has fully set or hardened. However, this has the drawback that the preceding layer is not yet stable at the time of deposition of the next layer. It can easily be damaged, i.e. so-called flushing effects can occur in the region of the deposition of the slurry. Initially uniformly deposited material of the layer lying beneath is flushed away or displaced in the region of the subsequently fed material and accumulates at other points of the board, in particular in its edge regions. The formation of layers is therefore non-uniform. The flushing effect may be more or less pronounced depending on the delivery pressure, the cross-section of the delivery hoses, the positioning of the discharge hoses and the impact angle of the slurry on the layer lying beneath. These flushing effects occur especially in the case of thin layers that are deposited directly on the casing material. Such layers are referred to as boundary layers. Since these layers often have special functions, for example a fire protection function or increased water resistance, weak points in these functions arise in the areas in which the material has been washed away. The quality of the end products is thus markedly reduced. Figure 1 shows a plan view of a gypsum plasterboard, there having been deposited on a coloured boundary layer 6 (represented shaded) a next layer of gypsum 7 by means of three hoses directly onto the boundary layer, the middle one of said hoses oscillating. The cardboard has been removed after completion of the gypsum plasterboard in order to allow the boundary layer to be seen. Straight-running regions 7 can be seen at the two longitudinal edges of the gypsum plasterboard and a meandering region 7 can be seen in the middle of the board. These regions 7 correspond to regions in which boundary layer 6 has been displaced by the flushing effect. Gypsum layer 6 lying beneath the latter is in direct contact with the cardboard (removed here). Regions 7 thus trace the regions in which the delivery hoses have delivered the gypsum slurry of the second layer onto the lower layer and washed away boundary layer 6. Various distributor devices are known from the prior art that are intended to counteract the occurrence of these flushing effects and to promote a more uniform layer deposition. In principle, it is the aim of all methods to reduce the discharge pressure in the delivery hoses, especially of the main mixer. This can be achieved by reducing the flow rates in the discharge hoses, in that the hose diameter or the number of discharge hoses is increased. The core material is typically discharged from the main mixer with three up to a maximum of four hoses. However, the individual hose diameters cannot be increased arbitrarily, because otherwise the self-cleaning of the hoses is not guaranteed. If the flow rate in the hoses is reduced excessively, the hoses become blocked with hardened gypsum, which leads to a production stoppage. The number of discharge hoses likewise cannot be increased arbitrarily. It is limited by the geometry of the mixer. Both measures, the enlargement of the hose diameter and the increase in the number of discharge hoses, lead to an improvement in the flushing effect, but they do not remove it sufficiently. Moreover, they lead to increased m