High-temperature kilning of southern pine poles, timbers, lumber, and thick veneer

Abstract

At dry-bulb temperatures above the boiling point of water, with large wet-bulb depressions and high air velocities, southern pine prodcuts can be dried quickly. In an impingement-jet kiln at 300^o F., veneer 3/8-inch to 5/8-inch thick can be brought to 10 percent moisture content in 40 to 75 minutes. Drying times for lumber arte linearly related to thickness, e.g., at dry- and wet-bulb temperatures of 240^o and 160^o F., time required is 10.4, 15.8 and 20.7 hours for thickness of 1.0, 1.5, and 1.9 inches. Under similiar conditions, planks or timbers 2, 3, and 4 inches thick can be dried to 10 percent moisture content in 22.4, 35.6, and 45.3 hours; surface checks in timbers so dried are absent or minor, but in 3- and 4-inch pieces end-checking may be moderate to severe. at 225^o F., with 50^o wet-bulb depression, poles 8 to 10 inches in diameter can be reduced to 30 percent moisture in about 44 hours.

Citation

Koch, Peter. 1973. High-temperature kilning of southern pine poles, timbers, lumber, and thick veneer. In: Proceedings, American Wood-Preserver''s Association, Vol. 69: 123-140