LUMBER DRYING METHOD Russian patent published in 1995 - IPC

FIELD: timber industry; lumber drying. SUBSTANCE: initial moisture and heat treatment is carried out at temperature of 94-96 C with subsequent holding at this temperature for 2-3 h and using steam liberated from lumber. Then temperature in drying chamber is reduced basing on readings of wet thermometer until equilibrium psychrometric difference equal to 4-5 C is obtained and this value is maintained stable during 2-3 h after which drying space is sealed to saturate drying agent with steam liberated from lumber and then first intermediate moisture and heat treatment is carried out at temperature of 94-96 C with holding for 2-3 h and subsequent reduction of temperature basing on readings of wet thermometer until equilibrium psychrometric difference equal to 6-7 C is obtained and holding the lumber under these conditions for 2-3 h. Then drying space is sealed again and second intermediate moisture and heat treatment is carried out at temperature of 94-96 C with holding for 2-3 h and subsequent reduction of temperature basing on wet thermometer readings until equilibrium psychrometric difference equal to 8-9 C transient moisture content of lumber are obtained. Equilibrium psychrometric difference is raised to value equal to 27-28 C with subsequent holding for 2-3 h. Then final moisture and heat treatment is carried out using steam liberated from lumber with subsequent holding for 2-3 h and cooling of lumber. EFFECT: enhanced quality of lumber treatment. 1 tbl