The basic concept of wood drying(3)
What are the basic concepts of wood drying, do you know?
4. Free water and sorbed water (adsorbed water)
Free water refers to the water that exists between the wood cell walls and not within the cells. Free water evaporates more easily, and the removal of free water only affects the density of the wood.
Sorptive water refers to water that is adsorbed on the cell walls of wood. Absorbed water does not easily evaporate from the wood. The exclusion of sorbed water affects not only the density of the wood, but also the dimensions of the wood.
5.fiber saturation point
Under atmospheric conditions, the moisture content of wood when the free water has evaporated and the absorbed water remains the highest is called the fiber saturation point (hygroscopic limit) of the wood. The temperature is 20°C and the relative humidity is 100%. The fiber saturation point of general wood is between 23% and 33%, with an average of about 30%. When the moisture content of the wood drops to the fiber saturation point, it is the moment when the wood undergoes a stress transition, and it is also the key to whether the wood produces drying damage. Therefore, drying before the fiber saturation point should be done carefully.
