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Continuous tunnel kiln direct-fired with bark to dry 1.75-inch southern pine in 12 hoursAuthor(s): Peter Koch; Walker L. Wellford
Source: Forest Products Journal, Vol. 27(5): 39-47
Publication Series: Miscellaneous Publication
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DescriptionLength-sorted lumber is surfaced on one side to 1.75-inch thickness, mechanically stacked 5 feet wide and 10 feet high on 1-1/4-inch-thick sticks, and continuously transported through a zone-controlled tunnel kiln at 8 ft./hr. to yield 500,000 fbm of lumber dried to 9 percent average MC per 168-hour week. In the tunnel, the lumber is dried for 8 (possibly 10) hours of 270°F, conditioned for 3 hours at 195°F, and cooled for 1 hour before discharge to cooling sheds and subsequent unstacking. During drying and conditioning, wet-bulb temperature is held constant at 185°F. air velocities vary by zone; i.e., 1,600 fpm at inlet, 300 fpm while conditioning, and 1,000 fpm while cooling. To control warp, a top load (12 in. of concrete) is automatically placed on the moving lumber stacks as they enter the tunnel kiln and removed as they exit.
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CitationKoch, Peter; Wellford, Walker L., Jr. 1976. Continuous tunnel kiln direct-fired with bark to dry 1.75-inch southern pine in 12 hours. Forest Products Journal, Vol. 27(5): 39-47
- Continuous tunnel kiln direct-fired with bark to dry 1.75-inch southern pine in 12 hours.
- High-temperature kilning of southern pine poles, timbers, lumber, and thick veneer
- Time to dry 2-, 3-, and 4-inch S4S southern pine at 240°F as related to board width
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