Method of drying workpieces made of organic material, in particular of wood, such as veneer sheets

摘要

The air circulation in the drying machine (1) is maintained by a blower (3) which guides the air via a heat exchanger (4) and through nozzle boxes (5) away over the material to be dried, such as wooden veneer sheets (2). A part of the air loaded with water vapour is carried off through the outlet pipe (6) which contains a regulating flap (7). According to this drying method, the pressure in the low-pressure space (9) in the region of the inflowing replacement air is then determined by a pressure transducer (10) and, by means of a controller (11) and a drive device (8), the regulating flap (7) is adjusted during the drying process in such a manner that a constant pressure difference is maintained between internal and external pressure, by means of which the quantity of inflowing replacement air and thus also the moisture content of the circulation air is determined. The control is preferably set in such a manner that with a low pressure difference the moisture content of the circulation air lies in the range of 250 to 400 g H2O per kg of air. With such a pressure regulation, approximately 30 to 40% energy to be expended can be saved in relation to drying with a fixedly set flap (7). <IMAGE>