Process and apparatus for seasoning wood
AssigneeDrywood Corporation
InventorEdward Koppelman
Life of this patent
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Abstract
A process and apparatus for accelerated drying of green lumber employs high voltage dielectric heating at subatmospheric pressure to effect a rapid removal of moisture from the wood without splitting, checking, case hardening, honeycombing or similar damage to the wood structure. The invention combines the advantages of both dielectric and vacuum drying techniques without inefficient and destructive corona, arcing, or ionization effects which have heretofore prevented combining such techniques. When desired, the use of subatmospheric pressures in the drying process also permits injection of suitable chemicals for fireproofing or other specialized treatments of the wood allowing the combination of such treatments with the drying of the wood in a single process.
Claims32
A process for drying unseasoned wood comprising the steps of placing the wood to be dried in an enclosed space, evacuating the gaseous substances from said enclosed space to impose a subatmospheric pressure on said wood, applying a non-discharging alternating electric potential across the wood between electrodes disposed within the enclosed space and maintained in fixed relationship to the wood while the electric potential is applied to effect a dielectric heating of the wood and the moisture entrapped within the interior thereof until the water content of the wood attains the desired level, and thereafter removing the dried wood from the enclosed space.
A process for drying commercial lumber to a moisture content of 12% or less by weight comprising the steps of placing green lumber having a moisture content above 20% by weight in an enclosed space, imposing a subatmospheric pressure on the green lumber for a period between 2 and 24 hours, applying a non-discharing alternating electric potential across the green lumber between electrodes disposed within the enclosed space and maintained in fixed relationship to the green lumber during application of the potential while the green lumber is under subatmospheric pressure and during the period it is at a moisture content between 12% and 20%, and removing the lumber from the enclosed space.
A process for drying commercial lumber to a moisture content of 8% or less by weight comprising the steps of placing green lumber having a moisture content above 20% by weight in an enclosed space, imposing a subatmospheric pressure on the green lumber for a period between 2 and 24 hours, applying a non-discharging alternating electric potential across the green lumber by charging electrodes disposed within the enclosed space and maintained in fixed relationship to the green lumber during application of the potential while the green lumber is between 8% and 20% in moisture content and under subatmospheric pressure, and removing the lumber from the enclosed space.
An apparatus for drying unseasoned wood comprising means defining a chamber, means for supporting wood to be dried within said chamber, means in communication with the interior of said chamber for evacuating the gaseous substances therefrom, means disposed within the chamber and adapted to be maintained in fixed relationship to the wood during the drying thereof for applying an alternating electric potential across the wood within the chamber to effect a heating of the interior thereof to the volatilization temperature of the water in the wood at the prevailing subatmospheric pressure present in the chamber, and means for preventing arcing and sudden discharge of the electric potential.
Dependencies are inferred from the claim text.