Process and apparatus for drying and treating lumber

Claim 1

APPARATUS FOR DRYING LUMBER COMPRISING A SEALED CHAMBER, WATER-VAPOR ABSORBER IN SAID CHAMBER, A SUPPORT MOUNTED IN SAID CHAMBER FOR SUPPORTING AND BEARING THE WEIGHT OF A STACK OF LUMBER TO BE DRIED, MEANS CONNECTED TO SAID CHAMBER FOR REDUCING THE GAS PRESSURE THEREIN TO A PREDETERMINED VALUE, MEANS FOR COOLING SAID ABSORBER AND FOR MAINTAINING THE SAME AT A TEMPERATURE BELOW THE TEMPERATURE OF LUMBER PLACED IN SAID CHAMBER, MEANS FOR REMOVING WATER FROM SAID ABSORBER SO AS TO MAINTAIN THE CONCENTRATION THEREOF RELATIVELY CONSTANT, SAID PRESSURE-REDUCING MEANS HAVING A CAPACITY AND SAID ABSORBER BEING MAINTAINED AT A TEMPERATURE THAT MOISTURE IN GREEN LUMBER IS VAPORIZED AT A RATE SUFFICIENT TO LOWER THE TEMPERATURE AT THE SURFACE OF THE LUMBER TO A POINT AT WHICH ICE CRYSTALS ARE FORMED, MEANS FOR HEATING THE LUMBER SURFACE AND SUBLIMING THE ICE CRYSTALS, SAID HEATING MEANS BEING RELATED TO SAID PRESSURE-REDUCING MEANS AND THE TEMPERATURE OF SAID ABSORBER THAT SAID LUMBER IS NEVER COOLED THROUGHOUT THE MASS THEREOF TO THE TEMPERATURE OF SAID ABSORBER AND THAT ONLY THE LUMBER SURFACE IS COOLED ENOUGH TO FORM ICE CRYSTALS.