Continuously operating multistage drying installation and a process for continuously drying a workpiece

A process for continuously drying a laminated workpiece while maintaining the workpiece free from surface cracks, the process comprising the steps of providing separate multi-belt drier and one-belt drier for treating workpiece having two opposite, longitudinally extending surfaces and containing excess moisture;

• preliminarily drying the workpiece in said multi-belt drier by turning over the workpiece at least once so as to expose both of its surfaces to heat within said one drier, which turning during the preliminary drying does not lead to cracking of the workpiece since the latter contains excess moisture and thereby its surfaces are not brittle;
• transporting the preliminarily dried workpiece to said one-piece drier for final drying;
• finally drying the workpiece in said one-belt drier to a desired moisture level while maintaining the workpiece free from being turned over to thereby avoid cracking the surfaces of the workpiece due to pressure applied to the demoisturized and consequently relatively brittle surfaces thereof, so that because of the preliminary drying of the workpiece with its turning in the multi-belt drier and the final drying of the workpiece without its turning in the one-belt drier a favorable drying efficiency is attained and a crackless dried workpiece is produced;
• and separately monitoring and regulating the respective drying temperatures and climates in each of said separate multi-belt and one-belt driers.