A wood drying kiln and airflow controlling process is described in which the kiln
includes an structure with a charge receiving chamber, and a door accessible opening to allow passage of a charge of lumber for drying. Circulating fans in the structure produce airflow that is directed by baffles in a prescribed path through the charge. At least one row of elongated resilient brush bristles within the structure are positioned therein to yieldably engage the charge of lumber placed within the charge receiving chamber. The brush bristles are provided with sufficient density to limit passage of air laterally through the row.
Wood drying kilns are used at saw mills and treatment plants to lower the moisture content of lumber to a selected desired level. The lumber fed into drying kilns is typically "green" lumber, cut from previously living trees and that typically has high moisture content. The lumber is dried usually by application of heat and airflow directed through and around layers of lumber arranged in stacks forming a charge within the kiln chamber.
A "charge" of lumber is comprised of at least one stack of boards with layers separated by thin transverse slats termed "stickers." The stickers are used at spaced locations along the layers to form air passages in the stack. It is an objective in wood drying kilns to move drying air through the charge in an even manner so the individual boards will dry uniformly. Thus it is desirable to have substantially equal airflow through each of the spaces formed by the stickers. This is not possible at the top of the typical charge, since the top layer of lumber is exposed. As a result, various baffle arrangements have been devised to engage the top of the charge and prevent or control airflow across the top board layer.
A process for controlling airflow in a wood drying kiln having a charge receiving chamber for receiving a charge of lumber and circulating fans operably mounted to the structure and configured to produce airflow within the charge receiving chamber.