The present invention pertains to a process and equipment for the continuous production of inorganically bonded materials.
One similar process is already known from DE-OS 34 41 839. The equipment and process described there for the continuous production of inorganically bonded materials require the presence of a high-pressure compression unit, followed immediately by a calibrating unit. The calibrating unit is directly connected to the high-pressure compression unit without a transition zone. This solution requires a special design. The use of available continuous high-pressure presses for overcompression is not possible, since the dimensions of the available high pressure presses do not allow the continuous sheet of material to pass directly into a calibrating unit. This is due, for example, to the necessary return of the roller carpet or roller chain (Siempelkamp Contiroll, Kusters Contipress), for which a sufficient amount of space is necessary. Accordingly, the equipment described in DE-OS 34 41 839 is not suitable for the available continuous high-pressure presses; it always requires a special design. This is a disadvantage because this solution is associate with high costs.
It is significantly easier and more cost-effective to use the available presses. However, as has already been explained, the use of presses that are already present requires a pressureless zone between the high-pressure compression unit and the calibrating unit. When the continuous sheet of material passes through this pressureless zone, the molding, which has been compressed to a thickness below its nominal thickness and to a density above its nominal density, springs back within this zone and cannot be transferred to the calibrating unit without active pressure application. The disadvantage of this is that the advantageous design of the equipment is lost, namely, the use of the relatively long calibrating unit without active pressure. This increases the cost of such equipment and reduces the economy of its use for the production of the material.
Furthermore, one of the problems associated with the continuous production of inorganically bonded particle board and especially fiberboard, especially at high nominal board density, is that the air contained in the fibrous material is compressed in the compression unit. When the molding is covered on both sides by shaping and conveyor belts during the entire period of (active or passive) pressure application, this compressed air can escape only through its edges. This results in splitting of the boards after they leave the press due, to the enclosed air. These conditions are disadvantageous.