Patent ID: 8465845

Claim:
A method for preserving wood, comprising: A) placing wood for treating in a treatment space; B) removing air, in particular, oxygen, from the treatment space; C) feeding steam into the treatment space, wherein the temperature of the wood is simultaneously increased, wherein the temperature is raised from 70 degrees Celsius with a temperature gradient of a maximum of 60 degrees Celsius per hour, to a temperature of at least 150 degrees Celsius; wherein the wood is heated at a temperature above 150 degrees Celsius during a reaction time of at least 10 minutes; D) polymerizing wood constituents thermally activated in step C by removing moisture from the wood up to a moisture content lower than 5% at a temperature of at least 130 degrees Celsius; and, E) cooling the wood, wherein the moisture content of the wood is simultaneously increased to at least 7% by weight, in the temperature path below 140 degrees.