WOODWORKING METHOD Russian patent published in 2002 - IPC

FIELD: woodworking. SUBSTANCE: invention relates to treatment of damp blanks of different species. Method can be used for working sawn timber irrespective of their position relative to longitudinal axis of log, for instance, heart board, center board or outer board and blanks including sections with defects of wood. Damp blanks are impregnated with at least 30% water solution of urea until at least 10% of urea to weight of absolutely dry wood is absorbed, and then material is subjected to seasoning in closed room under normal conditions. Two step drying is carried out to residual humidity of wood not exceeding 30% at temperature of first stage drying not exceeding 55 C, and temperature of second stage drying not exceeding 70 C. before thermal treatment, material is cooled for 3 h maximum, and subsequent thermal treatment is carried out successively in three steps at temperature of first step not exceeding 80 C with duration of up to 2 h, that of second step, not exceeding 100 C with duration up to 4 h and that of third step, not exceeding 120-130 C to final humidity of blanks not exceeding 4-6% which makes it possible to provide technological process with expedient heat balance preventing cracking and buckling and warping of wood with heterogeneous structure and natural defects of raw materials. EFFECT: no special expensive equipment is required for treatment. 3 ex