Automation of Lumber Drying System(I) -Continuously Rising Temperature Drying of Pinus densiflora-

목재건조(木材乾燥)의 자동화(自動化)에 관한 연구(硏究)(I) -연속온도상승(連續溫度上昇)스케쥴을 이용한 목재건조장치(木材乾燥裝置) 자동화(自動化)-

An electrically heated experimental lumber dry kiln was retrofitted with a computer-based control system to control kiln conditions more precisely and monitor and record several kiln variables. Flat-sawn 2.5cm-thick Pinus densiflora boards were dried in constant temperature process(65$^{\circ}C$ & 50~60 %RH) and continuously rising temperature process, respectively. The average drying rate in continuously rising temperature process was 5.7 %/hr, which was above 3 times faster than that in constant temperature process. But, the average rate of case-hardening and moisture difference between shells and cores of boards dried in continuously rising temperature process were 82 % and 5.5 %, respectively, which were much larger than those of boards dried in constant temperature process.