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Drying southern pine at 240°F. -- effects of air velocity and humidity, board thickness and density

Informally Refereed

Abstract

Kiln time to each 10 percent moisture content was shortened by circulating air at high velocity, but was little affected by board specific gravity. A wet-bulb depression of 80oF. provided faster drying than depressions of 40 or 115oF. At 80 depression and with air circulated at 930 f.p.m., kiln time was directly proportional to board thickness. Under these optimum conditions, 1 by 4's required 10.4 hours to reach 10 percent moisture content; boards 1.5 and 1.9 inches thick required 15.8 and 20.7 hours respectively. Total energy expanded in drying to 10 percent moisture content was affected by board thickness and specific gravity; air circulation velocity did no significantly affect total energy. Boards kilned for 24 hours at 240oF. and then overdried showed significant variation in shrinkage according to the drying schedule used. No significant modulus of rupture in bending, or toughness were detected in clear-wood specimens cut from lumber dried by the six schedules.

Citation

Koch, Peter. 1972. Drying southern pine at 240°F. -- effects of air velocity and humidity, board thickness and density. Forest Products Journal, Vol 22(9): 62-67
https://www.fs.usda.gov/research/treesearch/24158