Abstract: A method of removing liquid solvent from wood after pressure treatment with a preservative solution evaporates the excess solvent by mechanically circulating heated vapor of the same solvent used in the preservative solution past the wood in an autoclave. The autoclave is maintained at a constant pressure by transferring evaporated solvent to a condenser at a rate equal to the evaporation rate of solvent from the wood in the autoclave. The heat extracted from the condensing solvent vapor provides the heat to the circulating vapor in the autoclave for evaporating additional liquid solvent from the treated wood. Preferably, the vapor transferred from the autoclave is compressed before its delivery to the condenser so that the heat needed for evaporation in the autoclave can be obtained by simple heat transfer of the excess heat from the condenser.

Abstract: The apparatus and the method for impregnation of wood. The apparatus has a closable tank which defines our interior space and comprises a vessel with at least one door for closing the vessel to isolate the interior space from the exterior of the tank. The tank being capable of supporting a pressure difference between the interior space and the exterior of the tank. The apparatus contains a device for supplying liquid to and receiving from the interior space of the tank, a device for establishing a pressure difference between the interior space and the exterior of the tank, a structure which is disposed in the interior space for holding wood to be treated and a structure supporting the holding structure to permit rotation of the holding structure about a non-vertical axis while holding wood to be treated.

Abstract: Cover for a cylinder-shaped pressure container such as a vacuum impregnation container or an autoclave which at the mouth edge has members for holding a tight fitting closure member against the mouth edge which members contrary to previously known and complicated members can be manufactured by means of generally known working processes and machine tools. The mouth edge of the container (1) and the closure member (3) both have a radially outwards directed annular flange (2,4) which flanges have cooperating contact faces (5) and each a sloping surface, whereby the width of the two flange members (2,4) is decreasing towards the outer edge. The cover further comprises a retaining ring (6) which is placed close to the flange members (2,4) and which is ended up by two free ends (8).