Patent ID: 7807224

Claim:
A method of treatment of wood susceptible to damage using a carrier fluid under pressure, wherein the wood has a length above a critical length, and the carrier fluid is under a pressure of at least 20 bar and at a temperature below 65° C. and has a critical point at a temperature of 20-50° C. and a pressure of 5-100 bar, comprising: a) charging a vessel with wood to be treated; b) pressurizing the vessel using the carrier fluid until the treatment pressure is reached; c) providing a holding period in which the pressure is essentially constant or the pressure changes at a low rate; and d) depressurizing the vessel to ambient temperature, followed by removing the treated wood, characterized in that the fluid is not allowed to exist in its liquid form inside the wood and that during at least one of the pressurizing step and the depressurizing step, the fluid inside the wood is kept out of its liquid form by supplying heat to the vessel, and wherein, in at least one initial sample of the wood, the temperature inside the wood is monitored by inserting a temperature sensor in at least one specimen of the wood, and the temperature of the carrier fluid inside the vessel is adjusted, when needed, in response to the monitoring to ensure that the fluid inside the wood is not in its liquid form.