Lumber drying kiln

Claim 1

A kiln for seasoning lumber, comprising: (a) a housing defining a drying chamber and having opposed side walls; (b) a top wall forming a roof; (c) an end wall; (d) closure means opposite said end wall for permitting lumber to be inserted within and removed from said chamber; (e) an air treatment and circulating assembly adjacent said top wall, said air treatment and circulating assembly including a series of fan assemblies for circulating air to the lumber stacked within said chamber and means for heating air within said chamber; (f) a power-operated exhaust venting system located on the downstream side of the airflow from the lumber stack and on the upstream side of said air treatment and circulating assembly, said exhaust venting system being operable to exhaust moisture-laden wet air prior to the air passing through said air treatment and circulating system; and (g) an intake air vent located downstream of the air flow from said air treatment and circulating assembly and upstream of the stacked lumber, said air vent being operable to add additional outside air to make up that portion of air which is exhausted through said exhaust venting system, whereby the flow of air circulated through the lumber stacked within said chamber remains substantially constant, wherein said air treatment and circulating assembly and said power-operated venting system are reversible, whereby said power-operated venting system is operable to add additional outside air and said air vent is operable to exhaust the moisture-laden air prior to the air passing through said air treatment and circulating assembly.