| 摘要 |
The air is fed through the timber stack in two phases, viz.: A) a heating phase, in which heating air with a temp. between 50 and 100 deg.C and a relative humidity of 50 - 100% is fed through the stack, causing the timber to absorb moisture, and this during a period of 2 - 60 min., B) A drying phase in which low temperature air with a relative humidity is fed through the stack, causing the timber to emit more moisture than it absorbed during the heating phase. In this phase, the drying air has a temp. of less than 50 deg. C., and a relative humidity of 0 - 100%, being passed through the stack during a period of 10 -100 min.. - The heating air is heated by the supply of steam at a temp. of 100 - 200 deg.C. At least five drying cycles per set of timber are carried out. The timber in each drying cycle is made to absorb at least 0.2 kg of water per cbm of timber on heating, and to emit at least 0.3 kg of water per cbm. during the subsequent drying. The air in both phases is fed at a speed of 2 - 10 m/s. |
